Refactor screen/monitor so that gfx::Screen returns monitor object.

ui/gfx/monitor.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.
+
+#ifndef UI_GFX_MONITOR_H_
+#define UI_GFX_MONITOR_H_
+#pragma once
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "ui/base/ui_export.h"
+#include "ui/gfx/rect.h"
+
+namespace gfx {
+
+// Note: The screen and monitor currently uses pixels coordinate
+// system.  ENABLE_DIP macro (which is enabled with enable_dip=1 gyp
+// flag) will make this inconsistent with views' coordinate system
+// because views will use DIP coordinate system, which uses
+// (1.0/device_scale_factor) scale of the pixel coordinate system.
+// TODO(oshima): Change aura/screen to DIP coordinate system and
+// update this comment.
+class UI_EXPORT Monitor {

[Ben Goodger (Google), 2012/04/13 19:57:19]

this could just be a struct. you can skip the setters.

e.g. 

struct UI_EXPORT Monitor {
  gfx::Rect bounds;
  gfx::Rect work_area;
  float device_scale_factor;
}

[oshima, 2012/04/13 21:18:41]

I was going to add a few methods, such as method that returns DIP
in addition to Pixels, a method that converts Pixels to DIP.
If it's ok to make it struct with these methods, I can.

If not, other options I can think of are

1) Add fields for DIP.
2) Let caller handle DIP.
3) Add GetMonitorXXInPixels() to gfx::Screen that returns Monitor with pixels
coordinate system.

These doesn't seem to look nice though. Let me know what you think.

+ public:
+  Monitor();
+  ~Monitor();
+
+  // Gets/Sets the monitor's bounds in gfx::Screen's coordinates.
+  const Rect& bounds() const { return bounds_; }
+  void set_bounds(const Rect& bounds) { bounds_ = bounds; }
+
+  // Gets/Sets the monitor's work area in gfx::Screen's coordinates.
+  const Rect& work_area() const { return work_area_; }
+  void set_work_area(const Rect& work_area) { work_area_ = work_area; }
+
+  // Output device's pixel scale factor. This specifies how much the
+  // UI should be scaled when the actual output has more pixels than
+  // standard monitors (which is around 100~120dpi.) The potential return
+  // values depend on each platforms.
+  float device_scale_factor() const { return device_scale_factor_; }
+  void set_device_scale_factor(float scale) { device_scale_factor_ = scale; }
+
+  // Utility functions that just return the size of monitor and
+  // work area.
+  const Size& size() const { return bounds_.size(); }
+  const Size& work_area_size() const { return work_area_.size(); }
+
+ private:
+  Rect bounds_;
+  Rect work_area_;
+  float device_scale_factor_;
+
+  DISALLOW_COPY_AND_ASSIGN(Monitor);
+};
+
+}  // namespace gfx
+
+#endif  // UI_GFX_MONITOR_H_