PgMatrix.transformDistance

Transforms the distance vector (@dx,@dy) by @matrix.

This is similar to [method@Pango.Matrix.transform_point], except that the translation components of the transformation are ignored. The calculation of the returned vector is as follows:

dx2 = dx1 * xx + dy1 * xy;
dy2 = dx1 * yx + dy1 * yy;

Affine transformations are position invariant, so the same vector always transforms to the same vector. If (@x1,@y1) transforms to (@x2,@y2) then (@x1+@dx1,@y1+@dy1) will transform to (@x1+@dx2,@y1+@dy2) for all values of @x1 and @x2.

class PgMatrix
void
transformDistance
(
ref double dx
,
ref double dy
)

Parameters

dx double

in/out X component of a distance vector

dy double

in/out Y component of a distance vector

Meta

Since

1.16