GTK2 Interface: what changed

Revision 3 to 4. Removed lines have a minus sign; added lines have a plus sign.

Old	New		Line
1	1		(GTK+ only)
2	2
3	3		## Introduction
4	4
5	5		The gtk2 widgetset is stable and all components work. And it needs optimizations.
6	6
7	7		The documentation can be found [here](http://www.gtk.org/).
8	8
9	9		The minimum Gtk 2 version supported is Gtk 2.8
10	10
11	11		## Road map for the gtk2 interface
12	12
13	13		Here: [[Roadmap\|Roadmap#Widgetset_dependent_components]]
14	14
15	15		## Quick start guide for Linux, FreeBSD, etc
16	16
17	17		The first thing to do is to install the gtk2 libraries including the development packages. For example: linux/debian systems call them libgtk2.0-dev. There are complete installers for Windows [here](http://www.gtk.org/).
18	18
19	19		The gtk2 is the default widgetset, so it should work out of the box.
20	20
21	21		You can compile the LCL for gtk2. First open your normal compiled Lazarus. Then go on the menu "Tools" --\> "Configure Build Lazarus". Set LCL to "clean+build" and everything else to "None". Now select "gtk2" and click on the "Ok" button. Next go to the menu "Tools" --\> "Build Lazarus". Now the LCL is compiled for gtk2 too.
22	22
23	23		To compile a project for gtk2 just select it as the target widgetset on the Compiler Options dialog.
24	24
25	25		### Ubuntu Unity liboverlay
26	26
27	27		The Ubuntu's Unity LIBOVERLAY override breaks the gtk_grab_add function, so mouse capturing does not work in synedit, treeview and many more LCL controls that descend from TCustomControl. That means dragging or selecting text with the mouse does not work.
28	28
29	29		This is true for many applications, which is why liboverlay has an internal list to disable itself for many famous applications (e.g. gimp).
30	30
31	31		That's why the gtk2 interface of the LCL disables liboverlay by default. You can enable it by compiling the LCL with -dEnableLibOverlay.
32	32
33	33		If it is enabled: The LCL will write a warning with [[DebugLn]] if it spots liboverlay.
34	34
35	35		To disable liboverlay for a single application set the environment variable LIBOVERLAY_SCROLLBAR to '0' before starting the application. There is no way to disable liboverlay when the application is already running. For example:
36	36
37		-	~~`LIBOVERLAY_SCROLLBAR=0 ./lazarus`~~
	37	+	```text
	38	+	LIBOVERLAY_SCROLLBAR=0 ./lazarus
	39	+	```
38	40
39	41		You can disable it on a whole machine by uninstalling the package "liboverlay-scrollbar-0.2-0".
40	42
41	43		The IDE starter "startlazarus" sets this variable before starting the IDE (since 1.0). startlazarus is called for example when you use the desktop menu item.
42	44
43	45		### Ubuntu Unity Menuproxy
44	46
45	47		In more recent Ubuntu versions, Ubuntu tries to create a "one menubar" look like macOS has, but this fails miserably with multi window programs like Lazarus. The main problem is not being able to access the menu without first selecting the main lazarus window. (the window that would hold the menubar).
46	48
47	49		Turning off seems to be impossible without massive changes (probably that is because then everybody would turn such features off immediately).
48	50
49	51		Turning off manually is possible through setting environment variable UBUNTU_MENUPROXY equal to 0 before starting.
