A pathname designator.
A keyword, or
specifies the index of the transparent color in the color map.
works only for images with a color map, that is, those with 256 colors or less. The default value is
, meaning that there is no transparent color.
that the image is in a particular graphics format. Currently the only recognised value is
, which means the image is read as a Bitmap. Other values of
to read the image according to the file type of
mean that the image is read as a Bitmap. Other file types are handled in Operating System-specific ways. See the Graphics Ports chapter in the
CAPI User Guide
for details. The default value of
(gp:read-external-image file :transparent-color-index 183)
CAPI Reference Manual - 15 Dec 2011