Re: [PATCH] d2d1: Partially implement StrokeContainsPoint() for rectangle geometry

[Nikolay Sivov]

On 01.09.2017 1:25, Henri Verbeet wrote:
> On 31 August 2017 at 14:00, Nikolay Sivov  wrote:
> > - if (transform)
> > - {
> > -
> >    if (!d2d_matrix_invert(&g_i, transform))
> > -
> >        return D2DERR_UNSUPPORTED_OPERATION;
> > -
> >    d2d_point_transform(&point, &g_i, point.x, point.y);
> > - }
> > - if (FAILED(hr = geometry_inv_transform_point(transform, &point)))
> > -
> >    return hr;
>
> That's fine in principle, but please do it in a separate commit, and
> please follow the existing conventions. E.g.:
> if (transform && FAILED(hr = d2d_point_transform_inverse(&point,
>
> transform, point.x, point.y)))
>         return hr;

Sure.
> > - stroke_width /= 2.0f;
> > -
> > - rect = geometry->u.rectangle.rect;
> > - rect.left -= stroke_width;
> > - rect.right += stroke_width;
> > - rect.top -= stroke_width;
> > - rect.bottom += stroke_width;
> > -
> > - dx = max(fabsf((rect.right  + rect.left) / 2.0f - point.x) - (rect.right  - rect.left) / 2.0f, 0.0f);
> > - dy = max(fabsf((rect.bottom + rect.top)  / 2.0f - point.y) - (rect.bottom - rect.top)  / 2.0f, 0.0f);
> > -
> > - if ((*contains = tolerance * tolerance > (dx * dx + dy * dy)))
> > - {
> > -
> >    rect = geometry->u.rectangle.rect;
> > -
> >    stroke_width += tolerance;
> > -
> >    rect.left += stroke_width;
> > -
> >    rect.right -= stroke_width;
> > -
> >    rect.top += stroke_width;
> > -
> >    rect.bottom -= stroke_width;
> > -
> > -
> >    *contains = rect.left >= point.x || rect.right <= point.x || rect.top >= point.y || rect.bottom <= point.y;
> > - }
>
> I think that looks a little more complicated than it needs to be. How about:
> D2D1_POINT_2F d, s;
>
> ...
>     s.x = rect.right - rect.left;
>     s.y = rect.bottom - rect.top;
>     d.x = fabsf((rect.right + rect.left) * 0.5f - point.x);
>     d.y = fabsf((rect.bottom + rect.top) * 0.5f - point.y);
> if (d.x < (s.x - stroke_width) * 0.5f - tolerance && d.y < (s.y -
>
> stroke_width) * 0.5f - tolerance)
>     {
>         *contains = FALSE;
>         return S_OK;
>     }
> d.x = max(d.x - (s.x + stroke_width) * 0.5f, 0.0f);
> d.y = max(d.y - (s.y + stroke_width) * 0.5f, 0.0f);
> *contains = (d.x * d.x + d.y * d.y) < tolerance * tolerance;

Ok, I'll take a look.
> I notice you don't have any tests with transformations, is that
> intentional? I think you'd need to transform the stroke width with the
> transformation matrix.

No particular reason, but it's a good point. Also we don't have any
tests for non-invertible case apparently, I'll add some.