added RectangleUtil::overlapRectangles() + test cases

1 files changed, 44 insertions, 0 deletions

diff --git a/src/RectangleUtil.hh b/src/RectangleUtil.hh
index 88c3a33..9725e63 100644
--- a/src/RectangleUtil.hh
+++ b/src/RectangleUtil.hh
@@ -24,6 +24,50 @@ bool insideBorder(const RectangleLike& rect,
         y < rect.y() + (int)rect.height() + border_width;
 }
 
+
+
+/*
+ * Determines if rectangle 'a' overlaps rectangle 'b'
+ * @returns true if 'a' overlaps 'b'
+ *
+ *    outside              overlap situations
+ *
+ *  a----a            a----a         a--------a  b--------b
+ *  |    | b----b     |  b-+--b      | b----b |  | a----a |
+ *  a----a |    |     a--+-a  |      | |    | |  | |    | |
+ *         b----b        b----b      | b----b |  | a----a |
+ *                                   a--------a  b--------b
+ *
+ */
+
+inline bool overlapRectangles(
+        int ax, int ay, int awidth, int aheight,
+        int bx, int by, int bwidth, int bheight) {
+
+    bool do_not_overlap =
+         ax > (bx + bwidth)
+      || bx > (ax + awidth)
+      || ay > (by + bheight)
+      || by > (ay + aheight);
+
+    return !do_not_overlap;
+}
+
+
+/*
+ * Determines if rectangle 'a' overlaps rectangle 'b'
+ * @param a - rectangle a
+ * @param b - rectangle b
+ * @returns true if 'a' overlaps 'b'
+ */
+template <typename RectangleLikeA, typename RectangleLikeB>
+bool overlapRectangles(const RectangleLikeA& a, const RectangleLikeB& b) {
+
+    return overlapRectangles(
+            a.x(), a.y(), a.width(), a.height(),
+            b.x(), b.y(), b.width(), b.height());
+}
+
 } // namespace RectangleUtil