Querying Device Support for MaskBlt

Last reviewed: November 2, 1995
Article ID: Q108929

The information in this article applies to:

Microsoft Win32 Application Programming Interface (API) included with:
```
    - Microsoft Windows NT versions 3.1, 3.5, and 3.51
```

The Win32 documentation for MaskBlt() states:

   Not all devices support the MaskBlt function. An application should call
   the GetDeviceCaps function to determine whether a device supports this
   function.

To query support for MaskBlt(), an application should query the device for BitBlt support by passing RC_BITBLT constant to GetDeviceCaps().

MaskBlt() implements transparent blts in Windows NT. For more information, please see the following article in the Microsoft Knowledge Base:

   ARTICLE-ID: Q89375
   TITLE     : Transparent Blts in Windows NT

GDI implements this application programming interface (API) by calling BitBlt(). Because BitBlt() is implemented at the driver level, applications that calls MaskBlt() should check for BitBlt() support on the device.

Additional reference words: 3.10 3.50
KBCategory: kbgraphic
KBSubcategory: GdiBmp

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Last reviewed: November 2, 1995
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