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
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!--Converted with LaTeX2HTML 2002-2-1 (1.70)
original version by: Nikos Drakos, CBLU, University of Leeds
* revised and updated by: Marcus Hennecke, Ross Moore, Herb Swan
* with significant contributions from:
Jens Lippmann, Marek Rouchal, Martin Wilck and others -->
<HTML>
<HEAD>
<TITLE>1 Class and object hierarchies</TITLE>
<META NAME="description" CONTENT="1 Class and object hierarchies">
<META NAME="keywords" CONTENT="ionnotes">
<META NAME="resource-type" CONTENT="document">
<META NAME="distribution" CONTENT="global">
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
<META NAME="Generator" CONTENT="LaTeX2HTML v2002-2-1">
<META HTTP-EQUIV="Content-Style-Type" CONTENT="text/css">
<LINK REL="STYLESHEET" HREF="ionnotes.css">
<LINK REL="next" HREF="node3.html">
<LINK REL="previous" HREF="node1.html">
<LINK REL="up" HREF="ionnotes.html">
<LINK REL="next" HREF="node3.html">
</HEAD>
<BODY >
<DIV CLASS="navigation"><!--Navigation Panel-->
<A NAME="tex2html82"
HREF="node3.html">
<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A>
<A NAME="tex2html76"
HREF="ionnotes.html">
<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A>
<A NAME="tex2html70"
HREF="node1.html">
<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A>
<A NAME="tex2html78"
HREF="node1.html">
<IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A>
<A NAME="tex2html80"
HREF="node8.html">
<IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index" SRC="index.png"></A>
<BR>
<B> Next:</B> <A NAME="tex2html83"
HREF="node3.html">2 Object system implementation</A>
<B> Up:</B> <A NAME="tex2html77"
HREF="ionnotes.html">Ion: Notes for the</A>
<B> Previous:</B> <A NAME="tex2html71"
HREF="node1.html">Contents</A>
<B> <A NAME="tex2html79"
HREF="node1.html">Contents</A></B>
<B> <A NAME="tex2html81"
HREF="node8.html">Index</A></B>
<BR>
<BR></DIV>
<!--End of Navigation Panel-->
<!--Table of Child-Links-->
<A NAME="CHILD_LINKS"><STRONG>Subsections</STRONG></A>
<UL CLASS="ChildLinks">
<LI><A NAME="tex2html84"
HREF="node2.html#SECTION00021000000000000000"><SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">1</SPAN> Class hierarchy</A>
<LI><A NAME="tex2html85"
HREF="node2.html#SECTION00022000000000000000"><SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN> Object hierarchies: WRegion parents and managers</A>
<UL>
<LI><A NAME="tex2html86"
HREF="node2.html#SECTION00022100000000000000"><SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">1</SPAN> Parent-child relations</A>
<LI><A NAME="tex2html87"
HREF="node2.html#SECTION00022200000000000000"><SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">2</SPAN> Manager-managed relations</A>
</UL>
<BR>
<LI><A NAME="tex2html88"
HREF="node2.html#SECTION00023000000000000000"><SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">3</SPAN> Summary</A>
</UL>
<!--End of Table of Child-Links-->
<HR>
<H1><A NAME="SECTION00020000000000000000"></A>
<A NAME="sec:objects"></A>
<BR>
<SPAN CLASS="arabic">1</SPAN> Class and object hierarchies
</H1>
<P>
While Ion does not not have a truly object-oriented design
<A NAME="tex2html1"
HREF="#foot214"><SUP><SPAN CLASS="arabic">1</SPAN></SUP></A>,
things that appear on the computer screen are, however, quite
naturally expressed as such ''objects''. Therefore Ion implements
a rather primitive OO system for these screen objects and some
other things.
<P>
It is essential for the module writer to learn this object
system, but also people who write their own binding configuration files
necessarily come into contact with the class and object hierarchies
- you need to know which binding setup routines apply where,
and what functions can be used as handlers in which bindings.
It is the purpose of this section to attempt to explain these
hierarchies. If you do not wish the read the full section, at least
read the summary at the end of it, so that you understand the very
basic relations.
<P>
For simplicity we consider only the essential-for-basic-configuration
Ioncore, <SPAN CLASS="textit">mod_ionws</SPAN> and <SPAN CLASS="textit">mod_query</SPAN> classes.
See Appendix <A HREF="#app:fullhierarchy"><IMG ALIGN="BOTTOM" BORDER="1" ALT="[*]" SRC="crossref.png"></A> for the full class hierachy visible
to Lua side.
<P>
<H2><A NAME="SECTION00021000000000000000">
<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">1</SPAN> Class hierarchy</A>
</H2>
<P>
One of the most important principles of object-oriented design methodology
is inheritance; roughly how classes (objects are instances of classes)
extend on others' features. Inheritance gives rise to class hierarchy.
In the case of single-inheritance this hierarchy can be expressed as a
tree where the class at the root is inherited by all others below it
and so on. Figure <A HREF="#fig:classhierarchy">1</A> lists out the Ion class
hierarchy and below we explain what features of Ion the classes
implement.
