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/ui_touch_selection_export.h"
  16
  17 namespace ui {
  18
  19 class TouchHandle;
  20
  21 enum TouchHandleOrientation {
  22   TOUCH_HANDLE_LEFT,
  23   TOUCH_HANDLE_CENTER,
  24   TOUCH_HANDLE_RIGHT,
  25   TOUCH_HANDLE_ORIENTATION_UNDEFINED,
  26 };
  27
  28 // Interface through which |TouchHandle| delegates rendering-specific duties.
  29 class UI_TOUCH_SELECTION_EXPORT TouchHandleDrawable {
  30  public:
  31   virtual ~TouchHandleDrawable() {}
  32   virtual void SetEnabled(bool enabled) = 0;
  33   virtual void SetOrientation(TouchHandleOrientation orientation) = 0;
  34   virtual void SetAlpha(float alpha) = 0;
  35   virtual void SetFocus(const gfx::PointF& position) = 0;
  36   virtual gfx::RectF GetVisibleBounds() const = 0;
  37 };
  38
  39 // Interface through which |TouchHandle| communicates handle manipulation and
  40 // requests concrete drawable instances.
  41 class UI_TOUCH_SELECTION_EXPORT TouchHandleClient {
  42  public:
  43   virtual ~TouchHandleClient() {}
  44   virtual void OnHandleDragBegin(const TouchHandle& handle) = 0;
  45   virtual void OnHandleDragUpdate(const TouchHandle& handle,
  46                                   const gfx::PointF& new_position) = 0;
  47   virtual void OnHandleDragEnd(const TouchHandle& handle) = 0;
  48   virtual void OnHandleTapped(const TouchHandle& handle) = 0;
  49   virtual void SetNeedsAnimate() = 0;
  50   virtual scoped_ptr<TouchHandleDrawable> CreateDrawable() = 0;
  51   virtual base::TimeDelta GetTapTimeout() const = 0;
  52   virtual float GetTapSlop() const = 0;
  53 };
  54
  55 // Responsible for displaying a selection or insertion handle for text
  56 // interaction.
  57 class UI_TOUCH_SELECTION_EXPORT TouchHandle {
  58  public:
  59   // The drawable will be enabled but invisible until otherwise specified.
  60   TouchHandle(TouchHandleClient* client, TouchHandleOrientation orientation);
  61   ~TouchHandle();
  62
  63   // Sets whether the handle is active, allowing resource cleanup if necessary.
  64   // If false, active animations or touch drag sequences will be cancelled.
  65   // While disabled, manipulation is *explicitly not supported*, and may lead to
  66   // undesirable and/or unstable side-effects. The handle can be safely
  67   // re-enabled to allow continued operation.
  68   void SetEnabled(bool enabled);
  69
  70   enum AnimationStyle { ANIMATION_NONE, ANIMATION_SMOOTH };
  71   // Update the handle visibility, fading in/out according to |animation_style|.
  72   // If an animation is in-progress, it will be overriden appropriately.
  73   void SetVisible(bool visible, AnimationStyle animation_style);
  74
  75   // Update the handle placement to |position|.
  76   // Note: If a fade out animation is active or the handle is invisible, the
  77   // handle position will not be updated until the handle regains visibility.
  78   void SetPosition(const gfx::PointF& position);
  79
  80   // Update the handle visuals to |orientation|.
  81   // Note: If the handle is being dragged, the orientation change will be
  82   // deferred until the drag has ceased.
  83   void SetOrientation(TouchHandleOrientation orientation);
  84
  85   // Allows touch-dragging of the handle. Returns true if the event was
  86   // consumed, in which case the caller should cease further handling.
  87   bool WillHandleTouchEvent(const MotionEvent& event);
  88
  89   // Ticks an active animation, as requested to the client by |SetNeedsAnimate|.
  90   // Returns true if an animation is active and requires further ticking.
  91   bool Animate(base::TimeTicks frame_time);
  92
  93   bool is_dragging() const { return is_dragging_; }
  94   const gfx::PointF& position() const { return position_; }
  95   TouchHandleOrientation orientation() const { return orientation_; }
  96
  97  private:
  98   void BeginDrag();
  99   void EndDrag();
 100   void BeginFade();
 101   void EndFade();
 102   void SetAlpha(float alpha);
 103
 104   scoped_ptr<TouchHandleDrawable> drawable_;
 105
 106   TouchHandleClient* const client_;
 107
 108   gfx::PointF position_;
 109   TouchHandleOrientation orientation_;
 110   TouchHandleOrientation deferred_orientation_;
 111
 112   gfx::PointF touch_down_position_;
 113   gfx::Vector2dF touch_to_focus_offset_;
 114   base::TimeTicks touch_down_time_;
 115
 116   // Note that when a fade animation is active, |is_visible_| and |position_|
 117   // may not reflect the actual visibilty and position of the drawable. This
 118   // discrepancy is resolved either upon fade completion or cancellation.
 119   base::TimeTicks fade_end_time_;
 120   gfx::PointF fade_start_position_;
 121   float alpha_;
 122   bool animate_deferred_fade_;
 123
 124   bool enabled_;
 125   bool is_visible_;
 126   bool is_dragging_;
 127   bool is_drag_within_tap_region_;
 128
 129   DISALLOW_COPY_AND_ASSIGN(TouchHandle);
 130 };
 131
 132 }  // namespace ui
 133
 134 #endif  // UI_TOUCH_SELECTION_TOUCH_HANDLE_H_