[NumLock]

Код:

procedure FillGradientBrush(ABitmap: TBitmap; ARect: TRect; StartColor, EndColor: DWORD);
var
  FBrush: TGPLinearGradientBrush;
  FGraphics: TGPGraphics;
begin
  FBrush:=TGPLinearGradientBrush.Create(MakeRect(ARect), StartColor, EndColor, LinearGradientModeHorizontal);
  FGraphics:=TGPGraphics.Create(ABitmap.Canvas.Handle);
  FGraphics.FillRectangle(FBrush, MakeRect(ARect));
  FGraphics.Free;
  FBrush.Free;
end;

begin
  FillGradientBrush(Image1.Picture.Bitmap, Image1.ClientRect, $80ff0000, $8000ff00);
end;