Größe in TImage

[DeddyH]

A short test:

Delphi-Quellcode:

procedure TFormTest.Button1Click(Sender: TObject);
var
  XIndex, YIndex, XMin, XMax, YMin, YMax: integer;
begin
  XMin := PaintBox1.ClientWidth;
  YMin := PaintBox1.ClientHeight;
  XMax := 0;
  YMax := 0;
  for YIndex := 0 to PaintBox1.ClientHeight - 1 do
    for XIndex := 0 to PaintBox1.ClientWidth - 1 do
      if PaintBox1.Canvas.Pixels[XIndex, YIndex] <>
        PaintBox1.Canvas.Brush.Color then
        begin
          if XIndex < XMin then
            XMin := XIndex;
          if YIndex < YMin then
            YMin := YIndex;
          if XIndex > XMax then
            XMax := XIndex;
          if YIndex > YMax then
            YMax := YIndex;
        end;
  PaintBox1.Canvas.Brush.Style := bsClear;
  PaintBox1.Canvas.Pen.Color := clBlue;
  PaintBox1.Canvas.Rectangle(XMin - 1, YMin - 1, XMax + 2, YMax + 2);
end;

As said before: Canvas.Pixels is quite slow, ScanLine is much faster, but you have to do some work yourself