逐个像素转换。
function RgbToGray(Source: TColor) : TColor;
var Target: Byte;
begin
Target := Round((0.30 * GetRValue(Source)) +
(0.59 * GetGValue(Source)) +
(0.11 * GetBValue(Source)));
Result := RGB(Target, Target, Target);
end;
function RgbToGray(Source: TColor) : TColor;
var Target: Byte;
begin
Target := Round((0.30 * GetRValue(Source)) +
(0.59 * GetGValue(Source)) +
(0.11 * GetBValue(Source)));
Result := RGB(Target, Target, Target);
end;