NextPrevUpTopContentsIndex Transparency

An External Image representing an image with a color map can specify a transparent color. When converted and drawn, this color is drawn using the background color of the port.

You can specify the transparent color by

(gp:read-external-image file :transparent-color-index 42)

or by

 (gp:external-image-transparent-color-index external-image

You can use an image tool such as the Gimp ( ) to figure out the transparent color index.

Note: transparent-color-index works only for images with a color map - those with 256 colors or less.

LispWorks CAPI User Guide (Unix version) - 8 Apr 2005