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 "webkit/child/fling_animator_impl_android.h"
6
7 #include "base/android/jni_android.h"
8 #include "base/android/scoped_java_ref.h"
9 #include "base/logging.h"
10 #include "jni/OverScroller_jni.h"
11 #include "third_party/WebKit/public/platform/WebFloatSize.h"
12 #include "third_party/WebKit/public/platform/WebGestureCurveTarget.h"
13 #include "ui/gfx/screen.h"
14 #include "ui/gfx/vector2d.h"
15
16 namespace webkit_glue {
17
18 namespace {
19 static const float kEpsilon = 1e-4;
20 }
21
FlingAnimatorImpl()22 FlingAnimatorImpl::FlingAnimatorImpl()
23 : is_active_(false) {
24 // hold the global reference of the Java objects.
25 JNIEnv* env = base::android::AttachCurrentThread();
26 java_scroller_.Reset(JNI_OverScroller::Java_OverScroller_ConstructorAWOS_ACC(
27 env,
28 base::android::GetApplicationContext()));
29 }
30
~FlingAnimatorImpl()31 FlingAnimatorImpl::~FlingAnimatorImpl()
32 {
33 }
34
35 //static
RegisterJni(JNIEnv * env)36 bool FlingAnimatorImpl::RegisterJni(JNIEnv* env) {
37 return JNI_OverScroller::RegisterNativesImpl(env);
38 }
39
StartFling(const gfx::PointF & velocity)40 void FlingAnimatorImpl::StartFling(const gfx::PointF& velocity)
41 {
42 // No bounds on the fling. See http://webkit.org/b/96403
43 // Instead, use the largest possible bounds for minX/maxX/minY/maxY. The
44 // compositor will ignore any attempt to scroll beyond the end of the page.
45
46 DCHECK(velocity.x() || velocity.y());
47 if (is_active_)
48 CancelFling();
49
50 is_active_ = true;
51 last_time_ = 0;
52 last_velocity_ = velocity;
53
54 JNIEnv* env = base::android::AttachCurrentThread();
55
56 JNI_OverScroller::Java_OverScroller_flingV_I_I_I_I_I_I_I_I(
57 env, java_scroller_.obj(), 0, 0,
58 static_cast<int>(velocity.x()),
59 static_cast<int>(velocity.y()),
60 INT_MIN, INT_MAX, INT_MIN, INT_MAX);
61 }
62
CancelFling()63 void FlingAnimatorImpl::CancelFling()
64 {
65 if (!is_active_)
66 return;
67
68 is_active_ = false;
69 JNIEnv* env = base::android::AttachCurrentThread();
70 JNI_OverScroller::Java_OverScroller_abortAnimation(env, java_scroller_.obj());
71 }
72
UpdatePosition()73 bool FlingAnimatorImpl::UpdatePosition()
74 {
75 JNIEnv* env = base::android::AttachCurrentThread();
76 bool result = JNI_OverScroller::Java_OverScroller_computeScrollOffset(
77 env,
78 java_scroller_.obj());
79 return is_active_ = result;
80 }
81
GetCurrentPosition()82 gfx::Point FlingAnimatorImpl::GetCurrentPosition()
83 {
84 JNIEnv* env = base::android::AttachCurrentThread();
85 gfx::Point position(
86 JNI_OverScroller::Java_OverScroller_getCurrX(env, java_scroller_.obj()),
87 JNI_OverScroller::Java_OverScroller_getCurrY(env, java_scroller_.obj()));
88 return position;
89 }
90
GetCurrentVelocity()91 float FlingAnimatorImpl::GetCurrentVelocity()
92 {
93 JNIEnv* env = base::android::AttachCurrentThread();
94 // TODO(jdduke): Add Java-side hooks for getCurrVelocityX/Y, and return
95 // vector velocity.
96 return JNI_OverScroller::Java_OverScroller_getCurrVelocity(
97 env, java_scroller_.obj());
98 }
99
apply(double time,blink::WebGestureCurveTarget * target)100 bool FlingAnimatorImpl::apply(double time,
101 blink::WebGestureCurveTarget* target) {
102 if (!UpdatePosition())
103 return false;
104
105 gfx::Point current_position = GetCurrentPosition();
106 gfx::Vector2d diff(current_position - last_position_);
107 last_position_ = current_position;
108 float dpi_scale = gfx::Screen::GetNativeScreen()->GetPrimaryDisplay()
109 .device_scale_factor();
110 blink::WebFloatSize scroll_amount(diff.x() / dpi_scale,
111 diff.y() / dpi_scale);
112
113 float delta_time = time - last_time_;
114 last_time_ = time;
115
116 // Currently, the OverScroller only provides the velocity magnitude; use the
117 // angle of the scroll delta to yield approximate x and y velocity components.
118 // TODO(jdduke): Remove this when we can properly poll OverScroller velocity.
119 gfx::PointF current_velocity = last_velocity_;
120 if (delta_time > kEpsilon) {
121 float diff_length = diff.Length();
122 if (diff_length > kEpsilon) {
123 float velocity = GetCurrentVelocity();
124 float scroll_to_velocity = velocity / diff_length;
125 current_velocity = gfx::PointF(diff.x() * scroll_to_velocity,
126 diff.y() * scroll_to_velocity);
127 }
128 }
129 last_velocity_ = current_velocity;
130 blink::WebFloatSize fling_velocity(current_velocity.x() / dpi_scale,
131 current_velocity.y() / dpi_scale);
132 target->notifyCurrentFlingVelocity(fling_velocity);
133
134 // scrollBy() could delete this curve if the animation is over, so don't touch
135 // any member variables after making that call.
136 target->scrollBy(scroll_amount);
137 return true;
138 }
139
CreateAndroidGestureCurve(const blink::WebFloatPoint & velocity,const blink::WebSize &)140 FlingAnimatorImpl* FlingAnimatorImpl::CreateAndroidGestureCurve(
141 const blink::WebFloatPoint& velocity,
142 const blink::WebSize&) {
143 FlingAnimatorImpl* gesture_curve = new FlingAnimatorImpl();
144 gesture_curve->StartFling(velocity);
145 return gesture_curve;
146 }
147
148 } // namespace webkit_glue
149