xemacs-beta: man/lispref/glyphs.texi comparison

comparison man/lispref/glyphs.texi @ 2182:c91543697b09

[xemacs-hg @ 2004-07-19 08:24:24 by stephent] manual improvements <87n01w9zi9.fsf@tleepslib.sk.tsukuba.ac.jp>

author	stephent
date	Mon, 19 Jul 2004 08:24:28 +0000
parents	4657b5a54253
children	13a418960a88

comparison

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 @setfilename ../../info/glyphs.info
 @node Glyphs, Annotations, Faces and Window-System Objects, top
 @chapter Glyphs
 @cindex glyphs
-A @dfn{glyph} is an object that is used for pixmaps, widgets and
+A @dfn{glyph} is an object that is used for pixmaps, widgets, and
 images of all sorts, as well as for things that ``act'' like pixmaps,
 such as non-textual strings (@dfn{annotations}) displayed in a buffer or
 in the margins.  It is used in begin-glyphs and end-glyphs attached to
 extents, marginal and textual annotations, overlay arrows
 (@code{overlay-arrow-*} variables), toolbar buttons, mouse pointers,
 frame icons, truncation and continuation markers, and the
-like. (Basically, any place there is an image or something that acts
+like.  Basically, any place there is an image or something that acts
-like an image, there will be a glyph object representing it.)
+like an image, there will be a glyph object representing it.
-The actual image that is displayed (as opposed to its position or
-clipping) is defined by an @dfn{image specifier} object contained
-within the glyph.  The separation between an image specifier object
-and a glyph object is made because the glyph includes other properties
-than just the actual image: e.g. the face it is displayed in (for text
-images), the alignment of the image (when it is in a buffer), etc.
 @defun glyphp object
 This function returns @code{t} if @var{object} is a glyph.
 @end defun
 @menu
-* Glyph Functions::	Functions for working with glyphs.
+* Glyph Intro::		Glyphs are abstract image specifications.
-* Images::		Graphical images displayed in a frame.
+* Images::		Specifying the appearance of glyphs.
-* Glyph Types::         Each glyph has a particular type.
+* Using Glyphs::	Creating and displaying glyphs.
-* Mouse Pointer::	Controlling the mouse pointer.
+* Manipulating Glyphs::	Getting and setting glyph properties.
-* Redisplay Glyphs::    Glyphs controlling various redisplay functions.
+* Glyph Examples::	Examples of how to work with glyphs.
-* Native GUI Widgets::  Complex active images treated as a single glyph.
-* Subwindows::          Inserting an externally-controlled subwindow
-into a buffer.
-* Glyph Examples::      Examples of how to work with glyphs.
 @end menu
-@node Glyph Functions
-@section Glyph Functions
+@node Glyph Intro
+@section Glyph Introduction
+In XEmacs, ``glyph'' does @strong{not} refer to a single unit of textual
+display (the XEmacs term for that is @dfn{rune}, and runes are confined
+to the internal implementation of redisplay), but rather is an
+object encapsulating a graphical element, such as an image or widget (an
+active GUI element such as a button or text entry field; X11 calls this a
+@dfn{widget}, while MS Windows uses the term @dfn{control}).
+This graphical element could appear in a buffer, a margin, a gutter, or
+a toolbar, or even externally to XEmacs as a mouse pointer or an icon,
+for example.
+On the other hand, by contrast with GNU Emacs 21, an XEmacs glyph is
+not ``just'' an image.  The actual image that is displayed (as opposed
+to its position or clipping) is defined by an ``image specifier'' object
+contained within the glyph.  The separation between an image specifier
+object and a glyph object is made because the glyph includes other
+properties than just the actual image: e.g. the face it is displayed in,
+the alignment of the image, @emph{etc}.  Also, an image specifier is
+used in at least one place in XEmacs in lieu of a glyphs, namely the
+backing pixmap of a face.
+An image specifier is used because glyphs often have locale-specific
+semantics.  The most important example is semantics determined by the
+display device: you can't usefully display a JPEG on stdout, or a color
+image on a monochrome display.  But because the image property is a
+specifier in XEmacs, you can specify that a given glyph appear as a
+monochrome image on monochrome displays, a color image on color
+displays, and as a string on TTYs.  (Specifying a string for the
+@code{tty} device locale would give behavior like the @code{ALT}
+attribute of an @code{IMG} element in HTML.)  Another is semantics
+determined by the buffer or mode.  (Unfortunately, currently there are
+no compelling examples of this for glyphs.)
+All this means that only one global glyph needs to exist for a
+particular purpose (e.g. the icon used to represent an iconified frame,
+the mouse pointer used over particular areas of a frame, etc.).  Often
+you need not (and should not!) create your own glyph, but rather modify
+an existing one.
+In working with glyphs it is important to keep in mind the distinction
+between a locale and a domain.  A @dfn{locale} is specified by the
+programmer, and is an abstract link between a specification (for a
+glyph, its visual appearance) and a displayable object.  The displayable
+object may be a buffer or a window, or an object containing buffers or
+windows such as frame, device, or console.  A @dfn{domain} is an actual
+display context, which must be concrete enough to enable XEmacs to
+identify the device type.  (Buffers may be displayed in windows on
+different devices, even simultaneously, so a buffer cannot be a domain.
+Similarly, the global locale cannot be a domain.)  @ref{Specifiers}, for
+more information about specifier locales and domains.
+@node Images
+@section Images
+@menu
+* Image Specifiers::			Specifying an image's appearance.
+* Image Instantiator Conversion::	Lazy realization of graphics.
+* Image Instantiator Formats::		A catalog of image descriptors.
+* Image Instances::			Classes of graphical objects.
+@end menu
+@node Image Specifiers
+@subsection Image Specifiers
+@cindex image specifiers
+An image specifier is a description of the actual graphical
+realization of a glyph.  For example, a typical image description is
+@emph{the file system path to a PNG file}.  Since redisplay doesn't know
+about files, and in any case the image may need to be manipulated
+(@emph{e.g.}, a face's background pixmap must be clipped and tiled), the
+PNG file must be converted internally to a window system bitmap or
+pixmap object.  We describe this process by writing that when XEmacs
+displays the image, it @dfn{instantiates} the @dfn{image instantiator}
+into an @dfn{image instance}.  Image instances are an internal object
+type (similar to font instances and color instances), describing how the
+image appears in a particular domain.  On the other hand, image
+instantiators, which are just descriptions of how the image should
+appear, are represented using Lisp strings or vectors.
+Furthermore the graphical realization will vary, and for some devices
+may not even be a bitmapped graphic.  These variations may be controlled
+by the program by specifying different @dfn{image instantiators} in
+different locales.  This is implemented with an @dfn{image specifier},
+a specifier whose specifications are image instantiators.
+Image specifiers are rarely if ever found by themselves.  However, an
+image specifier results from calling @code{glyph-image} on a glyph, or
+retrieving the @code{background-pixmap} property of a face, and you can
+check if some random object is an image specifier.
+@defun image-specifier-p object
+This function returns non-@code{nil} if @var{object} is an image specifier.
+@end defun
+@defun make-image-specifier spec-list
+This function creates a new image specifier object and initializes it
+according to @var{spec-list}.  @xref{Specifiers}.
+@end defun
+This function exists mainly for completeness.  In practice, you rarely,
+if ever, need to actually create an image specifier.  Instead, they are
+implicitly created by the initialization of glyphs and faces, and the
+specifier member of these objects cannot be changed after
+initialization; you may only set the specifications it contains.
+Image instantiators come in many formats: @code{xbm}, @code{xpm},
+@code{gif}, @code{jpeg}, etc.  These denote the format of the data
+describing the image.  The resulting image instances also come in many
+types---@code{mono-pixmap}, @code{color-pixmap}, @code{text},
+@code{pointer}, etc.  This refers to the behavior of the image and the
+sorts of places it can appear. (For example, a color-pixmap image has
+fixed colors specified for it, while a mono-pixmap image comes in two
+unspecified shades ``foreground'' and ``background'' that are determined
+from the face of the glyph or surrounding text; a text image appears as
+a string of text and has an unspecified foreground, background, and
+font; a pointer image behaves like a mono-pixmap image but can only be
+used as a mouse pointer [mono-pixmap images cannot be used as mouse
+pointers]; etc.)
+It is important to keep the distinction between image instantiator
+format and image instance type in mind.  Typically, a given image
+instantiator format can result in many different image instance types.
+For example, @code{xpm} can be instanced as @code{color-pixmap},
+@code{mono-pixmap}, or @code{pointer}; whereas @code{cursor-font} can be
+instanced only as @code{pointer}.  On the other hand, a particular image
+instance type can be generated by many different image instantiator
+formats (e.g.  @code{color-pixmap} can be generated by @code{xpm},
+@code{gif}, @code{jpeg}, etc.).
+@xref{Image Instances}, for a more detailed discussion of image
+instance types.
+An image instantiator should be a string or a vector of the form
+@example
+@code{[@var{format} @var{:keyword} @var{value} ...]}
+@end example
+i.e. a format symbol followed by zero or more alternating keyword-value
+pairs.
+The form of an instantiator can be checked with
+@code{valid-instantiator-p} with a @var{TYPE} of @code{image},
+@ref{Specifier Validation Functions}.
+For a complete list of the format symbols and their usage,
+@ref{Image Instantiator Formats}.
+If the instantiator is a string, it will be converted into a vector by
+looking it up according to the specs in the
+@code{console-type-image-conversion-list} for the console type of the
+domain (usually a window; sometimes a frame or device) over which the
+image is being instantiated.
+If the instantiator specifies data from a file, the data will be read in
+at the time that the instantiator is added to the image specifier (which
+may be well before the image is actually displayed), and the
+instantiator will be converted into one of the inline-data forms, with
+the filename retained using a @code{:file} keyword.  This implies that
+the file must exist when the instantiator is added to the image, but
+does not need to exist at any other time (e.g. it may safely be a
+temporary file).
+The available keywords are given below.  Note that some keywords are
+generally available (for example, the @code{:data} keyword may be used
+with any format except @code{nothing}), while others are only available
+for one format (@code{resource-id} is unique to the
+@code{mswindows-resource} format).
+@table @code
+@item :data
+Inline image data.  If available for a given format, it may be specified
+directly by the program, or it may be a cache of file data previously
+read.  When present, it is used to instantiate the image in preference
+to the file named by the @code{:file} property.
+The format of inline data is image-format-specific.  For example, in
+pixmap formats, the value should be a string, which is interpreted as an
+octet-stream representing a bitmap or pixmap.  But for text formats,
+it's string containing the text to be displayed, and for resource
+formats, it's a string containing the name of the resource.
+@item :file
+Data contained in a file.  The value is the name of this file.  If both
+@code{:data} and @code{:file} are specified, the image is created from
+what is specified in @code{:data} and the string in @code{:file} becomes
+the value of the @code{image-instance-file-name} function when applied
+to the resulting image-instance.  Note that there is nothing to stop a
+program from changing either the @code{:file} or the @code{:data}
+property, and there is no way to detect such mischief.  This means that
+the data will @emph{not} be automatically reread if you change the
+@code{file} property; you must force it by removing the @code{:data}
+property.
+@c #### If there are ways to do this in-place, describe them.
+(One way to do this is replacing the whole specification with a new
+vector.)  This keyword is not valid for instantiator formats
+@code{nothing}, @code{string}, @code{formatted-string},
+@code{cursor-font}, @code{font}, and @code{autodetect}.
+@item :mask-data
+Inline data for @code{xbm} and @code{xface}.  This specifies a mask to
+be used with the bitmap.  Pixels which are not set in the mask will not
+be written to the imaging device.  The format is a list of width,
+height, and bits, as for @code{:data}.
+@item :mask-file
+For @code{xbm} and @code{xface}.  This specifies a file containing the
+mask data.  If neither a mask file nor inline mask data is given for an
+XBM image, and the XBM image comes from a file, XEmacs will look for a
+mask file with the same name as the image file but with @samp{Mask} or
+@samp{msk} appended.  For example, if you specify the XBM file
+@file{left_ptr} [usually located in @file{/usr/include/X11/bitmaps}],
+the associated mask file @file{left_ptrmsk} will automatically be picked
+up.
+@item :resource-id
+Only for @code{mswindows-resource}.  This must be either an integer
+(which directly specifies a resource number) or a string.  See the
+description of @code{mswindows-resource} for valid strings.  @xref{Image
+Instantiator Formats}.
+@item :foreground
+@itemx :background
+For @code{xbm}, @code{xface}, @code{cursor-font}, and @code{font}.
+These keywords allow you to explicitly specify foreground and background
+colors.  The value should be anything acceptable to
+@code{make-color-instance}.  This will cause an external format that
+would by default be instantiated as a @code{mono-pixmap} to instead be
+instantiated as a two-color color-pixmap.  This can be used to override
+the colors specified by a glyph's face, for example.  If the image is
+instantiated as a pointer, they specify its foreground and/or
+background, instead of the defaults of black and white.
+@item :hotspot-x
+@itemx :hotspot-y
+For @code{xbm} and @code{xface}.  These keywords specify a hotspot if
+the image is instantiated as a @code{pointer}.  Note that if the XBM
+image file specifies a hotspot, it will automatically be picked up if no
+explicit hotspot is given.
+@item :color-symbols
+Only for @code{xpm}.  This specifies an alist that maps strings that
+specify symbolic color names to the actual color to be used for that
+symbolic color (in the form of a string or a color-specifier object).
+If this is not specified, the contents of @code{xpm-color-symbols} are
+used to generate the alist.
+@item :resource-type
+Only for @code{mswindows-resource}.  This must be a symbol, either
+@code{cursor}, @code{icon}, or @code{bitmap}, specifying the type of
+resource to be retrieved.
+@item :face
+For @code{inherit} and the widget formats.  This specifies the face to
+inherit from.  For widgets this specifies the face to use for display.
+It defaults to gui-element-face.
+@item :selected
+@itemx :active
+@itemx :suffix
+@itemx :keys
+@itemx :style
+@itemx :filter
+@itemx :config
+@itemx :included
+@itemx :key-sequence
+@itemx :accelerator
+@itemx :label
+@itemx :callback
+These keywords, accepted as menu item specs, are also accepted by images
+instantiated as @code{widget}.  For their semantics, @ref{Menu Format}.
+@end table
+@node Image Instantiator Conversion
+@subsection Image Instantiator Conversion
+@cindex image instantiator conversion
+@cindex conversion of image instantiators
+Conversion is applied to image instantiators at the time they are added
+to an image specifier or at the time they are passed to
+@code{make-image-instance}.
+@defun set-console-type-image-conversion-list console-type list
+This function sets the image-conversion-list for consoles of the given
+@var{console-type}.  The image-conversion-list specifies how image
+instantiators that are strings should be interpreted.  Each element of
+the list should be a list of two elements (a regular expression string
+and a vector) or a list of three elements (the preceding two plus an
+integer index into the vector).  The string is converted to the vector
+associated with the first matching regular expression.  If a vector
+index is specified, the string itself is substituted into that position
+in the vector.
