diff options
| -rw-r--r-- | components/script/dom/htmlareaelement.rs | 26 | ||||
| -rw-r--r-- | tests/unit/script/htmlareaelement.rs | 15 |
2 files changed, 39 insertions, 2 deletions
diff --git a/components/script/dom/htmlareaelement.rs b/components/script/dom/htmlareaelement.rs index a9d94cbd7b2..535d296a29f 100644 --- a/components/script/dom/htmlareaelement.rs +++ b/components/script/dom/htmlareaelement.rs @@ -46,6 +46,8 @@ pub enum Area { bottom_right: (f32, f32), }, Polygon { + /// Stored as a flat array of coordinates + /// e.g. [x1, y1, x2, y2, x3, y3] for a triangle points: Vec<f32>, }, } @@ -203,8 +205,28 @@ impl Area { p.y >= top_left.1 }, - //TODO polygon hit_test - _ => false, + Area::Polygon { ref points } => { + // Ray-casting algorithm to determine if point is inside polygon + // https://en.wikipedia.org/wiki/Point_in_polygon#Ray_casting_algorithm + let mut inside = false; + + debug_assert!(points.len() % 2 == 0); + let vertices = points.len() / 2; + + for i in 0..vertices { + let next_i = if i + 1 == vertices { 0 } else { i + 1 }; + + let xi = points[2 * i]; + let yi = points[2 * i + 1]; + let xj = points[2 * next_i]; + let yj = points[2 * next_i + 1]; + + if (yi > p.y) != (yj > p.y) && p.x < (xj - xi) * (p.y - yi) / (yj - yi) + xi { + inside = !inside; + } + } + inside + }, } } diff --git a/tests/unit/script/htmlareaelement.rs b/tests/unit/script/htmlareaelement.rs index be4cb12c0cc..becfd17b88a 100644 --- a/tests/unit/script/htmlareaelement.rs +++ b/tests/unit/script/htmlareaelement.rs @@ -187,4 +187,19 @@ fn test_hit_test_polygon() { points: vec![7.0, 7.5, 8.2, 9.0, 11.0, 12.0], }; assert!(!poly2.hit_test(&Point2D::new(10.0, 5.0))); + let poly3 = Area::Polygon { + points: vec![0.0, 0.0, 5.0, 0.0, 5.0, 5.0, 0.0, 5.0], + }; + assert!(poly3.hit_test(&Point2D::new(1.0, 1.0))); + assert!(poly3.hit_test(&Point2D::new(2.0, 4.0))); + assert!(poly3.hit_test(&Point2D::new(4.0, 2.0))); + assert!(!poly3.hit_test(&Point2D::new(6.0, 0.0))); + assert!(!poly3.hit_test(&Point2D::new(0.0, 6.0))); + assert!(!poly3.hit_test(&Point2D::new(6.0, 6.0))); + // Concave polygon test + let poly4 = Area::Polygon { + points: vec![0.0, 0.0, 1.0, 1.0, 2.0, 0.0, 2.0, 2.0, 0.0, 2.0], + }; + assert!(poly4.hit_test(&Point2D::new(1.5, 1.5))); + assert!(!poly4.hit_test(&Point2D::new(1.0, 0.0))); } |