Toolbar
*******

Toolbar Intro
=============

A toolbar is a bar of icons displayed along one edge of a frame. You can view a toolbar as a series of menu shortcuts---the most common menu options can be accessed with a single click rather than a series of clicks and/or drags to select the option from a menu. Consistent with this, a help string (called the help-echo) describing what an icon in the toolbar (called a toolbar button) does, is displayed in the minibuffer when the mouse is over the button.

In XEmacs, a toolbar can be displayed along any of the four edges of the frame, and two or more different edges can be displaying toolbars simultaneously.  The contents, thickness, and visibility of the toolbars can be controlled separately, and the values can be per-buffer, per-frame, etc., using specifiers (see Specifiers).

Normally, there is one toolbar displayed in a frame.  Usually, this is the standard toolbar, but certain modes will override this and substitute their own toolbar.  In some cases (e.g. the VM package), a package will supply its own toolbar along a different edge from the standard toolbar, so that both can be visible at once.  This standard toolbar is usually positioned along the top of the frame, but this can be changed using set-default-toolbar-position.

Note that, for each of the toolbar properties (contents, thickness, and visibility), there is a separate specifier for each of the four toolbar positions (top, bottom, left, and right), and an additional specifier for the ``default'' toolbar, i.e. the toolbar whose position is controlled by set-default-toolbar-position.  The way this works is that set-default-toolbar-position arranges things so that the appropriate position-specific specifiers for the default position inherit from the corresponding default specifiers. That way, if the position-specific specifier does not give a value (which it usually doesn't), then the value from the default specifier applies.  If you want to control the default toolbar, you just change the default specifiers, and everything works.  A package such as VM that wants to put its own toolbar in a different location from the default just sets the position-specific specifiers, and if the user sets the default toolbar to the same position, it will just not be visible.

Creating Toolbar
================

 -- Function: make-toolbar-specifier spec-list

     Return a new toolbar specifier object with the given specification list.  SPEC-LIST can be a list of specifications (each of which is a cons of a locale and a list of instantiators), a single instantiator, or a list of instantiators.  See Specifiers, for more information about specifiers.

     Toolbar specifiers are used to specify the format of a toolbar.  The values of the variables default-toolbar, top-toolbar, left-toolbar, right-toolbar, and bottom-toolbar are always toolbar specifiers.

     Valid toolbar instantiators are called "toolbar descriptors" and are lists of vectors.  See default-toolbar for a description of the exact format.

The default toolbar is created in toolbar-items.el.  An example which modifies an existing toolbar (by adding a button) is presented in the specifier section see Simple Specifier Usage.

Toolbar Descriptor Format
=========================

The contents of a toolbar are specified using a toolbar descriptor. The format of a toolbar descriptor is a list of toolbar button descriptors.  Each toolbar button descriptor is a vector in one of the following formats:

  * [GLYPH-LIST FUNCTION ENABLED-P HELP]

  * [:style 2D-OR-3D]

  * [:style 2D-OR-3D :size WIDTH-OR-HEIGHT]

  * [:size WIDTH-OR-HEIGHT :style 2D-OR-3D]

Optionally, one of the toolbar button descriptors may be nil instead of a vector; this signifies the division between the toolbar buttons that are to be displayed flush-left, and the buttons to be displayed flush-right.

The first vector format above specifies a normal toolbar button; the others specify blank areas in the toolbar.

For the first vector format:

  * GLYPH-LIST should be a list of one to six glyphs (as created by make-glyph) or a symbol whose value is such a list.  The first glyph, which must be provided, is the glyph used to display the toolbar button when it is in the ``up'' (not pressed) state.  The optional second glyph is for displaying the button when it is in the ``down'' (pressed) state.  The optional third glyph is for when the button is disabled.  The last three glyphs are for displaying the button in the ``up'', ``down'', and ``disabled'' states, respectively, but are used when the user has called for captioned toolbar buttons (using toolbar-buttons-captioned-p).  The function toolbar-make-button-list is useful in creating these glyph lists.

  * Even if you do not provide separate down-state and disabled-state glyphs, the user will still get visual feedback to indicate which state the button is in.  Buttons in the up-state are displayed with a shadowed border that gives a raised appearance to the button.  Buttons in the down-state are displayed with shadows that give a recessed appearance.  Buttons in the disabled state are displayed with no shadows, giving a 2-d effect.

