+/**
+ * Describe a rectangular area with coordinates expressed in pixels.
+ *
+ * The rectangle is represented in terms of its top/left and
+ * right/bottom borders.
+ *
+ * In some cases, rectangles are assumed to obey to the
+ * following invariants:
+ *
+ * xmin <= xmax
+ * ymin <= ymax
+ *
+ * Oddly, the xmin and ymin coordinates are inclusive, while the
+ * xmax and ymax coordinates are non-inclusive. This design
+ * decision makes several computations simpler and lets you
+ * specify empty (0x0) rectangles without breaking the
+ * invariants.
+ *
+ * Computing the size of a rectangle can be done by simply
+ * subtracting the maximum X or Y coordinate from the minimum
+ * X or Y coordinate.
+ */