+Note: The conversion above is applied when the image instantiator is
+added to an image specifier, not when the specifier is actually
+instantiated.  Therefore, changing the image-conversion-list only affects
+newly-added instantiators.  Existing instantiators in glyphs and image
+specifiers will not be affected.
+@end defun
+@defun console-type-image-conversion-list console-type
+This function returns the image-conversion-list for consoles of the given
+@var{console-type}.
+@end defun
+@node Image Instantiator Formats
+@subsection Image Instantiator Formats
+@cindex image instantiator formats
+The @dfn{format} field of an image instantiator should be a symbol
+denoting a valid format.  Which formats are valid will depend on the
+features (such as image decoding libraries) available, on platform
+support (MS Windows resource IDs make no sense on other platforms), and
+on the locale.
+@defun valid-image-instantiator-format-p format &optional locale
+This function returns non-@code{nil} if @var{format} is a valid image
+instantiator format.
+If @var{locale} is non-@code{nil} then the format is checked in that locale.
+If @var{locale} is @code{nil} the current console is used.
+Note that the return value for many formats listed above depends on
+whether XEmacs was compiled with support for that format.
+@end defun
+@defun image-instantiator-format-list
+This function returns a list of valid image-instantiator formats.
+@end defun
+Here is a table of image-instantiator formats, giving the keywords that
+are usable with each, and the kinds of instances that may result.
+@table @code
+@item nothing
+Don't display anything; no keywords are valid for this format.  Can only be
+instanced as @code{nothing}.
+@item string
+Display this image as a text string.  Can only be instanced
+as @code{text}, although support for instancing as @code{mono-pixmap}
+should be added.  The valid keyword is @code{:data}.  The value should
+be a string, and it is interpreted as a string of characters.
+@item formatted-string
+Display this image as a text string with replaceable fields,
+similar to a modeline format string.  The valid keyword is @code{:data}.
+The value should be a string, and it is interpreted as a string of
+characters containing format sequences.
+Not currently implemented.
+@item xbm
+An X bitmap; available only if X support was compiled into this XEmacs.
+If used in a buffer glyph, icon glyph, or face background pixmap, it
+will be instantiated as @code{mono-pixmap} unless the @code{:foreground}
+or @code{:background} keywords are present.  In the latter case it will
+be instantiated as @code{color-pixmap} with the two specified colors.
+@c #### Check this.
+(Probably if @code{:foreground} or @code{:background} is omitted, it
+defaults to black or white respectively.)  If used in a pointer glyph,
+it will be instantiated as an @code{pointer}.
+The valid keywords and their values are
+@table @code
+@item :data
+A list containing the height and width of the bitmap as integers, and
+a string interpreted as a bit vector according to the X11 standard XBM
+bitmap format, in that order.
+@item :file
+The name of a file containing standard XBM-format data.  If it contains
+a hotspot specification, it will be parsed and used if the hotspot is
+not explicitly specified.
+@item :mask-data
+A list containing the height and width of the bitmap as integers, and
+a string interpreted as a bit vector according to the X11 standard XBM
+bitmap format, in that order.  This bitmap is interpreted as the
+clipping region for the bitmap contained in the @code{:data} property.
+@item :mask-file
+The name of a file containing standard XBM-format data.  Interpreted as
+the clipping region for the bitmap contained in the @code{:data} property.
+@item :foreground
+@itemx :background
+These keywords allow you to explicitly specify foreground and background
+colors.  The values should be acceptable to @code{make-color-instance}.
+@item :hotspot-x
+@itemx :hotspot-y
+Integers denoting the hotspot (mouse pointer position), with (0,0) at
+the top left corner.  If given, these override any specification in the
+XBM file.
+@end table
+@item xpm
+An XPM pixmap; only available if XPM support was compiled into this XEmacs.
+Can be instanced as @code{color-pixmap}, @code{mono-pixmap}, or
+@code{pointer}.
+XPM is an add-on library for X that was designed to rectify the
+shortcomings of the XBM format.  Many icons and labels used in the
+XEmacs GUI are still distributed in XPM format (although we are moving
+to standardize on the PNG format).  It is therefore highly desirable
+that XPM be available in your XEmacs.
+Most implementations of X include the XPM library as a standard part.
+If your vendor does not, it is highly recommended that you download it
+and install it.  You can get it from the XEmacs FTP site and mirrors, as
+well as from most sites that distribute X11.
+The valid keywords and their values are
+@table @code
+@item :data
+A string interpreted as the contents of a standard XPM file.
+@item :file
+The name of a file containing standard XPM-format data.  If it contains
+a hotspot specification, it will be parsed and used if the hotspot is
+not explicitly specified.
+@c #### Does XPM provide for a hotspot?
+@item :hotspot-x
+@itemx :hotspot-y
+Integers denoting the hotspot (mouse pointer position), with (0,0) at
+the top left corner.  If given, these override any specification in the
+XBM file.
+@c #### Check this.
+(This may not be true.  The original documentation doesn't mention them
+in connection with XPM, but a pointer needs a hotspot.)
+@item :color-symbols
+An alist that maps the one- or two-character strings that specify
+symbolic color names in the XPM file to the actual color to be used for
+that symbolic color (in the form of a string acceptable as a color
+instantiator, @ref{Color Specifiers}, or a color-specifier object).
+If this is not specified, the contents of @code{xpm-color-symbols} are
+used to generate the alist.
+@end table
+@item xface
+An X-Face bitmap, used to encode people's faces in e-mail messages;
+only available if X-Face support was compiled into this XEmacs.
+Will be instanced as @code{mono-pixmap}, @code{color-pixmap}, or
+@code{pointer}, depending on the target instance type and the presence
+of color keywords.
+The valid keywords and their values are
+@table @code
+@item :data
+A list containing the height and width of the bitmap as integers, and
+a string interpreted as a bit vector according to the X11 standard XBM
+bitmap format, in that order.
+@item :file
+The name of a file containing standard XBM-format data.  If it contains
+a hotspot specification, it will be parsed and used if the hotspot is
+not explicitly specified.
+@item :mask-data
+A list containing the height and width of the bitmap as integers, and
+a string interpreted as a bit vector according to the X11 standard XBM
+bitmap format, in that order.  This bitmap is interpreted as the
+clipping region for the bitmap contained in the @code{:data} property.
+@item :mask-file
+The name of a file containing standard XBM-format data.  Interpreted as
+the clipping region for the bitmap contained in the @code{:data} property.
+@item :foreground
+@itemx :background
+These keywords allow you to explicitly specify foreground and background
+colors.  The values should be acceptable to @code{make-color-instance}.
+@item :hotspot-x
+@itemx :hotspot-y
+Integers denoting the hotspot (mouse pointer position), with (0,0) at
+the top left corner.  If given, these override any specification in the
+XBM file.
+@end table
+@item gif
+@itemx jpeg
+@itemx png
+@itemx tiff
+These are GIF87- or GIF89-format, JPEG-format, PNG/GIF24-format, and
+TIFF-format images, respectively.  They are available only if
+appropriate decoding support was built into XEmacs.  XEmacs includes GIF
+decoding functions as a standard part of it, so if you have X support,
+you will normally have GIF support, unless you explicitly disable it at
+configure time.  If you have development support (both the libraries and
+the relevant C header files) available when XEmacs is built, the JPEG,
+PNG, and TIFF libraries will automatically be detected (in the ``usual
+places'') and linked into the build.
+Note that PNG is the standard format for images distributed with XEmacs,
+so it is highly recommended that PNG support be built in.
+All of these instantiators will be instanced as @code{color-pixmap}.
+The valid keywords and their values are
+@table @code
+@item :data
+A string interpreted as the contents of a file containing data in the
+appropriate standard format.
+@item :file
+The name of a file containing standard-format data.
+@end table
+@item cursor-font
+Most window systems provide a set of standard cursors, which in X11 is
+called a cursor font.  Can only be instanced as @code{pointer}.  This
+should probably be fixed.
+The valid keyword is @code{:data}.  Its value should be a string
+containing one of the standard cursor-font names, such as @samp{watch}
+or @samp{right_ptr} under X.  More specifically, in the X Window System
+it may be any of the standard cursor names from appendix B of the Xlib
+manual, provided in the file @file{<X11/cursorfont.h>} by most
+distributions, minus the @samp{XC_} prefix.  For MS Windows, use
+@code{mswindows-resource} instantiator format, not @code{cursor-font}.
+Other window systems may have different lists.
+@item font
+A glyph from a font; i.e. the name of a font, and glyph index into it
+of the form @samp{@var{font} fontname index [[mask-font] mask-index]}.
+Only if X support was compiled into this XEmacs.  Currently can only be
+instanced as @code{pointer}.  This should probably be fixed.
+@c #### The above description is not very helpful, so it's not obvious
+@c how to instantiate a font image.
+@item mswindows-resource
+An MS Windows pointer resource.  Specifies a resource to retrieve
+directly from the system (an OEM resource) or from a file, particularly
+an executable file.  Can be instanced as @code{pointer} or
+@code{color-pixmap}.
+The valid keywords and their values are
+@table @code
+@item :resource-type
+A string naming the type (@code{cursor}, @code{bitmap}, or @code{icon})
+of the resource.  Required.
+@item :file
+A string containing the name of the file containing the resource (often
+an executable).  If a system resource, @code{:file} should be omitted.
+@item :resource-id
+A string containing the name of a resource.   Required if @code{:file}
+is not specified.
+This must be either an integer (which directly specifies a resource
+number) or a string.  Valid strings are
+For bitmaps:
+"close", "uparrow", "dnarrow", "rgarrow", "lfarrow",
+"reduce", "zoom", "restore", "reduced", "zoomd",
+"restored", "uparrowd", "dnarrowd", "rgarrowd", "lfarrowd",
+"mnarrow", "combo", "uparrowi", "dnarrowi", "rgarrowi",
+"lfarrowi", "size", "btsize", "check", "checkboxes", and
+"btncorners".
+For cursors:
+"normal", "ibeam", "wait", "cross", "up", "sizenwse",
+"sizenesw", "sizewe", "sizens", "sizeall", and "no".
+For icons:
+"sample", "hand", "ques", "bang", "note", and "winlogo".
+@end table
+@item subwindow
+An embedded windowing system window.  Can only be instanced as
+@code{subwindow}.  Not implemented.
+@c #### Check status of subwindows ... I thought Andy implemented them.
+@item button
+A button widget; either a push button, radio button or toggle button.
+Can only be instanced as @code{widget}.
+@item combo-box
+A drop list of selectable items in a widget, for editing text.
+Can only be instanced as @code{widget}.
+@item edit-field
+A text editing widget.  Can only be instanced as @code{widget}.
+@item label
+A static, text-only, widget; for displaying text.  Can only be instanced
+as @code{widget}.
+@item layout
+A widget for controlling the positioning of children underneath it.
+Through the use of nested layouts, a widget hierarchy can be created
+which can have the appearance of any standard dialog box or similar
+arrangement; all of this is counted as one @dfn{glyph} and could appear
+in many of the places that expect a single glyph.  Can only be instanced
+as @code{widget}.
+@item native-layout
+The native version of a layout widget.
+Can only be instanced as @code{widget}.
+@item progress-gauge
+A sliding widget, for showing progress.  Can only be instanced as
+@code{widget}.
+@item tab-control
+A tab widget; a series of user selectable tabs.  Can only be instanced
+as @code{widget}.
+@item tree-view
+A folding widget.  Can only be instanced as @code{widget}.
+@item scrollbar
+A scrollbar widget.  Can only be instanced as @code{widget}.
+@item autodetect
+XEmacs tries to guess what format the data is in.  If X support exists,
+the data string will be checked to see if it names a filename.  If so,
+and this filename contains XBM or XPM data, the appropriate sort of
+pixmap or pointer will be created. [This includes picking up any
+specified hotspot or associated mask file.] Otherwise, if @code{pointer}
+is one of the allowable image-instance types and the string names a
+valid cursor-font name, the image will be created as a pointer.
+Otherwise, the image will be displayed as text.  If no X support exists,
+the image will always be displayed as text.
+@item inherit
+Inherit from the background-pixmap property of a face.  Can only be
+instanced as @code{mono-pixmap}.
+@end table
+There are two convenience variables for use with the XBM and XPM image
+formats.
+@defvar xpm-color-symbols
+This variable holds definitions of logical color-names used when reading
+XPM files.  Elements of this list should be of the form
+@code{(@var{color-name} @var{form-to-evaluate})}.  The @var{color-name}
+should be a string, which is the name of the color to define; the
+@var{form-to-evaluate} should evaluate to a color specifier object, or a
+string to be passed to @code{make-color-instance} (@pxref{Colors}).  If
+a loaded XPM file references a symbolic color called @var{color-name},
+it will display as the computed color instead.
+The default value of this variable defines the logical color names
+@samp{"foreground"} and @samp{"background"} to be the colors of the
+@code{default} face.
+@end defvar
+@defvar x-bitmap-file-path
+A list of the directories in which X bitmap files may be found.  If @code{nil},
+this is initialized from the @samp{"*bitmapFilePath"} resource.  This is
+used by the @code{make-image-instance} function (however, note that if
+the environment variable @samp{XBMLANGPATH} is set, it is consulted
+first).
+@end defvar
+@node Image Instances
+@subsection Image Instances
+@cindex image instances
+Image-instance objects encapsulate the way a particular image (pixmap,
+etc.) is displayed on a particular device.
+In most circumstances, you do not need to directly create image
+instances; use a glyph instead.  However, it may occasionally be useful
+to explicitly create image instances, if you want more control over the
+instantiation process.
+@defun image-instance-p object
+This function returns non-@code{nil} if @var{object} is an image instance.
+@end defun
+@menu
+* Image Instance Types::         Each image instances has a particular type.
+* Image Instance Functions::	 Functions for working with image instances.
+@end menu
+@node Image Instance Types
+@subsubsection Image Instance Types
+@cindex image instance types
+Image instances come in a number of different types.  The type
+of an image instance specifies the nature of the image: Whether
+it is a text string, a mono pixmap, a color pixmap, etc.
+The valid image instance types are
+@table @code
+@item nothing
+Nothing is displayed.
+@item text
+Displayed as text.  The foreground and background colors and the
+font of the text are specified independent of the pixmap.  Typically
+these attributes will come from the face of the surrounding text,
+unless a face is specified for the glyph in which the image appears.
+@item mono-pixmap
+Displayed as a mono pixmap (a pixmap with only two colors where the
+foreground and background can be specified independent of the pixmap;
+typically the pixmap assumes the foreground and background colors of
+the text around it, unless a face is specified for the glyph in which
+the image appears).
+@item color-pixmap
+Displayed as a color pixmap.
+@item pointer
+Used as the mouse pointer for a window.
+@item subwindow
+A child window that is treated as an image.  This allows (e.g.)
+another program to be responsible for drawing into the window.
+Not currently implemented.
+@c #### Check status of subwindows ... I thought Andy implemented them.
+@item widget
+An active GUI element implemented as a ``widget'' or ``control'' of the
+underlying window system.
