Filling a region draws it off canvas
- by Xanyx
Hi
Using the following code in Delphi 2007:
procedure TfrmTest.PaintBox1Paint(Sender: TObject);
const
Rect_Size = 10;
begin
PaintBox1.Canvas.Brush.Color := clYellow;
PaintBox1.Canvas.FillRect(Rect(0, 0, PaintBox1.width, PaintBox1.height));
PaintBox1.Canvas.Brush.Color := clRed;
DrawARect(PaintBox1.Canvas, 0, 0, Rect_Size, Rect_Size);
end;
procedure TfrmTest.DrawARect(ACanvas: TCanvas; iLeft, iTop, iWidth, iHeight: Integer);
var
rgnMain: HRGN;
begin
rgnMain := CreateRectRgn(iLeft, iTop, iLeft + iWidth, iTop + iHeight);
try
SelectClipRgn(ACanvas.handle, rgnMain);
ACanvas.FillRect(ACanvas.ClipRect);
SelectClipRgn(ACanvas.handle, 0);
finally
DeleteObject(rgnMain);
end;
end;
I get this:
(Yellow area shows boundaries of PaintBox1).
HMMM, NOT ALLOWED TO POST IMAGE
Please go to: http://www.freeimagehosting.net/uploads/62cf687d29.jpg
(Linked image shows a form with a yellow box [PaintBox1] in the center. However my red rectange [rgnMain] has been drawn at pos 0,0 on the form)
My expectation was that the red rectangle would be at the top left of the PaintBox1 canvas, not the form's canvas. Why is it not? Can regions only be used with controls that have a Windows handle?
Thanks
