Completed webkit radiusX, radiusY and rotationAngle handling.

content/browser/renderer_host/input/motion_event_web.cc

 // 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.
 
+// MSVC++ requires this to be set before any other includes to get M_PI.
+#define _USE_MATH_DEFINES
+
 #include "content/browser/renderer_host/input/motion_event_web.h"
 
+#include <cmath>
+
 #include "base/logging.h"
 #include "content/common/input/web_touch_event_traits.h"
 
 using blink::WebInputEvent;
 using blink::WebTouchEvent;
 using blink::WebTouchPoint;
 
 namespace content {
 namespace {
 
@@ skipping 78 matching lines @@
   return event_.touches[pointer_index].screenPosition.x;
 }
 
 float MotionEventWeb::GetRawY(size_t pointer_index) const {
   DCHECK_LT(pointer_index, GetPointerCount());
   return event_.touches[pointer_index].screenPosition.y;
 }
 
 float MotionEventWeb::GetTouchMajor(size_t pointer_index) const {
   DCHECK_LT(pointer_index, GetPointerCount());
-  // TODO(jdduke): We should be a bit more careful about axes here.
   return 2.f * std::max(event_.touches[pointer_index].radiusX,
                         event_.touches[pointer_index].radiusY);
 }
 
+float MotionEventWeb::GetTouchMinor(size_t pointer_index) const {
+  DCHECK_LT(pointer_index, GetPointerCount());
+  return 2.f * std::min(event_.touches[pointer_index].radiusX,
+                        event_.touches[pointer_index].radiusY);
+}
+
+float MotionEventWeb::GetOrientation(size_t pointer_index) const {
+  DCHECK_LT(pointer_index, GetPointerCount());
+
+  float rotation_angle_rad = event_.touches[pointer_index].rotationAngle
+      * M_PI / 180.f;
+  DCHECK(0 <= rotation_angle_rad && rotation_angle_rad <= M_PI_2)
+      << "Unexpected touch rotation angle";
+
+  if (event_.touches[pointer_index].radiusX

[jdduke (slow), 2014/08/28 15:31:57]

Is this correct? Consider the case where |rotationAngle| is 0, radiusX = 5 and
radiusY = 10 (a vertically-aligned ellipse). This code will produce a
rotation_angle_rad of -M_PI_2, when it should really be zero (as orientation
defines the angle from the vertical of the *major* axis, which in this case is
defined by radiusY). I think there may be some issues with your MotionEventAura
math as well, please add tests where appropriate.

[mustaq, 2014/08/28 18:21:13]

I think the rotation angle is measured from vertical, so rotationAngle would be
90 degrees in this case. Since exact 90 degrees is not allowed, we will have
angle=0 with swapped radii.

[mustaq, 2014/08/28 21:56:02]

Fixed.

+      < event_.touches[pointer_index].radiusY) {
+    rotation_angle_rad -= (float) M_PI_2;
+  }
+
+  return rotation_angle_rad;
+}
+
 float MotionEventWeb::GetPressure(size_t pointer_index) const {
   return 0.f;
 }
 
 base::TimeTicks MotionEventWeb::GetEventTime() const {
   return base::TimeTicks() +
          base::TimeDelta::FromMicroseconds(event_.timeStampSeconds *
                                            base::Time::kMicrosecondsPerSecond);
 }
 
@@ skipping 17 matching lines @@
   WebTouchEvent cancel_event(event_);
   WebTouchEventTraits::ResetTypeAndTouchStates(
       blink::WebInputEvent::TouchCancel,
       // TODO(rbyers): Shouldn't we use a fresh timestamp?
       event_.timeStampSeconds,
       &cancel_event);
   return scoped_ptr<MotionEvent>(new MotionEventWeb(cancel_event));
 }
 
 }  // namespace content