<P>
<DIV ALIGN="CENTER"><A NAME="fig:classhierarchy"></A><A NAME="312"></A>
<TABLE>
<CAPTION ALIGN="BOTTOM"><STRONG>Figure 1:</STRONG>
Ioncore, <SPAN CLASS="textit">mod_ionws</SPAN> and <SPAN CLASS="textit">mod_query</SPAN> class hierarchy.</CAPTION>
<TR><TD><PRE>
Obj
|-->WRegion
| |-->WClientWin
| |-->WWindow
| | |-->WRootWin
| | |-->WMPlex
| | | |-->WScreen
| | | |-->WFrame
| | |-->WInput (mod_query)
| | |-->WEdln (mod_query)
| | |-->WMessage (mod_query)
| |-->WGenWS
| |-->WIonWS (mod_ionws)
|-->WSplit (mod_ionws)
</PRE></TD></TR>
</TABLE>
</DIV>
<P>
The core classes:
<P>
<DL>
<DT><STRONG>Obj</STRONG></DT>
<DD><A NAME="318"></A>
Is the base of Ion's object system.
<P>
</DD>
<DT><STRONG>WRegion</STRONG></DT>
<DD><A NAME="319"></A>
is the base class for everything corresponding to something on the
screen. Each object of type WRegion has a size and position
relative to the parent WRegion. While a big part of Ion
operates on these instead of more specialised classes, WRegion
is a ''virtual'' base class in that there are no objects of ''pure''
type WRegion; all concrete regions are objects of some class
that inherits WRegion.
<P>
</DD>
<DT><STRONG>WClientWin</STRONG></DT>
<DD><A NAME="320"></A> is a class for
client window objects, the objects that window managers are
supposed to manage.
<P>
</DD>
<DT><STRONG>WWindow</STRONG></DT>
<DD><A NAME="321"></A> is the base class for all
internal objects having an X window associated to them
(WClientWins also have X windows associated to them).
<P>
</DD>
<DT><STRONG>WRootWin</STRONG></DT>
<DD><A NAME="322"></A> is the class for
root windows<A NAME="244"></A> of X screens<A NAME="245"></A>.
Note that an ''X screen'' or root window is not necessarily a
single physical screen<A NAME="246"></A> as a root window
may be split over multiple screens when multi-head extensions
such as Xinerama<A NAME="247"></A> are used. (Actually there
can be only one WRootWin when Xinerama is used.)
<P>
</DD>
<DT><STRONG>WMPlex</STRONG></DT>
<DD>is a base class for all regions that''multiplex''
other regions. This means that of the regions managed by the multiplexer,
only one can be displayed at a time. Classes that inhereit WMPlex
include screens and frames.
<P>
</DD>
<DT><STRONG>WScreen</STRONG></DT>
<DD><A NAME="323"></A> is the class for objects
corresponding to physical screens. Screens may share a root
window when Xinerama multihead extensions are used as explained
above.
<P>
</DD>
<DT><STRONG>WFrame</STRONG></DT>
<DD><A NAME="324"></A> is the class for frames.
While most Ion's objects have no graphical presentation, frames basically
add to WMPlexes the decorations around client windows
(borders, tabs).
<P>
</DD>
<DT><STRONG>WGenWS</STRONG></DT>
<DD><A NAME="325"></A> is a light base class for
different types of workspaces.
</DD>
</DL>
<P>
Classes implemented by the ionws module:
<P>
<DL>
<DT><STRONG>WIonWS</STRONG></DT>
<DD><A NAME="326"></A> is the class for the
usual tiled workspaces.
</DD>
<DT><STRONG>WSplit</STRONG></DT>
<DD><A NAME="327"></A> (or, more specifically, classes
that inherit it) encode the WIonWS tree structure.
</DD>
</DL>
<P>
Classes implemented by the query module:
<P>
<DL>
<DT><STRONG>WInput</STRONG></DT>
<DD><A NAME="328"></A> is a virtual base class for the
two classes below.
</DD>
<DT><STRONG>WEdln</STRONG></DT>
<DD><A NAME="329"></A> is the class for the ''queries'',
the text inputs that usually appear at bottoms of frames and sometimes
screens. Queries are the functional equivalent of ''mini buffers'' in
many text editors.
</DD>
<DT><STRONG>WMessage</STRONG></DT>
<DD><A NAME="330"></A> implements the boxes for
warning and other messages that Ion may wish to display to the user.
These also usually appear at bottoms of frames.
</DD>
</DL>
<P>
<H2><A NAME="SECTION00022000000000000000">
<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN> Object hierarchies: WRegion parents and managers</A>
</H2>
<P>
<H3><A NAME="SECTION00022100000000000000">
<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">1</SPAN> Parent-child relations</A>
</H3>
Each object of type WRegion has a parent and possibly a manager
associated to it. The parent<A NAME="277"></A> for an object is always a
WWindow and for WRegion with an X window (WClientWin,
WWindow) the parent WWindow is given by the same relation of
the X windows. For other WRegions the relation is not as clear.
