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