1.120 class pixmap

A pixmap object is a coloured image: a rectangular area of pixmap<-width x pixmap<-height pixels, each of which may have its own colour.

Coloured images are actually supported by class image using image<-kind. This class is introduced to provide type specification for coloured images as needed for some graphical operations as well as automatic conversion of monochrome bitmaps into colour pixmaps.

This class is often used implicitly:‘window pixmap->background: @grey25_image’will automatically convert the @grey25_image into a pixmap using pixmap<-convert.

Explicit usage is normally done to create a coloured version of some monochrome bitmap:

?- new(I, pixmap(image('pce.bm'), red, green)).

Will create a version of the library image pce.bm using a red pixmap<-foreground and a green <background. See also pixmap->initialise.

Pixmaps are in general reusable objects like normal images. Therefore, the pixmap<-convert method ensure reuse of a pixmap create from some monochrome image.

1.120.1 Send methods

pixmap ->initialise: source=[image|file]*, width=[int], height=[int]

The initialisation of a pixmap can take three forms:

pixmap(@nil, foreground, background, width, height)

Creates a read-write pixmap of specified dimensions with specified colours.

pixmap(image, [foreground], [background])

Creates a pixmap with specified colours of the same dimensions as the image and copies the image to the pixmap, where each 1 maps to a foreground and each 0 to a background pixel.

After doing so, it will establish a hyper object with names pixmap and image that relates the original image and the new pixmap. See also pixmap<-lookup and pixmap<-source.

pixmap(file, [foreground], [background])

Load the pixmap from a file. If the file is an image file, the colour will be used to map the 1's and 0's.

1.120.2 Get methods

pixmap <-convert: name|image|graphical|file -> pixmap

Converts the below types to a full-colour image object.

name

Do general transformation of @some-name, verifying that the result is a pixmap.

image

Converts an monochrome image into a coloured pixmap. Basically simply calls new(Pm, pixmap(image)), first trying pixmap<-lookup to reuse an older transformation and then pixmap->initialise to create a new pixmap object.

graphical

Create a pixmap object of the required size and then use image->draw_in to paint the graphical in the pixmap.

file

Create a pixmap object and load the file-data into it.

pixmap <-lookup: source=image, width=[int], height=[int] -> pixmap

Checks whether it can find a pixmap object from the image using object<-hypered: pixmap with the same foreground and background.

This method ensures reuse of converted monochrome images. see also pixmap<-source.

pixmap <-source: -> image|file*

Determine source for term representation: if the image<-file is not @nil, this value is returned. If object<-hypered: image returns an image object, this is returned. Otherwise @nil is returned.

Used for converting a pixmap to its term representation.