Re: [PATCH] gdiplus: Implement transform matrix for line gradient brushes

[Vincent Povirk]

I wrote a test program (attached), and it doesn't work when the start
point isn't 0,0.
> - if (line->startpoint.X == line->endpoint.X)
> -
>    t = line->startpoint.Y > line->endpoint.Y ? 3.f * M_PI / 2.f : M_PI / 2.f;
> - else
> -
>    t = atanf((line->endpoint.Y - line->startpoint.Y) / (line->endpoint.X - line->startpoint.X));
> -
> - t_cos = cosf(t);
> - t_sin = sinf(t);

This seems like an oddly complicated and fragile way to normalize a vector.