50	52
51	53		UBUNTU_MENUPROXY=0 ./lazarus
52	54
53	55		or put it in a script like:
54	56
55		-	~~`#!/bin/sh`\~~
56		-	~~`export UBUNTU_MENUPROXY=0`\~~
57		-	~~`./startlazarus`~~
	57	+	```text
	58	+	#!/bin/sh
	59	+	export UBUNTU_MENUPROXY=0
	60	+	./startlazarus
	61	+	```
58	62
59	63		### Raspberry Pi OS
60	64
61	65		Note: the following advice is proably not necessary if you have installed libgtk2.0-dev as mentioned further up this page
62	66
63	67		Lazarus GTK2 cannot be compiled by default, because of missing symlinks for libraries. These symlinks are missed:
64	68
65	69		- libgdk-x11-2.0.so
66	70		- libgtk-x11-2.0.so
67	71		- libX11.so
68	72		- libgdk_pixbuf-2.0.so
69	73		- libglib-2.0
70	74		- libgthread-2.0.so
71	75		- libgmodule-2.0.so
72	76		- libpango-1.0.so
73	77		- libcairo.so
74	78		- libatk-1.0.so
75	79
76	80		The existing .so files are located in the "/usr/lib/aarch64-linux-gnu". For all mentioned files, you need to make symlinks like this:
77	81
78		-	~~`cd /usr/lib/aarch64-linux-gnu`\~~
79		-	~~`sudo ln -s libatk-1.0.so.0 libatk-1.0.so`~~
	82	+	```text
	83	+	cd /usr/lib/aarch64-linux-gnu
	84	+	sudo ln -s libatk-1.0.so.0 libatk-1.0.so
	85	+	```
80	86
81	87		## Using the GTK2 interface under macOS
82	88
83	89		### Installing X11
84	90
85	91		If you want to use the gtk widgetset instead of the default Carbon widgetset, then make sure X11 is installed. X11 is no longer included with Mac, but X11 server and client libraries are available from the [XQuartz project](https://www.xquartz.org/). The last XQuartz release was version 2.7.11 on 2016-10-29 for Snow Leopard 10.6.3 or later.
86	92
87	93		How do you know whether X11 is installed? Look in the /Applications/Utilities folder for an application named XQuartz.app. All further details are in /opt/X11/ (soft linked from /usr/X11).
88	94
89	95		Tip - Drag and drop X11 onto the dock so you'll have a one-click way of opening an X11 window.
90	96
91	97		### Installing GTK2-Lazarus with fink
92	98
93	99		Install [Fink](http://www.finkproject.org/), the package manager for macOS. Install the GTK2 version of Lazarus with the following command:
94	100
95		-	~~` fink install lazarus-gtk2`~~
	101	+	```text
	102	+	fink install lazarus-gtk2
	103	+	```
96	104
97	105		You will be asked to install a number of other packages. Simply answer yes. The installation takes quite a while. After it has finished, the GTK2 application can be started with a double click on /Applications/Fink/lazarus.
98	106
99	107		Note: Projects using GTK2 can equally be created using the Aqua version of Lazarus, which is installed with "fink install lazarus-aqua".
100	108
101	109		### Installing gtk using MacPorts
102	110
103	111		Follow these steps to install the libraries using MacPorts. Install MacPorts from [www.macports.org](http://www.macports.org/). When MacPorts is set up, you need to install two library sets using the following commands:
104	112
105		-	~~`sudo /opt/local/bin/port install gtk1`\~~
106		-	~~`sudo /opt/local/bin/port install gdk-pixbuf`~~
	113	+	```text
	114	+	sudo /opt/local/bin/port install gtk1
	115	+	sudo /opt/local/bin/port install gdk-pixbuf
	116	+	```
107	117
108	118		Then make sure that Lazarus can find the library by using the command below before running Lazarus. Alternatively you can add this command to your bash startup script (`/etc/profile` or `~/.bash_profile`) before you start the shell to run Lazarus:
109	119
110		-	~~`export DYLD_FALLBACK_LIBRARY_PATH="/opt/local/lib:$DYLD_FALLBACK_LIBRARY_PATH"`~~
	120	+	```text
	121	+	export DYLD_FALLBACK_LIBRARY_PATH="/opt/local/lib:$DYLD_FALLBACK_LIBRARY_PATH"
	122	+	```
111	123
112	124		If this doesn't work, simply do
113	125
114		-	~~`sudo ln -s /opt/local /sw`~~
	126	+	```text
	127	+	sudo ln -s /opt/local /sw
	128	+	```
115	129
116	130		### Using the GTK2 libraries included with Gimp
117	131
118	132		Now that the Cocoa widgetset is the default for Lazarus on macOS, there probably isn't much need for developing or distributing GTK2-based apps on macOS. However, you might want to test your apps with the GTK2 widgetset to see how well the graphical portion will work under Linux, where GTK2 is likely to be the default. You can also compile Lazarus itself against the GTK2 widgetset if you're curious about how Lazarus looks with GTK2.
