chrome/browser/chromeos/ui/accessibility_focus_ring_controller.h

// Copyright 2014 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 CHROME_BROWSER_CHROMEOS_UI_ACCESSIBILITY_FOCUS_RING_CONTROLLER_H_
#define CHROME_BROWSER_CHROMEOS_UI_ACCESSIBILITY_FOCUS_RING_CONTROLLER_H_

#include <vector>

#include "base/basictypes.h"
#include "base/memory/scoped_ptr.h"
#include "base/memory/singleton.h"
#include "base/time/time.h"
#include "chrome/browser/chromeos/ui/accessibility_focus_ring_layer.h"
#include "ui/compositor/compositor_animation_observer.h"
#include "ui/gfx/rect.h"

namespace ui {
class Compositor;
}

namespace chromeos {

// AccessibilityFocusRingController manages a custom focus ring (or multiple
// rings) for accessibility.
class AccessibilityFocusRingController
    : public FocusRingLayerDelegate,
      public ui::CompositorAnimationObserver {
 public:
  // Get the single instance of this class.
  static AccessibilityFocusRingController* GetInstance();

  // Draw a focus ring around the given set of rects, in global screen
  // coordinates.
  void SetFocusRing(const std::vector<gfx::Rect>& rects);

 protected:
  AccessibilityFocusRingController();
  virtual ~AccessibilityFocusRingController();

  // Given an unordered vector of bounding rectangles that cover everything
  // that currently has focus, populate a vector of one or more
  // AccessibilityFocusRings that surround the rectangles. Adjacent or
  // overlapping rectangles are combined first. This function is protected
  // so it can be unit-tested.
  void RectsToRings(const std::vector<gfx::Rect>& rects,
                    std::vector<AccessibilityFocusRing>* rings) const;

  virtual int GetMargin() const;

 private:
  // FocusRingLayerDelegate.
  virtual void OnDeviceScaleFactorChanged() override;

  // CompositorAnimationObserver.
  virtual void OnAnimationStep(base::TimeTicks timestamp) override;

  void Update();

  AccessibilityFocusRing RingFromSortedRects(
      const std::vector<gfx::Rect>& rects) const;
  void SplitIntoParagraphShape(
      const std::vector<gfx::Rect>& rects,
      gfx::Rect* top,
      gfx::Rect* middle,
      gfx::Rect* bottom) const;
  bool Intersects(const gfx::Rect& r1, const gfx::Rect& r2) const;

  std::vector<gfx::Rect> rects_;
  std::vector<AccessibilityFocusRing> previous_rings_;
  std::vector<AccessibilityFocusRing> rings_;
  std::vector<scoped_ptr<AccessibilityFocusRingLayer> > layers_;
  base::TimeTicks focus_change_time_;
  ui::Compositor* compositor_;

  friend struct DefaultSingletonTraits<AccessibilityFocusRingController>;

  DISALLOW_COPY_AND_ASSIGN(AccessibilityFocusRingController);
};

}  // namespace chromeos

#endif  // CHROME_BROWSER_CHROMEOS_UI_ACCESSIBILITY_FOCUS_RING_CONTROLLER_H_