Out of memory

[smallbit]

Hello guys,
New riddle for you,

I am using a method to rotate images in a form.

private: System::Drawing::Image^ rotateImage(Image^ b, float angle)
        {
            //create a new empty bitmap to hold rotated image
			Bitmap^ returnBitmap = gcnew Bitmap(b->Width, b->Height);
            //make a graphics object from the empty bitmap
            Graphics^ g = Graphics::FromImage(returnBitmap);
            //move rotation point to center of image
			g->TranslateTransform((float)b->Width / 2, (float)b->Height / 2);
            //rotate
            g->RotateTransform(angle);
            //move image back
            g->TranslateTransform(-(float)b->Width / 2, -(float)b->Height / 2);
            //draw passed in image onto graphics object
           
			g->DrawImage(b, 0, 0);
			return returnBitmap;
	      }

and it goes good, but sometimes after some time running the program I get Out of Memory error in line

g->DrawImage(b, 0, 0);

Is this a disposal issue ? do you have any idea how to fix it ?

Thanks and best regards,
Smallbit

[Alex F]

Graphics is disposable class and should be deleted after using:
delete g;

[Eri523]

Alex F's objection emphasizes that your program may be suffering from a memory or other resource leak. Did you try to observe memory consumption of the program using Task Manager or Sysinternals' Process Explorer? If you don't observe a steady increase in memory consumption, you should have a look at the GDI object count and handle count.

Also, the methods from the System::Drawing namespace are more or less known for throwing an OutOfMemoryException in case the underlying GDI+ function encounters any problem in handling the bitmap format. (This has for instance been discussed in http://www.codeguru.com/forum/showthread.php?t=513030.) Perhaps they may even do that if it's not documented on MSDN (which would be the case for Graphics::DrawImage()). While I'm not quite sure now whether that's true for that sort of GDI+ problems as well, in general the information carried by the .NET exception objects often is quite helpful, so I'd say it's definitely worth a try to have a closer look at the exception object you catch. In case it's a GDI+ problem, the exception being thrown is likely to be correlated to the use of certain (types of) bitmap objects and/or rotation angles.

[smallbit]

Thanks for your answer,

It is not very easy to reproduce the exception (since as I wrote it appears in unexpected moments). However I am now disposing the Graphics, and also I have rewrite a bit my source code, because i was kind of exploiting this method .

Now I don't get this out of memory error anymore. When I will have some spare time I will look into what You have written Eri.

Thanks for your help and time guys !
Best regards,
Smallbit.