119	133
120	134		An easy way to obtain recent GTK2 libraries is to download and install Gimp from <http://www.gimp.org/macintosh/>. Gimp is not only a useful image editor in its own right, but it also installs GTK2 version 2.16.6 libraries that you can link your apps against.
121	135
122	136		Copy and paste the files given below into a text editor and save them as gimplib.cfg and glaunch.sh. File gimplib.cfg tells FPC how to link against the GTK2 libraries; file glaunch.sh initializes GTK2 and starts a GTK2-compiled executable specified on the command line.
123	137
124	138		To compile an app against the GTK2 widgetset and link it with the Gimp GTK2 libraries, do the following:
125	139
126	140		- In the Lazarus Compiler Options dialog, on the Other tab, check Use Additional Compiler Config File and enter the path to gimplib.cfg in the text box (for example, ~/tools/scripts/gimplib.cfg).
127	141		- In the Lazarus Compiler Options dialog, on the Paths tab, select GTK2 as the LCL Widget Type.
128	142		- Choose Run \\| Build.
129	143
130	144		To run a GTK2-compiled executable, open an X11 window, change to your app's folder, and enter the following (which assumes glaunch.sh is in ~/tools/scripts):
131	145
132	146		- ~/tools/scripts/glaunch.sh myexec
133	147
134	148		To compile Lazarus itself, do the following:
135	149
136	150		- Open an X11 window and change to your Lazarus source folder.
137	151		- Make a copy of your Carbon-based Lazarus, in case something goes wrong (cp -p lazarus lazarus-carb).
138	152		- make clean all LCL_PLATFORM=gtk2 FPC=fpc OPT="@~/tools/scripts/gimplib.cfg -dHasX"
139	153
140	154		This will rebuild lazarus, lazbuild and startlazarus. You'll probably want to rename your lazarus executables:
141	155
142	156		- mv lazarus lazarus-gtk2
143	157		- mv lazarus-carb lazarus
144	158
145	159		To run the GTK2-compiled Lazarus:
146	160
147	161		- ~/tools/scripts/glaunch.sh lazarus-gtk2
148	162
149	163		Here is the gimplib.cfg config file. Note that this assumes you installed Gimp in your Applications folder.
150	164
151	165		-k'-headerpad_max_install_names'
152	166		-k'-L/usr/lib'
153	167		-k'-L/usr/X11R6/lib'
154	168		-k'-L/Applications/Gimp.app/Contents/Resources/lib'
155	169		-k'-lgthread-2.0'
156	170
157	171		-k'-dylib_file'
158	172		-k'/tmp/skl/Gimp.app/Contents/Resources/lib/libpangoft2-1.0.0.dylib:/Applications/Gimp.app/Contents/Resources/lib/libpangoft2-1.0.0.dylib'
159	173		-k'-dylib_file'
160	174		-k'/tmp/skl/Gimp.app/Contents/Resources/lib/libz.1.dylib:/Applications/Gimp.app/Contents/Resources/lib/libz.1.dylib'
161	175		-k'-dylib_file'
162	176		-k'/tmp/skl/Gimp.app/Contents/Resources/lib/libpangocairo-1.0.0.dylib:/Applications/Gimp.app/Contents/Resources/lib/libpangocairo-1.0.0.dylib'
163	177		-k'-dylib_file'
164	178		-k'/tmp/skl/Gimp.app/Contents/Resources/lib/libgmodule-2.0.0.dylib:/Applications/Gimp.app/Contents/Resources/lib/libgmodule-2.0.0.dylib'
165	179		-k'-dylib_file'
