Drawing difference between linux widgetsets and windows

[Jonny]

There seems to be a drawing issue somewhere. Below is a simple program to illustrate the problem.

This code should draw a 10x10px black square with a white outline square having a 1px border around it.

The linux qt5 and qt6 versions are fine, gtk2 has a black pixel at top left, and the windows version has top-left always off by one.

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, Forms, Controls, Graphics, StdCtrls, InterfaceBase, LCLPlatformDef;
9.  
10. type
11.  
12.   { TForm1 }
13.  
14.   TForm1 = class(TForm)
15.     procedure FormCreate(Sender: TObject);
16.   private
17.   public
18.   end;
19.  
20. var
21.   Form1: TForm1;
22.  
23. implementation
24.  
25. {$R *.lfm}
26.  
27. procedure TForm1.FormCreate(Sender: TObject);
28. var
29.   bmpGrid: TBitmap;
30. begin
31.   bmpGrid := TBitmap.Create;
32.   try
33.     bmpGrid.Width := 10;
34.     bmpGrid.Height := 10;
35.     bmpGrid.Canvas.Brush.Color := clBlack;
36.     bmpGrid.Canvas.Clear;
37.     bmpGrid.Canvas.Pen.Color := clWhite;
38.     bmpGrid.Canvas.Pen.Style := psInsideframe;
39.     bmpGrid.Canvas.Pen.Width := 2;
40.     bmpGrid.Canvas.Brush.Style := bsClear;
41.     // Draw a rectangle with a 1px border all around
42.     bmpGrid.Canvas.Rectangle(2,2,9,9);
43.     bmpGrid.SaveToFile(LCLPlatformDirNames[GetDefaultLCLWidgetType]+'-canvas.bmp');
44.   finally
45.     bmpGrid.Free;
46.     Halt;
47.   end;
48. end;
49.  
50. end.
51.  

Please see attached bitmap images.

Running latest trunk on Debian 12 and Windows 10:

Code: [Select]

Lazarus 4.99 (rev main_4_99-920-g0d73603378) FPC 3.3.1 x86_64-linux-gtk2
Free Pascal Compiler version 3.3.1-17333-g08f44aff2c-dirty [2025/01/20] for x86_64