1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
|
<sect1 id="Widget_Source_File">
<title>Widget Source File</title>
<para>
<!-- .LP -->
The source code file implements the widget class itself. The unique
part of this file is the declaration and initialization of the
widget class record structure and the declaration of all resources and
action routines added by the widget class.
</para>
<para>
<!-- .LP -->
The contents of the Template implementation file,
<filename class="headerfile"><X11/Xaw/Template.c></filename>,
are:
</para>
<!-- .CB -->
<!-- .\".so ../../lib/Xaw/Template.c -->
<literallayout class="monospaced">
/* Copyright (c) X Consortium 1987, 1988
*/
#include <X11/IntrinsicP.h>
#include <X11/StringDefs.h>
#include "TemplateP.h"
static XtResource resources[] = {
#define offset(field) XtOffsetOf(TemplateRec, template.field)
/* {name, class, type, size, offset, default_type, default_addr}, */
{ XtNtemplateResource, XtCTemplateResource, XtRTemplateResource,
sizeof(char*), offset(resource), XtRString, (XtPointer) "default" },
#undef offset
};
static void TemplateAction(/* Widget, XEvent*, String*, Cardinal* */);
static XtActionsRec actions[] =
{
/* {name, procedure}, */
{"template", TemplateAction},
};
static char translations[] =
" <Key>: template( ) \\n\\
";
TemplateClassRec templateClassRec = {
{ /* core fields */
/* superclass */ (WidgetClass) &widgetClassRec,
/* class_name */ "Template",
/* widget_size */ sizeof(TemplateRec),
/* class_initialize */ NULL,
/* class_part_initialize */ NULL,
/* class_inited */ FALSE,
/* initialize */ NULL,
/* initialize_hook */ NULL,
/* realize */ XtInheritRealize,
/* actions */ actions,
/* num_actions */ XtNumber(actions),
/* resources */ resources,
/* num_resources */ XtNumber(resources),
/* xrm_class */ NULLQUARK,
/* compress_motion */ TRUE,
/* compress_exposure */ TRUE,
/* compress_enterleave */ TRUE,
/* visible_interest */ FALSE,
/* destroy */ NULL,
/* resize */ NULL,
/* expose */ NULL,
/* set_values */ NULL,
/* set_values_hook */ NULL,
/* set_values_almost */ XtInheritSetValuesAlmost,
/* get_values_hook */ NULL,
/* accept_focus */ NULL,
/* version */ XtVersion,
/* callback_private */ NULL,
/* tm_table */ translations,
/* query_geometry */ XtInheritQueryGeometry,
/* display_accelerator */ XtInheritDisplayAccelerator,
/* extension */ NULL
},
{ /* template fields */
/* empty */ 0
}
};
WidgetClass templateWidgetClass = (WidgetClass)&templateClassRec;
</literallayout>
<!-- .CE -->
<para>
The resource list for the "WindowWidget" might look like the following:
</para>
<!-- .CB -->
<literallayout class="monospaced">
static XtResource resources[] = {
#define offset(field) XtOffsetOf(WindowWidgetRec, window.field)
/* {name, class, type, size, offset, default_type, default_addr}, */
{ XtNdrawingColor1, XtCColor, XtRPixel, sizeof(Pixel),
offset(color_1), XtRString, XtDefaultForeground },
{ XtNdrawingColor2, XtCColor, XtRPixel, sizeof(Pixel),
offset(color_2), XtRString, XtDefaultForeground },
{ XtNfont, XtCFont, XtRFontStruct, sizeof(XFontStruct*),
offset(font), XtRString, XtDefaultFont },
{ XtNexposeCallback, XtCCallback, XtRCallback, sizeof(XtCallbackList),
offset(expose_callback), XtRCallback, NULL },
{ XtNcallback, XtCCallback, XtRCallback, sizeof(XtCallbackList),
offset(input_callback), XtRCallback, NULL },
#undef offset
};
</literallayout>
<!-- .CE -->
<para>
<!-- .LP -->
The user input callback will be implemented by an action procedure which
passes the event pointer as call_data. The action procedure
is declared as:
<!-- .CB -->
</para>
<literallayout class="monospaced">
/* ARGSUSED */
static void InputAction(w, event, params, num_params)
Widget w;
XEvent *event;
String *params; /* unused */
Cardinal *num_params; /* unused */
{
XtCallCallbacks(w, XtNcallback, (XtPointer)event);
}
static XtActionsRec actions[] =
{
/* {name, procedure}, */
{"input", InputAction},
};
</literallayout>
<!-- .CE -->
<para>
<!-- .LP -->
and the default input binding will be to execute the input callbacks on
<function>KeyPress</function> and <function>ButtonPress : </function>
</para>
<literallayout class="monospaced">
static char translations[] =
" <Key>: input( ) \\n\\
<BtnDown>: input( ) \\
";
</literallayout>
<!-- .CE -->
<para>
In the class record declaration and initialization, the only field that
is different from the Template is the expose procedure:
</para>
<!-- .CB -->
<literallayout class="monospaced">
/* ARGSUSED */
static void Redisplay(w, event, region)
Widget w;
XEvent *event; /* unused */
Region region;
{
XtCallCallbacks(w, XtNexposeCallback, (XtPointer)region);
}
WindowClassRec windowClassRec = {
...
/* expose */ Redisplay,
</literallayout>
<!-- .CE -->
<para>
<!-- .LP -->
<!-- .sp -->
The "WindowWidget" will also declare three public procedures to return the
drawing colors and the font id, saving the application the effort of
constructing an argument list for a call to
<function>XtGetValues :</function>
</para>
<!-- .LP -->
<!-- .CB -->
<literallayout class="monospaced">
Pixel WindowColor1(w)
Widget w;
{
return ((WindowWidget)w)->window.color_1;
}
Pixel WindowColor2(w)
Widget w;
{
return ((WindowWidget)w)->window.color_2;
}
Font WindowFont(w)
Widget w;
{
return ((WindowWidget)w)->window.font->fid;
}
</literallayout>
<para>
The "WindowWidget" is now complete. The application can retrieve the two
drawing colors from the widget instance by calling either
<function>XtGetValues</function>,
or the <function>WindowColor</function> functions. The actual window created for the
"WindowWidget" is available by calling the
<function>XtWindow</function> function.
</para>
</sect1>
|
