Trying to save an Animated GIF [SOLVED]

[zxandris]

Hey there, I've been trying to save an ani gif using BGRA and a snipet of the code I'm using below.

Code: Pascal  [Select][+][-]

1.  
2.                     for a := 0 to frm.lvFiles.items.count - 1 do
3.                     begin
4.                          pbar.value := a;
5.                          application.ProcessMessages;
6.                          Bgra := TBgraBitmap.create;
7.                          try
8.                             LoadToBgra(frm.lvFiles.items.item[a].caption, bgra);
9.                             application.ProcessMessages;
10.                             Bgra.ResampleFilter := rfBestQuality;
11.                             bgraSized := TbgraBitmap.create(size.x, size.y);
12.                             try
13.                                BgraSized.ResampleFilter := rfBestQuality;
14.                                BgraSized := Bgra.Resample(size.x, size.y, rmFineResample);
15.                                GIF.AddFullFrame(BgraSized, 50);
16.                             finally
17.                                    BgraSized.free;
18.                             end;
19.                          finally
20.                                 bgra.free;
21.                          end;
22.                     end;
23.                     if fileEXists(strOutput) then RecycleItem(strOutput, true, false, true);
24.                     strm := TFileStream.create(strOutput, fmCreate);
25.                     try
26.                        Gif.SaveToStream(strm, BGRAColorQuantizerFactory, daFloydSteinberg);
27.                     finally
28.                            strm.free;
29.                     end;
30.  

Crashes when trying to save, either with stream or just save to File.  I really don't know why.  I'm sizing all the frames to the first frame, so I'm a little confused.

CJ

[zxandris]

Just in case I'm not adding them correctly or something here is the entire creation action

Code: Pascal  [Select][+][-]

