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Painting on another application canvas

Code snippet that shows how to paint in another application's window or on the screen itself. Ever wished to paint in the window of Word, or on the desktop? Have a look at this: procedure TForm1.Button1Click(Sender: TObject); var thehandle:thandle; thecanvas:tcanvas; begin thecanvas:=tcanvas.create; winexec('notepad.exe',sw_normal); thehandle:=findwindow('notepad',nil); thecanvas.handle:=getdc(thehandle); thecanvas.rectangle(0,0,100,100); thecanvas.free; end; For painting the screen itself, use: thecanvas.handle:=createdc('DISPLAY',Nil,Nil,Nil);