FCL Image SIGSEGV Raised on run

[BeanzMaster]

Hi to all
can anyone explain me why the following code don't work

Code: Pascal  [Select][+][-]

1. Unit uMainForm;
2.  
3. {$mode objfpc}{$H+}
4.  
5. Interface
6.  
7. Uses
8.   Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs,
9.   FPImage, FPCanvas, FPImgCanv,
10.   FPReadBMP, FPReadGIF;
11.  
12. Type
13.  
14.   { TMainForm }
15.  
16.   TMainForm = Class(TForm)
17.     Procedure FormActivate(Sender: TObject);
18.     Procedure FormCreate(Sender: TObject);
19.     Procedure FormDestroy(Sender: TObject);
20.     Procedure FormDropFiles(Sender: TObject; Const FileNames: Array Of String);
21.     Procedure FormPaint(Sender: TObject);
22.   private
23.     InDrawingMode : Boolean;
24.   protected
25.     FPCanvas : TFPcustomCanvas;
26.     FPImage : TFPCustomImage;
27.     FPReader : TFPCustomImageReader;
28.   public
29.  
30.     procedure DrawFPImageToCanvas(ACanvas: TFPCustomCanvas);
31.   End;
32.  
33. Var
34.   MainForm: TMainForm;
35.  
36. Implementation
37.  
38. {$R *.lfm}
39.  
40. { TMainForm }
41. Const
42.   FPColorRed: TFPColor = (Red: 65535; Green: 0; Blue: 0; Alpha: 65535);
43.  
44. procedure TMainForm.DrawFPImageToCanvas(ACanvas: TFPCustomCanvas);
45. begin
46.   Canvas.CopyRect(Rect(0,0,Canvas.Width,Canvas.Height),TCanvas(ACanvas) , Rect(0,0,ACanvas.Width,ACanvas.Height));
47. end;
48.  
49. Procedure TMainForm.FormActivate(Sender: TObject);
50. Begin
51.   InDrawingMode:= True;
52. end;
53.  
54. Procedure TMainForm.FormCreate(Sender: TObject);
55. Begin
56.   FPImage := TFPMemoryImage.Create (256, 256);
57.   FPCanvas := TFPImageCanvas.Create (FPImage);
58.   FPCanvas.Brush.FPColor := FPColorRed ;
59.   FPCanvas.Brush.Style := bsSolid;
60.   FPCanvas.Clear;
61.   InDrawingMode:= False;
62. end;
63.  
64. Procedure TMainForm.FormDestroy(Sender: TObject);
65. Begin
66.   FreeAndNil(FPCanvas);
67.   FreeAndNil(FPImage);
68. end;
69.  
70. Procedure TMainForm.FormDropFiles(Sender: TObject; Const FileNames: Array Of String);
71. Var
72.   ImageFileName : String;
73.   FileExtension : String;
74. Begin
75.   ImageFileName := FileNames[0];
76.   FileExtension := ExtractFileExt(ImageFileName);
77.   showmessage(FileExtension);
78.   if FIleExtension ='.bmp' then
79.     FPReader := TFPReaderBMP.Create
80.   else if FIleExtension ='.gif' then
81.     FPReader := TFPReaderGIF.Create;
82.  
83.   Try
84.     Try
85.       Screen.Cursor := crHourGlass;
86.  
87.       FPImage.LoadFromFile(ImageFileName, FPReader);
88.  
89.     Finally
90.         Screen.Cursor := crDefault;
91.     End;
92.   Except
93.     On E: FPImageException Do
94.     Begin
95.       MessageDlg(E.Message, mtWarning, [mbOK], 0);
96.       Exit;
97.     End
98.     Else
99.     Begin
100.       MessageDlg('Unknown Error', mtError, [mbOK, mbAbort], 0);
101.     End;
102.   End;
103.  
104. end;
105.  
106. Procedure TMainForm.FormPaint(Sender: TObject);
107. Begin
108.   if InDrawingMode then DrawFPImageToCanvas(FPCanvas);
109. end;
110.  
111. End.

Note :  TCanvas = class(TFPCustomCanvas)

Thanks

[Blaazen]

Method

Code: Pascal  [Select][+][-]

1. procedure TCanvas.CopyRect(const Dest: TRect; SrcCanvas: TCanvas; const Source: TRect);

has line

Code: Pascal  [Select][+][-]

1. SrcCanvas.RequiredState([csHandleValid]);

but class TFPCustomCanvas has NOT this method. RequiredState is protected method of TCanvas.