There is generally very few restrictions other than the above on the
parent--child relation but the most common is as described in
Figure <A HREF="#fig:parentship">2</A>.
<P>
<DIV ALIGN="CENTER"><A NAME="fig:parentship"></A><A NAME="288"></A>
<TABLE>
<CAPTION ALIGN="BOTTOM"><STRONG>Figure 2:</STRONG>
Most common parent-child relations</CAPTION>
<TR><TD><PRE>
WRootWins
|-->WScreens
|-->WIonWSs
|-->WClientWins in full screen mode
|-->WFrames
|-->WClientWins, including transients
|-->a possible WEdln or WMessage
</PRE></TD></TR>
</TABLE>
</DIV>
<P>
WRegions have very little control over their children as a parent.
The manager<A NAME="292"></A> WRegion has much more control over its
managed WRegions. Managers, for example, handle resize requests,
focusing and displaying of the managed regions. Indeed the manager--managed
relationship gives a better picture of the logical ordering of objects on
the screen. Again, there are generally few limits, but the most common
hierarchy is given in Figure <A HREF="#fig:managership">3</A>. Note that sometimes
the parent and manager are the same object and not all objects may have
a manager (e.g. the dock in the dock module at the time of writing this)
but all have a parent-a screen if not anything else.
<P>
<H3><A NAME="SECTION00022200000000000000">
<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">2</SPAN>.<SPAN CLASS="arabic">2</SPAN> Manager-managed relations</A>
</H3>
<P>
<DIV ALIGN="CENTER"><A NAME="fig:managership"></A><A NAME="300"></A>
<TABLE>
<CAPTION ALIGN="BOTTOM"><STRONG>Figure 3:</STRONG>
Most common manager-managed relations</CAPTION>
<TR><TD><PRE>
WRootWins
|-->WScreens
|-->full screen WClientWins
| |-->transient WClientWins (dialogs)
|-->WScratchpad
|-->WIonWSs/WFloatWS/WPaneWS
|-->WFrames
| |-->WClientWins
| | |-->transient WClientWins (dialogs)
| |-->possibly a WEdln or WMessage
|-->WIonWSs/WFloatWS/WPaneWS
</PRE></TD></TR>
</TABLE>
</DIV>
<P>
Note that a workspace can manage another workspace. This can be
achieved with the <A HREF="#fn:attach_new"><TT>attach_new</TT></A> function, and allows you to nest
workspaces as deep as you want.
<P>
<H2><A NAME="SECTION00023000000000000000">
<SPAN CLASS="arabic">1</SPAN>.<SPAN CLASS="arabic">3</SPAN> Summary</A>
</H2>
<P>
In the standard setup, keeping queries, messages and menus out of
consideration:
<P>
<UL>
<LI>The top-level objects that matter are screens and they correspond
to physical screens. The class for screens is WScreen.
</LI>
<LI>Screens contain (multiplex) workspaces and full screen client
windows. Only one of them can be viewed at a time.
Workspace classes are WIonWS and WFloatWS
for the two different types of workspaces (and WGenWS).
</LI>
<LI>Frames are managed by workspaces. Frames are the objects with
decorations such as tabs and borders.
</LI>
<LI>Frames contain (multiplex) client windows, to each of which
corresponds a tab in the frame's decoration. Only one client
window (or other object) can be shown at a time in each frame.
The class for client windows is WClientWin.
</LI>
</UL>
<P>
<BR><HR><H4>Footnotes</H4>
<DL>
<DT><A NAME="foot214">... design</A><A
HREF="node2.html#tex2html1"><SUP><SPAN CLASS="arabic">1</SPAN></SUP></A></DT>
<DD>the author doesn't like such artificial designs
</DD>
</DL>
<DIV CLASS="navigation"><HR>
<!--Navigation Panel-->
<A NAME="tex2html82"
HREF="node3.html">
<IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="next.png"></A>
<A NAME="tex2html76"
HREF="ionnotes.html">
<IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="up.png"></A>
<A NAME="tex2html70"
HREF="node1.html">
<IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="prev.png"></A>
<A NAME="tex2html78"
HREF="node1.html">
<IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="contents.png"></A>
<A NAME="tex2html80"
HREF="node8.html">
<IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index" SRC="index.png"></A>
<BR>
<B> Next:</B> <A NAME="tex2html83"
HREF="node3.html">2 Object system implementation</A>
<B> Up:</B> <A NAME="tex2html77"
HREF="ionnotes.html">Ion: Notes for the</A>
<B> Previous:</B> <A NAME="tex2html71"
HREF="node1.html">Contents</A>
<B> <A NAME="tex2html79"
HREF="node1.html">Contents</A></B>
<B> <A NAME="tex2html81"
HREF="node8.html">Index</A></B> </DIV>
<!--End of Navigation Panel-->
</BODY>
</HTML>
|
