[SOLVED] Strange bitmap bug
lazarus / 31-LCL

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MiniApp · 2017-03-05 15:10

Hello,

I'm trying to create a program who need lot of pictures (I load more
than 1 042 PNG's at start). I don't know why but after a massive load
I have a access violation after a random time.

I think this can be a LCL bug because the bug is when I move my mouse
in my main form. Stranger I have created and show a form before my
massive load, and he work perfectly !

My function to load bitmaps is
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i function
LoadPicture(const FileName:TFilename):TBitmap;begin  Result :=
TBitmap.Create;  LoadPicture(FileName,Result);end;procedure
LoadPicture(const FileName:TFilename;const Bitmap:TBitmap);begin//
 LoadPicturePicture := TPicture.Create;  InternalLogger.Info('Begin
LoadPicture from "%s"',[FileName]);  try   
LoadPicturePicture.LoadFromFile(FileName);   
Bitmap.SetSize(LoadPicturePicture.Width,LoadPicturePicture.Height);  
Bitmap.Canvas.Draw(0,0,LoadPicturePicture.Graphic);  except    on
E:Exception do      begin        InternalLogger.Error('End LoadPicture
fail ! [%s] %s',[E.ClassName,E.Message]);        raise;      end; 
end;  InternalLogger.Info('End LoadPicture');//
 LoadPicturePicture.Free;end;
I load pictures in a FormCreate and I store them into a array.

I have two times this bug and this make me   . Have you a answer ?

ps:Sorry if my english is bad...

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Thaddy · 2017-03-05 15:24

How big are these pictures?
I suspect this is caused by out-of-memory.
In that case the exception can not be handled in your code.
You can test this by making a small change to your code:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i   except  
// add this first. Only works if first.    on E:EOutOfMemory do     
 raise;  // This gets handled by a pre-allocated Dialog    on
E:Exception do    begin              // this won't work for an
EOutOfMemory exception because it needs new memory     
 InternalLogger.Error('End LoadPicture fail ! [%s]
%s',[E.ClassName,E.Message]);       raise;    end;  end;  
I have added a screenshot.

It is usually a bad   idea to try to store 1042 png's in memory at the
same time.....

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MiniApp · 2017-03-06 17:30

Thank you for your reply, but it's not a memory overload. Pictures
makes 128x128 (I have calculated 48MB for all pixels of pictures). And
I have the same problem with 100 pictures of 64x64. I will try to use
the no OS handle Bitmap.

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MiniApp · 2017-03-06 19:50

This work !

But look my func...
 Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i function
LoadLCLPicture(const FileName:TFilename):TLazIntfImage;var 
Bmp:TBitmap;begin  Bmp := LoadPicture(FileName);  Result :=
Bmp.CreateIntfImage;  Bmp.Free;end;I don't know how is possible  . My
project is very strangly bugged (A other subproc create a undefined
number of TImage, but he work only one time !  ).

For the  memory consumption, I'm in 50MB after start, this should not
be problematic on today computer.

Note:If anyone have more information on this strange bug I listen him

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Thaddy · 2017-03-06 20:25

Yes. CreateIntfImage makes it either an interfaced image instance or
it makes a copy as an interface.
An interface is refcounted and free'd when out of scope.
It is either a copy or the refcount for bmp.free is not 0. (So it can
be a fake free).
You have to find out what CreateIntfImage exactly does, though, in the
sourcecode....

Nice task for you...!!

Mixing interface instantiation with class instantiation on the same
class and in one program, though, is not a brilliant idea and should
be avoided to keep it clean.
Strictly either / or.