RFC: MatrixTrait::try_invert()

[federicomenaquintero]

I appreciate how MatrixTrait::invert() actually ensures that the matrix is invertible, and panics otherwise; it has caught a lot of bugs in librsvg.

Now, I need to know if a matrix is actually invertible, to validate user-supplied data (actually, transformations that come from an SVG file).

The quick-and-dirty way is to call ffi::cairo_matrix_invert() by hand and test the result.

A more idiomatic way could be to have this in MatrixTrait:

pub trait MatrixTrait {
    ...
     fn try_invert(&self) -> Result <Matrix, Status>;
    ...
}

What do you think? I can submit a pull request for this if you like the API.

[GuillaumeGomez]

Seems reasonable and a good idea.

[federicomenaquintero]

This has been merged; closing.