Support for Adaptive Handle Orientation

ui/touch_selection/touch_handle.h

 // Copyright 2014 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 UI_TOUCH_SELECTION_TOUCH_HANDLE_H_
 #define UI_TOUCH_SELECTION_TOUCH_HANDLE_H_
 
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/time/time.h"
 #include "ui/events/gesture_detection/motion_event.h"
 #include "ui/gfx/geometry/point_f.h"
 #include "ui/gfx/geometry/rect_f.h"
 #include "ui/gfx/geometry/vector2d_f.h"
 #include "ui/touch_selection/touch_handle_orientation.h"
 #include "ui/touch_selection/ui_touch_selection_export.h"
 
 namespace ui {
 
 class TouchHandle;
 
 // Interface through which |TouchHandle| delegates rendering-specific duties.
 class UI_TOUCH_SELECTION_EXPORT TouchHandleDrawable {
  public:
   virtual ~TouchHandleDrawable() {}
   virtual void SetEnabled(bool enabled) = 0;
-  virtual void SetOrientation(TouchHandleOrientation orientation) = 0;
+  virtual void SetLayout(const gfx::PointF& position,
+                         ui::TouchHandleOrientation orientation,
+                         bool mirror_vertical,
+                         bool mirror_horizontal) = 0;
   virtual void SetAlpha(float alpha) = 0;
-  virtual void SetFocus(const gfx::PointF& position) = 0;
   virtual gfx::RectF GetVisibleBounds() const = 0;
 };
 
 // Interface through which |TouchHandle| communicates handle manipulation and
 // requests concrete drawable instances.
 class UI_TOUCH_SELECTION_EXPORT TouchHandleClient {
  public:
   virtual ~TouchHandleClient() {}
   virtual void OnHandleDragBegin(const TouchHandle& handle) = 0;
   virtual void OnHandleDragUpdate(const TouchHandle& handle,
@@ skipping 19 matching lines @@
   // While disabled, manipulation is *explicitly not supported*, and may lead to
   // undesirable and/or unstable side-effects. The handle can be safely
   // re-enabled to allow continued operation.
   void SetEnabled(bool enabled);
 
   enum AnimationStyle { ANIMATION_NONE, ANIMATION_SMOOTH };
   // Update the handle visibility, fading in/out according to |animation_style|.
   // If an animation is in-progress, it will be overriden appropriately.
   void SetVisible(bool visible, AnimationStyle animation_style);
 
-  // Update the handle placement to |position|.
+  // Update the focus points for the handles. The Handle will be positioned
+  // either |top| or |bottom| based on the mirror parameters.
   // Note: If a fade out animation is active or the handle is invisible, the
   // handle position will not be updated until the handle regains visibility.
-  void SetPosition(const gfx::PointF& position);
+  void SetFocus(const gfx::PointF& top, const gfx::PointF& bottom);

[mfomitchev, 2015/05/13 22:19:14]

We always call both SetFocus and SetViewportRect, and we end up doing the layout
twice. Can we combine these methods into one like we did for
CompositedTouchHandleDrawable?

[jdduke (slow), 2015/05/14 15:20:10]

Hmm, but we would only do the layout twice if the viewport size changes
(hopefully infrequent?). Don't have a problem merging the two calls, not sure
what the best name would be.

[AviD, 2015/05/19 16:26:28]

SetSelectionParams() ?

[AviD, 2015/05/21 09:23:14]

I have changed this to update the viewport rect only if it changes and active
selection/insertion is present, instead of updating for every selectionChanged()
event.

+
+  // Update the Viewport rect, based on which the handle decide its inversion
+  void SetViewportRect(const gfx::RectF viewport_rect);
 
   // Update the handle visuals to |orientation|.
   // Note: If the handle is being dragged, the orientation change will be
   // deferred until the drag has ceased.
   void SetOrientation(TouchHandleOrientation orientation);
 
   // Allows touch-dragging of the handle. Returns true if the event was
   // consumed, in which case the caller should cease further handling.
   bool WillHandleTouchEvent(const MotionEvent& event);
 
   // Ticks an active animation, as requested to the client by |SetNeedsAnimate|.
   // Returns true if an animation is active and requires further ticking.
   bool Animate(base::TimeTicks frame_time);
 
   bool is_dragging() const { return is_dragging_; }
-  const gfx::PointF& position() const { return position_; }
+  const gfx::PointF& position() const { return focus_bottom_; }

[mfomitchev, 2015/05/13 22:19:14]

rename to focus_bottom()?

[AviD, 2015/05/19 16:26:28]

Done.

   TouchHandleOrientation orientation() const { return orientation_; }
 
  private:
+  void UpdateLayout();
   void BeginDrag();
   void EndDrag();
   void BeginFade();
   void EndFade();
   void SetAlpha(float alpha);
 
   scoped_ptr<TouchHandleDrawable> drawable_;
 
   TouchHandleClient* const client_;
 
-  gfx::PointF position_;
+  gfx::PointF focus_bottom_;
+  gfx::PointF focus_top_;
+  gfx::RectF viewport_rect_;
   TouchHandleOrientation orientation_;
   TouchHandleOrientation deferred_orientation_;
 
   gfx::PointF touch_down_position_;
   gfx::Vector2dF touch_to_focus_offset_;
   base::TimeTicks touch_down_time_;
 
   // Note that when a fade animation is active, |is_visible_| and |position_|
   // may not reflect the actual visibilty and position of the drawable. This
   // discrepancy is resolved either upon fade completion or cancellation.
   base::TimeTicks fade_end_time_;
   gfx::PointF fade_start_position_;
   float alpha_;
   bool animate_deferred_fade_;
 
   bool enabled_;
   bool is_visible_;
   bool is_dragging_;
   bool is_drag_within_tap_region_;
 
+  // Mirror variables determine if the handles should be inverted or not.
+  bool mirror_vertical_;
+  bool mirror_horizontal_;
+
   DISALLOW_COPY_AND_ASSIGN(TouchHandle);
 };
 
 }  // namespace ui
 
 #endif  // UI_TOUCH_SELECTION_TOUCH_HANDLE_H_