BAGRABitmap load images proportions [SOLVED ]

[Pe3s]

Hello, how can I load an image while maintaining its proportions to fit the window?

[Handoko]

Maybe this can help:
https://forum.lazarus.freepascal.org/index.php/topic,43823.msg307918.html#msg307918

[Pe3s]

  
how to solve the problem, when scaling the window the image disappears, the invalidate and repaint instructions are not available

[Roland57]

Hello.

The same question was asked on the French-speaking Lazarus forum some days ago. I attach below the provided solution. Hope that you can adapt it to your needs.

Best regards.

[Pe3s]

Hello, where did I make a mistake that the image is not displayed when it is opened?

Code: Pascal  [Select][+][-]

1. private
2.     image: TBGRABitmap;
3.     imageLoaded: Boolean;
4.  
5.   public
6.  
7.   end;
8.  
9. var
10.   Form1: TForm1;
11.  
12. implementation
13.  
14. {$R *.lfm}
15.  
16. { TForm1 }
17.  
18. procedure TForm1.FormDestroy(Sender: TObject);
19. begin
20.   image.Free;
21. end;
22.  
23. procedure TForm1.FormCreate(Sender: TObject);
24. begin
25.   imageloaded := False;
26.   image := TBGRABitmap.Create;
27. end;
28.  
29. procedure TForm1.Panel1Paint(Sender: TObject);
30. var
31.   image2: TBGRABitmap;
32.   hw, wh, w, h, x, y: Integer;
33. begin
34.   if not(imageLoaded) then Exit;
35.  
36.   hw := image.Height * Panel1.ClientWidth;
37.   wh := image.Width * Panel1.ClientHeight;
38.  
39.   if wh > hw then
40.   begin
41.     w := Panel1.ClientWidth;
42.     h := hw div image.Width;
43.   end else
44.   begin
45.     h := Panel1.ClientHeight;
46.     w := wh div image.Height;
47.   end;
48.   x := (Panel1.ClientWidth - w) div 2;
49.   y := (Panel1.ClientHeight - h) div 2;
50.  
51.   image2 := image.Resample(w, h) as TBGRABitmap;
52.   image2.Draw(Panel1.Canvas, x, y, True);
53.   image2.Free;
54. end;
55.  
56. procedure TForm1.ToolButton1Click(Sender: TObject);
57. begin
58.   if OpenPictureDialog1.Execute then
59.   begin
60.     image.LoadFromFile(OpenPictureDialog1.FileName);
61.     imageLoaded:= True;
62.   end;
63. end;      
64.  

[Handoko]

Maybe you need to put this:

  Panel1.Invalidate;

between line #61 and #62.

[Dzandaa]

Hi
@Pe3s

I don't know if this is what you need, but here is a template that create a resizable Form with BGRAPicture Load and save
with Zoom and Pan.

You need the BGRABitmap Pack.

https://wiki.freepascal.org/Project_Templates

Extract from the .zip and put the BGRAPicture in you Template Directory.

You'll have a new entry in File->New project from template->BGRA Picture Form
Fill the Dialog box with the name of your program, Form and Unit and select where you want to create your new program.

Feel free to modify.

B->

[Pe3s]

Thank you