166	180		-k'/tmp/skl/Gimp.app/Contents/Resources/lib/libintl.8.dylib:/Applications/Gimp.app/Contents/Resources/lib/libintl.8.dylib'
167	181		-k'-dylib_file'
168	182		-k'/tmp/skl/Gimp.app/Contents/Resources/lib/libiconv.2.dylib:/Applications/Gimp.app/Contents/Resources/lib/libiconv.2.dylib'
169	183		-k'-dylib_file'
170	184		-k'/tmp/skl/Gimp.app/Contents/Resources/lib/libcairo.2.dylib:/Applications/Gimp.app/Contents/Resources/lib/libcairo.2.dylib'
171	185		-k'-dylib_file'
172	186		-k'/tmp/skl/Gimp.app/Contents/Resources/lib/libfreetype.6.dylib:/Applications/Gimp.app/Contents/Resources/lib/libfreetype.6.dylib'
173	187		-k'-dylib_file'
174	188		-k'/tmp/skl/Gimp.app/Contents/Resources/lib/libfontconfig.1.dylib:/Applications/Gimp.app/Contents/Resources/lib/libfontconfig.1.dylib'
175	189		-k'-dylib_file'
176	190		-k'/tmp/skl/Gimp.app/Contents/Resources/lib/libexpat.1.dylib:/Applications/Gimp.app/Contents/Resources/lib/libexpat.1.dylib'
177	191		-k'-dylib_file'
178	192		-k'/tmp/skl/Gimp.app/Contents/Resources/lib/libXrender.1.dylib:/Applications/Gimp.app/Contents/Resources/lib/libXrender.1.dylib'
179	193		-k'-dylib_file'
180	194		-k'/tmp/skl/Gimp.app/Contents/Resources/lib/libtiff.3.dylib:/Applications/Gimp.app/Contents/Resources/lib/libtiff.3.dylib'
181	195		-k'-dylib_file'
182	196		-k'/tmp/skl/Gimp.app/Contents/Resources/lib/libjpeg.62.dylib:/Applications/Gimp.app/Contents/Resources/lib/libjpeg.62.dylib'
183	197		-k'-dylib_file'
184	198		-k'/tmp/skl/Gimp.app/Contents/Resources/lib/libpng12.0.dylib:/Applications/Gimp.app/Contents/Resources/lib/libpng12.0.dylib'
185	199		-k'-dylib_file'
186	200		-k'/tmp/skl/Gimp.app/Contents/Resources/lib/libXinerama.1.dylib:/Applications/Gimp.app/Contents/Resources/lib/libXinerama.1.dylib'
187	201		-k'-dylib_file'
188	202		-k'/tmp/skl/Gimp.app/Contents/Resources/lib/libpixman-1.0.dylib:/Applications/Gimp.app/Contents/Resources/lib/libpixman-1.0.dylib'
189	203		-k'-dylib_file'
190	204		-k'/tmp/skl/Gimp.app/Contents/Resources/lib/libgio-2.0.0.dylib:/Applications/Gimp.app/Contents/Resources/lib/libgio-2.0.0.dylib'
191	205		-k'-dylib_file'
192	206		-k'/tmp/skl/Gimp.app/Contents/Resources/lib/libjasper.1.dylib:/Applications/Gimp.app/Contents/Resources/lib/libjasper.1.dylib'
193	207
194	208		Here is the glaunch.sh script file:
195	209
196	210		#!/bin/sh
197	211
198	212		TMP="/tmp/$UID/TemporaryItems"
199	213		GRES="Gimp.app/Contents/Resources"
200	214		GIMP="/Applications/$GRES"
201	215		if ! [ -e "$GIMP" ]
202	216		then
203	217		GIMP="~/Desktop/$GRES"
204	218		if ! [ -e "$GIMP" ]
205	219		then
206	220		GIMP="~/$GRES"
207	221		if ! [ -e "$GIMP" ]
208	222		then
209	223		GIMP="~/Applications/$GRES"
210	224		if ! [ -e "$GIMP" ]
211	225		then
212	226		GIMP=""
213	227		fi
214	228		fi
215	229		fi
216	230		fi
217	231
218	232		if [ "$GIMP" = "" ]
219	233		then
220	234		echo "Can't locate Gimp"
221	235		else
222	236		export "DYLD_FORCE_FLAT_NAMESPACE=1"
223	237		export "DYLD_INSERT_LIBRARIES=/usr/lib/libiconv.dylib"
