Pass through tilt_x and tilt_y to blink

ui/events/gesture_detection/motion_event.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_EVENTS_GESTURE_DETECTION_MOTION_EVENT_H_
 #define UI_EVENTS_GESTURE_DETECTION_MOTION_EVENT_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 58 matching lines @@
   virtual size_t GetPointerCount() const = 0;
   virtual int GetPointerId(size_t pointer_index) const = 0;
   virtual float GetX(size_t pointer_index) const = 0;
   virtual float GetY(size_t pointer_index) const = 0;
   virtual float GetRawX(size_t pointer_index) const = 0;
   virtual float GetRawY(size_t pointer_index) const = 0;
   virtual float GetTouchMajor(size_t pointer_index) const = 0;
   virtual float GetTouchMinor(size_t pointer_index) const = 0;
   virtual float GetOrientation(size_t pointer_index) const = 0;
   virtual float GetPressure(size_t pointer_index) const = 0;
-  virtual float GetTilt(size_t pointer_index) const = 0;
+  virtual float GetTiltX(size_t pointer_index) const = 0;
+  virtual float GetTiltY(size_t pointer_index) const = 0;
   virtual ToolType GetToolType(size_t pointer_index) const = 0;
   virtual int GetButtonState() const = 0;
   virtual int GetFlags() const = 0;
   virtual base::TimeTicks GetEventTime() const = 0;
 
   // Optional historical data, default implementation provides an empty history.
   virtual size_t GetHistorySize() const;
   virtual base::TimeTicks GetHistoricalEventTime(size_t historical_index) const;
   virtual float GetHistoricalTouchMajor(size_t pointer_index,
                                         size_t historical_index) const;
@@ skipping 13 matching lines @@
   float GetRawY() const { return GetRawY(0); }
   float GetRawOffsetX() const { return GetRawX() - GetX(); }
   float GetRawOffsetY() const { return GetRawY() - GetY(); }
 
   float GetTouchMajor() const { return GetTouchMajor(0); }
   float GetTouchMinor() const { return GetTouchMinor(0); }
 
   // Returns the orientation in radians. The meaning is overloaded:
   // * For a touch screen or pad, it's the orientation of the major axis
   //   clockwise from vertical. The return value lies in [-PI/2, PI/2].
   // * For a stylus, it indicates the direction in which the stylus is pointing.

[use mustaq_at_chromium.org, 2017/05/15 19:46:53]

Please add a comment: "Stylus 3D orientation is returned in GetTiltX/Y. TODO:
Cleanup the stylus comment & usage here."

   //   The return value lies in [-PI, PI].
   float GetOrientation() const { return GetOrientation(0); }
 
   float GetPressure() const { return GetPressure(0); }
-  float GetTilt() const { return GetTilt(0); }
+  float GetTiltX() const { return GetTiltX(0); }

[use mustaq_at_chromium.org, 2017/05/15 19:46:53]

We need a clear description here because these angle values in degrees is
neither in the spec nor consistent with the rest of the angles here.

Please say something like this:

"We have GetTiltX/Y here instead of GetTilt because MotionEvent spec is not
expressive enough for both 2D touch-surface geometry and 3D pen-orientation
geometry, as needed for PointerEvents:
https://w3c.github.io/pointerevents

Both GetTiltX and GetTiltY return angles in **degrees**, in the range [-90,90].
See the PointerEvent spec link above for details."

[jkwang, 2017/05/16 01:13:26]

Done.

+  float GetTiltY() const { return GetTiltY(0); }
   ToolType GetToolType() const { return GetToolType(0); }
 
   // O(N) search of pointers (use sparingly!). Returns -1 if |id| nonexistent.
   int FindPointerIndexOfId(int id) const;
 
   // Note that these methods perform shallow copies of the originating events.
   // They guarantee only that the returned type will reflect the same
   // data exposed by the MotionEvent interface; no guarantees are made that the
   // underlying implementation is identical to the source implementation.
   std::unique_ptr<MotionEvent> Clone() const;
   std::unique_ptr<MotionEvent> Cancel() const;
 };
 
 }  // namespace ui
 
 #endif  // UI_EVENTS_GESTURE_DETECTION_MOTION_EVENT_H_