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// Copyright (c) 2012 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.
#include "webkit/glue/fling_animator_impl_android.h"
#include "base/android/jni_android.h"
#include "base/android/scoped_java_ref.h"
#include "base/logging.h"
#include "jni/OverScroller_jni.h"
#include "third_party/WebKit/public/platform/WebFloatSize.h"
#include "third_party/WebKit/public/platform/WebGestureCurveTarget.h"
#include "ui/gfx/screen.h"
#include "ui/gfx/vector2d.h"
namespace webkit_glue {
namespace {
static const float kEpsilon = 1e-4;
}
FlingAnimatorImpl::FlingAnimatorImpl()
: is_active_(false) {
// hold the global reference of the Java objects.
JNIEnv* env = base::android::AttachCurrentThread();
java_scroller_.Reset(JNI_OverScroller::Java_OverScroller_ConstructorAWOS_ACC(
env,
base::android::GetApplicationContext()));
}
FlingAnimatorImpl::~FlingAnimatorImpl()
{
}
//static
bool FlingAnimatorImpl::RegisterJni(JNIEnv* env) {
return JNI_OverScroller::RegisterNativesImpl(env);
}
void FlingAnimatorImpl::StartFling(const gfx::PointF& velocity)
{
// No bounds on the fling. See http://webkit.org/b/96403
// Instead, use the largest possible bounds for minX/maxX/minY/maxY. The
// compositor will ignore any attempt to scroll beyond the end of the page.
DCHECK(velocity.x() || velocity.y());
if (is_active_)
CancelFling();
is_active_ = true;
last_time_ = 0;
last_velocity_ = velocity;
JNIEnv* env = base::android::AttachCurrentThread();
JNI_OverScroller::Java_OverScroller_flingV_I_I_I_I_I_I_I_I(
env, java_scroller_.obj(), 0, 0,
static_cast<int>(velocity.x()),
static_cast<int>(velocity.y()),
INT_MIN, INT_MAX, INT_MIN, INT_MAX);
}
void FlingAnimatorImpl::CancelFling()
{
if (!is_active_)
return;
is_active_ = false;
JNIEnv* env = base::android::AttachCurrentThread();
JNI_OverScroller::Java_OverScroller_abortAnimation(env, java_scroller_.obj());
}
bool FlingAnimatorImpl::UpdatePosition()
{
JNIEnv* env = base::android::AttachCurrentThread();
bool result = JNI_OverScroller::Java_OverScroller_computeScrollOffset(
env,
java_scroller_.obj());
return is_active_ = result;
}
gfx::Point FlingAnimatorImpl::GetCurrentPosition()
{
JNIEnv* env = base::android::AttachCurrentThread();
gfx::Point position(
JNI_OverScroller::Java_OverScroller_getCurrX(env, java_scroller_.obj()),
JNI_OverScroller::Java_OverScroller_getCurrY(env, java_scroller_.obj()));
return position;
}
float FlingAnimatorImpl::GetCurrentVelocity()
{
JNIEnv* env = base::android::AttachCurrentThread();
// TODO(jdduke): Add Java-side hooks for getCurrVelocityX/Y, and return
// vector velocity.
return JNI_OverScroller::Java_OverScroller_getCurrVelocity(
env, java_scroller_.obj());
}
bool FlingAnimatorImpl::apply(double time,
WebKit::WebGestureCurveTarget* target) {
if (!UpdatePosition())
return false;
gfx::Point current_position = GetCurrentPosition();
gfx::Vector2d diff(current_position - last_position_);
last_position_ = current_position;
float dpi_scale = gfx::Screen::GetNativeScreen()->GetPrimaryDisplay()
.device_scale_factor();
WebKit::WebFloatSize scroll_amount(diff.x() / dpi_scale,
diff.y() / dpi_scale);
float delta_time = time - last_time_;
last_time_ = time;
// Currently, the OverScroller only provides the velocity magnitude; use the
// angle of the scroll delta to yield approximate x and y velocity components.
// TODO(jdduke): Remove this when we can properly poll OverScroller velocity.
gfx::PointF current_velocity = last_velocity_;
if (delta_time > kEpsilon) {
float diff_length = diff.Length();
if (diff_length > kEpsilon) {
float velocity = GetCurrentVelocity();
float scroll_to_velocity = velocity / diff_length;
current_velocity = gfx::PointF(diff.x() * scroll_to_velocity,
diff.y() * scroll_to_velocity);
}
}
last_velocity_ = current_velocity;
WebKit::WebFloatSize fling_velocity(current_velocity.x() / dpi_scale,
current_velocity.y() / dpi_scale);
target->notifyCurrentFlingVelocity(fling_velocity);
// scrollBy() could delete this curve if the animation is over, so don't touch
// any member variables after making that call.
target->scrollBy(scroll_amount);
return true;
}
FlingAnimatorImpl* FlingAnimatorImpl::CreateAndroidGestureCurve(
const WebKit::WebFloatPoint& velocity,
const WebKit::WebSize&) {
FlingAnimatorImpl* gesture_curve = new FlingAnimatorImpl();
gesture_curve->StartFling(velocity);
return gesture_curve;
}
} // namespace webkit_glue
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