2.3 DUIM-Geometry Module

make-reflection-transform

Function

Summary

Returns a transform that reflects every point through the line passing through the positions x1,y1 and x2,y2 or through the points point1 and point2.

Signature

make-reflection-transform x1 y1 x2 y2 => transform

make-reflection-transform* point-1 point-2 => transform

Arguments

The following arguments are specific to make-reflection-transform.

x1: An instance of type <real>.
y1: An instance of type <real>.
x2: An instance of type <real>.
y2: An instance of type <real>.

The following arguments are specific to make-reflection-transform*.

point1: An instance of type <point>. The first point.
point2: An instance of type <point>. The second point.

Values

transform: An instance of type <transform>. The resultant transformation.

Library

duim-geometry

Module

duim-geometry

Description

Returns a transform that reflects every point through the line passing through the positions x1,y1 and x2,y2 or through the points point1 and point2.

The arguments x1 and y1 represent the coordinates of the first point of reflection. The arguments x2 and y2 represent the coordinates of the second point of reflection.

A reflection is a transform that preserves lengths and magnitudes of angles, but changes the sign (or handedness) of angles. If you think of the drawing plane on a transparent sheet of paper, a reflection is a transformation that turns the paper over.

The function make-reflection-transform* is identical to make-reflection-transform, except that it passes composite objects, rather than separate coordinates, in its arguments. You should be aware that using this function may lead to a loss of performance.