Article #17728: How do I convert a color to a shade of gray?

 Question and Answer Database
FAQ2728D.txt How do I convert a color to a shade of gray?
Category :Windows API
Platform :All
Product :All 32 bit
Question:
How do I convert a color to a shade of gray?
Answer:
The following example shows how to convert an RGB color to the
equivalent color of gray using the same method that a black and white
television would render a color broadcast:
function RgbToGray(RGBColor : TColor) : TColor;
var
Gray : byte;
begin
Gray := Round((0.30 * GetRValue(RGBColor)) +
(0.59 * GetGValue(RGBColor)) +
(0.11 * GetBValue(RGBColor )));
Result := RGB(Gray, Gray, Gray);
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
Shape1.Brush.Color := RGB(255, 64, 64);
Shape2.Brush.Color := RgbToGray(Shape1.Brush.Color);
end;
7/16/98 4:31:28 PM

Last Modified: 01-SEP-99