All Manuals > CAPI User Guide > 13 Graphics Ports > 13.9 Working with images > 13.9.3 External images

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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

) 42)

You can use an image tool such as 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.

CAPI User Guide (Macintosh version) - 30 Aug 2011