1.  
2. procedure TfrmMain.actGeneratorPagedImageExecute(Sender: TObject);
3. var
4.    frm : TfrmDLGPagedImageGenerator;
5.    lst : TStringList;
6.    a : Integer;
7.    TIF : TBGRAWriterTiff;
8.    img : TFPMemoryImage;
9.    Bgra, bgraSized : TBgraBitmap;
10.    strm : TFileStream;
11.    strOutput : string;
12.    Gif : TBGRAAnimatedGif;
13.    Size : TPoint;
14. //   opt : TBGRAColorQuantizerAny;
15. //   ADitheringAlgorithm : TDitheringAlgorithm
16. begin
17.      frm := TfrmDLGPagedImageGenerator.create(self);
18.      try
19.         lst := TStringList.create;
20.         try
21.            GetCurrentList(lst);
22.            for A := 0 to lst.count - 1 do
23.            begin
24.                 frm.AddToFiles(lst[a]);
25.            end;
26.         finally
27.                lst.free;
28.         end;
29.         if frm.ShowModal = mrOK then
30.         begin
31.              strOutput := frm.feOutput.filename;
32.              if frm.cboType.ItemIndex = 0 then ChangeFileExt(strOutput, '.tif')
33.              else if frm.cboType.ItemIndex = 1 then changeFileExt(strOutput, '.gif');
34.              if frm.cboType.ItemIndex = 0 then
35.              begin
36.                  // TIFF Image
37.                  TIF := TBgraWriterTiff.Create;
38.                  try
39.                      tif.PremultiplyRGB := true;
40.                      tif.SaveCMYKAsRGB := true;
41.                      pbar.MaxValue := frm.lvFiles.items.count - 1;
42.                      for A := 0 to frm.lvFiles.items.count - 1 do
43.                      begin
44.                           pbar.value := a;
45.                           application.ProcessMessages;
46.                           Bgra := TBgraBitmap.create;
47.                           try
48.                                LoadToBgra(frm.lvFiles.items.item[a].Caption, bgra);
49.                                Bgra.ClearTransparentPixels;
50.                                img := TFPMemoryImage.Create(bgra.width, bgra.height);
51.                                try
52.                                   img.assign(bgra);
53.                                   Tif.AddImage(img);
54.                                finally
55.                                       img.free;
56.                                end;
57.                           finally
58.                                  bgra.free;
59.                           end;
60.                      end;
61.                      if fileExists(strOutput) then RecycleItem(strOutput, true, false, true);
62.                      strm := TFilestream.create(strOutput, fmCreate);
63.                      try
64.                         tif.SaveToStream(strm);
65.                      finally
66.                             strm.free;
67.                      end;
68.                      application.ProcessMessages;
69.                      if fileExists(strOutput) then
70.                      begin
71.                           DoMessage('Paged Image Generator', ExtractFileName(strOutput) + ' - Generated!');
72.                           if ask('Would you like to open the file?') = mrYes then LoadAnyFile(strOutput);
73.                      end else DoWarning('Paged Image Generator', ExtractFileName(strOutput) + ' - Not Generated!');
74.                  finally
75.                         TIF.free;
76.                  end;
77.              end else if frm.cboType.ItemIndex = 1 then
78.              begin
79.                  // Write to GIF
80.                  Gif := TBGRAAnimatedGif.Create;
81.                  try
82.                     if frm.lvFiles.items.count-1=-1 then
83.                     begin
84.                         DoWarning('Paged Image Generator', 'Cannot add zero images!');
85.                         exit;
86.                     end;
87.                     Bgra := TBgraBitmap.create;
88.                     try
89.                        LoadToBgra(frm.lvFiles.items.item[0].caption, bgra);
90.                        size.x := Bgra.Width;
91.                        size.y := bgra.height;
92.                     finally
93.                            bgra.free;
94.                     end;
95.                     gif.SetSize(size.x, size.y);
96.                     gif.LoopCount := frm.lvFiles.items.count-1;
97.                     pbar.MaxValue := frm.lvFiles.items.count - 1;
98.                     for a := 0 to frm.lvFiles.items.count - 1 do
99.                     begin
100.                          pbar.value := a;
101.                          application.ProcessMessages;
102.                          Bgra := TBgraBitmap.create;
103.                          try
104.                             LoadToBgra(frm.lvFiles.items.item[a].caption, bgra);
105.                             application.ProcessMessages;
106.                             Bgra.ResampleFilter := rfBestQuality;
107.                             bgraSized := TbgraBitmap.create(size.x, size.y);
108.                             try
109.                                BgraSized.ResampleFilter := rfBestQuality;
110.                                BgraSized := Bgra.Resample(size.x, size.y, rmFineResample);
111.                                GIF.AddFullFrame(BgraSized, 50);
112.                             finally
113.                                    BgraSized.free;
114.                             end;
115.                          finally
116.                                 bgra.free;
117.                          end;
118.                     end;
119.                     ShowMessage(strOutput);
120.                     if fileExists(strOutput) then RecycleItem(strOutput, true, false, true);
121.                     strm := TFileStream.create(strOutput, fmCreate);
122.                     try
123.                        try
124.                           Gif.SaveToStream(strm, BGRAColorQuantizerFactory, daFloydSteinberg);
125.                        except
126.                              //
127.                        end;
128.                     finally
129.                            strm.free;
130.                     end;
131.                     application.ProcessMessages;
132.                     if fileExists(strOutput) then
133.                     begin
134.                          DoMessage('Paged Image Generator', ExtractFileName(strOutput) + ' - Generated!');
135.                          if ask('Would you like to open the file?') = mrYes then LoadAnyFile(strOutput);
136.                     end else DoWarning('Paged Image Generator', ExtractFileName(strOutput) + ' - Not Generated!');
137.                  finally
138.                         gif.free;
139.                  end;
140.              end;
141.         end;
142.      finally
143.             frm.free;
144.      end;
145. end;
146.  

[circular]

Hi zxandris,

Maybe the color quantizer is missing. It is provided by BGRAColorQuantization unit. You need to:

• Either pass TBGRAColorQuantizer class as a parameter of SaveToStream,
• Or assign TBGRAColorQuantizer class to BGRAPalette.BGRAColorQuantizerFactory

Code snippet to do the latter:

Code: Pascal  [Select][+][-]

1. uses BGRAPalette, BGRAColorQuantization;
2. begin
3.   BGRAColorQuantizerFactory := TBGRAColorQuantizer;

Note that when it crashes, it gives you a message or a type of error. This can give you a clue on what is going on.

