Difference between revisions of "Application full screen mode"
(Applies to Lazarus development, not really FPC development, so category is useful) |
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==Introduction== | ==Introduction== | ||
Revision as of 20:18, 17 April 2014
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Introduction
Some applications like some web browsers allow show in full screen mode using key F11. In full screen mode window haven't border and title bar and use entire screen space. Task bar is hidden too.
To be able to switch to fullscreen mode you will need:
- Remember previous form state as position and size and window state
- Be able to determine screen size
- Capture some key and perform operation
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.
Example program
unit Unit1;
{$mode objfpc}{$H+}
interface
uses
Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls,
Menus;
type
{ TForm1 }
TForm1 = class(TForm)
procedure FormKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState);
private
public
OriginalBounds: TRect;
OriginalWindowState: TWindowState;
ScreenBounds: TRect;
procedure SwitchFullScreen;
end;
var
Form1: TForm1;
implementation
{$R *.lfm}
{ TForm1 }
procedure TForm1.FormKeyDown(Sender: TObject; var Key: Word; Shift: TShiftState
);
const
KeyF11 = 122;
begin
if Key = KeyF11 then SwitchFullScreen;
end;
procedure TForm1.SwitchFullScreen;
begin
if BorderStyle <> bsNone then begin
// To full screen
OriginalWindowState := WindowState;
OriginalBounds := BoundsRect;
BorderStyle := bsNone;
ScreenBounds := Screen.MonitorFromWindow(Handle).BoundsRect;
with ScreenBounds do
SetBounds(Left, Top, Right - Left, Bottom - Top) ;
end else begin
// From full screen
{$IFDEF MSWINDOWS}
BorderStyle := bsSizeable;
{$ENDIF}
if OriginalWindowState = wsMaximized then
WindowState := wsMaximized
else
with OriginalBounds do
SetBounds(Left, Top, Right - Left, Bottom - Top) ;
{$IFDEF LINUX}
BorderStyle := bsSizeable;
{$ENDIF}
end;
end;
end.
Get task bar size
If you want to have task bar visible you have to adjust size according task bar position and size.
For Windows:
function GetTaskBarSize: TRect;
begin
SystemParametersInfo(SPI_GETWORKAREA, 0, @Result, 0);
end;
GTK way to switch to fullscreen mode
To switch form to full screen dimensions:
gdk_window_fullscreen(PGtkWidget(Handle)^.window);
To roll back to normal mode:
gdk_window_unfullscreen(PGtkWidget(Handle)^.window);
This is GTK2 only. You must add to uses section such modules as gtk2, gdk2, glib2. You can do it by the directive {$IFDEF LCLGTK2}, gtk2, gdk2, glib2{$ENDIF}.
Changing screen resolution
There is no OS independent way to switch screen resolution now.
For Windows you can find information in article for Delphi Get and Set Screen Resolution (Display Device Modes)