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Q82378: 24-Bit DIBs Draw Very Slowly When Running on an 8514

Article: Q82378
Product(s): Microsoft Windows 95.x Retail Product
Version(s): WINDOWS:3.1,3.11
Operating System(s): 
Keyword(s): 
Last Modified: 02-NOV-1999

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The information in this article applies to:

- Microsoft Windows versions 3.1, 3.11 
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SUMMARY
=======

When you use the 8514 video driver included with the Microsoft Windows, a 24-bit
DIB (device independent bitmap) draws slowly because of 24-bit to 8-bit color
matching.

MORE INFORMATION
================

24-Bit DIBs paint or appear slow on machines configured for the 8514 driver, and
it may appear as though the machine has stopped. Actually, the machine is merely
color-matching every pixel in the DIB. The video driver calls into the GDI
(graphical device interface) for each pixel. This process causes the GDI to
search the current system palette, containing 256 color elements, for the
closest matching color. This color value is then returned to the driver. The
slowdown occurs with any operation that converts a 24-bit DIB to an 8-bit DIB.

Additional query words: 3.10 3.11

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Keywords          :  
Technology        : kbWin3xSearch kbZNotKeyword3 kbWin310 kbWin311
Version           : WINDOWS:3.1,3.11

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