I noticed one small mistake when resampling. The following code will lead to a small memory leak:

Code: Pascal  [Select][+][-]

1.   bgraSized := TbgraBitmap.create(size.x, size.y); // one instance
2.   try
3.     BgraSized.ResampleFilter := rfBestQuality;
4.     BgraSized := Bgra.Resample(size.x, size.y, rmFineResample); // another instance
5.  

The reason is that Bgra.Resample returns a new instance of TBGRABitmap, so here you get 2 instances. Regarding the ResampleFilter property, it needs to be set in the source bitmap.

Regards

[zxandris]

I'm probably being dense here, but I did create the class as per snippet to pass but I'm unsure what to actually do with the class, like what settings need to be applied to make that work.  Would you mind helping me there.  Say I pass that to the save stream, what should I set on that class to make that save and work.  It did actually save I found out, but the gif is certainly not animated so this really has me at a loss.

CJ

Hi zxandris,

Maybe the color quantizer is missing. It is provided by BGRAColorQuantization unit. You need to:

• Either pass TBGRAColorQuantizer class as a parameter of SaveToStream,
• Or assign TBGRAColorQuantizer class to BGRAPalette.BGRAColorQuantizerFactory

Code snippet to do the latter:

Code: Pascal  [Select][+][-]

1. uses BGRAPalette, BGRAColorQuantization;
2. begin
3.   BGRAColorQuantizerFactory := TBGRAColorQuantizer;

Note that when it crashes, it gives you a message or a type of error. This can give you a clue on what is going on.

I noticed one small mistake when resampling. The following code will lead to a small memory leak:

Code: Pascal  [Select][+][-]

1.   bgraSized := TbgraBitmap.create(size.x, size.y); // one instance
2.   try
3.     BgraSized.ResampleFilter := rfBestQuality;
4.     BgraSized := Bgra.Resample(size.x, size.y, rmFineResample); // another instance
5.  

The reason is that Bgra.Resample returns a new instance of TBGRABitmap, so here you get 2 instances. Regarding the ResampleFilter property, it needs to be set in the source bitmap.

Regards

[circular]

It's great that you ask, so that we can clear out any confusion.

You don't need to create the class. TBGRAColorQuantizer is the class type, it doesn't have any instance. It is created internally by TBGRAAnimatedGif when writing.

I am not sure what is the reason you don't get an animation. You saved it with TBGRAAnimatedGif class? Maybe try with a simpler example:

Code: Pascal  [Select][+][-]

1. var
2.   img: TBGRABitmap;
3.   gif: TBGRAAnimatedGif;
4.   i, delayms: integer;
5. begin
6.   delayms := 100;
7.   gif := TBGRAAnimatedGif.Create;
8.   gif.SetSize(355, 355);
9.   gif.LoopCount := 0;  //endless loop
10.   for i := 0 to 2 do
11.   begin
12.     img := TBGRABitmap.Create(Format('frame%d.png', [i]));
13.     //add frame
14.     gif.AddFullFrame(img, delayms);
15.     img.Free;
16.   end;
17.   gif.OptimizeFrames;
18.   gif.SaveToFile('sample-ani-2.gif'); //save to file
19.   gif.Free; //clean
20. end;

Copied from: https://forum.lazarus.freepascal.org/index.php/topic,61283.msg468570.html#msg468570

Hope it helps

[zxandris]

I reallyl don't know what I'm doing wrong, I used the example to change my code (excuse the comments) to this :-

Code: Pascal  [Select][+][-]