  * If some of the toolbar glyphs are not provided, they inherit as follows:

               UP:                up
               DOWN:              down -> up
               DISABLED:          disabled -> up
               CAP-UP:            cap-up -> up
               CAP-DOWN:          cap-down -> cap-up -> down -> up
               CAP-DISABLED:      cap-disabled -> cap-up -> disabled -> up

  * The second element FUNCTION is a function to be called when the toolbar button is activated (i.e. when the mouse is released over the toolbar button, if the press occurred in the toolbar).  It can be any form accepted by call-interactively, since this is how it is invoked.

  * The third element ENABLED-P specifies whether the toolbar button is enabled (disabled buttons do nothing when they are activated, and are displayed differently; see above).  It should be either a boolean or a form that evaluates to a boolean.

  * The fourth element HELP, if non-nil, should be a string. This string is displayed in the echo area when the mouse passes over the toolbar button.

For the other vector formats (specifying blank areas of the toolbar):

  * 2D-OR-3D should be one of the symbols 2d or 3d, indicating whether the area is displayed with shadows (giving it a raised, 3-d appearance) or without shadows (giving it a flat appearance).

  * WIDTH-OR-HEIGHT specifies the length, in pixels, of the blank area.  If omitted, it defaults to a device-specific value (8 pixels for X devices).

 -- Function: toolbar-make-button-list up &optional down disabled cap-up cap-down cap-disabled
     This function calls make-glyph on each arg and returns a list of the results.  This is useful for setting the first argument of a toolbar button descriptor (typically, the result of this function is assigned to a symbol, which is specified as the first argument of the toolbar button descriptor).

 -- Function: check-toolbar-button-syntax button &optional noerror
     Verify the syntax of entry BUTTON in a toolbar description list. If you want to verify the syntax of a toolbar description list as a whole, use check-valid-instantiator with a specifier type of toolbar.

Specifying the Toolbar
======================

In order to specify the contents of a toolbar, set one of the specifier variables default-toolbar, top-toolbar, bottom-toolbar, left-toolbar, or right-toolbar. These are specifiers, which means you set them with set-specifier and query them with specifier-specs or specifier-instance. You will get an error if you try to set them using setq.  The valid instantiators for these specifiers are toolbar descriptors, as described above.  See Specifiers, for more information.

Most of the time, you will set default-toolbar, which allows the user to choose where the toolbar should go.

 -- Specifier: default-toolbar
     The position of this toolbar is specified in the function default-toolbar-position.  If the corresponding position-specific toolbar (e.g. top-toolbar if default-toolbar-position is top) does not specify a toolbar in a particular domain, then the value of default-toolbar in that domain, of any, will be used instead.

Note that the toolbar at any particular position will not be displayed unless its thickness (width or height, depending on orientation) is non-zero and its visibility status is true.  The thickness is controlled by the specifiers top-toolbar-height, bottom-toolbar-height, left-toolbar-width, and right-toolbar-width, and the visibility status is controlled by the specifiers top-toolbar-visible-p, bottom-toolbar-visible-p, left-toolbar-visible-p, and right-toolbar-visible-p (see Other Toolbar Variables).

 -- Function: set-default-toolbar-position position
     This function sets the position that the default-toolbar will be displayed at.  Valid positions are the symbols top, bottom, left and right.  What this actually does is set the fallback specifier for the position-specific specifier corresponding to the given position to default-toolbar, and set the fallbacks for the other position-specific specifiers to nil. It also does the same thing for the position-specific thickness and visibility specifiers, which inherit from one of default-toolbar-height or default-toolbar-width, and from default-toolbar-visible-p, respectively (see Other Toolbar Variables).

 -- Function: default-toolbar-position
     This function returns the position that the default-toolbar will be displayed at.

You can also explicitly set a toolbar at a particular position.  When redisplay determines what to display at a particular position in a particular domain (i.e. window), it first consults the position-specific toolbar.  If that does not yield a toolbar descriptor, the default-toolbar is consulted if default-toolbar-position indicates this position.

