This topic documents a feature of Visual Filters and Transitions, which is deprecated as of Windows Internet Explorer 9 and obsolete as of Internet Explorer 10.
Determines whether a temporary buffer is needed when calling sample input methods on the IDXARGBReadPtr interface.
BOOL NeedSrcPMBuff( ULONG i );
- [in] Index of the specified input surface. The default value is zero.
Returns TRUE to indicate that you need to allocate a sample buffer for surface read methods.
If the native pixel format of your transform is PMARGB32, you will call methods such as IDXARGBReadPtr::UnpackPremult to read sample data. If the format of the input surface does not match, a temporary buffer is required by the input methods. The CDXBaseNTo1::NeedDestPMBuff method tests for this condition and lets the implementer know if a buffer will need to be allocated or not.