Question

I have used a function to create screenshot of my desktop in Delphi 7. I am getting correct screenshots, however the picture taken has a size of around 3 MB. Normally, screenshots have a size of 150 KB or so. I am not sure why.
Here is my code:

procedure TForm1.btnDesktopShotClick(Sender: TObject);
VAR
   ScreenH, ScreenW : Integer;
   dc : HDC;
   hWin :Cardinal;
   bm : TBitMap;
begin

  //get handle of desktop
 try
   hWin :=GetDesktopWindow;
  dc:=getDC(hWin);
  ScreenH :=GetDeviceCaps(dc,VertRes);
  ScreenW :=GetDeviceCaps(dc,HORZRES );
  //set bitmap
  bm:=TBitmap.Create;
  bm.Width :=ScreenW ;
  bm.Height :=ScreenH ;
  //copy to dest bitmap
  BitBlt(bm.Canvas.Handle,0,0,bm.Width ,bm.Height ,dc,0,0,SRCCOPY );
  Image1.Picture.Bitmap.Assign(bm);
  Image1.Picture.SaveToFile('screenShotDesktop.jpeg');
finally

  ReleaseDC(hWin,DC);
end;
end;

Help will be appreciated.

Thanks

Answer 1

Your saved file is a bmp format, example of saving a jpeg:

 with TJPEGImage.Create do
 try
   Assign(bm) ;
   SaveToFile('screenShotDesktop.jpeg') ;
 finally
   Free;
 end;