224	238		export "DYLD_LIBRARY_PATH=/System/Library/Frameworks/ApplicationServices.framework/Versions/A/Frameworks/ImageIO.framework/Versions/A/Resources:$GIMP/lib"
225	239		export "PANGO_RC_FILE=$TMP/pangorc"
226	240		export "FONTCONFIG_PATH=$GIMP/etc/fonts"
227	241		export "GTK_IM_MODULE_FILE=$TMP/gtk.immodules"
228	242		export "GDK_PIXBUF_MODULE_FILE=$TMP/gdk-pixbuf.loaders"
229	243		export "GTK_DATA_PREFIX=$GIMP"
230	244		export "GTK_EXE_PREFIX=$GIMP"
231	245
232	246		mkdir -p "$TMP"
233	247		sed 's\|/tmp/skl/Gimp.app/Contents/Resources/etc/pango\|'"$TMP\|g" "$GIMP/etc/pango/pangorc" > "$TMP/pangorc"
234	248		sed 's\|/tmp/skl/Gimp.app/Contents/Resources\|'"$GIMP\|g" "$GIMP/etc/pango/pango.modules" > "$TMP/pango.modules"
235	249		cp -f "$GIMP/etc/pango/pangox.aliases" "$TMP"
236	250		sed 's\|/tmp/skl/Gimp.app/Contents/Resources\|'"$GIMP\|g" "$GIMP/etc/gtk-2.0/gtk.immodules" > "$TMP/gtk.immodules"
237	251		sed 's\|/tmp/skl/Gimp.app/Contents/Resources\|'"$GIMP\|g" "$GIMP/etc/gtk-2.0/gdk-pixbuf.loaders" > "$TMP/gdk-pixbuf.loaders"
238	252
239	253		./$1
240	254		fi
241	255
242	256		## Using the Gtk2 interface under Microsoft Windows
243	257
244	258		### Getting the needed Gtk2 libraries
245	259
246	260		Using the Gtk2 libraries from gtk.org:
247	261
248	262		- <http://www.gtk.org/download>
249	263
250	264		or using the GTK-Runtime project:
251	265
252	266		- <https://gtk-win.sourceforge.io>
253	267
254	268		or using the Gtk2 libraries provided by Gimp:
255	269
256	270		- <http://gimp-win.sourceforge.net/stable.html>
257	271
258	272		### Standalone Application under Windows
259	273
260	274		You may prefer a standalone application to avoid versions conflicts. All needed libraries are in the packages mentioned above. They should be placed in the same folder of your executable. You will need all these libraries:
261	275
262	276		- libcairo-2.dll
263	277		- libglib-2.0-0.dll
264	278		- libpangocairo-1.0-0.dll
265	279		- libpng12.dll
266	280		- libgdk-win32-2.0-0.dll
267	281		- libgmodule-2.0-0.dll
268	282		- libgtk-win32-2.0-0.dll
269	283		- libatk-1.0-0.dll
270	284		- libgdk_pixbuf-2.0-0.dll
271	285		- libgobject-2.0-0.dll
272	286		- libpango-1.0-0.dll
273	287		- libpangowin32-1.0-0.dll
274	288		- libgio-2.0-0.dll
275	289		- zlib1.dll
276	290
277	291		### Themes
278	292
279	293		The default GTK2 interface is quite ugly and not very integrated with the Windows Desktop. Your GTK2 application may use the Windows Theme if you use the [gtk-wimp project](http://gtk-wimp.sourceforge.net/). Into your application's folder you should add the following files ([Available here](http://sourceforge.net/project/showfiles.php?group_id=76416)):
280	294
281	295		- .\lib\gtk-2.0\engines\libwimp.dll
282	296		- .\share\themes\Raleigh\gtk-2.0\gtkrc
283	297
284	298		### A sample project
285	299
286	300		A complete and working "Hello world" project (with sources) is available [here](http://www.lazarusforum.de/lazwiki/winGTK2_Demo.zip).
