Author: Ernesto De Spirito 

How can I change the screen resolution?

Answer:

To change the screen resolution you can use the following function which is a 
wrapper for the Windows API ChangeDisplaySettings. The function takes the desired 
width and height as parameters and returns 
the return value of ChangeDisplaySettings (see the documentation for more datails). 
1   
2   function SetScreenResolution(Width, Height: integer): Longint;
3   var
4     DeviceMode: TDeviceMode;
5   begin
6     with DeviceMode do
7     begin
8       dmSize := SizeOf(TDeviceMode);
9       dmPelsWidth := Width;
10      dmPelsHeight := Height;
11      dmFields := DM_PELSWIDTH or DM_PELSHEIGHT;
12    end;
13    Result := ChangeDisplaySettings(DeviceMode, CDS_UPDATEREGISTRY);
14  end;


You can use ChangeDisplaySettings to change other properties of the display like 
the color depth and the display frequency. 

Sample call 

In the following example first we get the current screen resolution before setting 
it to 800x600, and then we restore it calling SetScreenResolution again. 

15  var
16    OldWidth, OldHeight: integer;
17  
18  procedure TForm1.Button1Click(Sender: TObject);
19  begin
20    OldWidth := GetSystemMetrics(SM_CXSCREEN);
21    OldHeight := GetSystemMetrics(SM_CYSCREEN);
22    SetScreenResolution(800, 600);
23  end;
24  
25  procedure TForm1.Button2Click(Sender: TObject);
26  begin
27    SetScreenResolution(OldWidth, OldHeight);
28  end;


Copyright (c) 2001 Ernesto De Spiritomailto:edspirito@latiumsoftware.com
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