cleanup and optimize rect intersect routines

include/core/SkRect.h

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkRect_DEFINED
@@ skipping 633 matching lines @@
        sides are moved inwards, making the rectangle narrower. The same holds
        true for dy and the top and bottom.
     */
     void outset(SkScalar dx, SkScalar dy)  { this->inset(-dx, -dy); }
 
     /** If this rectangle intersects r, return true and set this rectangle to that
         intersection, otherwise return false and do not change this rectangle.
         If either rectangle is empty, do nothing and return false.
     */
     bool intersect(const SkRect& r);
-    bool intersect2(const SkRect& r);
 
     /** If this rectangle intersects the rectangle specified by left, top, right, bottom,
         return true and set this rectangle to that intersection, otherwise return false
         and do not change this rectangle.
         If either rectangle is empty, do nothing and return false.
     */
     bool intersect(SkScalar left, SkScalar top, SkScalar right, SkScalar bottom);
 
     /**
+     *  If rectangles a and b intersect, return true and set this rectangle to
+     *  that intersection, otherwise return false and do not change this
+     *  rectangle. If either rectangle is empty, do nothing and return false.
+     */
+    bool intersect(const SkRect& a, const SkRect& b);
+
+
+private:
+    static bool Intersects(SkScalar al, SkScalar at, SkScalar ar, SkScalar ab,
+                           SkScalar bl, SkScalar bt, SkScalar br, SkScalar bb) {
+        SkScalar L = SkMaxScalar(al, bl);
+        SkScalar R = SkMinScalar(ar, br);
+        SkScalar T = SkMaxScalar(at, bt);
+        SkScalar B = SkMinScalar(ab, bb);
+        return L < R && T < B;
+    }
+
+public:
+    /**
      *  Return true if this rectangle is not empty, and the specified sides of
      *  a rectangle are not empty, and they intersect.
      */
     bool intersects(SkScalar left, SkScalar top, SkScalar right, SkScalar bottom) const {
-        return // first check that both are not empty
-               left < right && top < bottom &&
-               fLeft < fRight && fTop < fBottom &&
-               // now check for intersection
-               fLeft < right && left < fRight &&
-               fTop < bottom && top < fBottom;
+        return Intersects(fLeft, fTop, fRight, fBottom, left, top, right, bottom);
     }
 
-    /** If rectangles a and b intersect, return true and set this rectangle to
-     *  that intersection, otherwise return false and do not change this
-     *  rectangle. If either rectangle is empty, do nothing and return false.
-     */
-    bool intersect(const SkRect& a, const SkRect& b);
-
     /**
      *  Return true if rectangles a and b are not empty and intersect.
      */
     static bool Intersects(const SkRect& a, const SkRect& b) {
-        return  !a.isEmpty() && !b.isEmpty() &&
-                a.fLeft < b.fRight && b.fLeft < a.fRight &&
-                a.fTop < b.fBottom && b.fTop < a.fBottom;
+        return Intersects(a.fLeft, a.fTop, a.fRight, a.fBottom,
+                          b.fLeft, b.fTop, b.fRight, b.fBottom);
     }
 
     /**
      *  Update this rectangle to enclose itself and the specified rectangle.
      *  If this rectangle is empty, just set it to the specified rectangle.
      *  If the specified rectangle is empty, do nothing.
      */
     void join(SkScalar left, SkScalar top, SkScalar right, SkScalar bottom);
 
     /** Update this rectangle to enclose itself and the specified rectangle.
@@ skipping 150 matching lines @@
      * rely on the existence of this function or the formatting of its output.
      */
     void dump() const {
         SkDebugf("{ l: %f, t: %f, r: %f, b: %f }", fLeft, fTop, fRight, fBottom);
     }
 #endif
 
 };
 
 #endif