287	301
288	302		![](/wiki-images/b/b1/WinGTK2.png)
289	303
290	304		## Current issues
291	305
292	306		Here are some notes about some of the current issues. It is not a complete list, but mainly a collection of the information about some of the most annoying problems, that can not be solved simply.
293	307
294	308		### Editor Options allows to select incompatible fonts
295	309
296	310		TFontDialog must be extended to show only monospace fonts by default and only if the users insists show all fonts.
297	311
298	312		### Moving with keys in the OI sometimes does not move the edit field
299	313
300	314		ToDo
301	315
302	316		### Destroying handle during OnKeyDown gives AV
303	317
304	318		This is a more general problem, not only KeyDown. There are two solutions:
305	319
306	320		- Increase reference counters of all used widgets during events. Difficult to maintain and we will never be sure to ref count every used widget.
307	321		- Instead of destroying widgets immediately, hide them, untie them and put them into a queue. The widgets will then be destroyed in the message loop and on gtk intf shut down.
308	322
309	323		### Z-Order of controls
310	324
311	325		In Gtk2 many controls don't have a window, so they are just painted on their parent. This makes they be painted before controls with a window, so we get a wrong Z-Order.
312	326
313	327		Here is a list of gtk widgets that don't have windows: <https://developer.gnome.org/gtk-tutorial/stable/x481.html>
314	328
315	329		The solution is adding a GtkEventBox under each of these widgets: <https://developer.gnome.org/gtk-tutorial/stable/c1226.html#SEC-EVENTBOX>
316	330
317	331		Bug reports
318	332
319	333		- <http://bugs.freepascal.org/view.php?id=964>
320	334		- <http://bugs.freepascal.org/view.php?id=8346>
321	335
322	336		### Open Dialog Options
323	337
324	338		TOpenDialog has several options to control the dialog. When implementing these options in Gtk2, however, one needs to watch out because of the vast amount of bugs in Gtk 2, which may prevent the options from working. For example, ofForceShowHidden doesn't work because of Gtk 2 bugs, althougth it is implemented correctly.
325	339
326	340		Bug reports
327	341
328	342		- ofForceShowHidden - <http://bugs.freepascal.org/view.php?id=8473>
329	343
330	344		### TScrollBox and Scrolling problems
331	345
332	346		TScrollBox and Scrolling seems deeply broken in Gtk 2.
333	347
334	348		Bug reports
335	349
336	350		- <http://bugs.freepascal.org/view.php?id=10779>
337	351		- <http://bugs.freepascal.org/view.php?id=10952>
338	352		- <http://bugs.freepascal.org/view.php?id=9049>
339	353		- <http://bugs.freepascal.org/view.php?id=11010>
340	354
341	355		### Shortcut keys
342	356
343	357		Bug reports
344	358
345	359		- <http://bugs.freepascal.org/view.php?id=1946>
346	360		- <http://bugs.freepascal.org/view.php?id=7249>
347	361		- <http://bugs.freepascal.org/view.php?id=10282>
348	362
349	363		### Up/Down key navigation between TEdits
350	364
351	365		A standard Gtk 2 feature allows the use of up/down key to navigate between GtkEntry widgets (like TEdits), but this is undesirable if the user implements a dropdrow list to be attached to the TEdit. As we cannot know what code the user has written, the best option is to disable this feature. Possible ways to do that are:
352	366
353	367		- Listen to key press events of GtkEntry and for Up/Down events shift the focus to implemented widget.
354	368		- Don't propagate Up/Down key press events to GtkEntry.
355	369
356	370		As of lazarus 0.9.31 r31562 GtkEntry behaviour is same as under other widgetsets - NO FOCUS CHANGING BY VK_UP or VK_DOWN.
357	371
358	372		Bug reports
359	373
360	374		- <http://bugs.freepascal.org/view.php?id=11115>
361	375
362	376		## Done issues
363	377
364	378		### Done: ~~Synedit is very slow~~
365	379
366	380		Actually this is not a bug of the gtk2 intf, but a problem of gtk2 and some video drivers. On some systems SynEdit is as fast as any other text editor. Some bugs were fixed with gtk 2.12. SynEdit already paints every token with the ExtTextOut function. It does not use a TCanvas text function, which would be even slower.