+@end table
+The following functions are used to check whether an image instance type
+is valid in the running XEmacs.
+@defun valid-image-instance-type-p type
+This function returns non-@code{nil} if @var{type} is a valid image
+instance type.
+@end defun
+@defun image-instance-type-list
+This function returns a list of the valid image instance types.
+@end defun
+The following functions are used to determine the type of an image
+instance.
+@defun image-instance-type image-instance
+Return the type of the given image instance.  The return
+value will be one of @code{nothing}, @code{text}, @code{mono-pixmap},
+@code{color-pixmap}, @code{pointer}, @code{subwindow}, or @code{widget}.
+@c #### Check status of subwindows ... I thought Andy implemented them.
+@end defun
+@defun text-image-instance-p object
+Return non-@code{nil} if @var{object} is an image instance of type
+@code{text}.
+@end defun
+@defun mono-pixmap-image-instance-p object
+Return non-@code{nil} if @var{object} is an image instance of type
+@code{mono-pixmap}.
+@end defun
+@defun color-pixmap-image-instance-p object
+Return non-@code{nil} if @var{object} is an image instance of type
+@code{color-pixmap}.
+@end defun
+@defun pointer-image-instance-p object
+Return non-@code{nil} if @var{object} is an image instance of type
+@code{pointer}.
+@end defun
+@defun subwindow-image-instance-p object
+Return non-@code{nil} if @var{object} is an image instance of type
+@code{subwindow}.
+@c #### Check status of subwindows ... I thought Andy implemented them.
+@end defun
+@defun nothing-image-instance-p object
+Return non-@code{nil} if @var{object} is an image instance of type
+@code{nothing}.
+@end defun
+@defun widget-image-instance-p object
+Return non-@code{nil} if @var{object} is an image instance of type
+@code{widget}.
+@end defun
+@node Image Instance Functions
+@subsubsection Image Instance Functions
+@defun make-image-instance data &optional domain dest-types noerror
+This function creates a new image-instance object.
+@var{data} is an image instantiator, which describes the image
+(@pxref{Image Specifiers}).
+@var{dest-types} should be a list of allowed image instance types that
+can be generated.  The @var{dest-types} list is unordered.  If multiple
+destination types are possible for a given instantiator, the ``most
+natural'' type for the instantiator's format is chosen.  These are
+@table @code
+@item XBM
+@c #### check xface
+@itemx xface
+@code{mono-pixmap}, then @code{color-pixmap}, then @code{pointer}.
+@item XPM
+@itemx GIF
+@itemx JPEG
+@itemx PNG
+@itemx TIFF
+@code{color-pixmap}, then @code{mono-pixmap}, then @code{pointer}.
+@item string
+@itemx formatted-string formats
+@code{text}, then @code{mono-pixmap} (not currently implemented), then
+@code{color-pixmap} (not currently implemented).
+@item mswindows-resource
+For pointer resources, @code{pointer}.
+For the others, @code{color-pixmap}.
+@end table
+@c #### So what?  This is a reference manual, list them, you lazy bastard!
+The other formats can only be instantiated as one type.
+If you want to control more specifically the order of the types into
+which an image is instantiated, call @code{make-image-instance}
+repeatedly until it succeeds, passing less and less preferred
+destination types each time.
+If @var{dest-types} is omitted, all possible types are allowed.
+@var{domain} specifies the domain to which the image instance will be
+attached.  This domain is termed the @dfn{governing domain}.  The type
+of the governing domain depends on the image instantiator format.
+(Although, more correctly, it should probably depend on the image
+instance type.)  For example, pixmap image instances are specific to a
+device, but widget image instances are specific to a particular XEmacs
+window because in order to display such a widget when two windows onto
+the same buffer want to display the widget, two separate underlying
+widgets must be created.  (That's because a widget is actually a child
+window-system window, and all window-system windows have a unique
+existence on the screen.)  This means that the governing domain for a
+pixmap image instance will be some device (most likely, the only
+existing device), whereas the governing domain for a widget image
+instance will be some XEmacs window.
+If you specify an overly general @var{domain} (e.g. a frame when a
+window was wanted), an error is signaled.  If you specify an overly
+specific @var{domain} (e.g. a window when a device was wanted), the
+corresponding general domain is fetched and used instead.  For
+@code{make-image-instance}, it makes no difference whether you specify
+an overly specific domain or the properly general domain derived from
+it.  However, it does matter when creating an image instance by
+instantiating a specifier or glyph (e.g. with
+@code{glyph-image-instance}), because the more specific domain causes
+spec lookup to start there and proceed to more general domains.  (It
+would also matter when creating an image instance with an instantiator
+format of @code{inherit}, but we currently disallow this.)
+@c #### We should fix that.
+If omitted, @var{domain} defaults to the selected window.
+@var{noerror} controls what happens when the image cannot be generated.
+If @code{nil}, an error message is generated.  If @code{t}, no messages
+are generated and this function returns @code{nil}.  If anything else, a
+warning message is generated and this function returns @code{nil}.
+@end defun
+@defun colorize-image-instance image-instance foreground background
+This function makes the image instance be displayed in the given
+colors.  Image instances come in two varieties: bitmaps, which are 1
+bit deep which are rendered in the prevailing foreground and background
+colors; and pixmaps, which are of arbitrary depth (including 1) and
+which have the colors explicitly specified.  This function converts a
+bitmap to a pixmap.  If the image instance was a pixmap already,
+nothing is done (and @code{nil} is returned).  Otherwise @code{t} is
+returned.
+@end defun
+The following functions are
+@defun image-instance-name image-instance
+This function returns the name of the given image instance.  The name is
+typically taken from the @code{:file} property of the instantiator if
+present, otherwise from the @code{:data} property.
+@end defun
+@defun image-instance-domain image-instance
+Return the governing domain of the given @var{image-instance}.  The
+governing domain of an image instance is the domain that the image
+instance is specific to.  It is @emph{NOT} necessarily the domain that
+was given to the call to @code{specifier-instance} that resulted in the
+creation of this image instance.  See @code{make-image-instance} for
+more information on governing domains.
+@end defun
+@defun image-instance-string image-instance
+This function returns the string of the given image instance.  This will
+only be non-@code{nil} for text image instances.
+@end defun
+@defun image-instance-file-name image-instance
+This function returns the file name from which @var{image-instance} was
+read, if known.
+@end defun
+@defun image-instance-mask-file-name image-instance
+This function returns the file name from which @var{image-instance}'s
+mask was read, if known.
+@end defun
+Pixmaps are considered to be three-dimensional.  The height and width of
+the pixel array that is displayed, and the color depth of its pixels,
+are accessed with these functions.
+@defun image-instance-depth image-instance
+This function returns the depth of the image instance.  This is 0 for a
+mono pixmap, or a positive integer for a color pixmap.
+@end defun
+@defun image-instance-height image-instance
+This function returns the height of the image instance, in pixels.
+@end defun
+@defun image-instance-width image-instance
+This function returns the width of the image instance, in pixels.
+@end defun
+The hotspot is a point relative to the origin of the pixmap.  When
+an image is used as a mouse pointer, the hotspot is the point on the
+image that sits over the location that the pointer points to.  This is,
+for example, the tip of the arrow or the center of the crosshairs.
+These functions access the coordinates of the hotspot.  They simply
+return @code{nil} for a non-pointer image instance.
+@defun image-instance-hotspot-x image-instance
+This function returns the X coordinate of the image instance's hotspot,
+if known.
+@end defun
+@defun image-instance-hotspot-y image-instance
+This function returns the Y coordinate of the image instance's hotspot,
+if known.
+@end defun
+Mono pixmaps and pointers may have their foreground and background
+colors set when instanced.  Use these functions to access color
+information.
+@defun image-instance-foreground image-instance
+This function returns the foreground color of @var{image-instance}, if
+applicable.  This will be a color instance or @code{nil}.  (It will only
+be non-@code{nil} for colorized mono pixmaps and for pointers.)
+@end defun
+@defun image-instance-background image-instance
+This function returns the background color of @var{image-instance}, if
+applicable.  This will be a color instance or @code{nil}.  (It will only
+be non-@code{nil} for colorized mono pixmaps and for pointers.)
+@end defun
+@node Using Glyphs
+@section Using Glyphs
+Glyph usage is unfortunately somewhat arcane.  (For discussion of
+rationale, @ref{Glyphs,,,Internals}.)  Because they are not ``text,''
+they cannot be inserted directly into a buffer.  Instead, they are
+values of properties of extents attached to buffers or strings, values
+of global variables such as mouse pointers, or as a component of a
+complex data structure such as a toolbar initializer.  Although these
+uses could probably streamlined, each structure has its own
+requirements.  Since glyphs are very flexible, it is possible to create
+applications like the @file{edit-toolbar} and @file{xpm-mode} libraries
+which display glyphs in a buffer (for reference while editing) that are
+normally used in a different context.
+Usage of glyphs can roughly be categorized as follows:
+@table @strong
+@item Buffer glyphs
+Glyphs that are inserted in a buffer may be used for their own sake (for
+example, image display in @file{w3}), as an accurate representation of
+text that can't be displayed in usual fonts (equation display in
+@file{preview-latex}), or as annotations (such as a marginal indication
+of a bookmark).  Glyphs are attached to buffers via extents.
+@item Redisplay glyphs
+Glyphs can be used to create XEmacs-specific ``fonts''.  For example,
+the character that indicates truncation of lines is implemented as the
+@code{truncation-glyph}.  It is also possible to have XEmacs display a
+certain character using a custom glyph, via display tables.
+@item Frame glyphs
+Glyphs are used to control the appearance of various other components of
+the frame.  They can be inserted in the modeline, the favicons are used
+in Web browsers.  They are used to specify the labels on toolbar
+buttons.  Finally, they can be inserted in the gutters.  (The difference
+between a glyph inserted in a gutter and a marginal annotation is that
+the marginal annotation is tied to the text in the buffer.  If the
+buffer line scrolls out of view, the marginal annotation will, as well.
+A gutter glyph does not move with the text.)
+Unfortunately, all these uses are special cases, and have their own
+APIs, in contrast to glyphs in a buffer.
+@item External glyphs
+External glyphs simply allow a consistent API for images.  The images
+are then passed to external software such as the window system itself
+(mouse cursor shapes) and the window manager (icons to represent
+minimized windows).  XEmacs has no role in managing their use.
+@item Subwindow and widget glyphs
+These do not constitute a context of use, but rather an important class of
+glyph types.  The difference between these and other glyphs is that
+while their geometry is determined by XEmacs, their behavior is managed
+separately, by internal mechanisms in the case of widgets, and
+(possibly) by another process in the case of subwindows.
+@c #### Check status of subwindows ... I thought Andy implemented them.
+@end table
+Some simple concrete examples showing how to insert a glyph in a
+buffer are presented later.  @ref{Glyph Examples}.
+``Creating Glyphs'' explains how to create glyphs.  Creating a glyph
+using @code{make-glyph} does not specify @emph{where} the glyph will be
+used, it only specifies @emph{what} the glyph will look like.  The next
+four sections explain how to embed glyphs in different display
+contexts.  Finally, the last two sections explain the special
+considerations of using glyphs whose behavior is not determined by the
+code creating them, but by the glyph itself (a ``widget'' in X11 or
+``control'' in MS Windows or Aqua), or even by a separate process.
 @menu
 * Creating Glyphs::	Creating new glyphs.
-* Glyph Properties::	Accessing and modifying a glyph's properties.
+* Buffer Glyphs::	Annotations are glyphs that appear in a buffer.
-* Glyph Convenience Functions::
+* Redisplay Glyphs::	Glyphs controlling various redisplay functions.
-			Convenience functions for accessing particular
+* Frame Glyphs::	Displaying glyphs in GUI components of the frame.
-			  properties of a glyph.
+* External Glyphs::	Icons and mouse pointers for the window system.
-* Glyph Dimensions::    Determining the height, width, etc. of a glyph.
+* Native GUI Widgets::	Complex active elements treated as a single glyph.
+* Subwindows::		Externally-controlled subwindows in buffers.
+@c #### Check status of subwindows ... I thought Andy implemented them.
 @end menu
 @node Creating Glyphs
 @subsection Creating Glyphs
 @defun make-glyph &optional spec-list type
 This function creates a new glyph object of type @var{type}.
-@var{spec-list} is used to initialize the glyph's image.  It is
+The optional @var{spec-list} is used to initialize the glyph's image.
-typically an image instantiator (a string or a vector; @ref{Image
+It can be any spec-list of @dfn{image instantiator} accepted by
-Specifiers}), but can also be a list of such instantiators (each one in
+@code{canonicalize-spec-list}, @ref{Adding Specifications}.  An
-turn is tried until an image is successfully produced), a cons of a
+individual image instantiator may be a string, which is converted to a
-locale (frame, buffer, etc.) and an instantiator, a list of such conses,
+vector according to @code{console-type-image-conversion-list}, or a
-or any other form accepted by @code{canonicalize-spec-list}.
+vector.  The vector's first element specifies the @emph{external} format
-@xref{Specifiers}, for more information about specifiers.
+of the data, such as a string, a PNG file, or an MS Windows resource.
+This is followed by properties (keyword-value pairs) specifying such
-@var{type} specifies the type of the glyph, which specifies in which
+information as the name of a file containing an image, or pixmap data
-contexts the glyph can be used, and controls the allowable image types
+directly.  @xref{Image Specifiers}.
-into which the glyph's image can be instantiated.  @var{type} should be
-one of @code{buffer} (used for glyphs in an extent, the modeline, the
+The optional @var{type} specifies the type of the glyph.  @var{type}
-toolbar, or elsewhere in a frame), @code{pointer} (used for the
+should be one of @code{buffer} (used for glyphs in an extent, the
-mouse-pointer), or @code{icon} (used for a frame's icon), and defaults
+modeline, the toolbar, or elsewhere in a frame), @code{pointer} (used
-to @code{buffer}.  @xref{Glyph Types}.
+for the mouse-pointer), or @code{icon} (used for a frame's icon), and
+defaults to @code{buffer}.
-A glyph in XEmacs does @strong{NOT} refer to a single unit of textual
+@end defun
-display (the XEmacs term for this is @dfn{rune}, and runes are confined
-to the internal implementation of redisplay), but rather is an
+@var{spec-list} is the initializer for the glyph's @code{image}
-object encapsulating a graphical element, such as an image or widget (an
+property, which is an image specifier.  (Note that @dfn{image} as used
-element such as a button or text entry field; @dfn{widget} is the term for
+in the context of a glyph's @code{image} property or in the terms
-this under X Windows, while @dfn{control} is the term under MS Windows).
+@dfn{image specifier}, @dfn{image instantiator}, or @dfn{image instance}
-This graphical element could appear in a buffer, a margin, a gutter, or
+does not refer to what people normally think of as an image (which in
-a toolbar, or as a mouse pointer or an icon, for example.
+XEmacs is called a @dfn{pixmap}), but to any graphical element---a
+pixmap, a widget, or even a block of text, when used in the places that
+call for a glyph.)
