/* Compute the intersection of two edges. The result is provided as a
* coordinate pair of 128-bit integers.
*
* Returns %CAIRO_BO_STATUS_INTERSECTION if there is an intersection
* that is within both edges, %CAIRO_BO_STATUS_NO_INTERSECTION if the
* intersection of the lines defined by the edges occurs outside of
* one or both edges, and %CAIRO_BO_STATUS_PARALLEL if the two edges
* are exactly parallel.
*
* Note that when determining if a candidate intersection is "inside"
* an edge, we consider both the infinitesimal shortening and the
* infinitesimal tilt rules described by John Hobby. Specifically, if
* the intersection is exactly the same as an edge point, it is
* effectively outside (no intersection is returned). Also, if the
* intersection point has the same
*/
static cairo_bool_t
_cairo_bo_edge_intersect (cairo_bo_edge_t *a,
cairo_bo_edge_t *b,
cairo_bo_point32_t *intersection)
{
cairo_bo_intersect_point_t quorem;
if (! intersect_lines (a, b, &quorem))
return FALSE;
if (! _cairo_bo_edge_contains_intersect_point (a, &quorem))
return FALSE;
if (! _cairo_bo_edge_contains_intersect_point (b, &quorem))
return FALSE;
/* Now that we've correctly compared the intersection point and
* determined that it lies within the edge, then we know that we
* no longer need any more bits of storage for the intersection
* than we do for our edge coordinates. We also no longer need the
* remainder from the division. */
intersection->x = quorem.x.ordinate;
intersection->y = quorem.y.ordinate;
return TRUE;
}
/* Compute the intersection of two edges. The result is provided as a
* coordinate pair of 128-bit integers.
*
* Returns %CAIRO_BO_STATUS_INTERSECTION if there is an intersection
* that is within both edges, %CAIRO_BO_STATUS_NO_INTERSECTION if the
* intersection of the lines defined by the edges occurs outside of
* one or both edges, and %CAIRO_BO_STATUS_PARALLEL if the two edges
* are exactly parallel.
*
* Note that when determining if a candidate intersection is "inside"
* an edge, we consider both the infinitesimal shortening and the
* infinitesimal tilt rules described by John Hobby. Specifically, if
* the intersection is exactly the same as an edge point, it is
* effectively outside (no intersection is returned). Also, if the
* intersection point has the same
*/
static cairo_bool_t
_cairo_bo_edge_intersect (cairo_bo_edge_t *a,
cairo_bo_edge_t *b,
cairo_bo_intersect_point_t *intersection)
{
if (! intersect_lines (a, b, intersection))
return FALSE;
if (! _cairo_bo_edge_contains_intersect_point (a, intersection))
return FALSE;
if (! _cairo_bo_edge_contains_intersect_point (b, intersection))
return FALSE;
return TRUE;
}
