Implemented util::rects_overlap and documented util

src/gui/gtk-lumiera.hpp

@@ -148,6 +148,11 @@ namespace widgets {}
  */
 namespace workspace {}
 
+/**
+ * The namespace of utility functions and classes.
+ */
+namespace util {}
+
 }   // namespace gui
 
 #endif // GTK_LUMIERA_HPP

src/gui/util/rectangle.cpp

@@ -22,6 +22,9 @@
 * *****************************************************/
 
 #include "rectangle.hpp"
+#include <algorithm>
+
+using namespace std;
 
 namespace gui {
 namespace util {
@@ -35,6 +38,18 @@ pt_in_rect(const Gdk::Point &point, const Gdk::Rectangle &rect)
     point.get_y() < rect.get_y() + rect.get_height());
 }
 
+bool
+rects_overlap(const Gdk::Rectangle &a, const Gdk::Rectangle &b)
+{ 
+  return (
+    max(a.get_x(), b.get_x()) <
+    min(a.get_x() + a.get_width(), b.get_x() + b.get_width())
+    &&
+    max(a.get_y(), b.get_y()) <
+    min(a.get_y() + a.get_height(), b.get_y() + b.get_height())
+    );
+}
+
 }   // namespace util
 }   // namespace gui
 

src/gui/util/rectangle.hpp

@@ -42,6 +42,13 @@ namespace util {
  **/
 bool pt_in_rect(const Gdk::Point &point, const Gdk::Rectangle &rect);
 
+/**
+ * Tests whether two rectangles overlap.
+ * @param a The first rectangle.
+ * @param b The second rectangle.
+ **/
+bool rects_overlap(const Gdk::Rectangle &a, const Gdk::Rectangle &b);
+
 }   // util
 }   // gui