Nicht-weißen-Bereich ausschneiden

[Flips]

OK...wie immer...
Schuld war mal wieder das berühmte Pixelformat -> pf24Bit
So sollte es dann stimmen:

Delphi-Quellcode:

procedure ArrangeSymbol(aSource: TBitmap;  Width: Integer = -1;Height : Integer = -1;threshold: Byte = 254);
var h,w : integer;
b : ^TRGBTriple;
start, last : TPoint;
buffer : TBitmap;
begin
last.X := 0;
last.Y := 0;
start.X := 1000;
start.Y := 1000;
buffer := TBitmap.Create;
try
  buffer.Assign(aSource);
  buffer.PixelFormat := pf24Bit;
  for h := 0 to buffer.Height -1 do
    begin
      b := buffer.ScanLine[h];
      for w := 0 to buffer.Width -1 do
        begin
          if (b^.rgbtBlue <= threshold) and (b^.rgbtRed <= threshold) and (b^.rgbtGreen <= threshold) then
            begin
              if w < start.X then
                start.X := w;
              if h < start.Y then
                start.Y := h;
              if w > last.X then
                last.X := w;
              if h > last.Y then
                last.Y := h;
            end;

          inc(b);
        end;
    end;
  if (Width = -1) or (Height = -1) then
    begin
      aSource.Width  := abs(last.X-start.X)+1;
      aSource.Height := abs(last.Y-start.Y)+1;
    end
  else
    begin
      aSource.Width  := Width;
      aSource.Height := Height;
    end;
  aSource.Canvas.FillRect(aSource.Canvas.ClipRect);
  BitBlt(aSource.Canvas.Handle,0,0,aSource.Width,aSource.Height,buffer.Canvas.Handle,start.X,start.Y,SRCCOPY);
  finally
    buffer.Free;
  end;
end;