+The most common form of @var{spec-list} is a single image instantiator.
+(@strong{Compatibility note:} in GNU Emacs 21, a string used to
+instantiate an image is interpreted as the name of an image file, which
+is searched for and instantiated.)  The conversion controlled by
+@code{console-type-image-conversion-list} typically attempts to look up
+the string as a file name in XEmacs's data directory path, and if this
+fails, defaults to displaying the string as a text image instance
+(@emph{i.e.}. the string itself.
+Fine control of a particular specification is provided by using a vector
+as the image instantiator.  More complicated instantiators allow lists
+of instantiators to be specified (which are tried in order), or mappings
+from locales to lists of instantiators, @emph{etc}.  @xref{Specifiers},
+for more information about specification formats.
+As well as using @var{spec-list} to initialize the glyph, you can set
+specifications using @code{set-glyph-image}.  The glyph itself is not
+actually a specifier, but rather is an object containing an image
+specifier (as well as other properties seldom set by user code).
+Therefore, you cannot set or access specifications for the glyph's image
+by directly using @code{set-specifier}, @code{specifier-instance} or the
+like on the glyph; instead use them on @code{(glyph-image @var{glyph})}
+or use the convenience functions @code{set-glyph-image},
+@code{glyph-image-instance}, and @code{glyph-image}.
+Glyph types reflect the fact that glyphs are used in contexts like
+pointers and window manager icons, which are defined by external
+programs such as the window system or window manager.  These require
+somewhat different @emph{internal} format, which is opaque to the user.
+It is extremely rare that you will ever have to specify a value for
+@var{type}, which should be one of @code{buffer} (used for glyphs in an
+extent, the modeline, the toolbar, or elsewhere in a buffer),
+@code{pointer} (used for the mouse-pointer), or @code{icon} (used for a
+frame's icon), and defaults to @code{buffer}.  The only cases where it
+needs to be specified is when creating icon or pointer glyphs, and in
+both cases the necessary glyphs have already been created at startup and
+are accessed through the appropriate variables,
+e.g. @code{text-pointer-glyph} (or in general, any
+@samp{*-pointer-glyph}) and @code{frame-icon-glyph}.  User code should
+never need to create @code{pointer} or @code{icon} glyphs.  @xref{Glyph
+Types}.
+There are a few other glyph creation functions, normally used only
+internally or at XEmacs initialization.
+@defun make-glyph-internal &optional type
+This function creates a new, uninitialized glyph of type @var{type}.
+@end defun
+@defun make-pointer-glyph &optional spec-list
+Return a new @code{pointer-glyph} object with the specification list
+@var{spec-list}.  This function is equivalent to calling
+@code{make-glyph} with a @var{type} of @code{pointer}.
+@end defun
+@code{make-pointer-glyph} is normally used only by XEmacs initialization
+code.  It is extremely unlikely that you will ever need to create a
+pointer glyph.  Instead, you probably want to be calling
+@code{set-glyph-image} on an existing glyph,
+e.g. @code{text-pointer-glyph}.
+@defun make-icon-glyph &optional spec-list
+Return a new @code{icon-glyph} object with the specification list
+@var{spec-list}.  This function is equivalent to calling
+@code{make-glyph} with a @var{type} of @code{icon}.
+@end defun
+@code{make-icon-glyph} is normally used only by XEmacs initialization
+code.  It is extremely unlikely that you will ever need to create a icon
+glyph.  Instead, you probably want to be calling @code{set-glyph-image}
+on the existing glyph, @code{frame-icon-glyph}.
+@node Buffer Glyphs
+@subsection Buffer Glyphs
 Creating a glyph using @code{make-glyph} does not specify @emph{where}
-the glyph will be used, but it does specify @emph{what} the glyph will
+the glyph will be used, it only specifies @emph{what} the glyph will
-look like.  @var{spec-list} is used to specify this, and it is the
+look like.  Once you have created a glyph, you specify where it will be
-initializer for the glyph's @code{image} property, which is an image
+used by attaching it to an extent as a @emph{begin-glyph} or
-specifier. (Note that @dfn{image} as used in the context of a glyph's
+@emph{end-glyph}.
-@code{image} property or in the terms @dfn{image specifier}, @dfn{image
-instantiator}, or @dfn{image instance} does not refer to what people
+@table @code
-normally think of as an image (which in XEmacs is called a
+@item buffer text
-@dfn{pixmap}), but to any graphical element---a pixmap, a widget, or
-even a block of text, when used in the places that call for a glyph.)
-The format of the @var{spec-list} is typically an image instantiator (a string
-or a vector; @ref{Image Specifiers}), but can also be a list of such
-instantiators (each one in turn is tried until an image is successfully
-produced), a cons of a locale (frame, buffer, etc.)  and an
-instantiator, a list of such conses, or any other form accepted by
-@code{canonicalize-spec-list}.
-Some understanding of specifiers is necessary in working with glyphs,
-because they do not behave like ordinary variables, and are accessed and
-mutated with special APIs.  @xref{Specifiers}, for more information
-about specifiers.  The docstring of
-@code{make-specifier} gives a capsule summary.  The most important
-aspect of specifiers is that a specifier lets you set a value for
-each buffer, window, frame, device, or console, or it will compute an
-appropriate default if no specific value is set for a particular
-@emph{locale} or @emph{domain} (display contexts; locales are used by
-the programmer create an abstract link between an object such as a
-buffer position and an image, while domains must be concrete enough to
-enable XEmacs to identify the device type: you can't
-usefully display a JPEG on stdout).  Therefore only one global glyph
-needs to exist for a particular purpose (e.g. the icon used to represent
-an iconified frame, the mouse pointer used over particular areas of a
-frame, etc.), and in these cases you do not create your own glyph, but
-rather modify the existing one.  You can specify that a given glyph
-appear as a monochrome image on monochrome displays, a color image on
-color displays, and as a string on TTYs.
-As well as using @var{spec-list} to initialize the glyph, you can set
-specifications using @code{set-glyph-image}.  Due to an
-arguable historical design decision, a glyph itself is not
-actually a specifier, but rather is an object containing an image
-specifier (as well as other, seldom-used properties).  Therefore, you
-cannot set or access specifications for the glyph's image by directly
-using @code{set-specifier}, @code{specifier-instance} or the like on the
-glyph; instead use them on @code{(glyph-image @var{glyph})} or use the
-convenience functions @code{set-glyph-image},
-@code{glyph-image-instance}, and @code{glyph-image}.
-Once you have created a glyph, you specify where it will be used by
-attaching it to an extent as a @emph{begin-glyph} or @emph{end-glyph}.
-There are also a number of special objects whose appearance is specified
-by a glyph.  Most of these a global objects that you update with
-@code{set-glyph-image}, such as mouse pointers and the glyph that
-denotes a line truncation.  Frame icons, toolbar button icons, and the
-modeline are the main non-text objects which accept glyphs as elements.
-@itemize @bullet
-@item
 To insert a glyph into a buffer, create an extent in the buffer and then
 use @code{set-extent-begin-glyph} or @code{set-extent-end-glyph} to set
-a glyph to be displayed at the corresponding edge of the extent. (It is
+a glyph to be displayed at the corresponding edge of the extent.  (It is
 common to create zero-width extents for this purpose.)
-@item
+@item margins
 To insert a glyph into the left or right margin of a buffer, first
 make sure the margin is visible by setting a value for the specifiers
-@code{left-margin-width} or @code{right-margin-width}. (Not strictly necessary
+@code{left-margin-width} or @code{right-margin-width}.  (Not strictly necessary
-when using margin glyphs with layout policy @code{whitespace}.) Then follow
+when using margin glyphs with layout policy @code{whitespace}.)  Follow
-the same procedure above for inserting a glyph in a buffer, and then
+the same procedure above for inserting a glyph in a buffer, then
 set a non-default layout policy for the glyph using
 @code{set-extent-begin-glyph-layout} or @code{set-extent-end-glyph-layout}.
 Alternatively, use the high-level annotations API (see
-@code{make-annotation}). (In fact, you can also use the annotations
+@code{make-annotation}).  (In fact, you can also use the annotations
 API for glyphs in a buffer, by setting a layout policy of @code{text}.)
-@item
+@end table
+@node Redisplay Glyphs
+@subsection Redisplay Glyphs
+To use a glyph to control the shape of miscellaneous redisplay effects
+such as the truncation and continuation markers, set the appropriate
+existing glyph variables with @code{set-glyph-image}.  See
+@code{continuation-glyph}, @code{control-arrow-glyph},
+@code{hscroll-glyph}, @code{invisible-text-glyph},
+@code{octal-escape-glyph}, and @code{truncation-glyph}.  See also
+@code{overlay-arrow-string}, an odd redisplay leftover which can be set
+to a glyph you created, and will cause the glyph to be displayed on top
+of the text position specified in the marker stored in
+@code{overlay-arrow-position}.
+To use a glyph in a display table (i.e. to control the appearance of any
+individual character), create the appropriate character glyphs and then
+set a specification for the specifier @code{current-display-table},
+which controls the appearance of characters.  You can also set an
+overriding display table for use with text displayed in a particular
+face; see @code{set-face-display-table} and @code{make-display-table}.
+#### Note: Display tables do not currently support general Mule
+characters.  They will be overhauled at some point to support this
+and to provide other features required under Mule.  @ref{Display Tables}.
+Glyphs are not actually used as the background pixmaps of faces, but the
+API is similar.  The
+background pixmap of a face is actually an image specifier -- probably
+the only place in XEmacs where an image specifier occurs outside of a
+glyph.  If you would like to use a glyph's image as a background pixmap,
+you can extract it with @code{glyph-image}, and then add it to a face.
+@xref{Face Convenience Functions}.
+@defvr Glyph truncation-glyph
+This variable specifies what is displayed at the end of truncated lines.
+@end defvr
+@defvr Glyph continuation-glyph
+This variable specifies what is displayed at the end of wrapped lines.
+@end defvr
+@defvr Glyph octal-escape-glyph
+This variable specifies what to prefix character codes displayed in octal
+with.
+@end defvr
+@defvr Glyph hscroll-glyph
+This variable specifies what to display at the beginning of horizontally
+scrolled lines.
+@end defvr
+@defvr Glyph invisible-text-glyph
+This variable specifies what to use to indicate the presence of
+invisible text.  This is the glyph that is displayed when an ellipsis is
+called for, according to @code{selective-display-ellipses} or
+@code{buffer-invisibility-spec}).  Normally this is three dots (``...'').
+@end defvr
+@defvr Glyph control-arrow-glyph
+This variable specifies what to use as an arrow for control characters.
+@end defvr
+@node Frame Glyphs
+@subsection Frame Glyphs
+There are also a number of special objects whose appearance is specified
+by a glyph.  Most of these a global objects that you update with
+@code{set-glyph-image}, such as mouse pointers.  Frame icons, toolbar
+button icons, and the modeline are the main non-text objects which
+accept glyphs as elements.
+@table @code
+@item modeline
 A glyph may be displayed in the modeline by inserting the glyph as one
 of the elements of the modeline format.  (Unfortunately you can't
 currently put a begin glyph or end glyph on one of the modeline
 extents---they're ignored.)
-@item
+@item toolbar
 To insert a glyph into a toolbar, specify it as the icon part of a toolbar
 button, which in turn must be part of a toolbar instantiator (typically
 set on the specifier @code{default-toolbar}).
 See @code{default-toolbar} for more information. (As a convenience, you
 may use a symbol in place of the glyph list in the toolbar button
 and then calling @code{(set-specifier-dirty-flag default-toolbar)}.
 (#### Unfortunately this doesn't quite work the way it should; the
 change will appear in new frames, but not existing ones, because once an
 image has been displayed the pixmap replaces the symbol for those domains.)
-@item
+@item gutter
 To insert a glyph into a gutter, use
 @code{set-extent-begin-glyph} or @code{set-extent-end-glyph} to set a
 glyph to be displayed at the corresponding edge of extent in a string,
 similar to the way you insert glyphs in a buffer.  Then insert the
-string into the gutter @ref{Specifying a Gutter}.
+string into the gutter @ref{Specifying a Gutter}.  Glyphs that are
+frequently used in this way are @code{tab control} and @code{progress
-@item To use a glyph as the icon for a frame, you do not actually create
+bar} glyphs.
-a new glyph; rather, you change the specifications for the existing
-glyph @code{frame-icon-glyph}.  (This is a unique, predefined object.
+@end table
-Remember that, because of the specifier nature of glyphs, you can set
-different values for any particular buffer or frame.)
+@node External Glyphs
-@item
+@subsection External Glyphs
+@cindex frame icon
+@cindex icon, frame
+@cindex mouse cursor
+@cindex cursor (mouse)
+@cindex pointer (mouse)
+@cindex mouse pointer
+There are two special kinds of glyph that are not displayed by XEmacs.
+Instead, they are used to set the appearance of iconified frames and the
+mouse pointer.  Because these uses are constrained by the window system,
+icons and pointers have their own special types @xref{Glyph Types}.
+You may use a glyph as the icon for a frame.  Do not create a new glyph;
+instead, change the specifications for the existing glyph
+@code{frame-icon-glyph} with @code{set-glyph-image}.  This is a unique,
+predefined object.  Although the natural usage is to set specifications
+for the global locale or a frame locale, you can also arrange for a
+special icon when a frame's selected window displays a particular buffer
+by using a buffer locale.
+The shape of the mouse pointer when over a particular section of a frame
+is controlled using various glyph variables.  Since the image of a glyph
+is a specifier, it can be controlled on a per-buffer, per-frame, per-window,
+or per-device basis.
 To use a glyph as the mouse pointer, in general you do not create a new
 glyph, but rather you change the specifications of various existing
 glyphs, such as @code{text-pointer-glyph} for the pointer used over
 text, @code{modeline-pointer-glyph} for the pointer used over the
 modeline, etc.  Do an apropos over @samp{pointer-glyph} to find all of
 pointer glyph variables are implemented as part of the default handler
 for mouse motion events.  If you want to customize this behavior, take a
 look at @code{mode-motion-hook}, or @code{mouse-motion-handler} if you
 really want to get low-level.)
-@item
-To use a glyph to control the shape of miscellaneous redisplay effects
-such as the truncation and continuation markers, set the appropriate
-existing glyph variables, as for icons and pointers above.  See
-@code{continuation-glyph}, @code{control-arrow-glyph},
-@code{hscroll-glyph}, @code{invisible-text-glyph},
-@code{octal-escape-glyph}, and @code{truncation-glyph}.  See also
-@code{overlay-arrow-string}, an odd redisplay leftover which can be set
-to a glyph you created, and will cause the glyph to be displayed on top
-of the text position specified in the marker stored in
-@code{overlay-arrow-position}.
-@item
-To use a glyph in a display table (i.e. to control the appearance of any
-individual character), create the appropriate character glyphs and then
-set a specification for the specifier @code{current-display-table},
-which controls the appearance of characters.  You can also set an
-overriding display table for use with text displayed in a particular
-face; see @code{set-face-display-table} and @code{make-display-table}.
