3.5 The Transformations Used by CLIM

**transformation-equal** [Generic Function]

- Arguments:
*transformation1 transformation2*

- Summary:
- Returns
**t**if the two transformations have equivalent effects (that is, are mathematically equal); otherwise, it returns**nil**.

- Arguments:
*transformation*

- Summary:
- Returns
**t**if transformation is equal (in the sense of**transformation-equal**) to the identity transformation; otherwise, it returns**nil**.

- Arguments:
*transformation*

- Summary:
- Returns
**t**if*transformation*is a pure translation, that is, a transformation that moves every point by the same distance in*x*and the same distance in*y*. Otherwise, it returns**nil**.

- Arguments:
*transformation*

- Summary:
- Returns
**t**if transformation has an inverse; otherwise, it returns**nil**.

- Arguments:
*transformation*

- Summary:
- Returns
**t**if transformation inverts the "handedness" of the coordinate system; otherwise, it returns**nil**. Note that this is a very inclusive category--transformations are considered reflections even if they distort, scale, or skew the coordinate system, as long as they invert the handedness.

- Arguments:
*transformation*

- Summary:
- Returns
**t**if transformation transforms the coordinate system as a rigid object, that is, as a combination of translations, rotations, and pure reflections. Otherwise, it returns**nil**. - Rigid transformations are the most general category of transformations that preserve magnitudes of all lengths and angles.

- Arguments:
*transformation*

- Summary:
- Returns
**t**if transformation multiplies all*x*-lengths and*y*-lengths by the same magnitude; otherwise, it returns**nil**. This includes pure reflections through vertical and horizontal lines.

- Arguments:
*transformation*

- Summary:
- Returns
**t**if transformation multiplies all*x*-lengths by one magnitude and all*y*-lengths by another magnitude; otherwise, it returns**nil**. This category includes even scalings as a subset.

- Arguments:
*transformation*

- Summary:
- Returns
**t**if transformation will always transform any axis-aligned rectangle into another axis-aligned rectangle; otherwise, it returns**nil**. This category includes scalings as a subset, and also includes 90 degree rotations. - Rectilinear transformations are the most general category of transformations for which the bounding rectangle of a transformed object can be found by transforming the bounding rectangle of the original object.

CLIM 2.0 User's Guide - OCT 1998

Generated with Harlequin WebMaker