Graphmath.Mat33.transform_vector

You're seeing just the function transform_vector, go back to Graphmath.Mat33 module for more information.
Link to this function

transform_vector(a, v)

Specs

transform_vector(mat33(), vec2()) :: vec2()

transform_vector( a, v ) transforms a vec2 vector by a mat33.

a is a mat33 used to transform the point.

v is a vec2 to be transformed.

This returns a vec2 representing the application of a to v.

The point a is internally treated as having a third coordinate equal to 0.0.

Note that transforming a vector will work for only rotations, scales, and shears.