1.                  // Write to GIF
2.                  Gif := TBGRAAnimatedGif.Create;
3.                  try
4.                     if frm.lvFiles.items.count-1=-1 then
5.                     begin
6.                         DoWarning('Paged Image Generator', 'Cannot add zero images!');
7.                         exit;
8.                     end;
9.                     Bgra := TBgraBitmap.create;
10.                     try
11.                        LoadToBgra(frm.lvFiles.items.item[0].caption, bgra);
12.                        size.x := Bgra.Width;
13.                        size.y := bgra.height;
14.                     finally
15.                            bgra.free;
16.                     end;
17.                     gif.SetSize(size.x, size.y);
18.                     gif.LoopCount := 0; // Endless Loop
19.                     intDelayMS := 100;
20.                     pbar.MaxValue := frm.lvFiles.items.count - 1;
21.                     for a := 0 to frm.lvFiles.items.count - 1 do
22.                     begin
23.                          pbar.value := a;
24.                          application.ProcessMessages;
25.                          Bgra := TBgraBitmap.create;
26.                          try
27.                             LoadToBgra(frm.lvFiles.items.item[a].caption, bgra);
28.                             application.ProcessMessages;
29.                             Bgra.ResampleFilter := rfBestQuality;
30.                             bgraSized := TbgraBitmap.create(size.x, size.y);
31.                             try
32.                                BgraSized := Bgra.Resample(size.x, size.y, rmFineResample);
33. //                               img := TFPMemoryImage.Create(size.x, size.y);
34.                                try
35. //                                  img.assign(bgraSized);
36.                                   GIF.AddFullFrame(bgraSized, intDelayMS);
37. //                               finally
38.                                except
39. //                                      img.free;
40.                                      // Ignore for now
41.                                end;
42.                             finally
43.                                    BgraSized.free;
44.                             end;
45.                          finally
46.                                 bgra.free;
47.                          end;
48.                     end;
49. //                    ShowMessage(CommaThou(gif.Count-1));
50.                     if fileExists(strOutput) then RecycleItem(strOutput, true, false, true);
51.                     gif.OptimizeFrames;
52.                     try
53.                        gif.SaveToFile(strOutput);
54.                     except
55.                           //
56.                     end;
57.  
58. {                    strm := TFileStream.create(strOutput, fmCreate);
59.                     try
60.                        try
61.                           Gif.SaveToStream(strm, BGRAColorQuantizerFactory, daFloydSteinberg);
62.                        except
63.                              //
64.                        end;
65.                     finally
66.                            strm.free;
67.                     end;
68. }
69.                     application.ProcessMessages;
70.                     if fileExists(strOutput) then
71.                     begin
72.                          DoMessage('Paged Image Generator', ExtractFileName(strOutput) + ' - Generated!');
73.                          if ask('Would you like to open the file?') = mrYes then LoadAnyFile(strOutput);
74.                     end else DoWarning('Paged Image Generator', ExtractFileName(strOutput) + ' - Not Generated!');
75.                  finally
76.                         gif.free;
77.                  end;
78.  
79.  

And the error I get is non-sensical, just an access error nothing meaningful to garner anything from, just an address, even with debug mode on.  I must admit I am totally lost right now.  Perhaps a more experienced eye would be able to see the error in my gif making code there.  I'm resizing the image to the first image loaded on purpose becuase it could be any size of image in that list.  I realised that it's possible to just assign a Bgra bitmap from the example you gave as you can tell from my comments, but it only seems to save the first frame then bails with that very confusing error. I attached a screenie of the error box.

It's great that you ask, so that we can clear out any confusion.

You don't need to create the class. TBGRAColorQuantizer is the class type, it doesn't have any instance. It is created internally by TBGRAAnimatedGif when writing.

