// Copyright 2013 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/40285824): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif
#include "ui/android/overscroll_glow.h"
#include <stddef.h>
#include "cc/slim/layer.h"
#include "ui/android/edge_effect.h"
#include "ui/android/window_android_compositor.h"
using std::max;
using std::min;
namespace ui {
namespace {
const float kEpsilon = 1e-3f;
bool IsApproxZero(float value) {
return std::abs(value) < kEpsilon;
}
gfx::Vector2dF ZeroSmallComponents(gfx::Vector2dF vector) {
if (IsApproxZero(vector.x()))
vector.set_x(0);
if (IsApproxZero(vector.y()))
vector.set_y(0);
return vector;
}
} // namespace
OverscrollGlow::OverscrollGlow(OverscrollGlowClient* client)
: client_(client),
edge_offsets_(),
initialized_(false),
allow_horizontal_overscroll_(true),
allow_vertical_overscroll_(true) {
DCHECK(client);
}
OverscrollGlow::~OverscrollGlow() {
Detach();
client_ = nullptr;
}
void OverscrollGlow::Reset() {
if (!initialized_)
return;
Detach();
for (size_t i = 0; i < EDGE_COUNT; ++i)
edge_effects_[i]->Finish();
}
bool OverscrollGlow::IsActive() const {
if (!initialized_)
return false;
for (size_t i = 0; i < EDGE_COUNT; ++i) {
if (!edge_effects_[i]->IsFinished())
return true;
}
return false;
}
float OverscrollGlow::GetVisibleAlpha() const {
float max_alpha = 0;
for (size_t i = 0; i < EDGE_COUNT; ++i) {
if (!edge_effects_[i]->IsFinished())
max_alpha = std::max(max_alpha, edge_effects_[i]->GetAlpha());
}
return std::min(max_alpha, 1.f);
}
bool OverscrollGlow::OnOverscrolled(base::TimeTicks current_time,
gfx::Vector2dF accumulated_overscroll,
gfx::Vector2dF overscroll_delta,
gfx::Vector2dF velocity,
gfx::Vector2dF overscroll_location) {
// The size of the glow determines the relative effect of the inputs; an
// empty-sized effect is effectively disabled.
if (viewport_size_.IsEmpty())
return false;
if (!allow_horizontal_overscroll_) {
overscroll_delta.set_x(0);
velocity.set_x(0);
}
if (!allow_vertical_overscroll_) {
overscroll_delta.set_y(0);
velocity.set_y(0);
}
// Ignore sufficiently small values that won't meaningfuly affect animation.
overscroll_delta = ZeroSmallComponents(overscroll_delta);
if (overscroll_delta.IsZero()) {
if (initialized_)
Release(current_time);
return CheckNeedsAnimate();
}
if (!InitializeIfNecessary())
return false;
gfx::Vector2dF old_overscroll = accumulated_overscroll - overscroll_delta;
bool x_overscroll_started =
!IsApproxZero(overscroll_delta.x()) && IsApproxZero(old_overscroll.x());
bool y_overscroll_started =
!IsApproxZero(overscroll_delta.y()) && IsApproxZero(old_overscroll.y());
velocity = ZeroSmallComponents(velocity);
if (!velocity.IsZero())
Absorb(current_time, velocity, x_overscroll_started, y_overscroll_started);
else
Pull(current_time, overscroll_delta, overscroll_location);
return CheckNeedsAnimate();
}
bool OverscrollGlow::Animate(base::TimeTicks current_time,
cc::slim::Layer* parent_layer) {
DCHECK(parent_layer);
if (!CheckNeedsAnimate())
return false;
UpdateLayerAttachment(parent_layer);
for (size_t i = 0; i < EDGE_COUNT; ++i) {
if (edge_effects_[i]->Update(current_time)) {
EdgeEffect::Edge edge = static_cast<EdgeEffect::Edge>(i);
edge_effects_[i]->ApplyToLayers(edge, viewport_size_, edge_offsets_[i]);
}
}
return CheckNeedsAnimate();
}
void OverscrollGlow::OnFrameUpdated(const gfx::SizeF& viewport_size,
const gfx::SizeF& content_size,
const gfx::PointF& content_scroll_offset) {
viewport_size_ = viewport_size;
edge_offsets_[EdgeEffect::EDGE_TOP] = -content_scroll_offset.y();
edge_offsets_[EdgeEffect::EDGE_LEFT] = -content_scroll_offset.x();
edge_offsets_[EdgeEffect::EDGE_BOTTOM] = content_size.height() -
content_scroll_offset.y() -
viewport_size.height();
edge_offsets_[EdgeEffect::EDGE_RIGHT] =
content_size.width() - content_scroll_offset.x() - viewport_size.width();
// Only allow overscroll on scrollable axes, matching platform behavior.
