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[xemacs-hg @ 2004-04-19 08:02:27 by stephent] texi doc improvements <87zn98wg4q.fsf@tleepslib.sk.tsukuba.ac.jp>
author stephent
date Mon, 19 Apr 2004 08:02:38 +0000
parents 8d350b095c21
children 1094d6d400fb
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2027:71477bc21fe8 2028:2ba4f06a264d
38 38
39 @node Introduction, User Interface, Top, Top 39 @node Introduction, User Interface, Top, Top
40 @comment node-name, next, previous, up 40 @comment node-name, next, previous, up
41 @section Introduction 41 @section Introduction
42 42
43 Most graphical user interface toolkits, such as Motif and XView, provide 43 @c XEmacs changes to reflect history, native widgets, and GTK
44 Most graphical user interface toolkits, since Motif and XView, provide
44 a number of standard user interface controls (sometimes known as 45 a number of standard user interface controls (sometimes known as
45 `widgets' or `gadgets'). Emacs doesn't really support anything like 46 `widgets' or `gadgets'). Historically, Emacs didn't support anything like
46 this, except for an incredible powerful text ``widget''. On the other 47 this, except for its incredible powerful text ``widget''. However,
47 hand, Emacs does provide the necessary primitives to implement many 48 since XEmacs 21.4, XEmacs has supported ``native'' widgets (GUI controls
48 other widgets within a text buffer. The @code{widget} package 49 implemented as Lisp APIs in C for the MS Windows, Motif, Athena, and GTK
49 simplifies this task. 50 toolkits) and libglade (GUI controls with an XML API for the GTK
50 51 toolkit). On the other hand, Emacs does provide the necessary
51 The basic widgets are: 52 primitives to implement many other widgets within a text buffer, and of
53 course this is the only way to implement self-contained controls in a
54 text terminal. The @code{widget} package simplifies this task.
55
56 Examples of some basic widgets include:
52 57
53 @table @code 58 @table @code
54 @item link 59 @item link
55 Areas of text with an associated action. Intended for hypertext links 60 Areas of text with an associated action. Intended for hypertext links
56 embedded in text. 61 embedded in text.
81 list. Each list item is itself a widget. 86 list. Each list item is itself a widget.
82 @end table 87 @end table
83 88
84 Now of what possible use can support for widgets be in a text editor? 89 Now of what possible use can support for widgets be in a text editor?
85 I'm glad you asked. The answer is that widgets are useful for 90 I'm glad you asked. The answer is that widgets are useful for
86 implementing forms. A @dfn{form} in emacs is a buffer where the user is 91 implementing forms. A @dfn{form} in Emacs is a buffer where the user is
87 supposed to fill out a number of fields, each of which has a specific 92 supposed to fill out a number of fields, each of which has a specific
88 meaning. The user is not supposed to change or delete any of the text 93 meaning. The user is not supposed to change or delete any of the text
89 between the fields. Examples of forms in Emacs are the @file{forms} 94 between the fields. Examples of forms in Emacs are the @file{forms}
90 package (of course), the customize buffers, the mail and news compose 95 package (of course), the customize buffers, the mail and news compose
91 modes, and the @sc{html} form support in the @file{w3} browser. 96 modes, and the @sc{html} form support in the @file{w3} browser.
98 More complex fields than just editable text are supported. 103 More complex fields than just editable text are supported.
99 @item 104 @item
100 You can give the user immediate feedback if he enters invalid data in a 105 You can give the user immediate feedback if he enters invalid data in a
101 text field, and sometimes prevent entering invalid data. 106 text field, and sometimes prevent entering invalid data.
102 @item 107 @item
103 You can have fixed sized fields, thus allowing multiple field to be 108 You can have fixed sized fields, thus allowing multiple fields to be
104 lined up in columns. 109 lined up in columns.
105 @item 110 @item
106 It is simple to query or set the value of a field. 111 It is simple to query or set the value of a field.
107 @item 112 @item
108 Editing happens in buffer, not in the mini-buffer. 113 Editing happens in a normal buffer, not in the mini-buffer.
109 @item 114 @item
110 Packages using the library get a uniform look, making them easier for 115 Packages using the library get a uniform look-and-feel, making them easier for
111 the user to learn. 116 the user to learn.
112 @item 117 @item
113 As support for embedded graphics improve, the widget library will 118 As support for embedded graphics has improved, the widget library will
114 extended to support it. This means that your code using the widget 119 extended to support it. This means that your code using the widget
115 library will also use the new graphic features by automatic. 120 library will also use the new graphic features automatically.
121 @item
122 A widget specification is implemented as a class, and new subclasses can
123 be derived from any class, by restricting or extending the behavior.
116 @end enumerate 124 @end enumerate
117 125
118 In order to minimize the code that is loaded by users who does not 126 In order to minimize the code that is loaded by users who does not
119 create any widgets, the code has been split in two files: 127 create any widgets, the code has been split in two files:
120 128
121 @table @file 129 @table @file
122 @item widget.el 130 @item widget.el
123 This will declare the user variables, define the function 131 This declares the user variables, defines the function
124 @code{define-widget}, and autoload the function @code{widget-create}. 132 @code{define-widget}, and autoloads the function @code{widget-create}.
125 @item wid-edit.el 133 @item wid-edit.el
126 Everything else is here, there is no reason to load it explicitly, as 134 Everything else is here. Do not load it explicitly, as
127 it will be autoloaded when needed. 135 it will be autoloaded when needed.
128 @end table 136 @end table
129 137
130 @node User Interface, Programming Example, Introduction, Top 138 @node User Interface, Programming Example, Introduction, Top
131 @comment node-name, next, previous, up 139 @comment node-name, next, previous, up
166 @b{( )} A Final One. 174 @b{( )} A Final One.
167 175
168 @b{[Apply Form]} @b{[Reset Form]} 176 @b{[Apply Form]} @b{[Reset Form]}
169 @end example 177 @end example
170 178
171 The top level widgets in is example are tagged @samp{Name}, 179 The top level widgets in this example are tagged @samp{Name},
172 @samp{Choose}, @samp{Address}, @samp{_other work_}, @samp{Numbers}, 180 @samp{Choose}, @samp{Address}, @samp{_other work_}, @samp{Numbers},
173 @samp{Select multiple}, @samp{Select one}, @samp{[Apply Form]}, and 181 @samp{Select multiple}, @samp{Select one}, @samp{[Apply Form]}, and
174 @samp{[Reset Form]}. There are basically two thing the user can do within 182 @samp{[Reset Form]}. There are basically two thing the user can do within
175 a form, namely editing the editable text fields and activating the 183 a form, namely editing the editable text fields and activating the
176 buttons. 184 buttons.