Make adding and subtracting gfx:: point types simpler.

ui/gfx/rect.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Defines a simple integer rectangle class.  The containment semantics
 // are array-like; that is, the coordinate (x, y) is considered to be
 // contained by the rectangle, but the coordinate (x + width, y) is not.
 // The class will happily let you create malformed rectangles (that is,
 // rectangles with negative width and/or height), but there will be assertions
 // in the operations (such as Contains()) to complain in this case.
@@ skipping 50 matching lines @@
 #if defined(OS_WIN)
   // Construct an equivalent Win32 RECT object.
   RECT ToRECT() const;
 #elif defined(TOOLKIT_GTK)
   GdkRectangle ToGdkRectangle() const;
 #elif defined(OS_MACOSX)
   // Construct an equivalent CoreGraphics object.
   CGRect ToCGRect() const;
 #endif
 
-  RectF ToRectF() const WARN_UNUSED_RESULT {
-    return RectF(origin().x(), origin().y(), size().width(), size().height());
-  }
-
   RectF Scale(float scale) const WARN_UNUSED_RESULT {
     return Scale(scale, scale);
   }
 
   RectF Scale(float x_scale, float y_scale) const WARN_UNUSED_RESULT {
-    return ToRectF().Scale(x_scale, y_scale);
+    return static_cast<RectF>(*this).Scale(x_scale, y_scale);
   }
 
   std::string ToString() const;
+
+  operator RectF() const {

[sky, 2012/10/01 21:02:20]

Why is this better than ToRectF?

[danakj, 2012/10/01 21:55:34]

So you don't have to cast all the ints to floats explicitly every time you have
some floating point values in the equation.

float f; int i;
float f2 = f + i; // does not need static_cast<float>(i).

RectF f; Rect i;
PointF f2 = f.origin() + i.origin(); // would need i.ToRectF().origin()

If I want to add something to a PointF, I don't care if it is a Point or a
PointF. I feel ToRectF() just decreases the signal to noise ratio of the code.

+    return RectF(origin().x(), origin().y(), size().width(), size().height());
+  }
 };
 
 #if !defined(COMPILER_MSVC)
 extern template class RectBase<Rect, Point, Size, Insets, int>;
 #endif
 
 }  // namespace gfx
 
 #endif  // UI_GFX_RECT_H_