Expose fractional TouchEvent coordinates

Source/web/WebInputEventConversion.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 406 matching lines @@
         return WebTouchPoint::StateCancelled;
     if (type == EventTypeNames::touchstart)
         return WebTouchPoint::StatePressed;
     if (type == EventTypeNames::touchmove)
         return WebTouchPoint::StateMoved;
     return WebTouchPoint::StateUndefined;
 }
 
 PlatformTouchPointBuilder::PlatformTouchPointBuilder(Widget* widget, const WebTouchPoint& point)
 {
-    float scale = widgetInputEventsScaleFactor(widget);
+    float scale = 1.0f / widgetInputEventsScaleFactor(widget);
     IntSize offset = widgetInputEventsOffset(widget);
     IntPoint pinchViewport = pinchViewportOffset(widget);
     m_id = point.id;
     m_state = toPlatformTouchPointState(point.state);
-    m_pos = widget->convertFromContainingWindow(IntPoint(
-        (point.position.x - offset.width()) / scale + pinchViewport.x(),
-        (point.position.y - offset.height()) / scale + pinchViewport.y()));
-    m_screenPos = IntPoint(point.screenPosition.x, point.screenPosition.y);
-    m_radiusY = point.radiusY / scale;
-    m_radiusX = point.radiusX / scale;
+    FloatPoint pos = (point.position - offset).scaledBy(scale);
+    pos.moveBy(pinchViewport);
+    IntPoint flooredPoint = flooredIntPoint(pos);
+    // This assumes convertFromContainingWindow does only translations, not scales.
+    m_pos = widget->convertFromContainingWindow(flooredPoint) + (pos - flooredPoint);
+    m_screenPos = FloatPoint(point.screenPosition.x, point.screenPosition.y);
+    m_radius = FloatSize(point.radiusX, point.radiusY).scaledBy(scale);
     m_rotationAngle = point.rotationAngle;
     m_force = point.force;
 }
 
 PlatformTouchEventBuilder::PlatformTouchEventBuilder(Widget* widget, const WebTouchEvent& event)
 {
     m_type = toPlatformTouchEventType(event.type);
 
     m_modifiers = 0;
     if (event.modifiers & WebInputEvent::ShiftKey)
@@ skipping 20 matching lines @@
         modifiers |= WebInputEvent::ControlKey;
     if (event.shiftKey())
         modifiers |= WebInputEvent::ShiftKey;
     if (event.altKey())
         modifiers |= WebInputEvent::AltKey;
     if (event.metaKey())
         modifiers |= WebInputEvent::MetaKey;
     return modifiers;
 }
 
+static FloatPoint convertAbsoluteLocationForRenderObjectFloat(const LayoutPoint& location, const WebCore::RenderObject& renderObject)
+{
+    return renderObject.absoluteToLocal(location, UseTransforms);
+}
+
 static IntPoint convertAbsoluteLocationForRenderObject(const LayoutPoint& location, const WebCore::RenderObject& renderObject)
 {
-    return roundedIntPoint(renderObject.absoluteToLocal(location, UseTransforms));
+    return roundedIntPoint(convertAbsoluteLocationForRenderObjectFloat(location, renderObject));
 }
 
 static void updateWebMouseEventFromWebCoreMouseEvent(const MouseRelatedEvent& event, const Widget& widget, const WebCore::RenderObject& renderObject, WebMouseEvent& webEvent)
 {
     webEvent.timeStampSeconds = event.timeStamp() / millisPerSecond;
     webEvent.modifiers = getWebInputModifiers(event);
 
     ScrollView* view =  toScrollView(widget.parent());
     IntPoint windowPoint = IntPoint(event.absoluteLocation().x(), event.absoluteLocation().y());
     if (view)
@@ skipping 247 matching lines @@
 
 static void addTouchPoints(const Widget* widget, const AtomicString& touchType, TouchList* touches, WebTouchPoint* touchPoints, unsigned* touchPointsLength, const WebCore::RenderObject* renderObject)
 {
     unsigned numberOfTouches = std::min(touches->length(), static_cast<unsigned>(WebTouchEvent::touchesLengthCap));
     for (unsigned i = 0; i < numberOfTouches; ++i) {
         const Touch* touch = touches->item(i);
 
         WebTouchPoint point;
         point.id = touch->identifier();
         point.screenPosition = WebFloatPoint(touch->screenX(), touch->screenY());
-        point.position = convertAbsoluteLocationForRenderObject(touch->absoluteLocation(), *renderObject);
+        point.position = convertAbsoluteLocationForRenderObjectFloat(touch->absoluteLocation(), *renderObject);
         point.radiusX = touch->webkitRadiusX();
         point.radiusY = touch->webkitRadiusY();
         point.rotationAngle = touch->webkitRotationAngle();
         point.force = touch->webkitForce();
         point.state = toWebTouchPointState(touchType);
 
         touchPoints[i] = point;
     }
     *touchPointsLength = numberOfTouches;
 }
@@ skipping 46 matching lines @@
     modifiers = getWebInputModifiers(event);
 
     globalX = event.screenX();
     globalY = event.screenY();
     IntPoint localPoint = convertAbsoluteLocationForRenderObject(event.absoluteLocation(), *renderObject);
     x = localPoint.x();
     y = localPoint.y();
 }
 
 } // namespace blink