Solved

CImage ReleaseDC Exception Mystery

Posted on 2008-10-22
1
1,300 Views
Last Modified: 2013-12-14
I have been applying the CImage class within a Visual C++/MFC DLL.  I am experiencing a mysterious exception in atlimage.h line 1217 when I call CImage::GetPixel(0,0).  The offending statement is:

hBitmap = HBITMAP( ::SelectObject( m_hDC, m_hOldBitmap ) );
ATLASSERT( hBitmap == m_hBitmap );

I have successfully loaded an 8x13 jpg 24 bpp image from disk and the pixel value is successfully read, yet the m_hOldBitmap member is null and thus SelectObject returns null.  The m_hBitmap member is valid and thus does not match hBitmap.

Has anyone experienced this error and found a solution?

Thanks!
0
Comment
Question by:fredsmullin
1 Comment
 

Accepted Solution

by:
fredsmullin earned 0 total points
ID: 22783196
Please disregard the question.  I found that it was operator error with CImage use.

If you use the CImage assignment operator, CImage a = CImage b, it merely copies the HBITMAP value from b to a.  But when b is destroyed, it destroys the HBITMAP as well.  But, a has no idea this has occurred and any subsequent operations will result in exceptions being generated.

The proper way to assign from one CImage to another is to use CImage::Attach and CImage::Detach functions.  This only moves the HBITMAP from one class to the next, but prevents it from being shared between two classes.
0

Featured Post

Networking for the Cloud Era

Join Microsoft and Riverbed for a discussion and demonstration of enhancements to SteelConnect:
-One-click orchestration and cloud connectivity in Azure environments
-Tight integration of SD-WAN and WAN optimization capabilities
-Scalability and resiliency equal to a data center

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
java ^ examples 8 69
haveThree challenge 22 121
CKEditor - will not function 7 72
Remove Password Protection from pdf (with password) using an command line executable 5 63
Programmer's Notepad is, one of the best free text editing tools available, simply because the developers appear to have second-guessed every weird problem or issue a programmer is likely to run into. One of these problems is selecting and deleti…
If you use Adobe Reader X it is possible you can't open OLE PDF documents in the standard. The reason is the 'save box mode' in adobe reader X. Many people think the protected Mode of adobe reader x is only to stop the write access. But this fe…
This tutorial covers a step-by-step guide to install VisualVM launcher in eclipse.
The viewer will learn how to synchronize PHP projects with a remote server in NetBeans IDE 8.0 for Windows.

828 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question