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Evas polygon: Implement "is_inside" for polygons. 

SVN revision: 60712
This commit is contained in:
Tom Hacohen 2011-06-27 02:18:34 +00:00
parent a6948c292f
commit e85f91b3a3
1 changed files with 49 additions and 5 deletions
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54
legacy/evas/src/lib/canvas/evas_object_polygon.c
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@ -485,13 +485,57 @@ evas_object_polygon_was_opaque(Evas_Object *obj __UNUSED__)
return 0;
}
/* We count the number of edges a "ray" 90 degs upwards from our point
* intersects with. If it's even, we are outside of the polygon, if it's odd,
* we are inside of it. */
static int
evas_object_polygon_is_inside(Evas_Object *obj __UNUSED__, Evas_Coord x __UNUSED__, Evas_Coord y __UNUSED__)
evas_object_polygon_is_inside(Evas_Object *obj, Evas_Coord x, Evas_Coord y)
{
/* this returns 1 if the canvas co-ordinates are inside the object based */
/* on object private data. not much use for rects, but for polys, images */
/* and other complex objects it might be */
return 1;
Evas_Object_Polygon *o;
int num_edges = 0; /* Number of edges we crossed */
Eina_List *itr;
Evas_Polygon_Point *p;
o = (Evas_Object_Polygon *)(obj->object_data);
if (!o) return 0;
if (!o->points) return 0;
/* Adjust X and Y according to current geometry */
x -= obj->cur.geometry.x;
y -= obj->cur.geometry.y;
if (eina_list_count(o->points) == 1)
{
p = eina_list_data_get(o->points);
return ((p->x == x) && (p->y == y));
}
EINA_LIST_FOREACH(o->points, itr, p)
{
Evas_Coord line_y;
Eina_List *next = eina_list_next(itr);
Evas_Polygon_Point *p_next;
/* Get the next, or if there's no next, take the first */
if (next)
{
p_next = eina_list_data_get(next);
}
else
{
p_next = eina_list_data_get(o->points);
}
line_y = ((double) (p->y - p_next->y) / (double) (p->x - p_next->x)) *
(x - p_next->x) + p_next->y;
/* We crossed that edge if the line is directly above us */
if ((line_y < y) &&
(((p->x < p_next->x) && (p->x <= x) && (x <= p_next->x)) ||
((p->x > p_next->x) && (p_next->x <= x) && (x <= p->x))))
num_edges++;
}
/* Return true if num_edges is odd */
return ((num_edges % 2) == 1);
}
static int