allow_horizontal_overscroll_ =
std::ceil(viewport_size_.width()) < std::floor(content_size.width());
allow_vertical_overscroll_ =
std::ceil(viewport_size_.height()) < std::floor(content_size.height());
}
bool OverscrollGlow::CheckNeedsAnimate() {
if (!initialized_) {
Detach();
return false;
}
if (IsActive())
return true;
Detach();
return false;
}
void OverscrollGlow::UpdateLayerAttachment(cc::slim::Layer* parent) {
DCHECK(parent);
if (!root_layer_.get())
return;
if (!CheckNeedsAnimate())
return;
if (root_layer_->parent() != parent)
parent->AddChild(root_layer_);
for (size_t i = 0; i < EDGE_COUNT; ++i)
edge_effects_[i]->SetParent(root_layer_.get());
}
void OverscrollGlow::Detach() {
if (root_layer_.get())
root_layer_->RemoveFromParent();
}
bool OverscrollGlow::InitializeIfNecessary() {
if (initialized_)
return true;
if (client_ == nullptr)
return false;
DCHECK(!root_layer_.get());
root_layer_ = cc::slim::Layer::Create();
for (size_t i = 0; i < EDGE_COUNT; ++i) {
edge_effects_[i] = client_->CreateEdgeEffect();
DCHECK(edge_effects_[i]);
}
initialized_ = true;
return true;
}
void OverscrollGlow::Pull(base::TimeTicks current_time,
const gfx::Vector2dF& overscroll_delta,
const gfx::Vector2dF& overscroll_location) {
DCHECK(initialized_);
DCHECK(!overscroll_delta.IsZero());
DCHECK(!viewport_size_.IsEmpty());
const float inv_width = 1.f / viewport_size_.width();
const float inv_height = 1.f / viewport_size_.height();
gfx::Vector2dF overscroll_pull =
gfx::ScaleVector2d(overscroll_delta, inv_width, inv_height);
const float edge_pull[EDGE_COUNT] = {
min(overscroll_pull.y(), 0.f), // Top
min(overscroll_pull.x(), 0.f), // Left
max(overscroll_pull.y(), 0.f), // Bottom
max(overscroll_pull.x(), 0.f) // Right
};
gfx::Vector2dF displacement =
gfx::ScaleVector2d(overscroll_location, inv_width, inv_height);
displacement.set_x(max(0.f, min(1.f, displacement.x())));
displacement.set_y(max(0.f, min(1.f, displacement.y())));
const float edge_displacement[EDGE_COUNT] = {
1.f - displacement.x(), // Top
displacement.y(), // Left
displacement.x(), // Bottom
1.f - displacement.y() // Right
};
for (size_t i = 0; i < EDGE_COUNT; ++i) {
if (!edge_pull[i])
continue;
edge_effects_[i]->Pull(
current_time, std::abs(edge_pull[i]), edge_displacement[i]);
GetOppositeEdge(i)->Release(current_time);
}
}
void OverscrollGlow::Absorb(base::TimeTicks current_time,
const gfx::Vector2dF& velocity,
bool x_overscroll_started,
bool y_overscroll_started) {
DCHECK(initialized_);
DCHECK(!velocity.IsZero());
// Only trigger on initial overscroll at a non-zero velocity
const float overscroll_velocities[EDGE_COUNT] = {
y_overscroll_started ? min(velocity.y(), 0.f) : 0, // Top
x_overscroll_started ? min(velocity.x(), 0.f) : 0, // Left
y_overscroll_started ? max(velocity.y(), 0.f) : 0, // Bottom
x_overscroll_started ? max(velocity.x(), 0.f) : 0 // Right
};
for (size_t i = 0; i < EDGE_COUNT; ++i) {
if (!overscroll_velocities[i])
continue;
edge_effects_[i]->Absorb(current_time, std::abs(overscroll_velocities[i]));
GetOppositeEdge(i)->Release(current_time);
}
}
void OverscrollGlow::Release(base::TimeTicks current_time) {
DCHECK(initialized_);
for (size_t i = 0; i < EDGE_COUNT; ++i)
edge_effects_[i]->Release(current_time);
}
EdgeEffect* OverscrollGlow::GetOppositeEdge(int edge_index) {
DCHECK(initialized_);
return edge_effects_[(edge_index + 2) % EDGE_COUNT].get();
}
} // namespace ui
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