Drawing to a Memory Bitmap for Faster Performance (130805)

The information in this article applies to:

Microsoft Windows Software Development Kit (SDK) 3.1
Microsoft Win32 Application Programming Interface (API), when used with:
- Microsoft Windows 95
- Microsoft Windows NT Server 3.5
- Microsoft Windows NT Workstation 3.5
- Microsoft Win32s 1.25
Microsoft Windows 2000 Advanced Server
Microsoft Windows 2000 Server
Microsoft Windows 2000 Professional

This article was previously published under Q130805

SUMMARY

An application whose client area is a complex image can realize a performance benefit from drawing to a memory bitmap. The complex, time consuming drawing code need only be performed once - to initialize the offscreen bitmap. During the handling of the WM_PAINT message, the only work that needs to be done is a simple BitBlt from the memory bitmap to the screen.

Sample code demonstrating this technique is available in the Microsoft Dowload Center. The MemDC sample code draws a complex pattern on its client area. A menu option toggle allows the user to see the speed difference between using and not using the offscreen bitmap.

MORE INFORMATION

The following file is available for download from the Microsoft Download Center:

Memdc.exe

For additional information about how to download Microsoft Support files, click the following article number to view the article in the Microsoft Knowledge Base:

119591 How to Obtain Microsoft Support Files from Online Services

Microsoft scanned this file for viruses. Microsoft used the most current virus-detection software that was available on the date that the file was posted. The file is stored on security-enhanced servers that help to prevent any unauthorized changes to the file.

Modification Type:	Minor	Last Reviewed:	3/7/2005
Keywords:	kbdownload kbfile kbgraphic kbinfo KB130805 kbAudDeveloper