-#### Note: Display tables do not currently support general Mule
-characters.  They will be overhauled at some point to support this
-and to provide other features required under Mule.
-@item
-Glyphs are not actually used as the background pixmaps of faces, but the
-API is similar.  The
-background pixmap of a face is actually an image specifier -- probably
-the only place in XEmacs where an image specifier occurs outside of a
-glyph.  If you would like to use a glyph's image as a background pixmap,
-you can extract it with @code{glyph-image}, and then add it to a face.
-@xref{Face Convenience Functions}.
-@end itemize
-It is extremely rare that you will ever have to specify a value for
-@var{type}, which should be one of @code{buffer} (used for glyphs in an
-extent, the modeline, the toolbar, or elsewhere in a buffer),
-@code{pointer} (used for the mouse-pointer), or @code{icon} (used for a
-frame's icon), and defaults to @code{buffer}.  The only cases where it
-needs to be specified is when creating icon or pointer glyphs, and in
-both cases the necessary glyphs have already been created at startup and
-are accessed through the appropriate variables,
-e.g. @code{text-pointer-glyph} (or in general, any @samp{*-pointer-glyph})
-and @code{frame-icon-glyph}.  @xref{Glyph Types}.
-@end defun
-@defun make-glyph-internal &optional type
-This function creates a new, uninitialized glyph of type @var{type}.
-@end defun
-@defun make-pointer-glyph &optional spec-list
-Return a new @code{pointer-glyph} object with the specification list
-@var{spec-list}.  This function is equivalent to calling
-@code{make-glyph} with a @var{type} of @code{pointer}.
-It is extremely unlikely that you will ever need to create a pointer
-glyph.  Instead, you probably want to be calling @code{set-glyph-image}
-on an existing glyph, e.g. @code{text-pointer-glyph}.
-@end defun
-@defun make-icon-glyph &optional spec-list
-Return a new @code{pointer-glyph} object with the specification list
-@var{spec-list}.  This function is equivalent to calling
-@code{make-glyph} with a @var{type} of @code{icon}.
-It is extremely unlikely that you will ever need to create a pointer
-glyph.  Instead, you probably want to be calling @code{set-glyph-image}
-on the existing glyph, @code{frame-icon-glyph}.
-@end defun
-@node Glyph Properties
-@subsection Glyph Properties
-Each glyph has a list of properties, which control all of the aspects of
-the glyph's appearance.  The following symbols have predefined meanings:
-@table @code
-@item image
-The image used to display the glyph.
-@item baseline
-Percent above baseline that glyph is to be displayed.  Only for glyphs
-displayed inside of a buffer.
-@item contrib-p
-Whether the glyph contributes to the height of the line it's on.
-Only for glyphs displayed inside of a buffer.
-@item face
-Face of this glyph (@emph{not} a specifier).
-@end table
-@defun set-glyph-property glyph property value &optional locale tag-set how-to-add
-This function changes a property of a @var{glyph}.
-For built-in properties, the actual value of the property is a specifier
-and you cannot change this; but you can change the specifications within
-the specifier, and that is what this function will do.  For user-defined
-properties, you can use this function to either change the actual value
-of the property or, if this value is a specifier, change the
-specifications within it.
-If @var{property} is a built-in property, the specifications to be added
-to this property can be supplied in many different ways:
-@itemize @bullet
-@item
-If @var{value} is a simple instantiator (e.g. a string naming a pixmap
-filename) or a list of instantiators, then the instantiator(s) will be
-added as a specification of the property for the given @var{locale}
-(which defaults to @code{global} if omitted).
-@item
-If @var{value} is a list of specifications (each of which is a cons of a
-locale and a list of instantiators), then @var{locale} must be
-@code{nil} (it does not make sense to explicitly specify a locale in
-this case), and specifications will be added as given.
-@item
-If @var{value} is a specifier (as would be returned by
-@code{glyph-property} if no @var{locale} argument is given), then some
-or all of the specifications in the specifier will be added to the
-property.  In this case, the function is really equivalent to
-@code{copy-specifier} and @var{locale} has the same semantics (if it is
-a particular locale, the specification for the locale will be copied; if
-a locale type, specifications for all locales of that type will be
-copied; if @code{nil} or @code{all}, then all specifications will be
-copied).
-@end itemize
-@var{how-to-add} should be either @code{nil} or one of the symbols
-@code{prepend}, @code{append}, @code{remove-tag-set-prepend},
-@code{remove-tag-set-append}, @code{remove-locale},
-@code{remove-locale-type}, or @code{remove-all}.  See
-@code{copy-specifier} and @code{add-spec-to-specifier} for a description
-of what each of these means.  Most of the time, you do not need to worry
-about this argument; the default behavior usually is fine.
-In general, it is OK to pass an instance object (e.g. as returned by
-@code{glyph-property-instance}) as an instantiator in place of an actual
-instantiator.  In such a case, the instantiator used to create that
-instance object will be used (for example, if you set a font-instance
-object as the value of the @code{font} property, then the font name used
-to create that object will be used instead).  In some cases, however,
-doing this conversion does not make sense, and this will be noted in the
-documentation for particular types of instance objects.
-If @var{property} is not a built-in property, then this function will
-simply set its value if @var{locale} is @code{nil}.  However, if
-@var{locale} is given, then this function will attempt to add
-@var{value} as the instantiator for the given @var{locale}, using
-@code{add-spec-to-specifier}.  If the value of the property is not a
-specifier, it will automatically be converted into a @code{generic}
-specifier.
-@end defun
-@defun glyph-property glyph property &optional locale
-This function returns @var{glyph}'s value of the given @var{property}.
-If @var{locale} is omitted, the @var{glyph}'s actual value for
-@var{property} will be returned.  For built-in properties, this will be
-a specifier object of a type appropriate to the property (e.g. a font or
-color specifier).  For other properties, this could be anything.
-If @var{locale} is supplied, then instead of returning the actual value,
-the specification(s) for the given locale or locale type will be
-returned.  This will only work if the actual value of @var{property} is
-a specifier (this will always be the case for built-in properties, but
-may or may not apply to user-defined properties).  If the actual value
-of @var{property} is not a specifier, this value will simply be returned
-regardless of @var{locale}.
-The return value will be a list of instantiators (e.g. vectors
-specifying pixmap data), or a list of specifications, each of which is a
-cons of a locale and a list of instantiators.  Specifically, if
-@var{locale} is a particular locale (a buffer, window, frame, device, or
-@code{global}), a list of instantiators for that locale will be
-returned.  Otherwise, if @var{locale} is a locale type (one of the
-symbols @code{buffer}, @code{window}, @code{frame}, or @code{device}),
-the specifications for all locales of that type will be returned.
-Finally, if @var{locale} is @code{all}, the specifications for all
-locales of all types will be returned.
-The specifications in a specifier determine what the value of
-@var{property} will be in a particular @dfn{domain} or set of
-circumstances, which is typically a particular Emacs window along with
-the buffer it contains and the frame and device it lies within.  The
-value is derived from the instantiator associated with the most specific
-locale (in the order buffer, window, frame, device, and @code{global})
-that matches the domain in question.  In other words, given a domain
-(i.e. an Emacs window, usually), the specifier for @var{property} will
-first be searched for a specification whose locale is the buffer
-contained within that window; then for a specification whose locale is
-the window itself; then for a specification whose locale is the frame
-that the window is contained within; etc.  The first instantiator that
-is valid for the domain (usually this means that the instantiator is
-recognized by the device [i.e. the X server or TTY device] that the
-domain is on).  The function @code{glyph-property-instance} actually does
-all this, and is used to determine how to display the glyph.
-@end defun
-@defun glyph-property-instance glyph property &optional domain default no-fallback
-This function returns the instance of @var{glyph}'s @var{property} in the
-specified @var{domain}.
-Under most circumstances, @var{domain} will be a particular window, and
-the returned instance describes how the specified property actually is
-displayed for that window and the particular buffer in it.  Note that
-this may not be the same as how the property appears when the buffer is
-displayed in a different window or frame, or how the property appears in
-the same window if you switch to another buffer in that window; and in
-those cases, the returned instance would be different.
-The returned instance is an image-instance object, and you can query it
-using the appropriate image instance functions.  For example, you could use
-@code{image-instance-depth} to find out the depth (number of color
-planes) of a pixmap displayed in a particular window.  The results might
-be different from the results you would get for another window (perhaps
-the user specified a different image for the frame that window is on; or
-perhaps the same image was specified but the window is on a different X
-server, and that X server has different color capabilities from this
-one).
-@var{domain} defaults to the selected window if omitted.
-@var{domain} can be a frame or device, instead of a window.  The value
-returned for such a domain is used in special circumstances when a
-more specific domain does not apply; for example, a frame value might be
-used for coloring a toolbar, which is conceptually attached to a frame
-rather than a particular window.  The value is also useful in
-determining what the value would be for a particular window within the
-frame or device, if it is not overridden by a more specific
-specification.
-If @var{property} does not name a built-in property, its value will
-simply be returned unless it is a specifier object, in which case it
-will be instanced using @code{specifier-instance}.
-Optional arguments @var{default} and @var{no-fallback} are the same as
-in @code{specifier-instance}.  @xref{Specifiers}.
-@end defun
-@defun remove-glyph-property glyph property &optional locale tag-set exact-p
-This function removes a property from a glyph.  For built-in properties,
-this is analogous to @code{remove-specifier}.  @xref{Specifiers,
-remove-specifier-p}, for the meaning of the @var{locale}, @var{tag-set},
-and @var{exact-p} arguments.
-@end defun
-@node Glyph Convenience Functions
-@subsection Glyph Convenience Functions
-The following functions are provided for working with specific
-properties of a glyph.  Note that these are exactly like calling
-the general functions described above and passing in the
-appropriate value for @var{property}.
-Remember that if you want to determine the ``value'' of a
-specific glyph property, you probably want to use the @code{*-instance}
-functions.  For example, to determine whether a glyph contributes
-to its line height, use @code{glyph-contrib-p-instance}, not
-@code{glyph-contrib-p}. (The latter will return a boolean specifier
-or a list of specifications, and you probably aren't concerned with
-these.)
-@defun glyph-image glyph &optional locale
-This function is equivalent to calling @code{glyph-property} with
-a property of @code{image}.  The return value will be an image
-specifier if @var{locale} is @code{nil} or omitted; otherwise,
-it will be a specification or list of specifications.
-@end defun
-@defun set-glyph-image glyph spec &optional locale tag-set how-to-add
-This function is equivalent to calling @code{set-glyph-property} with
-a property of @code{image}.
-@end defun
-@defun glyph-image-instance glyph &optional domain default no-fallback
-This function returns the instance of @var{glyph}'s image in the given
-@var{domain}, and is equivalent to calling
-@code{glyph-property-instance} with a property of @code{image}.  The
-return value will be an image instance.
-Normally @var{domain} will be a window or @code{nil} (meaning the
-selected window), and an instance object describing how the image
-appears in that particular window and buffer will be returned.
-@end defun
-@defun glyph-contrib-p glyph &optional locale
-This function is equivalent to calling @code{glyph-property} with
-a property of @code{contrib-p}.  The return value will be a boolean
-specifier if @var{locale} is @code{nil} or omitted; otherwise,
-it will be a specification or list of specifications.
-@end defun
-@defun set-glyph-contrib-p glyph spec &optional locale tag-set how-to-add
-This function is equivalent to calling @code{set-glyph-property} with
-a property of @code{contrib-p}.
-@end defun
-@defun glyph-contrib-p-instance glyph &optional domain default no-fallback
-This function returns whether the glyph contributes to its line height
-in the given @var{domain}, and is equivalent to calling
-@code{glyph-property-instance} with a property of @code{contrib-p}.  The
-return value will be either @code{nil} or @code{t}. (Normally @var{domain}
-will be a window or @code{nil}, meaning the selected window.)
-@end defun
-@defun glyph-baseline glyph &optional locale
-This function is equivalent to calling @code{glyph-property} with a
-property of @code{baseline}.  The return value will be a specifier if
-@var{locale} is @code{nil} or omitted; otherwise, it will be a
-specification or list of specifications.
-@end defun
-@defun set-glyph-baseline glyph spec &optional locale tag-set how-to-add
-This function is equivalent to calling @code{set-glyph-property} with
-a property of @code{baseline}.
-@end defun
-@defun glyph-baseline-instance glyph &optional domain default no-fallback
-This function returns the instance of @var{glyph}'s baseline value in
-the given @var{domain}, and is equivalent to calling
-@code{glyph-property-instance} with a property of @code{baseline}.  The
-return value will be an integer or @code{nil}.
-Normally @var{domain} will be a window or @code{nil} (meaning the
-selected window), and an instance object describing the baseline value
-appears in that particular window and buffer will be returned.
-@end defun
-@defun glyph-face glyph
-This function returns the face of @var{glyph}. (Remember, this is
-not a specifier, but a simple property.)
-@end defun
-@defun set-glyph-face glyph face
-This function changes the face of @var{glyph} to @var{face}.
-@end defun
-@node Glyph Dimensions
-@subsection Glyph Dimensions
-@defun glyph-width glyph &optional window
-This function returns the width of @var{glyph} on @var{window}.  This
-may not be exact as it does not take into account all of the context
-that redisplay will.
-@end defun
-@defun glyph-ascent glyph &optional window
-This function returns the ascent value of @var{glyph} on @var{window}.
-This may not be exact as it does not take into account all of the
-context that redisplay will.
-@end defun
-@defun glyph-descent glyph &optional window
-This function returns the descent value of @var{glyph} on @var{window}.
-This may not be exact as it does not take into account all of the
-context that redisplay will.
-@end defun
-@defun glyph-height glyph &optional window
-This function returns the height of @var{glyph} on @var{window}.  (This
-is equivalent to the sum of the ascent and descent values.)  This may
-not be exact as it does not take into account all of the context that
-redisplay will.
-@end defun
-@node Images
-@section Images
-@menu
-* Image Specifiers::		Specifying how an image will appear.
-* Image Instantiator Conversion::
-				Conversion is applied to image instantiators
-				  at the time they are added to an
-				  image specifier or at the time they
-				  are passed to @code{make-image-instance}.
-* Image Instances::		What an image specifier gets instanced as.
-@end menu
-@node Image Specifiers
-@subsection Image Specifiers
-@cindex image specifiers
-An image specifier is used to describe the actual image of a glyph.
-It works like other specifiers (@pxref{Specifiers}), in that it contains
-a number of specifications describing how the image should appear in a
-variety of circumstances.  These specifications are called @dfn{image
-instantiators}.  When XEmacs wants to display the image, it instantiates
-the image into an @dfn{image instance}.  Image instances are their own
-primitive object type (similar to font instances and color instances),
-describing how the image appears in a particular domain. (On the other
-hand, image instantiators, which are just descriptions of how the image
-should appear, are represented using strings or vectors.)
-@defun image-specifier-p object
-This function returns non-@code{nil} if @var{object} is an image specifier.
-Usually, an image specifier results from calling @code{glyph-image} on
-a glyph.
