int
licomposite(kobject src1_obj, kobject src2_obj, kobject dst_obj, int flag)
INPUT
src1_obj - First input image
src2_obj - Second input image
flag - indicates the type of compositing
aPLUSb - A, B where the other do not exist,
and both A and B where both exist.
(default)
aOVERb - A, B where the other do not exist,
and A where both exist.
bOVERa - A, B where the other do not exist,
and B where both exist.
aINb - A where B exists.
bINa - B where A exists.
aOUTb - A where B doesn't exist.
aATOPb - B where A doesn't exist, A where
B exists.
bATOPa - A where B doesn't exist, B where
A exists.
aXORb - A, B where the other do not exist.
OUTPUT
dst_obj - Output image
RETURN VALUE
TRUE (1) on success, FALSE (0) otherwise
DESCRIPTION
This library function implements a variety of
compositing routines for combining images as
detailed by Thomas Porter and Tom Duff in
"Compositing Digital Images", Computer Graphics,
ACM, Vol. 18, 1984.
ADDITIONAL INFORMATION
none
EXAMPLES
none
SIDE EFFECTS
Output is scaled between 0 and 1. If the
datatype of the first source is double the
datatype of the destination will be the same.
Otherwise the datatype of the destination will
be float in order to hold the scaled output.
RESTRICTIONS
If an input image does not have an alpha
channel, this routine will create one with
value of 1 (appropriate for a background
image). Input images are required to have
either four channels or three if no alpha
channel is supplied. Masked or gated images
currently are not supported.