Specifications

Image Arithmetic and Logical Operations
5-19
5
void iplAlphaCompositeC(IplImage* srcImageA , IplImage*
srcImageB , IplImage* dstImage , int compositeType , int aA ,
int aB , BOOL premulAlpha , BOOL divideMode );
srcImageA The foreground input image.
srcImageB The background input image.
dstImage The resultant output image.
compositeType The composition type to perform. See Table 5-2 for the
type value and description.
aA The constant alpha value to use for the source image
srcImageA . Should be a positive number.
aB The constant alpha value to use for the source image
srcImageB . Should be a positive number.
alphaImageA The image to use as the alpha channel for srcImageA .If
the image
alphaImageA contains an alpha channel, that
channel is used. Otherwise channel 1 in
alphaImageA is
used as the alpha channel. If this is not suitable for the
application, then the alpha channel number in the
IplImage header for the image should be set
appropriately before calling this function. If the
argument
alphaImageA is NULL, then the internal alpha
channel of srcImageA is used. If srcImageA does not
contain an alpha channel, an error message is issued.
alphaImageB The image to use as the alpha channel for srcImageB .If
the image alphaImageB already contains an alpha
channel, that channel is used. Otherwise channel 1 in
alphaImageB is used as the alpha channel. If this is not
suitable for the application, then the alpha channel
number in the image header for the image should be set
appropriately before calling this function. If the
argument
alphaImageB is NULL, then the internal alpha
channel of
srcImageB is used.