[BeanzMaster]

It's not help me

and i use

Code: Pascal  [Select][+][-]

1. procedure TMainForm.DrawFPImageToCanvas(ACanvas: TFPCustomCanvas);
2. begin
3.   Canvas.CopyRect(Rect(0,0,Canvas.Width,Canvas.Height),TCanvas(ACanvas) , Rect(0,0,ACanvas.Width,ACanvas.Height));
4. end;

If i not uses the form's paint event i don't any SIGSEGV but Image (bmp or gif) is not displayed at loading, and no SIGSEV raised.

What wrong with this code or how can i display directly the FPImage

[Blaazen]

I usually use TBitmap and its Canvas. Also, I'm not sure if it is possible to paint to Form.Canvas directly. Qt does not support it, for example. I have to use TPaintBox or TImage. You can then draw via PaintBox.CopyRect() or PaintBox.Draw().

[Jurassic Pork]

hello,
you can try this :

Code: Pascal  [Select][+][-]

1. procedure TMainForm.DrawFPImageToCanvas(ACanvas: TFPCustomCanvas);
2. begin
3.  TFPCustomCanvas(Canvas).CopyRect(0,0,ACanvas , Rect(0,0,ACanvas.Width,ACanvas.Height));
4.  //Canvas.CopyRect(Rect(0,0,Canvas.Width,Canvas.Height),ACanvas , Rect(0,0,ACanvas.Width,ACanvas.Height));
5. end;

have a look to this message : Re: Mixing Between FCL and LCL

Edit : in your code, an invalidate is missing after the FPImage.LoadFromFile  to redraw the canvas. Try this :

Code: Pascal  [Select][+][-]

1.       FPImage.LoadFromFile(ImageFileName, FPReader);
2.       Invalidate;  
3.  

Friendly, J.P

[BeanzMaster]

Hello

hello,
you can try this :

Code: Pascal  [Select][+][-]

1. procedure TMainForm.DrawFPImageToCanvas(ACanvas: TFPCustomCanvas);
2. begin
3.  TFPCustomCanvas(Canvas).CopyRect(0,0,ACanvas , Rect(0,0,ACanvas.Width,ACanvas.Height));
4.  //Canvas.CopyRect(Rect(0,0,Canvas.Width,Canvas.Height),ACanvas , Rect(0,0,ACanvas.Width,ACanvas.Height));
5. end;

have a look to this message : Re: Mixing Between FCL and LCL

Edit : in your code, an invalidate is missing after the FPImage.LoadFromFile  to redraw the canvas. Try this :

Code: Pascal  [Select][+][-]

1.       FPImage.LoadFromFile(ImageFileName, FPReader);
2.       Invalidate;  
3.  

Friendly, J.P

Thanks it work, but like i supposed TFPxxx is bugged see attached screenshots

This is  the code

Code: Pascal  [Select][+][-]

1.   FPImage := TFPMemoryImage.Create (256, 256);
2.   FPCanvas := TFPImageCanvas.Create (FPImage);
3.   FPCanvas.Pen.Style := psClear ;
4.   FPCanvas.Brush.FPColor := FPColorRed ;
5.   FPCanvas.Brush.Style := bsSolid;
6.   FPCanvas.Clear;

How work correctly in this case ????? the black lin on top and left normally not to be here

[BeanzMaster]

Like i said :

here are some screenshots wherer we can see that the BMP format is not supported correctly.

Test under Windows. Thumbnails are those of the file explorer

The BMP provide from my BMP-ImageTestSuite here : https://github.com/jdelauney/BMP-ImageTestSuite

The worst is that no error message appears or is raised

FCL/LCL Bitmap management really need a big update

[BeanzMaster]

Next part

And those screenshot is just some problems. Many other BMP don't displayed correctly

[Jurassic Pork]

hello,
you can also try to use the last version of vampyre imaging library to read images in lazarus :

1 - The last version is here
2 - Download the zip file and uncompress it.
3 - Install the packages vampyreimagingpackage.lpk and vampyreimagingpackage_ext.lpk  from the folder Extras\IdePackages\Lazarus
4 - Try the demo lclimager in the folder Demos\ObjectPascal\LCLImager
Note : it seems that there is problem to read jpeg with this version of the library (rangecheck error in the file imjdhuff.pas). So to run the demo :
1 - Disable the automatic load of the tiger.jpg image in the create of the mainform unit.
2 - Don't try to load jpeg file or correct the range check error (and say to us how  ).
i have tried this on Windows 10 Lazarus 1.8.2 32 bits.
See screenshots in attachments (load a gif and a bmp image).

Friendly, J.P

[EDIT] if i put the line Dec(entropy^.restarts_to_go); in comment in the function decode_mcu of the file imjdhuff.pas no more range check error :

Code: Pascal  [Select][+][-]

1.   { Account for restart interval (no-op if not using restarts) }
2. //  Dec(entropy^.restarts_to_go);

[BeanzMaster]

Hi JP thanks but i don't use. I test FCL-Image cause of the message from wp in Annoucement/TGIfViewer topic

I already can open all of those file in my project.