367	381
368	382		Bug Tracker item: <http://www.freepascal.org/mantis/view.php?id=7717>
369	383
370	384		For people using the Nvidia drivers, setting GlyphCache=1 may speed up SynEdit. You will need the beta-drivers: <http://www.nvnews.net/vbulletin/showthread.php?s=399832e3761a522d34db6faaf8423ad9&t=118088>
371	385
372	386		### Done: ~~Small TButton does not center text~~
373	387
374	388		Actually the text is centered, but some themes (like the default under ubuntu) define a big minimum space above and below the label. The gtk2 default is not that big. So, it is a user setting.
375	389
376	390		- a\) It might be possible to override this setting and set the space to 0.
377	391		- Pro: Most small autosize buttons would look better.
378	392		- Cons: the AutoSize would be incorrect. And the bug is still there for themes with big text.
379	393		- b\) set the interface constraint to the gtk_button normal height.
380	394		- Pro: there are no small buttons.
381	395		- Con: Enlarging a button requires autosizing all surrounding controls too. And you need a nice auto shrink feature, which does not exist yet.
382	396		- c\) Set the space to 0 and when calculating the preferred size, restore temporarily the space size.
383	397		- Pro: Most small buttons will look better, autosize will still work.
384	398		- Con: Most difficult solution to implement. Maybe not possible without a hack.
385	399
386	400		Bug Reports
387	401
388	402		- <http://bugs.freepascal.org/view.php?id=11120>
389	403		- <http://bugs.freepascal.org/view.php?id=8765>
390	404
391	405		### Done: ~~TOpenPictureDialog does not update the preview~~
392	406
393	407		### Done: ~~Only the main form appears in the window list~~
394	408
395	409		Probably a bug in the window hints parameters.
396	410
397	411		### Done: ~~Slow and visible resizing when creating/resizing a dialog~~
398	412
399	413		This has several reasons, which fall into 3 categories:
400	414
401	415		1\. Too many resizes. Status: Acceptable.
402	416
403	417		2\. Slow painting. Status: It seems other gtk2 apps are as slow, so maybe it is a gtk2 issue.
404	418
405	419		3\. Some resizes happen after painting. Status: Acceptable.
406	420
407	421		- The application does not resize the controls in one step, but in many small steps. For example: It resizes a control in several small steps SetBounds, AnchorParallel, ... . Or first the the Form is resized, then the a TPageControl, then a TButton, ... . Solution: The LCL sets BeginAlign/EndAlign during loading/creation.
408	422		- If there are anchored or autosized controls, every resize triggers the resize system of the the LCL. The LCL tries to combine many resizes during csLoading and Begin/EndAlign. During creation the LCL still sends several times the bounds to the interface. ToDo Solution: Send bounds not during BeginAlign (including parents), but send them all in EndAlign.
409	423		- The hen-egg problem. In order to autosize, the LCL needs the current gtk theme sizes. The current gtk theme sizes can only be calculated by creating a handle. When you create a handle you need the size. Solution: Create some hidden widgets to test the current gtk sizes. This already works for TCustomGroupBox and descendants. ToDo: the other controls.
410	424		- The gtk does not resize immediately, but puts resizes on a queue and resizes later. These values are stored in private, hidden variables. Especially if you resize a TGroupBox, the inner borders are updated later by the gtk. That means the GetClientRect function is not reliable during resizing. That's why the LCL first works with the wrong ClientRect. Solution: The LCL anticipates the new ClientRect based on the old. And there is now a GetDefaultClientRect function to ask the interface for an estimation of the ClientRect.
411	425		- The gtk1 intf caches LCL resize requests. This accelerates many typical overhead, but it only works with delayed painting and creates flicker during creation and resizing a form never works smooth. The delayed painting breaks the gtk2 double buffering and special paint contexts (opengl), so this trick is disabled under gtk2 and therefore the delayed resize does not work under gtk2.
