content/browser/android/touch_point.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "content/browser/android/touch_point.h"
   6
   7 #include "base/debug/debugger.h"
   8 #include "base/logging.h"
   9 #include "base/time/time.h"
  10
  11 #include "jni/TouchPoint_jni.h"
  12
  13 using blink::WebTouchEvent;
  14 using blink::WebTouchPoint;
  15
  16 namespace {
  17
  18 void MaybeAddTouchPoint(JNIEnv* env,
  19                         jobject pt,
  20                         float dpi_scale,
  21                         blink::WebTouchEvent& event) {
  22   WebTouchPoint::State state = static_cast<WebTouchPoint::State>(
  23       Java_TouchPoint_getState(env, pt));
  24   if (state == WebTouchPoint::StateUndefined)
  25     return;
  26
  27   // When generating a cancel event from an event of a different type, the
  28   // touch points are out of sync, so we ensure the points are marked as
  29   // canceled as well.
  30   if (event.type == WebTouchEvent::TouchCancel)
  31     state = WebTouchPoint::StateCancelled;
  32
  33   // Record the current number of points in the WebTouchEvent
  34   const int idx = event.touchesLength;
  35   DCHECK_LT(idx, blink::WebTouchEvent::touchesLengthCap);
  36
  37   WebTouchPoint wtp;
  38   wtp.id = Java_TouchPoint_getId(env, pt);
  39   wtp.state = state;
  40   wtp.position.x = Java_TouchPoint_getX(env, pt) / dpi_scale;
  41   wtp.position.y = Java_TouchPoint_getY(env, pt) / dpi_scale;
  42   // TODO(joth): Raw event co-ordinates.
  43   wtp.screenPosition = wtp.position;
  44   wtp.force = Java_TouchPoint_getPressure(env, pt);
  45
  46   const int radiusMajor = static_cast<int>(
  47       Java_TouchPoint_getTouchMajor(env, pt) * 0.5f / dpi_scale);
  48   const int radiusMinor = static_cast<int>(
  49       Java_TouchPoint_getTouchMinor(env, pt) * 0.5f / dpi_scale);
  50   const float majorAngleInRadiansClockwiseFromVertical =
  51       Java_TouchPoint_getOrientation(env, pt);
  52   const float majorAngleInDegreesClockwiseFromVertical =
  53       std::isnan(majorAngleInRadiansClockwiseFromVertical)
  54           ? 0.f : (majorAngleInRadiansClockwiseFromVertical * 180.f) / M_PI;
  55   // Android provides a major axis orientation clockwise with respect to the
  56   // vertical of [-90, 90], while the W3C specifies a range of [0, 90].
  57   if (majorAngleInDegreesClockwiseFromVertical >= 0) {
  58     wtp.radiusX = radiusMinor;
  59     wtp.radiusY = radiusMajor;
  60     wtp.rotationAngle = majorAngleInDegreesClockwiseFromVertical;
  61   } else {
  62     wtp.radiusX = radiusMajor;
  63     wtp.radiusY = radiusMinor;
  64     wtp.rotationAngle = majorAngleInDegreesClockwiseFromVertical + 90.f;
  65   }
  66   DCHECK_GE(wtp.rotationAngle, 0.f);
  67   DCHECK_LE(wtp.rotationAngle, 90.f);
  68
  69   // Add the newly created WebTouchPoint to the event
  70   event.touches[idx] = wtp;
  71   ++(event.touchesLength);
  72 }
  73
  74 }  // namespace
  75
  76 namespace content {
  77
  78 void TouchPoint::BuildWebTouchEvent(JNIEnv* env,
  79                                     jint type,
  80                                     jlong time_ms,
  81                                     float dpi_scale,
  82                                     jobjectArray pts,
  83                                     blink::WebTouchEvent& event) {
  84   event.type = static_cast<WebTouchEvent::Type>(type);
  85   event.timeStampSeconds =
  86       static_cast<double>(time_ms) / base::Time::kMillisecondsPerSecond;
  87   int arrayLength = env->GetArrayLength(pts);
  88   // Loop until either all of the input points have been consumed or the output
  89   // array has been filled
  90   for (int i = 0; i < arrayLength; i++) {
  91     jobject pt = env->GetObjectArrayElement(pts, i);
  92     MaybeAddTouchPoint(env, pt, dpi_scale, event);
  93     if (event.touchesLength >= event.touchesLengthCap)
  94       break;
  95   }
  96   DCHECK_GT(event.touchesLength, 0U);
  97 }
  98
  99 static void RegisterConstants(JNIEnv* env) {
 100    Java_TouchPoint_initializeConstants(
 101        env,
 102        blink::WebTouchEvent::TouchStart,
 103        blink::WebTouchEvent::TouchMove,
 104        blink::WebTouchEvent::TouchEnd,
 105        blink::WebTouchEvent::TouchCancel,
 106        blink::WebTouchPoint::StateUndefined,
 107        blink::WebTouchPoint::StateReleased,
 108        blink::WebTouchPoint::StatePressed,
 109        blink::WebTouchPoint::StateMoved,
 110        blink::WebTouchPoint::StateStationary,
 111        blink::WebTouchPoint::StateCancelled);
 112 }
 113
 114 bool RegisterTouchPoint(JNIEnv* env) {
 115   if (!RegisterNativesImpl(env))
 116     return false;
 117
 118   RegisterConstants(env);
 119
 120   return true;
 121 }
 122
 123 }  // namespace content