RenderingWorkingWindowsNotAndroid.pas

procedure TForm1.PaintImage(index: integer; value : string; rows, columns : integer);
var
  image : Timage;
  i, j, k : integer;
  MyRect: TRectF;
begin
  image := GetImage(index);

  //start painting
  image.Canvas.BeginScene;
  k := 1;
  for i := 0 to rows-1 do
  begin
    for j := 0 to columns-1 do
    begin
      if value[k] = '1' then
        image.Canvas.Fill.Color := TAlphaColors.Lime
      else
        image.Canvas.Fill.Color := TAlphaColors.Black;
      inc(k);
      image.Canvas.Stroke.Color := TAlphaColors.Green;
      image.Canvas.Stroke.Thickness := 0;
      //Use LocalToAbsolute to paint within the boundaries of TImage and not the form canvas!
      MyRect := TRectF.Create(image.LocalToAbsolute(TPointF.Create(round(((i)*image.Width)/rows), round(((j)*image.Height)/rows))), round((image.Width)/rows), round((image.Height)/rows));
      image.Canvas.FillRect(MyRect, 0, 0, AllCorners, 1);
    end;
  end;
  image.Canvas.EndScene;
end;