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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 "ui/views/controls/slide_out_view.h"
#include "ui/compositor/layer.h"
#include "ui/compositor/scoped_layer_animation_settings.h"
#include "ui/gfx/transform.h"
namespace views {
SlideOutView::SlideOutView()
: gesture_scroll_amount_(0.f) {
SetPaintToLayer(true);
SetFillsBoundsOpaquely(false);
}
SlideOutView::~SlideOutView() {
}
ui::EventResult SlideOutView::OnGestureEvent(ui::GestureEvent* event) {
if (event->type() == ui::ET_SCROLL_FLING_START) {
// The threshold for the fling velocity is computed empirically.
// The unit is in pixels/second.
const float kFlingThresholdForClose = 800.f;
if (fabsf(event->details().velocity_x()) > kFlingThresholdForClose) {
SlideOutAndClose(event->details().velocity_x() < 0 ? SLIDE_LEFT :
SLIDE_RIGHT);
return ui::ER_CONSUMED;
}
RestoreVisualState();
return ui::ER_UNHANDLED;
}
if (!event->IsScrollGestureEvent())
return ui::ER_UNHANDLED;
if (event->type() == ui::ET_GESTURE_SCROLL_BEGIN) {
gesture_scroll_amount_ = 0.f;
} else if (event->type() == ui::ET_GESTURE_SCROLL_UPDATE) {
// The scroll-update events include the incremental scroll amount.
gesture_scroll_amount_ += event->details().scroll_x();
gfx::Transform transform;
transform.Translate(gesture_scroll_amount_, 0.0);
layer()->SetTransform(transform);
layer()->SetOpacity(
1.f - std::min(fabsf(gesture_scroll_amount_) / width(), 1.f));
} else if (event->type() == ui::ET_GESTURE_SCROLL_END) {
const float kScrollRatioForClosingNotification = 0.5f;
float scrolled_ratio = fabsf(gesture_scroll_amount_) / width();
if (scrolled_ratio >= kScrollRatioForClosingNotification) {
SlideOutAndClose(gesture_scroll_amount_ < 0 ? SLIDE_LEFT : SLIDE_RIGHT);
return ui::ER_CONSUMED;
}
RestoreVisualState();
}
return ui::ER_HANDLED;
}
void SlideOutView::RestoreVisualState() {
// Restore the layer state.
const int kSwipeRestoreDurationMS = 150;
ui::ScopedLayerAnimationSettings settings(layer()->GetAnimator());
settings.SetTransitionDuration(
base::TimeDelta::FromMilliseconds(kSwipeRestoreDurationMS));
layer()->SetTransform(gfx::Transform());
layer()->SetOpacity(1.f);
}
void SlideOutView::SlideOutAndClose(SlideDirection direction) {
const int kSwipeOutTotalDurationMS = 150;
int swipe_out_duration = kSwipeOutTotalDurationMS * layer()->opacity();
ui::ScopedLayerAnimationSettings settings(layer()->GetAnimator());
settings.SetTransitionDuration(
base::TimeDelta::FromMilliseconds(swipe_out_duration));
settings.AddObserver(this);
gfx::Transform transform;
transform.Translate(direction == SLIDE_LEFT ? -width() : width(), 0.0);
layer()->SetTransform(transform);
layer()->SetOpacity(0.f);
}
void SlideOutView::OnImplicitAnimationsCompleted() {
OnSlideOut();
}
} // namespace views
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