Completed webkit radiusX, radiusY and rotationAngle handling.

content/browser/renderer_host/input/web_input_event_util.cc

Index: content/browser/renderer_host/input/web_input_event_util.cc
diff --git a/content/browser/renderer_host/input/web_input_event_util.cc b/content/browser/renderer_host/input/web_input_event_util.cc
index 303a8d0844c86fa99f345dc34908ac808d600193..953b27fe2cd24e18845449d27e4ed67074d3e46e 100644
--- a/content/browser/renderer_host/input/web_input_event_util.cc
+++ b/content/browser/renderer_host/input/web_input_event_util.cc
@@ -2,6 +2,9 @@
 // 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.

[tdresser, 2014/08/27 18:31:34]

Add an
#include <cmath>

(Include what you use)

[mustaq, 2014/08/27 20:51:08]

Done.

+#define _USE_MATH_DEFINES
+
 #include "content/browser/renderer_host/input/web_input_event_util.h"
 
 #include "base/strings/string_util.h"
@@ -182,13 +185,31 @@ WebTouchPoint CreateWebTouchPoint(const MotionEvent& event,
   WebTouchPoint touch;
   touch.id = event.GetPointerId(pointer_index);
   touch.state = ToWebTouchPointState(
-      event.GetAction(),
-      static_cast<int>(pointer_index) == event.GetActionIndex());
+    event.GetAction(),

[jdduke (slow), 2014/08/27 18:21:10]

This indentation looks off by a couple spaces?

[tdresser, 2014/08/27 18:31:34]

Revert indentation change.

[mustaq, 2014/08/27 20:51:08]

Done.

+    static_cast<int>(pointer_index) == event.GetActionIndex());
   touch.position.x = event.GetX(pointer_index);
   touch.position.y = event.GetY(pointer_index);
   touch.screenPosition.x = event.GetRawX(pointer_index);
   touch.screenPosition.y = event.GetRawY(pointer_index);
-  touch.radiusX = touch.radiusY = event.GetTouchMajor(pointer_index) * 0.5f;
+
+  float major_radius = event.GetTouchMajor(pointer_index) / 2.f;
+  float minor_radius = event.GetTouchMinor(pointer_index) / 2.f;
+  float orientationDeg = event.GetOrientation(pointer_index) * 180.f / M_PI;

[jdduke (slow), 2014/08/27 18:21:10]

Nit: orientation_deg, though it's still not clear what exactly that means in
this context. It's probably worth retaining some of the comment I originally
used with this code
(https://codereview.chromium.org/178193022/diff/110001/content/browser/rendere...)

// MotionEvent provides a major axis orientation clockwise with respect to the	
// vertical of [-90, 90].  The proposed W3C extension specifies the angle that	
// the ellipse described by radiusX and radiusY is rotated clockwise about	
// its center, with a value of [0, 90], see	
// http://www.w3.org/TR/2011/WD-touch-events-20110505/.

[mustaq, 2014/08/27 19:08:57]

I totally agree, thanks for pointing to the original comments.

I was looking for a place to document the major/minor vs radiusX/radiusY
differences (along with the differences in angle definitions), but wasn't sure.
Do you think CreateWebTouchPoint() is the best place for all of these?

[jdduke (slow), 2014/08/27 19:16:13]

Yeah, this is probably as reasonable a place as any. I would still put a short
comment at the |MotionEvent::GetOrientation()| interface method  describing how
the orientation relates to the touch major value.

[mustaq, 2014/08/27 20:51:08]

Done.

+  DCHECK_GE(major_radius, 0) << "Unexpected touch major < 0";
+  DCHECK_GE(minor_radius, 0) << "Unexpected touch minor < 0";
+  DCHECK_GE(major_radius, minor_radius) << "Unexpected major/minor touch radii";
+  DCHECK(-90 <= orientationDeg && orientationDeg <= 90)
+      << "Unexpected touch orientation angle";
+  if (orientationDeg >= 0) {
+    touch.radiusX = major_radius;
+    touch.radiusY = minor_radius;
+    touch.rotationAngle = orientationDeg;
+  } else {
+    touch.radiusX = minor_radius;
+    touch.radiusY = major_radius;
+    touch.rotationAngle = orientationDeg + 90;
+  }
+
   touch.force = event.GetPressure(pointer_index);
 
   return touch;