 -- Specifier: top-toolbar
     Specifier for the toolbar at the top of the frame.

 -- Specifier: bottom-toolbar
     Specifier for the toolbar at the bottom of the frame.

 -- Specifier: left-toolbar
     Specifier for the toolbar at the left edge of the frame.

 -- Specifier: right-toolbar
     Specifier for the toolbar at the right edge of the frame.

 -- Function: toolbar-specifier-p object
     This function returns non-nil if OBJECT is a toolbar specifier. Toolbar specifiers are the actual objects contained in the toolbar variables described above, and their valid instantiators are toolbar descriptors (see Toolbar Descriptor Format).

Other Toolbar Variables
=======================

The variables to control the toolbar thickness, visibility status, and captioned status are all specifiers.  See Specifiers.

 -- Specifier: default-toolbar-height
     This specifies the height of the default toolbar, if it's oriented horizontally.  The position of the default toolbar is specified by the function set-default-toolbar-position.  If the corresponding position-specific toolbar thickness specifier (e.g. top-toolbar-height if default-toolbar-position is top) does not specify a thickness in a particular domain (a window or a frame), then the value of default-toolbar-height or default-toolbar-width (depending on the toolbar orientation) in that domain, if any, will be used instead.

 -- Specifier: default-toolbar-width
     This specifies the width of the default toolbar, if it's oriented vertically.  This behaves like default-toolbar-height.

Note that default-toolbar-height is only used when default-toolbar-position is top or bottom, and default-toolbar-width is only used when default-toolbar-position is left or right.

 -- Specifier: top-toolbar-height
     This specifies the height of the top toolbar.

 -- Specifier: bottom-toolbar-height
     This specifies the height of the bottom toolbar.

 -- Specifier: left-toolbar-width
     This specifies the width of the left toolbar.

 -- Specifier: right-toolbar-width
     This specifies the width of the right toolbar.

Note that all of the position-specific toolbar thickness specifiers have a fallback value of zero when they do not correspond to the default toolbar.  Therefore, you will have to set a non-zero thickness value if you want a position-specific toolbar to be displayed.

 -- Specifier: default-toolbar-visible-p
     This specifies whether the default toolbar is visible.  The position of the default toolbar is specified by the function set-default-toolbar-position.  If the corresponding position-specific toolbar visibility specifier (e.g. top-toolbar-visible-p if default-toolbar-position is top) does not specify a visible-p value in a particular domain (a window or a frame), then the value of default-toolbar-visible-p in that domain, if any, will be used instead.

 -- Specifier: top-toolbar-visible-p
     This specifies whether the top toolbar is visible.

 -- Specifier: bottom-toolbar-visible-p
     This specifies whether the bottom toolbar is visible.

 -- Specifier: left-toolbar-visible-p
     This specifies whether the left toolbar is visible.

 -- Specifier: right-toolbar-visible-p
     This specifies whether the right toolbar is visible.

default-toolbar-visible-p and all of the position-specific toolbar visibility specifiers have a fallback value of true.

Internally, toolbar thickness and visibility specifiers are instantiated in both window and frame domains, for different purposes.  The value in the domain of a frame's selected window specifies the actual toolbar thickness or visibility that you will see in that frame.  The value in the domain of a frame itself specifies the toolbar thickness or visibility that is used in frame geometry calculations.

Thus, for example, if you set the frame width to 80 characters and the left toolbar width for that frame to 68 pixels, then the frame will be sized to fit 80 characters plus a 68-pixel left toolbar.  If you then set the left toolbar width to 0 for a particular buffer (or if that buffer does not specify a left toolbar or has a nil value specified for left-toolbar-visible-p), you will find that, when that buffer is displayed in the selected window, the window will have a width of 86 or 87 characters---the frame is sized for a 68-pixel left toolbar but the selected window specifies that the left toolbar is not visible, so it is expanded to take up the slack.

 -- Specifier: toolbar-buttons-captioned-p
     Whether toolbar buttons are captioned.  This affects which glyphs from a toolbar button descriptor are chosen.  See Toolbar Descriptor Format.

You can also reset the toolbar to what it was when XEmacs started up.

 -- Constant: initial-toolbar-spec
     The toolbar descriptor used to initialize default-toolbar at startup.