# Keyword Reference

# $tagBLENDFUNCTION

$tagBLENDFUNCTION structure controls blending by specifying the blending functions for source and destination bitmaps

Global Const $tagBLENDFUNCTION = "byte Op;byte Flags;byte Alpha;byte Format"

## Parameters

Op | Specifies the source blend operation:
Flags | Must be zero
Alpha | Specifies an alpha transparency value to be used on the entire source bitmap. This value is combined with any per-pixel alpha values in the source bitmap. If set to 0, it is assumed that your image is transparent. Set to 255 (opaque) when you only want to use per-pixel alpha values.
Format | This member controls the way the source and destination bitmaps are interpreted: AC_SRC_ALPHA - This flag is set when the bitmap has an Alpha channel (that is, per-pixel alpha). Note that the APIs use premultiplied alpha, which means that the red, green and blue channel values in the bitmap must be premultiplied with the alpha channel value.

## Remarks

The source bitmap used with $tagBLENDFUNCTION must be 32 bpp