Graphics is not a priority for dev team. I regret it because this bug I am sure it causes many others downstream. Dev team must do a brainstorming around graphics with FPC and LCL. It's a very important part, but it seems not actually. This kind of bug can really cause great instability over time

Thanks

I come back to my own solution it work better

[wp]

I test FCL-Image cause of the message from wp in Annoucement/TGIfViewer topic

My comment refered to the drawing of the GIF images. I don't believe that it is needed to provide a dedicated "fastbitmap" class. FCL-image can paint other formats, so why shouldn't it be able to paint animated GIF?

[...] because this bug I am sure it causes many others downstream. Dev team must do a brainstorming around graphics with FPC and LCL. It's a very important part, but it seems not actually. This kind of bug can really cause great instability over time

I always have been able to load all my bmp files without any error using the LCL/FPC routines. I could imagine that the BMP specification contains a variety of options which are not supported by the bmp reader because they were not considered to be relevant when the units were written. But of course, if your collection contains all these corner cases the bmp reader will appear like crap.

Instead of lamenting about the bugginess of the bmp reader you should write patches which address all these issues. You seem to be a programmer who has good knowledge of the graphics formats, and it appears to be a waste of resources if you write your own image library instead of improving the existing one.

But of course, you can do what you want...

[BeanzMaster]

My comment refered to the drawing of the GIF images. I don't believe that it is needed to provide a dedicated "fastbitmap" class. FCL-image can paint other formats, so why shouldn't it be able to paint animated GIF?

It's exactly what i want and for understing how work FCL-Image i begining from the start with simple code

I always have been able to load all my bmp files without any error using the LCL/FPC routines. I could imagine that the BMP specification contains a variety of options which are not supported by the bmp reader because they were not considered to be relevant when the units were written. But of course, if your collection contains all these corner cases the bmp reader will appear like crap.

Just test image in my imagetestsuite and you'll see by yourself
 Sorry not understanding well.
 BMP is one the most old image format it will be supported correctly
In the case of 512x128x16.bmp and 512x128x32 those two images was made by me in gimp (see the screen shoot) More standard of that you can't.

Instead of lamenting about the bugginess of the bmp reader you should write patches which address all these issues. You seem to be a programmer who has good knowledge of the graphics formats, and it appears to be a waste of resources if you write your own image library instead of improving the existing one.

But of course, you can do what you want...

What i tell is the bug with black line can produce error code in others part like in widgets and it's not good.
Yes i 'm developping my own solution. Like you said to me Graphics is actually not a priority. I think that that's too bad.

It's my opinion that FCL-Image did not go in the right direction. Modified all this part of the FCL is not my responsibility. I do not know enough about the content of the code. Moreover, doing or adding things to something that is not working properly is not a long-term solution.
But it is clear that I can provide solutions for reading support for several image formats. And that's why I need to know the functioning of the FCL-Image and this first bug can cause serious problem to the display.

and this why i posted this : http://forum.lazarus.freepascal.org/index.php/topic,41706.msg289856/boardseen.html#new. But you already see it 

[wp]

I don't know what's going on here. I wrote a test application to easily load your test images (see attachment), and all of them seem to be displayed correctly except for the "bmp_*.bmp" pictures which do not show up at all. In the attachment you see the screenshot lena_02.bmp which you cannot display. I normally use Win10/64bit and Laz-trunk/fpc3.0.4-32bit, but the 64-bit is working here too, as well as Laz-1.8.4/fpc3.0.4-32bit/Win10 and Laz-trunk/fpc 3.0.4/Win 7

Please post your code in a compilable project. You must be doing something severely wrong.

[BeanzMaster]

Hi wp

My test code is very basic and normally  it must be work as is.

Tested on win10/64 with lazarus 1.8.5 FPC 3.0.4 and lazarus 1.9 FPC 3.1.1 same result

Note i beginning to patch the FPReadBMP unit. When i'll find how to recompil fpc source correctly. I'll test.
I'll also prepare some little report for  bugtraker. i found very minor bugs in FCL-Image. 

[wp]

I have the feeling that something is missing here. You are working with a simple TFPMemoryImage. Does it do all the required adaptions to the device format? Lazarus introduced TLazIntfImage for this purpose. There is an example in the wiki:
http://wiki.freepascal.org/Developing_with_Graphics#Working_with_TLazIntfImage.2C_TRawImage_and_TLazCanvas. This is similar to what the LCL is doing when reading an image. And the LCL can read all your test bmp images without any problems (I reported above that the bmp*.bmp images cannot be read - this is not true, I just did not see them due to their small size; with the gifs there are some issues, though).