Mega Code Archive
How to change the color channels of a bitmap
<![CDATA[
Title: How to change the color channels of a bitmap
function SetRGBChannelValue(Bitmap: TBitmap; Red, Green, Blue: Integer): Boolean;
var
i, j: Integer;
rgbc: array[0..2] of Byte;
c: TColor;
r, g, b: Byte;
begin
//Wenn keine ?nderungen vorgenommen werden, Vorgang beenden:
//If there is no change, exit:
if (Red = 0) and (Green = 0) and (Blue = 0) then
begin
Result := False;
Exit;
end;
for i := 0 to Bitmap.Height do
begin
for j := 0 to Bitmap.Width do
begin
// Get the old Color
c := Bitmap.Canvas.Pixels[j, i];
// Splitt the old color into the different colors:
rgbc[0] := GetRValue(c);
rgbc[1] := GetGValue(c);
rgbc[2] := GetBValue(c);
//Check that there is no "new" color while the addition
//of the values:
if not (rgbc[0] + Red 0) and not (rgbc[0] + Red 255) then
rgbc[0] := rgbc[0] + Red;
if not (rgbc[1] + Green 0) and not (rgbc[1] + Green 255) then
rgbc[1] := rgbc[1] + Green;
if not (rgbc[2] + Blue 0) and not (rgbc[2] + Blue 255) then
rgbc[2] := rgbc[2] + Blue;
r := rgbc[0];
g := rgbc[1];
b := rgbc[2];
//set the new color back to the picture:
Bitmap.Canvas.Pixels[j, i] := RGB(r, g, b);
end;
end;
Result := True;
end;
//Beispiel, wie man die Funktion benutzen kann:
//Example, how to use it:
procedure TForm1.Button1Click(Sender: TObject);
begin
SetColorValue(Image1.picture.Bitmap, Spinedit1.Value, Spinedit2.Value,
Spinedit3.Value);
end;
]]>