-@end defun
-@defun make-image-specifier spec-list
-This function creates a new image specifier object and initializes it
-according to @var{spec-list}. @xref{Specifiers}.
-Note that, in practice, you rarely, if ever, need to actually create an
-image specifier! (This function exists mainly for completeness.) Pretty
-much the only use for image specifiers is to control how glyphs are
-displayed, and the image specifier associated with a glyph (the
-@code{image} property of a glyph) is created automatically when a glyph
-is created and need not (and cannot, for that matter) ever be changed
-(@pxref{Glyphs}).  In fact, the design decision to create a separate
-image specifier type, rather than make glyphs themselves be specifiers,
-is debatable---the other properties of glyphs are rarely used and could
-conceivably have been incorporated into the glyph's instantiator.  The
-rarely used glyph types (buffer, pointer, icon) could also have been
-incorporated into the instantiator.
-@end defun
-Image instantiators come in many formats: @code{xbm}, @code{xpm},
-@code{gif}, @code{jpeg}, etc.  This describes the format of the data
-describing the image.  The resulting image instances also come in many
-types---@code{mono-pixmap}, @code{color-pixmap}, @code{text},
-@code{pointer}, etc.  This refers to the behavior of the image and the
-sorts of places it can appear. (For example, a color-pixmap image has
-fixed colors specified for it, while a mono-pixmap image comes in two
-unspecified shades ``foreground'' and ``background'' that are determined
-from the face of the glyph or surrounding text; a text image appears as
-a string of text and has an unspecified foreground, background, and
-font; a pointer image behaves like a mono-pixmap image but can only be
-used as a mouse pointer [mono-pixmap images cannot be used as mouse
-pointers]; etc.) It is important to keep the distinction between image
-instantiator format and image instance type in mind.  Typically, a given
-image instantiator format can result in many different image instance
-types (for example, @code{xpm} can be instanced as @code{color-pixmap},
-@code{mono-pixmap}, or @code{pointer}; whereas @code{cursor-font} can be
-instanced only as @code{pointer}), and a particular image instance type
-can be generated by many different image instantiator formats (e.g.
-@code{color-pixmap} can be generated by @code{xpm}, @code{gif},
-@code{jpeg}, etc.).
-@xref{Image Instances}, for a more detailed discussion of image
-instance types.
-An image instantiator should be a string or a vector of the form
-@example
-@code{[@var{format} @var{:keyword} @var{value} ...]}
-@end example
-i.e. a format symbol followed by zero or more alternating keyword-value
-pairs.  The @dfn{format} field should be a symbol, one of
-@table @code
-@item nothing
-Don't display anything; no keywords are valid for this.  Can only be
-instanced as @code{nothing}.
-@item string
-Display this image as a text string.  Can only be instanced
-as @code{text}, although support for instancing as @code{mono-pixmap}
-should be added.
-@item formatted-string
-Display this image as a text string with replaceable fields,
-similar to a modeline format string; not currently implemented.
-@item xbm
-An X bitmap; only if X support was compiled into this XEmacs.  Can be
-instanced as @code{mono-pixmap}, @code{color-pixmap}, or
-@code{pointer}.
-@item xpm
-An XPM pixmap; only if XPM support was compiled into this XEmacs.  Can
-be instanced as @code{color-pixmap}, @code{mono-pixmap}, or
-@code{pointer}.  XPM is an add-on library for X that was designed to
-rectify the shortcomings of the XBM format.  Most implementations of X
-include the XPM library as a standard part.  If your vendor does not, it
-is highly recommended that you download it and install it.  You can get
-it from the standard XEmacs FTP site, among other places.
-@item xface
-An X-Face bitmap, used to encode people's faces in e-mail messages;
-only if X-Face support was compiled into this XEmacs.  Can be instanced
-as @code{mono-pixmap}, @code{color-pixmap}, or @code{pointer}.
-@item gif
-A GIF87 or GIF89 image; only if GIF support was compiled into this
-XEmacs.  Can be instanced as @code{color-pixmap}.  Note that XEmacs
-includes GIF decoding functions as a standard part of it, so if you have
-X support, you will normally have GIF support, unless you explicitly
-disable it at configure time.
-@item jpeg
-A JPEG-format image; only if JPEG support was compiled into this
-XEmacs.  Can be instanced as @code{color-pixmap}.  If you have the JPEG
-libraries present on your system when XEmacs is built, XEmacs will
-automatically detect this and use them, unless you explicitly disable it
-at configure time.
-@item png
-A PNG/GIF24 image; only if PNG support was compiled into this XEmacs.
-Can be instanced as @code{color-pixmap}.
-@item tiff
-A TIFF-format image; only if TIFF support was compiled into this XEmacs.
-@item cursor-font
-One of the standard cursor-font names, such as @samp{watch} or
-@samp{right_ptr} under X.  Under X, this is, more specifically, any of
-the standard cursor names from appendix B of the Xlib manual [also known
-as the file @file{<X11/cursorfont.h>}] minus the @samp{XC_} prefix.  On
-other window systems, the valid names will be specific to the type of
-window system.  Can only be instanced as @code{pointer}.
-@item font
-A glyph from a font; i.e. the name of a font, and glyph index into it
-of the form @samp{@var{font} fontname index [[mask-font] mask-index]}.
-Only if X support was compiled into this XEmacs.  Currently can only be
-instanced as @code{pointer}, although this should probably be fixed.
-@item mswindows-resource
-An MS Windows pointer resource.  Specifies a resource to retrieve
-directly from the system (an OEM resource) or from a file, particularly
-an executable file.  If the resource is to be retrieved from a file, use
-:file and optionally :resource-id.  Otherwise use :resource-id.  Always
-specify :resource-type to specify the type (cursor, bitmap or icon) of
-the resource.  Possible values for :resource-id are listed below.  Can
-be instanced as @code{pointer} or @code{color-pixmap}.
-@item subwindow
-An embedded windowing system window.  Can only be instanced as
-@code{subwindow}.
-@item button
-A button widget; either a push button, radio button or toggle button.
-Can only be instanced as @code{widget}.
-@item combo-box
-A drop list of selectable items in a widget, for editing text.
-Can only be instanced as @code{widget}.
-@item edit-field
-A text editing widget.  Can only be instanced as @code{widget}.
-@item label
-A static, text-only, widget; for displaying text.  Can only be instanced
-as @code{widget}.
-@item layout
-A widget for controlling the positioning of children underneath it.
-Through the use of nested layouts, a widget hierarchy can be created
-which can have the appearance of any standard dialog box or similar
-arrangement; all of this is counted as one @dfn{glyph} and could appear
-in many of the places that expect a single glyph.  Can only be instanced
-as @code{widget}.
-@item native-layout
-@c   #### Document me better!
-The native version of a layout widget.
-Can only be instanced as @code{widget}.
-@item progress-gauge
-A sliding widget, for showing progress.  Can only be instanced as
-@code{widget}.
-@item tab-control
-A tab widget; a series of user selectable tabs.  Can only be instanced
-as @code{widget}.
-@item tree-view
-A folding widget.  Can only be instanced as @code{widget}.
-@item scrollbar
-A scrollbar widget.  Can only be instanced as @code{widget}.
-@item autodetect
-XEmacs tries to guess what format the data is in.  If X support exists,
-the data string will be checked to see if it names a filename.  If so,
-and this filename contains XBM or XPM data, the appropriate sort of
-pixmap or pointer will be created. [This includes picking up any
-specified hotspot or associated mask file.] Otherwise, if @code{pointer}
-is one of the allowable image-instance types and the string names a
-valid cursor-font name, the image will be created as a pointer.
-Otherwise, the image will be displayed as text.  If no X support exists,
-the image will always be displayed as text.
-@item inherit
-Inherit from the background-pixmap property of a face.  Can only be
-instanced as @code{mono-pixmap}.
-@end table
-The valid keywords are:
-@table @code
-@item :data
-Inline data.  For most formats above, this should be a string.  For
-XBM images, this should be a list of three elements: width, height, and
-a string of bit data.  This keyword is not valid for instantiator
-format @code{nothing}.
-@item :file
-Data is contained in a file.  The value is the name of this file.  If
-both @code{:data} and @code{:file} are specified, the image is created
-from what is specified in @code{:data} and the string in @code{:file}
-becomes the value of the @code{image-instance-file-name} function when
-applied to the resulting image-instance.  This keyword is not valid for
-instantiator formats @code{nothing}, @code{string},
-@code{formatted-string}, @code{cursor-font}, @code{font}, and
-@code{autodetect}.
-@item :foreground
-@itemx :background
-For @code{xbm}, @code{xface}, @code{cursor-font}, and @code{font}.
-These keywords allow you to explicitly specify foreground and background
-colors.  The argument should be anything acceptable to
-@code{make-color-instance}.  This will cause what would be a
-@code{mono-pixmap} to instead be colorized as a two-color color-pixmap,
-and specifies the foreground and/or background colors for a pointer
-instead of black and white.
-@item :mask-data
-For @code{xbm} and @code{xface}.  This specifies a mask to be used with the
-bitmap.  The format is a list of width, height, and bits, like for
-@code{:data}.
-@item :mask-file
-For @code{xbm} and @code{xface}.  This specifies a file containing the
-mask data.  If neither a mask file nor inline mask data is given for an
-XBM image, and the XBM image comes from a file, XEmacs will look for a
-mask file with the same name as the image file but with @samp{Mask} or
-@samp{msk} appended.  For example, if you specify the XBM file
-@file{left_ptr} [usually located in @file{/usr/include/X11/bitmaps}],
-the associated mask file @file{left_ptrmsk} will automatically be picked
-up.
-@item :hotspot-x
-@itemx :hotspot-y
-For @code{xbm} and @code{xface}.  These keywords specify a hotspot if
-the image is instantiated as a @code{pointer}.  Note that if the XBM
-image file specifies a hotspot, it will automatically be picked up if no
-explicit hotspot is given.
-@item :color-symbols
-Only for @code{xpm}.  This specifies an alist that maps strings that
-specify symbolic color names to the actual color to be used for that
-symbolic color (in the form of a string or a color-specifier object).
-If this is not specified, the contents of @code{xpm-color-symbols} are
-used to generate the alist.
-@item :resource-id
-Only for @code{mswindows-resource}.  This must be either an integer
-(which directly specifies a resource number) or a string.  Valid strings
-are
-For bitmaps:
-"close", "uparrow", "dnarrow", "rgarrow", "lfarrow",
-"reduce", "zoom", "restore", "reduced", "zoomd",
-"restored", "uparrowd", "dnarrowd", "rgarrowd", "lfarrowd",
-"mnarrow", "combo", "uparrowi", "dnarrowi", "rgarrowi",
-"lfarrowi", "size", "btsize", "check", "checkboxes", and
-"btncorners".
-For cursors:
-"normal", "ibeam", "wait", "cross", "up", "sizenwse",
-"sizenesw", "sizewe", "sizens", "sizeall", and "no".
-For icons:
-"sample", "hand", "ques", "bang", "note", and "winlogo".
-@item :resource-type
-Only for @code{mswindows-resource}.  This must be a symbol, either
-@code{cursor}, @code{icon}, or @code{bitmap}, specifying the type of
-resource to be retrieved.
-@item :face
-Only for @code{inherit}.  This specifies the face to inherit from.  For
-widgets this also specifies the face to use for display. It defaults to
-gui-element-face.
-@end table
-Keywords accepted as menu item specs are also accepted by widgets.
-These are @code{:selected}, @code{:active}, @code{:suffix},
-@code{:keys}, @code{:style}, @code{:filter}, @code{:config},
-@code{:included}, @code{:key-sequence}, @code{:accelerator},
-@code{:label} and @code{:callback}.
-If instead of a vector, the instantiator is a string, it will be
-converted into a vector by looking it up according to the specs in the
-@code{console-type-image-conversion-list} for the console type of
-the domain (usually a window; sometimes a frame or device) over which
-the image is being instantiated.
-If the instantiator specifies data from a file, the data will be read in
-at the time that the instantiator is added to the image specifier (which
-may be well before the image is actually displayed), and the
-instantiator will be converted into one of the inline-data forms, with
-the filename retained using a @code{:file} keyword.  This implies that
-the file must exist when the instantiator is added to the image, but
-does not need to exist at any other time (e.g. it may safely be a
-temporary file).
-@defun valid-image-instantiator-format-p format &optional locale
-This function returns non-@code{nil} if @var{format} is a valid image
-instantiator format.
-If @var{locale} is non-@code{nil} then the format is checked in that locale.
-If @var{locale} is @code{nil} the current console is used.
-Note that the return value for many formats listed above depends on
-whether XEmacs was compiled with support for that format.
-@end defun
-@defun image-instantiator-format-list
-This function return a list of valid image-instantiator formats.
-@end defun
-@defvar xpm-color-symbols
-This variable holds definitions of logical color-names used when reading
-XPM files.  Elements of this list should be of the form
-@code{(@var{color-name} @var{form-to-evaluate})}.  The @var{color-name}
-should be a string, which is the name of the color to define; the
-@var{form-to-evaluate} should evaluate to a color specifier object, or a
-string to be passed to @code{make-color-instance} (@pxref{Colors}).  If
-a loaded XPM file references a symbolic color called @var{color-name},
-it will display as the computed color instead.
-The default value of this variable defines the logical color names
-@samp{"foreground"} and @samp{"background"} to be the colors of the
-@code{default} face.
-@end defvar
-@defvar x-bitmap-file-path
-A list of the directories in which X bitmap files may be found.  If @code{nil},
-this is initialized from the @samp{"*bitmapFilePath"} resource.  This is
-used by the @code{make-image-instance} function (however, note that if
-the environment variable @samp{XBMLANGPATH} is set, it is consulted
-first).
-@end defvar
-@node Image Instantiator Conversion
-@subsection Image Instantiator Conversion
-@cindex image instantiator conversion
-@cindex conversion of image instantiators
-@defun set-console-type-image-conversion-list console-type list
-This function sets the image-conversion-list for consoles of the given
-@var{console-type}.  The image-conversion-list specifies how image
-instantiators that are strings should be interpreted.  Each element of
-the list should be a list of two elements (a regular expression string
-and a vector) or a list of three elements (the preceding two plus an
-integer index into the vector).  The string is converted to the vector
-associated with the first matching regular expression.  If a vector
-index is specified, the string itself is substituted into that position
-in the vector.
-Note: The conversion above is applied when the image instantiator is
-added to an image specifier, not when the specifier is actually
-instantiated.  Therefore, changing the image-conversion-list only affects
-newly-added instantiators.  Existing instantiators in glyphs and image
-specifiers will not be affected.
-@end defun
-@defun console-type-image-conversion-list console-type
-This function returns the image-conversion-list for consoles of the given
-@var{console-type}.
-@end defun
-@node Image Instances
-@subsection Image Instances
-@cindex image instances
-Image-instance objects encapsulate the way a particular image (pixmap,
-etc.) is displayed on a particular device.
-In most circumstances, you do not need to directly create image
-instances; use a glyph instead.  However, it may occasionally be useful
-to explicitly create image instances, if you want more control over the
-instantiation process.
