Function

Summary

Creates a pixmap port and its window system representation.

Package

graphics-ports

Signature

create-pixmap-port pane width height &key background collect
relative clear => pixmap-port

Arguments

pane

A graphics port for a window.

width

An integer.

height

An integer.

background

A color designator.

collect

A boolean.

relative

A boolean.

clear

A list or t .

Values

pixmap-port

A pixmap graphics port.

Description

The create-pixmap-port function creates a pixmap-port and its window system representation. The pane argument specifies the color-user, used for color conversions, and its representation may also be used by the library to match the pixmap port properties. The value of background is used to initialize the graphics-state-background .

If clear is t , the pixmap is cleared to its background color, otherwise the initial pixel values will be non-deterministic. If clear is a list of the form ( x y width height ), only that part of the pixmap is cleared initially. The default value is nil .

If relative is non- nil , the pixmap graphics port collects pixel coordinates corresponding to the left, top, right, and bottom extremes of the drawing operations taking place within the body forms, and if these extend beyond the edges of the pixmap (into negative coordinates for example) the entire drawing is offset by an amount which ensures it remains within the port. It is as if the port moves its relative origin in order to accommodate the drawing. If the drawing size is greater than the screen size, then some of it is lost. The default value is nil .

If collect is non- nil , this causes the drawing extremes to be collected but without having the pixmap shift to accommodate the drawing, as relative does. The extreme values can be read using the get-bounds function, and make-image-from-port.