Durchschnittsfarbe eines Bitmap "schnell" ermitteln

[TiGü]

Delphi-Quellcode:

function TForm3.GetAvgBmpColor: TColor;
type
  TRgbTriple = packed record
    // do not change the order of the fields, do not add any fields
    Blue: Byte;
    Green: Byte;
    Red: Byte;
  end;
  TRgbTripleArray = packed array[0..MaxInt div SizeOf(TRgbTriple) - 1] of TRgbTriple;
  PRgbTripleArray = ^TRgbTripleArray;
var
  x, y: Integer;
  r, g, b: Integer;
  Pixel: TRgbTriple;
  Bmp: TBitmap;
  Filename: string;
  wic: TWICImage;
  Resolution: Integer;
  ScanLinePtr: Pointer;
begin
  Result := 0;
  Filename := 'Der magische Pfad';
  if not FileExists(Filename) then
    Exit;
  bmp := TBitmap.Create;
  wic := TWICImage.Create;
  try
    wic.LoadFromFile(Filename);
    bmp.Assign(wic);
    bmp.PixelFormat := pf24bit;
    r := 0;
    g := 0;
    b := 0;
    Assert(bmp.PixelFormat = pf24bit);

    for y := 0 to Pred(Bmp.Height) do
    begin
      ScanLinePtr := bmp.Scanline[y];  // der springende Punkt!
      for x := 0 to Pred(Bmp.Width) do
      begin
        Pixel := PRgbTripleArray(ScanLinePtr)^[x];
        r := r + Pixel.Red;
        g := g + Pixel.Green;
        b := b + Pixel.Blue;
      end;
    end;

    Resolution := (bmp.Width * bmp.Height);
    r := r div Resolution;
    g := g div Resolution;
    b := b div Resolution;
    Result := RGB(r, g, b);
  finally
    bmp.Free;
    wic.Free;
  end;
end;