ui/wm/core/shadow.h

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef UI_WM_CORE_SHADOW_H_
   6 #define UI_WM_CORE_SHADOW_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/memory/scoped_ptr.h"
  10 #include "ui/compositor/layer_animation_observer.h"
  11 #include "ui/gfx/geometry/rect.h"
  12 #include "ui/wm/wm_export.h"
  13
  14 namespace ui {
  15 class Layer;
  16 }  // namespace ui
  17
  18 namespace wm {
  19
  20 // Simple class that draws a drop shadow around content at given bounds.
  21 class WM_EXPORT Shadow : public ui::ImplicitAnimationObserver {
  22  public:
  23   enum Style {
  24     // Active windows have more opaque shadows, shifted down to make the window
  25     // appear "higher".
  26     STYLE_ACTIVE,
  27
  28     // Inactive windows have less opaque shadows.
  29     STYLE_INACTIVE,
  30
  31     // Small windows like tooltips and context menus have lighter, smaller
  32     // shadows.
  33     STYLE_SMALL,
  34   };
  35
  36   Shadow();
  37   ~Shadow() override;
  38
  39   void Init(Style style);
  40
  41   // Returns |layer_.get()|. This is exposed so it can be added to the same
  42   // layer as the content and stacked below it.  SetContentBounds() should be
  43   // used to adjust the shadow's size and position (rather than applying
  44   // transformations to this layer).
  45   ui::Layer* layer() const { return layer_.get(); }
  46
  47   const gfx::Rect& content_bounds() const { return content_bounds_; }
  48   Style style() const { return style_; }
  49
  50   // Moves and resizes the shadow layer to frame |content_bounds|.
  51   void SetContentBounds(const gfx::Rect& content_bounds);
  52
  53   // Sets the shadow's style, animating opacity as necessary.
  54   void SetStyle(Style style);
  55
  56   // ui::ImplicitAnimationObserver overrides:
  57   void OnImplicitAnimationsCompleted() override;
  58
  59  private:
  60   // Updates the shadow images to the current |style_|.
  61   void UpdateImagesForStyle();
  62
  63   // Updates the shadow layer bounds based on the inteior inset and the current
  64   // |content_bounds_|.
  65   void UpdateLayerBounds();
  66
  67   // The current style, set when the transition animation starts.
  68   Style style_;
  69
  70   // The parent layer of the shadow layer. It serves as a container accessible
  71   // from the outside to control the visibility of the shadow.
  72   scoped_ptr<ui::Layer> layer_;
  73
  74   // The actual shadow layer corresponding to a cc::NinePatchLayer.
  75   scoped_ptr<ui::Layer> shadow_layer_;
  76
  77   // Size of the current shadow image.
  78   gfx::Size image_size_;
  79
  80   // Bounds of the content that the shadow encloses.
  81   gfx::Rect content_bounds_;
  82
  83   // The interior inset of the shadow images. The content bounds of the image
  84   // grid should be set to |content_bounds_| inset by this amount.
  85   int interior_inset_;
  86
  87   DISALLOW_COPY_AND_ASSIGN(Shadow);
  88 };
  89
  90 }  // namespace wm
  91
  92 #endif  // UI_WM_CORE_SHADOW_H_