Function

Summary

Constructs the inverse of a transform.

Package

graphics-ports

Signature

invert-transform transform &optional into => inverse

Arguments

transform

A transform object.

into

A transform object or nil .

Values

inverse

A transform object.

Description

This function constructs the inverse of transform . If T is transform and T' is its inverse, then TT ' = I. If into is non- nil it is modified to contain T' and returned, otherwise a new transform is constructed and returned.