-@defun image-instance-p object
-This function returns non-@code{nil} if @var{object} is an image instance.
-@end defun
-@menu
-* Image Instance Types::         Each image instances has a particular type.
-* Image Instance Functions::	 Functions for working with image instances.
-@end menu
-@node Image Instance Types
-@subsubsection Image Instance Types
-@cindex image instance types
-Image instances come in a number of different types.  The type
-of an image instance specifies the nature of the image: Whether
-it is a text string, a mono pixmap, a color pixmap, etc.
-The valid image instance types are
-@table @code
-@item nothing
-Nothing is displayed.
-@item text
-Displayed as text.  The foreground and background colors and the
-font of the text are specified independent of the pixmap.  Typically
-these attributes will come from the face of the surrounding text,
-unless a face is specified for the glyph in which the image appears.
-@item mono-pixmap
-Displayed as a mono pixmap (a pixmap with only two colors where the
-foreground and background can be specified independent of the pixmap;
-typically the pixmap assumes the foreground and background colors of
-the text around it, unless a face is specified for the glyph in which
-the image appears).
-@item color-pixmap
-Displayed as a color pixmap.
-@item pointer
-Used as the mouse pointer for a window.
-@item subwindow
-A child window that is treated as an image.  This allows (e.g.)
-another program to be responsible for drawing into the window.
-Not currently implemented.
-@end table
-@defun valid-image-instance-type-p type
-This function returns non-@code{nil} if @var{type} is a valid image
-instance type.
-@end defun
-@defun image-instance-type-list
-This function returns a list of the valid image instance types.
-@end defun
-@defun image-instance-type image-instance
-This function returns the type of the given image instance.  The return
-value will be one of @code{nothing}, @code{text}, @code{mono-pixmap},
-@code{color-pixmap}, @code{pointer}, or @code{subwindow}.
-@end defun
-@defun text-image-instance-p object
-This function returns non-@code{nil} if @var{object} is an image
-instance of type @code{text}.
-@end defun
-@defun mono-pixmap-image-instance-p object
-This function returns non-@code{nil} if @var{object} is an image
-instance of type @code{mono-pixmap}.
-@end defun
-@defun color-pixmap-image-instance-p object
-This function returns non-@code{nil} if @var{object} is an image
-instance of type @code{color-pixmap}.
-@end defun
-@defun pointer-image-instance-p object
-This function returns non-@code{nil} if @var{object} is an image
-instance of type @code{pointer}.
-@end defun
-@defun subwindow-image-instance-p object
-This function returns non-@code{nil} if @var{object} is an image
-instance of type @code{subwindow}.
-@end defun
-@defun nothing-image-instance-p object
-This function returns non-@code{nil} if @var{object} is an image
-instance of type @code{nothing}.
-@end defun
-@defun widget-image-instance-p object
-Return @code{t} if @var{object} is an image instance of type @code{widget}.
-@end defun
-@node Image Instance Functions
-@subsubsection Image Instance Functions
-@defun make-image-instance data &optional domain dest-types noerror
-This function creates a new image-instance object.
-@var{data} is an image instantiator, which describes the image
-(@pxref{Image Specifiers}).
-@var{dest-types} should be a list of allowed image instance types that
-can be generated.  The @var{dest-types} list is unordered.  If multiple
-destination types are possible for a given instantiator, the ``most
-natural'' type for the instantiator's format is chosen. (For XBM, the
-most natural types are @code{mono-pixmap}, followed by
-@code{color-pixmap}, followed by @code{pointer}.  For the other normal
-image formats, the most natural types are @code{color-pixmap}, followed
-by @code{mono-pixmap}, followed by @code{pointer}.  For the string and
-formatted-string formats, the most natural types are @code{text},
-followed by @code{mono-pixmap} (not currently implemented), followed by
-@code{color-pixmap} (not currently implemented).  For MS Windows
-resources, the most natural type for pointer resources is
-@code{pointer}, and for the others it's @code{color-pixmap}.  The other
-formats can only be instantiated as one type. (If you want to control
-more specifically the order of the types into which an image is
-instantiated, just call @code{make-image-instance} repeatedly until it
-succeeds, passing less and less preferred destination types each time.
-If @var{dest-types} is omitted, all possible types are allowed.
-@var{domain} specifies the domain to which the image instance will be
-attached.  This domain is termed the @dfn{governing domain}.  The type
-of the governing domain depends on the image instantiator
-format. (Although, more correctly, it should probably depend on the
-image instance type.) For example, pixmap image instances are specific
-to a device, but widget image instances are specific to a particular
-XEmacs window because in order to display such a widget when two windows
-onto the same buffer want to display the widget, two separate underlying
-widgets must be created. (That's because a widget is actually a child
-window-system window, and all window-system windows have a unique
-existence on the screen.) This means that the governing domain for a
-pixmap image instance will be some device (most likely, the only
-existing device), whereas the governing domain for a widget image
-instance will be some XEmacs window.
-If you specify an overly general @var{domain} (e.g. a frame when a
-window was wanted), an error is signaled.  If you specify an overly
-specific @var{domain} (e.g. a window when a device was wanted), the
-corresponding general domain is fetched and used instead.  For
-@code{make-image-instance}, it makes no difference whether you specify
-an overly specific domain or the properly general domain derived from
-it.  However, it does matter when creating an image instance by
-instantiating a specifier or glyph (e.g. with
-@code{glyph-image-instance}), because the more specific domain causes
-spec lookup to start there and proceed to more general domains. (It
-would also matter when creating an image instance with an instantiator
-format of @code{inherit}, but we currently disallow this. #### We should
-fix this.)
-n
-If omitted, @var{domain} defaults to the selected window.
-@var{noerror} controls what happens when the image cannot be generated.
-If @code{nil}, an error message is generated.  If @code{t}, no messages
-are generated and this function returns @code{nil}.  If anything else, a
-warning message is generated and this function returns @code{nil}.
-@end defun
-@defun colorize-image-instance image-instance foreground background
-This function makes the image instance be displayed in the given
-colors.  Image instances come in two varieties: bitmaps, which are 1
-bit deep which are rendered in the prevailing foreground and background
-colors; and pixmaps, which are of arbitrary depth (including 1) and
-which have the colors explicitly specified.  This function converts a
-bitmap to a pixmap.  If the image instance was a pixmap already,
-nothing is done (and @code{nil} is returned).  Otherwise @code{t} is
-returned.
-@end defun
-@defun image-instance-name image-instance
-This function returns the name of the given image instance.
-@end defun
-@defun image-instance-domain image-instance
-Return the governing domain of the given @var{image-instance}.  The
-governing domain of an image instance is the domain that the image
-instance is specific to.  It is @emph{NOT} necessarily the domain that
-was given to the call to @code{specifier-instance} that resulted in the
-creation of this image instance.  See @code{make-image-instance} for
-more information on governing domains.
-@end defun
-@defun image-instance-string image-instance
-This function returns the string of the given image instance.  This will
-only be non-@code{nil} for text image instances.
-@end defun
-@defun image-instance-file-name image-instance
-This function returns the file name from which @var{image-instance} was
-read, if known.
-@end defun
-@defun image-instance-mask-file-name image-instance
-This function returns the file name from which @var{image-instance}'s
-mask was read, if known.
-@end defun
-@defun image-instance-depth image-instance
-This function returns the depth of the image instance.  This is 0 for a
-mono pixmap, or a positive integer for a color pixmap.
-@end defun
-@defun image-instance-height image-instance
-This function returns the height of the image instance, in pixels.
-@end defun
-@defun image-instance-width image-instance
-This function returns the width of the image instance, in pixels.
-@end defun
-@defun image-instance-hotspot-x image-instance
-This function returns the X coordinate of the image instance's hotspot,
-if known.  This is a point relative to the origin of the pixmap.  When
-an image is used as a mouse pointer, the hotspot is the point on the
-image that sits over the location that the pointer points to.  This is,
-for example, the tip of the arrow or the center of the crosshairs.
-This will always be @code{nil} for a non-pointer image instance.
-@end defun
-@defun image-instance-hotspot-y image-instance
-This function returns the Y coordinate of the image instance's hotspot,
-if known.
-@end defun
-@defun image-instance-foreground image-instance
-This function returns the foreground color of @var{image-instance}, if
-applicable.  This will be a color instance or @code{nil}. (It will only
-be non-@code{nil} for colorized mono pixmaps and for pointers.)
-@end defun
-@defun image-instance-background image-instance
-This function returns the background color of @var{image-instance}, if
-applicable.  This will be a color instance or @code{nil}. (It will only
-be non-@code{nil} for colorized mono pixmaps and for pointers.)
-@end defun
-@node Glyph Types
-@section Glyph Types
-Each glyph has a particular type, which controls how the glyph's image
-is generated.  Each glyph type has a corresponding list of allowable
-image instance types that can be generated.  When you call
-@code{glyph-image-instance} to retrieve the image instance of a glyph,
-XEmacs does the equivalent of calling @code{make-image-instance} and
-passing in @var{dest-types} the list of allowable image instance types
-for the glyph's type.
-@itemize @bullet
-@item
-@code{buffer} glyphs can be used as the begin-glyph or end-glyph of an
-extent, in the modeline, and in the toolbar.  Their image can be
-instantiated as @code{nothing}, @code{mono-pixmap}, @code{color-pixmap},
-@code{text}, and @code{subwindow}.
-@item
-@code{pointer} glyphs can be used to specify the mouse pointer.  Their
-image can be instantiated as @code{pointer}.
-@item
-@code{icon} glyphs can be used to specify the icon used when a frame is
-iconified.  Their image can be instantiated as @code{mono-pixmap} and
-@code{color-pixmap}.
-@end itemize
-@defun glyph-type glyph
-This function returns the type of the given glyph.  The return value
-will be a symbol, one of @code{buffer}, @code{pointer}, or @code{icon}.
-@end defun
-@defun valid-glyph-type-p glyph-type
-Given a @var{glyph-type}, this function returns non-@code{nil} if it is
-valid.
-@end defun
-@defun glyph-type-list
-This function returns a list of valid glyph types.
-@end defun
-@defun buffer-glyph-p object
-This function returns non-@code{nil} if @var{object} is a glyph of type
-@code{buffer}.
-@end defun
-@defun icon-glyph-p object
-This function returns non-@code{nil} if @var{object} is a glyph of type
-@code{icon}.
-@end defun
-@defun pointer-glyph-p object
-This function returns non-@code{nil} if @var{object} is a glyph of type
-@code{pointer}.
-@end defun
-@node Mouse Pointer
-@section Mouse Pointer
-@cindex mouse cursor
-@cindex cursor (mouse)
-@cindex pointer (mouse)
-@cindex mouse pointer
-The shape of the mouse pointer when over a particular section of a frame
-is controlled using various glyph variables.  Since the image of a glyph
-is a specifier, it can be controlled on a per-buffer, per-frame, per-window,
-or per-device basis.
 You should use @code{set-glyph-image} to set the following variables,
 @emph{not} @code{setq}.
 @defvr Glyph text-pointer-glyph
 This variable specifies the shape of the mouse pointer when over text.
 This function sets the mouse pointer of @var{frame} to the given pointer
 image instance.  You should not call this function directly.
 (If you do, the pointer will change again the next time the mouse moves.)
 @end defun
-@node Redisplay Glyphs
-@section Redisplay Glyphs
-@defvr Glyph truncation-glyph
-This variable specifies what is displayed at the end of truncated lines.
-@end defvr
-@defvr Glyph continuation-glyph
-This variable specifies what is displayed at the end of wrapped lines.
-@end defvr
-@defvr Glyph octal-escape-glyph
-This variable specifies what to prefix character codes displayed in octal
-with.
-@end defvr
-@defvr Glyph hscroll-glyph
-This variable specifies what to display at the beginning of horizontally
-scrolled lines.
-@end defvr
-@defvr Glyph invisible-text-glyph
-This variable specifies what to use to indicate the presence of
-invisible text.  This is the glyph that is displayed when an ellipsis is
-called for, according to @code{selective-display-ellipses} or
-@code{buffer-invisibility-spec}).  Normally this is three dots (``...'').
-@end defvr
-@defvr Glyph control-arrow-glyph
-This variable specifies what to use as an arrow for control characters.
-@end defvr
 @node Native GUI Widgets
-@section Native GUI Widgets
+@subsection Native GUI Widgets
 @cindex native widget
 A ``native widget'' is a primitive GUI object defined either by the host
 GUI platform or an external toolkit, and accessed from Lisp as a
 ``glyph.''
 * Layouts::                     Specifying composite widgets from Lisp.
 * Primitive Widgets::           Catalogue of available native widgets.
 @end menu
 @node Introduction to Widgets
-@subsection Introduction to Native Widgets and Subwindow Glyphs
+@subsubsection Introduction to Native Widgets and Subwindow Glyphs
 Traditionally Emacsen have hidden the GUI apparatus from the Lisp
 programmer, but in XEmacs 21.4 the ability to embed autonomous GUI
 objects, called @dfn{native widgets}, in text was added to Lisp.  They
 are handled as @emph{glyphs}.  Unlike traditional XEmacs
 However, composite widgets can be created in Lisp using ``layouts,''
 which are horizontal or vertical arrays of subwidgets.  For example, the
 search dialog is formatted using layouts.
 @node Lisp API to Native Widgets
-@subsection Lisp API to Native Widgets
+@subsubsection Lisp API to Native Widgets
 Native widgets are manipulated as @emph{glyphs} (@pxref{Glyphs}).  Thus
 they are created using @code{make-glyph}, with a format of one of the
 widget types and a @code{:data} property specific to the widget being
 instanced.
 However, there is a technical difference between widgets and other kinds
-of glyphs that is theoretically important, which is that because widgets
+of glyphs that is theoretically important.  Because widgets
 are active (that is, they can respond to user input events themselves),
 it is possible for the user to become aware that two appearances of the
 ``same'' glyph are actually separate instances.  For example, if a user
 changes an image glyph from red to blue, and the buffer containing the
 glyph appears in more than one window, the user will perceive all the
 that attention will focus on the widget being manipulated, and having
 other instances of the widget respond simultaneously might be more
 disconcerting than the actual case.
 @node Layouts
-@subsection Layouts
+@subsubsection Layouts
 An XEmacs @dfn{layout} is a one-dimensional array of glyphs.  It is a
 widget for controlling the positioning of children underneath it.
 Through the use of nested layouts, a widget hierarchy can be created
 which can have the appearance of any standard dialog box or similar
 value must be one of the symbols @code{:right}, @code{:center}, or
 @code{:left}.
 @item :vertically-justify
 Specifies the vertical justification of the items in the array.  The
-value must be one of the symbols @code{:center}, @code{:center}, or
+value must be one of the symbols @code{:top}, @code{:center}, or
 @code{:bottom}.
 @item :justify
 Specifies justification.  #### not understood.
