A:
var
TheMask: TBitmap;
TheRect: TRect;
begin
TheMask := TBitmap.Create;
TheRect := rect(0, 0, image1.width, image1.height);
try
with TheMask do begin
Monochrome := False;
Width := image1.width;
Height := image1.height;
canvas.brush.color := clBlack;
canvas.brush.style := bsDiagCross;
canvas.Ellipse(0, 0, image1.width, image1.height);
canvas.CopyMode := cmSrcAnd;
canvas.copyrect(TheRect, image1.canvas,
TheRect);
end;
image1.canvas.CopyMode := cmSrcCopy;
image1.Canvas.CopyRect(TheRect, TheMask.Canvas, TheRect);
finally
TheMask.free;
end;
end;