I am not sure what is the reason you don't get an animation. You saved it with TBGRAAnimatedGif class? Maybe try with a simpler example:

Code: Pascal  [Select][+][-]

1. var
2.   img: TBGRABitmap;
3.   gif: TBGRAAnimatedGif;
4.   i, delayms: integer;
5. begin
6.   delayms := 100;
7.   gif := TBGRAAnimatedGif.Create;
8.   gif.SetSize(355, 355);
9.   gif.LoopCount := 0;  //endless loop
10.   for i := 0 to 2 do
11.   begin
12.     img := TBGRABitmap.Create(Format('frame%d.png', [i]));
13.     //add frame
14.     gif.AddFullFrame(img, delayms);
15.     img.Free;
16.   end;
17.   gif.OptimizeFrames;
18.   gif.SaveToFile('sample-ani-2.gif'); //save to file
19.   gif.Free; //clean
20. end;

Copied from: https://forum.lazarus.freepascal.org/index.php/topic,61283.msg468570.html#msg468570

Hope it helps

[zxandris]

It's odd, just ran a debug through and it seems to fail on the second image it tries to write??

[circular]

I am puzzled as well. An access violation is often related to memory allocation. I don't know if you already have heaptrc unit (either checked in compiler options or explicitly in the uses clause). It can detect memory allocation errors.

It can also be that BGRABitmap needs to be recompiled clean, this can be done from the package window of this package.

Hmm let's see. In the code, I only see a memory leak, which shouldn't crash the program. It is about initializing bgraSized instead of calling TBGRABitmap.Create:

Code: Pascal  [Select][+][-]

1. bgraSized := nil;

If that still doesn't work, can you send me a sample project that I can run on my computer. You can send as PM if you prefer to keep it private.

[qk]

If I try to run the example, an exception is raised because BGRAColorQuantizerFactory is not assigned.

Adding the line

Code: Pascal  [Select][+][-]

1. BGRAColorQuantizerFactory := TBGRAColorQuantizer;

on top it works.

Code: Pascal  [Select][+][-]

1. uses
2.   ...
3.   BGRABitmap,
4.   BGRAAnimatedGif,
5.   BGRAPalette,
6.   BGRAColorQuantization;
7.  
8. ...  
9.  
10. var
11.   img: TBGRABitmap;
12.   gif: TBGRAAnimatedGif;
13.   i, delayms: integer;
14. begin
15.   delayms := 100;
16.   BGRAColorQuantizerFactory := TBGRAColorQuantizer;
17.   gif := TBGRAAnimatedGif.Create;
18.   gif.SetSize(355, 355);
19.   gif.LoopCount := 0;  //endless loop
20.   for i := 0 to 2 do
21.   begin
22.     img := TBGRABitmap.Create(Format('frame%d.png', [i]));
23.     //add frame
24.     gif.AddFullFrame(img, delayms);
25.     img.Free;
26.   end;
27.   gif.OptimizeFrames;
28.   gif.SaveToFile('sample-ani-2.gif'); //save to file
29.   gif.Free; //clean
30. end;  

[zxandris]

I think this is what did it, thank you!  But I also did Circular's suggestion so I'm not entirely sure which worked, but it is working now!.

Thanks Guys, this was a puzzler huh?

CJ

If I try to run the example, an exception is raised because BGRAColorQuantizerFactory is not assigned.

Adding the line

Code: Pascal  [Select][+][-]

1. BGRAColorQuantizerFactory := TBGRAColorQuantizer;

on top it works.

Code: Pascal  [Select][+][-]

1. uses
2.   ...
3.   BGRABitmap,
4.   BGRAAnimatedGif,
5.   BGRAPalette,
6.   BGRAColorQuantization;
7.  
8. ...  
9.  
10. var
11.   img: TBGRABitmap;
12.   gif: TBGRAAnimatedGif;
13.   i, delayms: integer;
14. begin
15.   delayms := 100;
16.   BGRAColorQuantizerFactory := TBGRAColorQuantizer;
17.   gif := TBGRAAnimatedGif.Create;
18.   gif.SetSize(355, 355);
19.   gif.LoopCount := 0;  //endless loop
20.   for i := 0 to 2 do
21.   begin
22.     img := TBGRABitmap.Create(Format('frame%d.png', [i]));
23.     //add frame
24.     gif.AddFullFrame(img, delayms);
25.     img.Free;
26.   end;
27.   gif.OptimizeFrames;
28.   gif.SaveToFile('sample-ani-2.gif'); //save to file
29.   gif.Free; //clean
30. end;