// Copyright 2013 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 CC_LAYERS_PAINTED_SCROLLBAR_LAYER_H_
#define CC_LAYERS_PAINTED_SCROLLBAR_LAYER_H_

#include "cc/base/cc_export.h"
#include "cc/input/scrollbar.h"
#include "cc/layers/contents_scaling_layer.h"
#include "cc/layers/scrollbar_theme_painter.h"
#include "cc/resources/layer_updater.h"
#include "cc/resources/scoped_ui_resource.h"

namespace cc {
class ScrollbarThemeComposite;

class CC_EXPORT PaintedScrollbarLayer : public ContentsScalingLayer {
 public:
  virtual scoped_ptr<LayerImpl> CreateLayerImpl(LayerTreeImpl* tree_impl)
      OVERRIDE;

  static scoped_refptr<PaintedScrollbarLayer> Create(
      scoped_ptr<Scrollbar> scrollbar,
      int scroll_layer_id);

  int scroll_layer_id() const { return scroll_layer_id_; }
  void SetScrollLayerId(int id);

  virtual bool OpacityCanAnimateOnImplThread() const OVERRIDE;

  ScrollbarOrientation Orientation() const;

  // Layer interface
  virtual bool Update(ResourceUpdateQueue* queue,
                      const OcclusionTracker* occlusion) OVERRIDE;
  virtual void SetLayerTreeHost(LayerTreeHost* host) OVERRIDE;
  virtual void PushPropertiesTo(LayerImpl* layer) OVERRIDE;
  virtual void CalculateContentsScale(float ideal_contents_scale,
                                      float device_scale_factor,
                                      float page_scale_factor,
                                      bool animating_transform_to_screen,
                                      float* contents_scale_x,
                                      float* contents_scale_y,
                                      gfx::Size* content_bounds) OVERRIDE;

  virtual PaintedScrollbarLayer* ToScrollbarLayer() OVERRIDE;

 protected:
  PaintedScrollbarLayer(scoped_ptr<Scrollbar> scrollbar, int scroll_layer_id);
  virtual ~PaintedScrollbarLayer();

  // For unit tests
  UIResourceId track_resource_id() {
    return track_resource_.get() ? track_resource_->id() : 0;
  }
  UIResourceId thumb_resource_id() {
    return thumb_resource_.get() ? thumb_resource_->id() : 0;
  }
  void UpdateThumbAndTrackGeometry();

 private:
  gfx::Rect ScrollbarLayerRectToContentRect(gfx::Rect layer_rect) const;
  gfx::Rect OriginThumbRect() const;

  int MaxTextureSize();
  float ClampScaleToMaxTextureSize(float scale);

  scoped_refptr<UIResourceBitmap> RasterizeScrollbarPart(gfx::Rect rect,
                                                         ScrollbarPart part);

  scoped_ptr<Scrollbar> scrollbar_;

  // Snapshot of properties taken in UpdateThumbAndTrackGeometry and used in
  // PushPropertiesTo.
  int thumb_thickness_;
  int thumb_length_;
  gfx::Point location_;
  gfx::Rect track_rect_;

  int scroll_layer_id_;

  scoped_ptr<ScopedUIResource> track_resource_;
  scoped_ptr<ScopedUIResource> thumb_resource_;

  DISALLOW_COPY_AND_ASSIGN(PaintedScrollbarLayer);
};

}  // namespace cc

#endif  // CC_LAYERS_PAINTED_SCROLLBAR_LAYER_H_