Function

Summary

Loads an image and returns the image object.

Package

graphics-ports

Signature

load-image gp id &key cache type force-plain image-translation-table => image

Arguments

gp

A graphics port.

id

An image identifier, a file, an external-image, or an image.

cache

A boolean.

type

A keyword, or nil .

force-plain

A boolean.

image-translation-table

An image translation table.

Values

image

An image object.

Description

The load-image function loads an image identified by id via the image-translation-table using the image load function registered with it. It returns an image object with the representation slot initialized. The gp argument specifies a graphics port used to identify the library. It also specifies the resource in which colors are defined and if necessary allocated for the image. If id is in the table but the translation is not an external image, and the image loader returns an external image as the second value, that external image replaces the translation in the table. The default value of image-translation-table is *default-image-translation-table*.

id can be an image, which is simply returned if it is a Plain Image or if force-plain is nil . Otherwise a new Plain Image object is returned, as described below.

id can also be a string or pathname denoting a file, and in this case the image is loaded according to type , as described below.

The cache argument controls whether the image translation is cached. See the convert-external-image function for more details.

type tells load-image that the image is in a particular graphics format. Currently the only recognised value is :bmp , which means the image is a Bitmap. Other values of type cause load-image to load the image according to the file type of id, if id denotes a file, as described for read-external-image . See the Graphics Ports chapter in the LispWorks CAPI User Guide for a discussion of image handling. The default value of type is nil .

force-plain , if true, forces image to be a Plain Image suitable for use with the Image Access API. Given an image my-image , call

(load-image port my-image :force-plain t)

to create an image guaranteed to work with make-image-access. The default value of force-plain is nil .

Note: gp must already be created at the time load-image is called. If you need to delay loading the image, for example if you are computing the image dynamically, then you can call load-image in the create-callback of the interface or even in the first display-callback of the pane.

See also

convert-external-image
*default-image-translation-table*
load-icon-image
make-image-access