Application full screen mode: what changed

Revision 1 to 2. Removed lines have a minus sign; added lines have a plus sign.

Old	New		Line
1	1		## Introduction
2	2
3		-	~~Some applications like some web browsers allow show in full screen mode using key <span class="kbd">F11</span>. In full screen mode window hasn't border and uses entire screen space.~~
	3	+	Some applications like some web browsers allow show in full screen mode using key `F11`. In full screen mode window hasn't border and uses entire screen space.
4	4
5	5		## Standard way
6	6
7	7		You can switch form to full screen mode simply by assigning wsFullScreen value to TForm.WindowState property. You can do that directly in design time in Object Inspector window or in runtime:
8	8
9	9		``` pascal
10	10		procedure TForm1.FormShow(Sender: TObject);
11	11		begin
12	12		WindowState := wsFullScreen;
13	13		end;
14	14		```
15	15
16	16		## Universal way to use full-screen
17	17
18	18		Universal way exists, using LCL, you need to call ShowWindow() with SW_SHOWFULLSCREEN. This ShowWindow call is handled inside widgetset, using low-level API (for example, OS X Carbon API, or GTK2 API). Example:
19	19
20	20		``` pascal
21	21		uses
22	22		..., LCLIntf, LCLType;
23	23
24	24		procedure TfmMain.SetFullScreen_Universal(AValue: boolean);
25	25		begin
26	26		if AValue then
27	27		ShowWindow(Handle, SW_SHOWFULLSCREEN)
28	28		else
29	29		ShowWindow(Handle, SW_SHOWNORMAL);
30	30		//maybe consider here previous maximized state?
31	31		end;
32	32		```
33	33
34	34		## Win32 way to use full-screen
35	35
36	36		Universal way, above, works for Win32, but window border still stays, so better code which works:
37	37
38	38		``` pascal
39	39		procedure TfmMain.SetFullScreen_Win32(AValue: boolean);
40	40		begin
41	41		if AValue then
42	42		begin
43	43		FOrigWndState:= WindowState;
44	44		FOrigBounds:= BoundsRect;
45	45
46	46		BorderStyle:= bsNone;
47	47		BoundsRect:= Monitor.BoundsRect;
48	48		end
49	49		else
50	50		begin
51	51		WindowState:= FOrigWndState;
52	52		BoundsRect:= FOrigBounds;
53	53		BorderStyle:= bsSizeable;
54	54		BoundsRect:= FOrigBounds; //again
55	55		end;
56	56		end;
57	57		```
58	58
59	59		### Win32 example program
60	60
61	61		This is example for Win32 only, since it don't use native full-screen mode on Linux/MacOS, it is here from old times.
62	62
63	63		To be able to switch to full screen mode you will need:
64	64
65	65		- Remember previous form state as position and size and window state
66	66		- Be able to determine screen size
67	67		- Capture some key and perform operation
68	68
69	69		Best way to capture desired key is using Actions. Simply define new action in action manager and assign key shortcut. Than shortcut will work even if main form would lost focus.
70	70
71	71		``` pascal
72	72		unit Unit1;
73	73
74	74		{$mode objfpc}{$H+}
75	75
76	76		interface
77	77
78	78		uses
79	79		Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls,
80	80		Menus;
81	81
82	82		type
83	83		TForm1 = class(TForm)
84	84		procedure FormKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState);
85	85		private
86	86		public
87	87		OriginalBounds: TRect;
88	88		OriginalWindowState: TWindowState;
89	89		ScreenBounds: TRect;
90	90		procedure SwitchFullScreen;
91	91		end;
92	92
93	93		var
94	94		Form1: TForm1;
95	95
96	96		implementation
97	97
98	98		{$R *.lfm}
99	99
100	100		{ TForm1 }
101	101
102	102		procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState);
103	103		begin
104	104		if Key = VK_F11 then
105	105		begin
106	106		SwitchFullScreen;
107	107		Key := 0;
108	108		end;
109	109		end;
110	110
111	111		procedure TForm1.SwitchFullScreen;
112	112		begin
113	113		if BorderStyle <> bsNone then begin
114	114		// To full screen
115	115		OriginalWindowState := WindowState;
116	116		OriginalBounds := BoundsRect;
117	117
118	118		BorderStyle := bsNone;
119	119		BoundsRect := Screen.MonitorFromWindow(Handle).BoundsRect;
120	120		end else begin
121	121		// From full screen
122	122		BorderStyle := bsSizeable;
123	123		if OriginalWindowState = wsMaximized then
124	124		WindowState := wsMaximized
125	125		else
126	126		BoundsRect := OriginalBounds;
127	127		end;
128	128		end;
129	129
130	130		end.
131	131		```
132	132
133	133		### Win32: get task bar size
134	134
135	135		If you want to have task bar visible you have to adjust size according task bar position and size. For Windows:
136	136
137	137		``` pascal
138	138		function GetTaskBarSize: TRect;
139	139		begin
140	140		SystemParametersInfo(SPI_GETWORKAREA, 0, @Result, 0);
141	141		end;
142	142		```
143	143
144	144		## GTK way to use full-screen
145	145
146	146		This is low-level code for GTK2, it is used already by LCL in "universal way" above.
147	147
148	148		To switch form to full screen dimensions:
149	149
150	150		``` pascal
151	151		gdk_window_fullscreen(PGtkWidget(Handle)^.window);
152	152		```
153	153
154	154		To roll back to normal mode:
155	155
156	156		``` pascal
157	157		gdk_window_unfullscreen(PGtkWidget(Handle)^.window);
158	158		```
159	159
160	160		This is GTK2 only. You must add to uses section such modules as gtk2, gdk2, glib2. You can do it by the directive
161	161
162	162		``` pascal
163	163		{$IFDEF LCLGTK2}, gtk2, gdk2, glib2{$ENDIF}
164	164		```
165	165
166	166		## Changing screen resolution
167	167
168	168		There is no OS independent way to switch screen resolution now.
169	169
170	170		For Windows you can find information in article for Delphi [Get and Set Screen Resolution (Display Device Modes)](http://delphi.about.com/od/graphics/a/change_display.htm)
171	171
172	172		## See also
173	173
174	174		- [[WinCE Programming Tips\|WinCE Programming Tips - Making a Fullscreen Application]]
175	175
176	176		## External links
177	177
178	178		- [Run Your Delphi Application in Full Screen - Implement "F11 - Full Screen"](http://delphi.about.com/od/delphitips2010/qt/delphi-application-full-screen-mode-f11.htm)
179	179		- [Very simple way to make your form Fullscreen & Restore (LazPlanet)](http://lazplanet.blogspot.com/2014/02/make-your-form-fullscreen.html)
180	180
181	181		---
182	182		From the Free Pascal wiki, page "Application full screen mode", as it stood on 2020-11-26 after a change by Chronos, 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).
183	183		Category: Lazarus
184	184		Category: Tutorials

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