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Fix winding number for circle contours

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If its open, it isn't winding. And if its closed,
its winding number depends on the direction.
This commit is contained in:
Matthias Clasen
2020-12-13 22:41:48 -05:00
parent 7a2d99576e
commit e4f4f6a810
1 changed files with 3 additions and 25 deletions
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28
gsk/gskcontour.c
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@@ -792,32 +792,10 @@ gsk_circle_contour_get_winding (const GskContour *contour,
if (fabs (self->start_angle - self->end_angle) >= 360)
{
return -1;
}
else
{
/* Check if the point and the midpoint are on the same side
* of the chord through start and end.
*/
double mid_angle = (self->end_angle - self->start_angle) / 2;
graphene_point_t start = GRAPHENE_POINT_INIT (self->center.x + cos (DEG_TO_RAD (self->start_angle)) * self->radius,
self->center.y + sin (DEG_TO_RAD (self->start_angle)) * self->radius);
graphene_point_t mid = GRAPHENE_POINT_INIT (self->center.x + cos (DEG_TO_RAD (mid_angle)) * self->radius,
self->center.y + sin (DEG_TO_RAD (mid_angle)) * self->radius);
graphene_point_t end = GRAPHENE_POINT_INIT (self->center.x + cos (DEG_TO_RAD (self->end_angle)) * self->radius,
self->center.y + sin (DEG_TO_RAD (self->end_angle)) * self->radius);
graphene_vec2_t n, m;
float a, b;
graphene_vec2_init (&n, start.y - end.y, end.x - start.x);
graphene_vec2_init (&m, mid.x, mid.y);
a = graphene_vec2_dot (&m, &n);
graphene_vec2_init (&m, point->x, point->y);
b = graphene_vec2_dot (&m, &n);
if ((a < 0) != (b < 0))
if (self->end_angle > self->start_angle)
return -1;
else
return 1;
}
return 0;