TBRGABitmap Resample(...)

[PaulANormanNZ]

Hi I have been going around in circles trying to Resample a TBGRABitmap

I am sure that I am missing something very obvious...

 

Code: Pascal  [Select][+][-]

1.  
2.   // Always works as a test...
3.    //    Image_Btabb_thumbnail.Picture.bitmap.Assign(global_main_image.Bitmap);
4.  
5.      // Both top two creation methods are definitely loading a displayable image...
6.  
7.    // thumbNail:= tbgrabitmap.Create(global_main_image.Bitmap);
8.     thumbNail:= tbgrabitmap.Create(global_FileName_plain);
9.    //   thumbNail:= tbgrabitmap.Create;
10.  
11.      try
12.  
13.   // This works...
14.   // Image_Btabb_thumbnail.Picture.bitmap.Assign(thumbNail.Bitmap);
15.  
16.  //   showmessage('ok');
17.  
18.   thumbNail.ResampleFilter:= rfBestQuality;
19.  
20.    // This comes out blank
21.         BGRAReplace(thumbNail,
22.                        thumbNail.Resample(
23.                         newWidth, newHeight,
24.                          rmFineResample)
25.                      );
26.  
27.            // This does not imrpove anything
28.            // thumbNail.InvalidateBitmap;
29.  
30.  
31.  //     showmessage('ok');
32.  
33.  {
34.      // this never works ...
35.  
36.      global_main_image.ResampleFilter:= rfBestQuality;
37.  
38.    thumbNail :=  global_main_image.Resample(
39.                         newWidth, newHeight,
40.                          rmFineResample)
41.                  as TBGRABitmap;
42.    }
43.  
44.  
45.         Application.ProcessMessages;
46.          //
47.  
48.  //   // this always  comes out blank after re-sample...
49.  
50.      Image_Btabb_thumbnail.Picture.bitmap.Assign(thumbNail.Bitmap);
51.  
52.    // And so, of course this only produces "data:image" and nothing else...
53.  
54.           thumbString :=  thumbNail.Canvas2D.toDataURL('image/jpeg');  
55.  
56.  

Any help appreciates please,

Paul

[lainz]

If I remember correctly is like this:

Code: Pascal  [Select][+][-]

1. BGRAReplace(Bitmap, Bitmap.Resample(...) as TBGRABitmap)

[PaulANormanNZ]

Thanks Lainz,

I was looking at ...

http://wiki.freepascal.org/BGRABitmap_tutorial_5

Which shows it in this form...

Code: Pascal  [Select][+][-]

1.  //load and scale texture
2.   tex := TBGRABitmap.Create('texture.png');
3.   BGRAReplace(tex,tex.Resample(128,80));
4.  

which doesn't show the cast..

Code: Pascal  [Select][+][-]

1. BGRAReplace(Bitmap, Bitmap.Resample(...) as TBGRABitmap)

I really appreciate the tutorials, they cover some amazing capabilities - is there though some straight forward primers anywhere which go over many of the more mundane use case scenarios, like these sorts of things, just processing images for web, storage in base64 etc...

Often people say look at the LazPaint code, but it is not a straight forward "design time" interface the way it is done.

Thanks,
paul

[lainz]

Yes, I was writting it from my memories only =)

You can attach a small program that reproduces the problem? Usually when you do that, you can find the problem, and if not, we can try to help.

[lainz]

This works for me:

Code: Pascal  [Select][+][-]

1. unit Unit1;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.   Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, ExtCtrls, BGRABitmap,
9.   BGRABitmapTypes;
10.  
11. type
12.  
13.   { TForm1 }
14.  
15.   TForm1 = class(TForm)
16.     Image1: TImage;
17.     procedure FormCreate(Sender: TObject);
18.     procedure FormDestroy(Sender: TObject);
19.   private
20.     bitmap: TBGRABitmap;
21.   public
22.  
23.   end;
24.  
25. var
26.   Form1: TForm1;
27.  
28. implementation
29.  
30. {$R *.lfm}
31.  
32. { TForm1 }
33.  
34. procedure TForm1.FormCreate(Sender: TObject);
35. begin
36.   bitmap := TBGRABitmap.Create('image.png');
37.   bitmap.ResampleFilter := rfBestQuality;
38.   BGRAReplace(bitmap, bitmap.Resample(Image1.Width, Image1.Height));
39.   Image1.Picture.Bitmap.Assign(bitmap.Bitmap);
40.  
41.   ShowMessage(bitmap.Canvas2D.toDataURL('image/jpeg'));
42. end;
43.  
44. procedure TForm1.FormDestroy(Sender: TObject);
45. begin
46.   bitmap.Free;
47. end;
48.  
49. end.
50.