2 GP Reference Entries

externalize-image

Function

Summary
: Returns an external image containing color information from an image.
Signature

externalize-image gp image &key maximum-colors important-colors &allow-other-keys => external-image

Arguments

gp: A graphics port
image: An image
maximum-colors: An integer ornil
important-colors: An integer ornil

Values

external-image: An external image

Description

Theexternal-image function returns an external image containing color information from image. If maximum-colors isnil, the default value, an external image using all the colors in image is created. If maximum-colors is an integer, the external image containing image will be created using no more than that number of colors. If the image contains more than maximum-colors colors, the maximum-colors most frequently used colors will be accurately stored; the remainder will be approximated by nearest colors out of the accurate ones, using the Color System parameterscolor::*local-rgb-color-distance-red-weight* and so on as the weighting factors for the color distance. The value of important-color is recorded in the external-image for later use, and specifies the number of colors required to draw a good likeness of the image. The default value is the number of colors in the image.