412	426		- Top level controls, like TForm can not move/resize freely. The window manager decides, what is possible. Often they take only the first position/size request and ignores the later changes. And even worse: first the window is created, realized, then resized, then mapped and 'shown' and finally moved to the final position. So, if the gtk intf asks the gtk where a form is during creation, it will most of the time get 0,0, even though it told the gtk to move the window long ago. Because this is a more general problem (not gtk specific, but X), the LCL tries avoids asking the interface for coords and only asks on rare occasions like LM_SIZE, LM_MOVE messages coming from the interface or if told to do so.
413	427		- The LCL expects a LM_SIZE message on resize, including window state changes like iconify/maximize. But the gtk first notifies about the change and then resizes. ToDo: 1. Maybe: Omit the message, if the state does not change (is this Delphi compatible?). 2. Send the current window state with the normal resizes (Should work for maximize and restore from maximize). 3. Find a solution for iconify and restore from iconify.
414	428
415	429		Things done to handle the above issues:
416	430
417	431		- The gtk2 intf now calls gtk_widget_size_allocate when resizing widgets. This initializes the Widget^.allocation, so that further reads by the LCL no longer give old values.
418	432		- Resizes of child widgets (not gtkwindow or not top level) are now given to the gtk immediately. This does not resize immediately, but together with other changes this resizes earlier, reducing the total number of resizes.
419	433		- gtk resize events are now given almost always directly to the LCL. The only exception is gtkwindow and the client areas (gtk_fixed). The gtk resize events come bottom up, so the client areas are always triggered before the widget itself is resized.
420	434		- The gtk intf now checks the mapped attribute for gtkwindow, which seems finally to work reliable under gtk2. This means the gtk intf no longer send window positions to the LCL, before the window is really moved.
421	435		- In order to let the LCL resize during component/handle creation, the new function GetDefaultClientRect allows every widget class to provide a nice clientrect even before the handle is created. This is done by using the hidden style widgets of the gtk intf.
422	436
423	437		### Done: ~~Selecting a TPage in the designer gives the wrong bounds rectangle~~
424	438
425	439		GetClientOrigin needed extra code for TNotebook, which does not have a normal client area.
426	440
427	441		### Done: ~~Sometimes the hint window of the component palette is not resized~~
428	442
429	443		Sometimes the gtk does not resize the gdkwindow. This is now forced and it seems to fix this problem.
430	444
431	445		### Done: ~~gtk criticals in IDE codetools options dialog~~
432	446
433	447		Empty comboboxes do not have all private structures, so you can not set callbacks.
434	448
435	449		### Done: System Colors
436	450
437	451		The system colors depend on the theme, but many themes don't give adequate colors and many controls use system colors, so we need them to have a correct value. To solve this, a list of ignored system colors was constructed, and in case the user sets any of these colors, it is ignored and the default theme color is used instead.
438	452
439	453		List of colors which were tested and need to be ignored for the correct functioning of programs:
440	454
441	455		- clBtnFace - Otherwise Notebooks and Buttons look bad
442	456
443	457		Bug reports
444	458
445	459		- <http://bugs.freepascal.org/view.php?id=8684>
446	460
447	461		## Gtk1/Gtk2 separation roadmap
448	462
449	463		List of already separated elements:
450	464
451	465		- gtk2wscomctrls --- gtkwscomctrls
452	466		- gtk2wsdialogs --- gtkwsdialogs
453	467		- gtk2wsspin --- gtkwsspin
454	468		- gtk2wscalendar --- gtkwscalendar
455	469
456	470		Next tasks:
457	471
458	472		- Rework of the events system
459	473		- Rework of private classes
460	474
461	475		## Profiling
462	476
463	477		There are various compiler switches:
464	478
465	479		- VerboseSizeMsg - This will show you all changes and messages, with coords and reasons. Even for simple forms this gives a lot of output.
466	480		- DisableLoadedClientSize - This will ignore the ClientWidth/Height stored in the .lfm/.lrs files. This way you can somehow simulate, what happens, if you start an application under a different theme.
467	481
468	482		---
469	483		From the Free Pascal wiki, page "GTK2 Interface", as it stood on 2022-11-25 after a change by Dbannon, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's [[Licensing]] page. If you have concerns about this material, [message the admin](/wiki-contact).

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