 		  (delete-frame
 		   (event-channel event)))])])])
 @end example
 @node Primitive Widgets
-@subsection Primitive Widgets
+@subsubsection Primitive Widgets
 @c #### the following table should be replaced with a menu of nodes
 @table @code
 @item button
 A button widget; either a push button, radio button or toggle
 controlling an Emacs window.)
 @end table
 @node Subwindows
-@section Subwindows
+@subsection Subwindows
 Subwindows are not currently implemented.
+@c #### Check status of subwindows ... I thought Andy implemented them.
 @defun subwindowp object
 This function returns non-@code{nil} if @var{object} is a subwindow.
 @end defun
+@node Manipulating Glyphs
+@section Manipulating Glyphs
+Each glyphs has properties that may be accessed.  Most of these can
+also be set after the glyph is initialized, with the exception of the
+glyph's type.  This is not a real restriction, as it is almost never
+useful to create glyphs of types other than @code{buffer}.
+@menu
+* Glyph Properties::	Accessing and modifying a glyph's properties.
+* Glyph Convenience Functions::  Accessing particular properties of a glyph.
+* Glyph Dimensions::	Determining the height, width, etc. of a glyph.
+* Glyph Types::		Each glyph has a particular type.
+@end menu
+@node Glyph Properties
+@subsection Glyph Properties
+Each glyph has a list of properties, which control all of the aspects of
+the glyph's appearance.  The following symbols have predefined meanings:
+@table @code
+@item image
+The image used to display the glyph.
+@item baseline
+Percent above baseline that glyph is to be displayed.  Only for glyphs
+displayed inside of a buffer.
+@item contrib-p
+Whether the glyph contributes to the height of the line it's on.
+Only for glyphs displayed inside of a buffer.
+@item face
+Face of this glyph (@emph{not} a specifier).
+@end table
+@defun set-glyph-property glyph property value &optional locale tag-set how-to-add
+This function changes a property of a @var{glyph}.
+For built-in properties, the actual value of the property is a specifier
+and you cannot change this; but you can change the specifications within
+the specifier, and that is what this function will do.  The glyph face
+is an exception; it is a face name (a symbol) or a face object, not a
+specifier.  (The face properties themselves are typically specifiers.)
+For user-defined properties, you can use this function to either change
+the actual value of the property or, if this value is a specifier,
+change the specifications within it.
+If @var{property} is a built-in property, the specifications to be added
+to this property can be supplied in many different ways:
+@itemize @bullet
+@item
+If @var{value} is a simple instantiator (e.g. a string naming a pixmap
+filename) or a list of instantiators, then the instantiator(s) will be
+added as a specification of the property for the given @var{locale}
+(which defaults to @code{global} if omitted).
+@item
+If @var{value} is a list of specifications (each of which is a cons of a
+locale and a list of instantiators), then @var{locale} must be
+@code{nil} (it does not make sense to explicitly specify a locale in
+this case), and specifications will be added as given.
+@item
+If @var{value} is a specifier (as would be returned by
+@code{glyph-property} if no @var{locale} argument is given), then some
+or all of the specifications in the specifier will be added to the
+property.  In this case, the function is really equivalent to
+@code{copy-specifier} and @var{locale} has the same semantics (if it is
+a particular locale, the specification for the locale will be copied; if
+a locale type, specifications for all locales of that type will be
+copied; if @code{nil} or @code{all}, then all specifications will be
+copied).
+@end itemize
+@var{how-to-add} should be either @code{nil} or one of the symbols
+@code{prepend}, @code{append}, @code{remove-tag-set-prepend},
+@code{remove-tag-set-append}, @code{remove-locale},
+@code{remove-locale-type}, or @code{remove-all}.  See
+@code{copy-specifier} and @code{add-spec-to-specifier} for a description
+of what each of these means.  Most of the time, you do not need to worry
+about this argument; the default behavior usually is fine.
+In general, it is OK to pass an instance object (e.g. as returned by
+@code{glyph-property-instance}) as an instantiator in place of an actual
+instantiator.  In such a case, the instantiator used to create that
+instance object will be used (for example, if you set a font-instance
+object as the value of the @code{font} property, then the font name used
+to create that object will be used instead).  In some cases, however,
+doing this conversion does not make sense, and this will be noted in the
+documentation for particular types of instance objects.
+If @var{property} is not a built-in property, then this function will
+simply set its value if @var{locale} is @code{nil}.  However, if
+@var{locale} is given, then this function will attempt to add
+@var{value} as the instantiator for the given @var{locale}, using
+@code{add-spec-to-specifier}.  If the value of the property is not a
+specifier, it will automatically be converted into a @code{generic}
+specifier.
+@end defun
+@defun glyph-property glyph property &optional locale
+This function returns @var{glyph}'s value of the given @var{property}.
+If @var{locale} is omitted, the @var{glyph}'s actual value for
+@var{property} will be returned.  For built-in properties, this will be
+a specifier object of a type appropriate to the property (e.g. a font or
+color specifier).  For other properties, this could be anything.
+If @var{locale} is supplied, then instead of returning the actual value,
+the specification(s) for the given locale or locale type will be
+returned.  This will only work if the actual value of @var{property} is
+a specifier (this will always be the case for built-in properties, but
+may or may not apply to user-defined properties).  If the actual value
+of @var{property} is not a specifier, this value will simply be returned
+regardless of @var{locale}.
+The return value will be a list of instantiators (e.g. vectors
+specifying pixmap data), or a list of specifications, each of which is a
+cons of a locale and a list of instantiators.  Specifically, if
+@var{locale} is a particular locale (a buffer, window, frame, device, or
+@code{global}), a list of instantiators for that locale will be
+returned.  Otherwise, if @var{locale} is a locale type (one of the
+symbols @code{buffer}, @code{window}, @code{frame}, or @code{device}),
+the specifications for all locales of that type will be returned.
+Finally, if @var{locale} is @code{all}, the specifications for all
+locales of all types will be returned.
+The specifications in a specifier determine what the value of
+@var{property} will be in a particular @dfn{domain} or set of
+circumstances, which is typically a particular Emacs window along with
+the buffer it contains and the frame and device it lies within.  The
+value is derived from the instantiator associated with the most specific
+locale (in the order buffer, window, frame, device, and @code{global})
+that matches the domain in question.  In other words, given a domain
+(i.e. an Emacs window, usually), the specifier for @var{property} will
+first be searched for a specification whose locale is the buffer
+contained within that window; then for a specification whose locale is
+the window itself; then for a specification whose locale is the frame
+that the window is contained within; etc.  The first instantiator that
+is valid for the domain (usually this means that the instantiator is
+recognized by the device [i.e. the X server or TTY device] that the
+domain is on).  The function @code{glyph-property-instance} actually does
+all this, and is used to determine how to display the glyph.
+@end defun
+@defun glyph-property-instance glyph property &optional domain default no-fallback
+This function returns the instance of @var{glyph}'s @var{property} in the
+specified @var{domain}.
+Under most circumstances, @var{domain} will be a particular window, and
+the returned instance describes how the specified property actually is
+displayed for that window and the particular buffer in it.  Note that
+this may not be the same as how the property appears when the buffer is
+displayed in a different window or frame, or how the property appears in
+the same window if you switch to another buffer in that window; and in
+those cases, the returned instance would be different.
+The returned instance is an image-instance object, and you can query it
+using the appropriate image instance functions.  For example, you could use
+@code{image-instance-depth} to find out the depth (number of color
+planes) of a pixmap displayed in a particular window.  The results might
+be different from the results you would get for another window (perhaps
+the user specified a different image for the frame that window is on; or
+perhaps the same image was specified but the window is on a different X
+server, and that X server has different color capabilities from this
+one).
+@var{domain} defaults to the selected window if omitted.
+@var{domain} can be a frame or device, instead of a window.  The value
+returned for such a domain is used in special circumstances when a
+more specific domain does not apply; for example, a frame value might be
+used for coloring a toolbar, which is conceptually attached to a frame
+rather than a particular window.  The value is also useful in
+determining what the value would be for a particular window within the
+frame or device, if it is not overridden by a more specific
+specification.
+If @var{property} does not name a built-in property, its value will
+simply be returned unless it is a specifier object, in which case it
+will be instanced using @code{specifier-instance}.
+Optional arguments @var{default} and @var{no-fallback} are the same as
+in @code{specifier-instance}.  @xref{Specifiers}.
+@end defun
+@defun remove-glyph-property glyph property &optional locale tag-set exact-p
+This function removes a property from a glyph.  For built-in properties,
+this is analogous to @code{remove-specifier}.  @xref{Specifiers,
+remove-specifier-p}, for the meaning of the @var{locale}, @var{tag-set},
+and @var{exact-p} arguments.
+@end defun
+@node Glyph Convenience Functions
+@subsection Glyph Convenience Functions
+The following functions are provided for working with specific
+properties of a glyph.  Note that these are exactly like calling
+the general functions described above and passing in the
+appropriate value for @var{property}.
+Remember that if you want to determine the ``value'' of a
+specific glyph property, you probably want to use the @code{*-instance}
+functions.  For example, to determine whether a glyph contributes
+to its line height, use @code{glyph-contrib-p-instance}, not
+@code{glyph-contrib-p}. (The latter will return a boolean specifier
+or a list of specifications, and you probably aren't concerned with
+these.)
+@defun glyph-image glyph &optional locale
+This function is equivalent to calling @code{glyph-property} with
+a property of @code{image}.  The return value will be an image
+specifier if @var{locale} is @code{nil} or omitted; otherwise,
+it will be a specification or list of specifications.
+@end defun
+@defun set-glyph-image glyph spec &optional locale tag-set how-to-add
+This function is equivalent to calling @code{set-glyph-property} with
+a property of @code{image}.
+@end defun
+@defun glyph-image-instance glyph &optional domain default no-fallback
+This function returns the instance of @var{glyph}'s image in the given
+@var{domain}, and is equivalent to calling
+@code{glyph-property-instance} with a property of @code{image}.  The
+return value will be an image instance.
+Normally @var{domain} will be a window or @code{nil} (meaning the
+selected window), and an instance object describing how the image
+appears in that particular window and buffer will be returned.
+@end defun
+@defun glyph-contrib-p glyph &optional locale
+This function is equivalent to calling @code{glyph-property} with
+a property of @code{contrib-p}.  The return value will be a boolean
+specifier if @var{locale} is @code{nil} or omitted; otherwise,
+it will be a specification or list of specifications.
+@end defun
+@defun set-glyph-contrib-p glyph spec &optional locale tag-set how-to-add
+This function is equivalent to calling @code{set-glyph-property} with
+a property of @code{contrib-p}.
+@end defun
+@defun glyph-contrib-p-instance glyph &optional domain default no-fallback
+This function returns whether the glyph contributes to its line height
+in the given @var{domain}, and is equivalent to calling
+@code{glyph-property-instance} with a property of @code{contrib-p}.  The
+return value will be either @code{nil} or @code{t}. (Normally @var{domain}
+will be a window or @code{nil}, meaning the selected window.)
+@end defun
+@defun glyph-baseline glyph &optional locale
+This function is equivalent to calling @code{glyph-property} with a
+property of @code{baseline}.  The return value will be a specifier if
+@var{locale} is @code{nil} or omitted; otherwise, it will be a
+specification or list of specifications.
+@end defun
+@defun set-glyph-baseline glyph spec &optional locale tag-set how-to-add
+This function is equivalent to calling @code{set-glyph-property} with
+a property of @code{baseline}.
+@end defun
+@defun glyph-baseline-instance glyph &optional domain default no-fallback
+This function returns the instance of @var{glyph}'s baseline value in
+the given @var{domain}, and is equivalent to calling
+@code{glyph-property-instance} with a property of @code{baseline}.  The
+return value will be an integer or @code{nil}.
+Normally @var{domain} will be a window or @code{nil} (meaning the
+selected window), and an instance object describing the baseline value
+appears in that particular window and buffer will be returned.
+@end defun
+@defun glyph-face glyph
+This function returns the face of @var{glyph}. (Remember, this is
+not a specifier, but a simple property.)
+@end defun
+@defun set-glyph-face glyph face
+This function changes the face of @var{glyph} to @var{face}.
+@end defun
+@node Glyph Dimensions
+@subsection Glyph Dimensions
+@defun glyph-width glyph &optional window
+This function returns the width of @var{glyph} on @var{window}.  This
+may not be exact as it does not take into account all of the context
+that redisplay will.
+@end defun
+@defun glyph-ascent glyph &optional window
+This function returns the ascent value of @var{glyph} on @var{window}.
+This may not be exact as it does not take into account all of the
+context that redisplay will.
+@end defun
+@defun glyph-descent glyph &optional window
+This function returns the descent value of @var{glyph} on @var{window}.
+This may not be exact as it does not take into account all of the
+context that redisplay will.
+@end defun
+@defun glyph-height glyph &optional window
+This function returns the height of @var{glyph} on @var{window}.  (This
+is equivalent to the sum of the ascent and descent values.)  This may
+not be exact as it does not take into account all of the context that
+redisplay will.
+@end defun
+@node Glyph Types
+@subsection Glyph Types
+Each glyph has a particular type, which controls how the glyph's image
+is generated.  Each glyph type has a corresponding list of allowable
+image instance types that can be generated.  When you call
+@code{glyph-image-instance} to retrieve the image instance of a glyph,
+XEmacs does the equivalent of calling @code{make-image-instance} and
+passing in @var{dest-types} the list of allowable image instance types
+for the glyph's type.
+@itemize @bullet
+@item
+@code{buffer} glyphs can be used as the begin-glyph or end-glyph of an
+extent, in the modeline, and in the toolbar.  Their image can be
+instantiated as @code{nothing}, @code{mono-pixmap}, @code{color-pixmap},
+@code{text}, and @code{subwindow}.
+@c #### Check status of subwindows ... I thought Andy implemented them.
+@item
+@code{pointer} glyphs can be used to specify the mouse pointer.  Their
+image can be instantiated as @code{pointer}.
+@item
+@code{icon} glyphs can be used to specify the icon used when a frame is
+iconified.  Their image can be instantiated as @code{mono-pixmap} and
+@code{color-pixmap}.
+@end itemize
+@defun glyph-type glyph
+This function returns the type of the given glyph.  The return value
+will be a symbol, one of @code{buffer}, @code{pointer}, or @code{icon}.
+@end defun
+@defun valid-glyph-type-p glyph-type
+Given a @var{glyph-type}, this function returns non-@code{nil} if it is
+valid.
+@end defun
+@defun glyph-type-list
+This function returns a list of valid glyph types.
+@end defun
+@defun buffer-glyph-p object
+This function returns non-@code{nil} if @var{object} is a glyph of type
+@code{buffer}.
+@end defun
+@defun icon-glyph-p object
+This function returns non-@code{nil} if @var{object} is a glyph of type
+@code{icon}.
+@end defun
+@defun pointer-glyph-p object
+This function returns non-@code{nil} if @var{object} is a glyph of type
+@code{pointer}.
+@end defun
 @node Glyph Examples
 @section Glyph Examples
 For many applications, displaying graphics is a simple process: you

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comparison man/lispref/glyphs.texi @ 2182:c91543697b09