ui/touch_selection/touch_handle.h

   1 // Copyright 2014 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_TOUCH_SELECTION_TOUCH_HANDLE_H_
   6 #define UI_TOUCH_SELECTION_TOUCH_HANDLE_H_
   7
   8 #include "base/logging.h"
   9 #include "base/memory/scoped_ptr.h"
  10 #include "base/time/time.h"
  11 #include "ui/events/gesture_detection/motion_event.h"
  12 #include "ui/gfx/geometry/point_f.h"
  13 #include "ui/gfx/geometry/rect_f.h"
  14 #include "ui/gfx/geometry/vector2d_f.h"
  15 #include "ui/touch_selection/touch_handle_orientation.h"
  16 #include "ui/touch_selection/touch_selection_draggable.h"
  17 #include "ui/touch_selection/ui_touch_selection_export.h"
  18
  19 namespace ui {
  20
  21 class TouchHandle;
  22
  23 // Interface through which |TouchHandle| delegates rendering-specific duties.
  24 class UI_TOUCH_SELECTION_EXPORT TouchHandleDrawable {
  25  public:
  26   virtual ~TouchHandleDrawable() {}
  27   virtual void SetEnabled(bool enabled) = 0;
  28   virtual void SetOrientation(TouchHandleOrientation orientation) = 0;
  29   virtual void SetAlpha(float alpha) = 0;
  30   virtual void SetFocus(const gfx::PointF& position) = 0;
  31   virtual gfx::RectF GetVisibleBounds() const = 0;
  32 };
  33
  34 // Interface through which |TouchHandle| communicates handle manipulation and
  35 // requests concrete drawable instances.
  36 class UI_TOUCH_SELECTION_EXPORT TouchHandleClient
  37     : public TouchSelectionDraggableClient {
  38  public:
  39   ~TouchHandleClient() override {}
  40   virtual void OnHandleTapped(const TouchHandle& handle) = 0;
  41   virtual void SetNeedsAnimate() = 0;
  42   virtual scoped_ptr<TouchHandleDrawable> CreateDrawable() = 0;
  43   virtual base::TimeDelta GetMaxTapDuration() const = 0;
  44 };
  45
  46 // Responsible for displaying a selection or insertion handle for text
  47 // interaction.
  48 class UI_TOUCH_SELECTION_EXPORT TouchHandle : public TouchSelectionDraggable {
  49  public:
  50   // The drawable will be enabled but invisible until otherwise specified.
  51   TouchHandle(TouchHandleClient* client, TouchHandleOrientation orientation);
  52   ~TouchHandle() override;
  53
  54   // TouchSelectionDraggable implementation.
  55   bool WillHandleTouchEvent(const MotionEvent& event) override;
  56   bool IsActive() const override;
  57
  58   // Sets whether the handle is active, allowing resource cleanup if necessary.
  59   // If false, active animations or touch drag sequences will be cancelled.
  60   // While disabled, manipulation is *explicitly not supported*, and may lead to
  61   // undesirable and/or unstable side-effects. The handle can be safely
  62   // re-enabled to allow continued operation.
  63   void SetEnabled(bool enabled);
  64
  65   enum AnimationStyle { ANIMATION_NONE, ANIMATION_SMOOTH };
  66   // Update the handle visibility, fading in/out according to |animation_style|.
  67   // If an animation is in-progress, it will be overriden appropriately.
  68   void SetVisible(bool visible, AnimationStyle animation_style);
  69
  70   // Update the handle placement to |position|.
  71   // Note: If a fade out animation is active or the handle is invisible, the
  72   // handle position will not be updated until the handle regains visibility.
  73   void SetPosition(const gfx::PointF& position);
  74
  75   // Update the handle visuals to |orientation|.
  76   // Note: If the handle is being dragged, the orientation change will be
  77   // deferred until the drag has ceased.
  78   void SetOrientation(TouchHandleOrientation orientation);
  79
  80   // Ticks an active animation, as requested to the client by |SetNeedsAnimate|.
  81   // Returns true if an animation is active and requires further ticking.
  82   bool Animate(base::TimeTicks frame_time);
  83
  84   // Get the visible bounds of the handle, based on the current position and
  85   // the drawable's size/orientation. If the handle is invisible or disabled,
  86   // the bounds will be empty.
  87   gfx::RectF GetVisibleBounds() const;
  88
  89   const gfx::PointF& position() const { return position_; }
  90   TouchHandleOrientation orientation() const { return orientation_; }
  91
  92  private:
  93   void BeginDrag();
  94   void EndDrag();
  95   void BeginFade();
  96   void EndFade();
  97   void SetAlpha(float alpha);
  98
  99   scoped_ptr<TouchHandleDrawable> drawable_;
 100
 101   TouchHandleClient* const client_;
 102
 103   gfx::PointF position_;
 104   TouchHandleOrientation orientation_;
 105   TouchHandleOrientation deferred_orientation_;
 106
 107   gfx::PointF touch_down_position_;
 108   gfx::Vector2dF touch_drag_offset_;
 109   base::TimeTicks touch_down_time_;
 110
 111   // Note that when a fade animation is active, |is_visible_| and |position_|
 112   // may not reflect the actual visibilty and position of the drawable. This
 113   // discrepancy is resolved either upon fade completion or cancellation.
 114   base::TimeTicks fade_end_time_;
 115   gfx::PointF fade_start_position_;
 116   float alpha_;
 117   bool animate_deferred_fade_;
 118
 119   bool enabled_;
 120   bool is_visible_;
 121   bool is_dragging_;
 122   bool is_drag_within_tap_region_;
 123
 124   DISALLOW_COPY_AND_ASSIGN(TouchHandle);
 125 };
 126
 127 }  // namespace ui
 128
 129 #endif  // UI_TOUCH_SELECTION_TOUCH_HANDLE_H_