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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ui/gfx/animation/keyframe/timing_function.h"
#include <algorithm>
#include <cmath>
#include <memory>
#include "base/check_op.h"
#include "base/memory/ptr_util.h"
#include "base/notreached.h"
namespace gfx {
TimingFunction::TimingFunction() = default;
TimingFunction::~TimingFunction() = default;
std::unique_ptr<CubicBezierTimingFunction>
CubicBezierTimingFunction::CreatePreset(EaseType ease_type) {
// These numbers come from
// http://www.w3.org/TR/css3-transitions/#transition-timing-function_tag.
switch (ease_type) {
case EaseType::EASE:
return base::WrapUnique(
new CubicBezierTimingFunction(ease_type, 0.25, 0.1, 0.25, 1.0));
case EaseType::EASE_IN:
return base::WrapUnique(
new CubicBezierTimingFunction(ease_type, 0.42, 0.0, 1.0, 1.0));
case EaseType::EASE_OUT:
return base::WrapUnique(
new CubicBezierTimingFunction(ease_type, 0.0, 0.0, 0.58, 1.0));
case EaseType::EASE_IN_OUT:
return base::WrapUnique(
new CubicBezierTimingFunction(ease_type, 0.42, 0.0, 0.58, 1));
default:
NOTREACHED();
}
}
std::unique_ptr<CubicBezierTimingFunction>
CubicBezierTimingFunction::Create(double x1, double y1, double x2, double y2) {
return base::WrapUnique(
new CubicBezierTimingFunction(EaseType::CUSTOM, x1, y1, x2, y2));
}
CubicBezierTimingFunction::CubicBezierTimingFunction(EaseType ease_type,
double x1,
double y1,
double x2,
double y2)
: bezier_(x1, y1, x2, y2), ease_type_(ease_type) {}
CubicBezierTimingFunction::~CubicBezierTimingFunction() = default;
TimingFunction::Type CubicBezierTimingFunction::GetType() const {
return Type::CUBIC_BEZIER;
}
double CubicBezierTimingFunction::GetValue(
double x,
TimingFunction::LimitDirection) const {
return bezier_.Solve(x);
}
double CubicBezierTimingFunction::Velocity(double x) const {
return bezier_.Slope(x);
}
std::unique_ptr<TimingFunction> CubicBezierTimingFunction::Clone() const {
return base::WrapUnique(new CubicBezierTimingFunction(*this));
}
std::unique_ptr<StepsTimingFunction> StepsTimingFunction::Create(
int steps,
StepPosition step_position) {
return base::WrapUnique(new StepsTimingFunction(steps, step_position));
}
StepsTimingFunction::StepsTimingFunction(int steps, StepPosition step_position)
: steps_(steps), step_position_(step_position) {}
StepsTimingFunction::~StepsTimingFunction() = default;
TimingFunction::Type StepsTimingFunction::GetType() const {
return Type::STEPS;
}
std::unique_ptr<TimingFunction> StepsTimingFunction::Clone() const {
return base::WrapUnique(new StepsTimingFunction(*this));
}
double StepsTimingFunction::Velocity(double x) const {
return 0;
}
double StepsTimingFunction::GetValue(double t, LimitDirection direction) const {
const double steps = static_cast<double>(steps_);
double current_step = std::floor((steps * t) + GetStepsStartOffset());
// Adjust step if using a left limit at a discontinuous step boundary.
if (direction == LimitDirection::LEFT &&
steps * t - std::floor(steps * t) == 0) {
current_step -= 1;
}
// Jumps may differ from steps based on the number of end-point
// discontinuities, which may be 0, 1 or 2.
int jumps = NumberOfJumps();
if (t >= 0 && current_step < 0)
current_step = 0;
if (t <= 1 && current_step > jumps)
current_step = jumps;
return current_step / jumps;
}
int StepsTimingFunction::NumberOfJumps() const {
switch (step_position_) {
case StepPosition::END:
case StepPosition::START:
case StepPosition::JUMP_END:
case StepPosition::JUMP_START:
return steps_;
case StepPosition::JUMP_BOTH:
return steps_ < std::numeric_limits<int>::max() ? steps_ + 1 : steps_;
case StepPosition::JUMP_NONE:
DCHECK_GT(steps_, 1);
return steps_ - 1;
default:
NOTREACHED();
}
}
float StepsTimingFunction::GetStepsStartOffset() const {
switch (step_position_) {
case StepPosition::JUMP_BOTH:
case StepPosition::JUMP_START:
case StepPosition::START:
return 1;
case StepPosition::JUMP_END:
case StepPosition::JUMP_NONE:
case StepPosition::END:
return 0;
default:
NOTREACHED();
}
}
LinearTimingFunction::LinearTimingFunction() = default;
LinearTimingFunction::LinearTimingFunction(
std::vector<LinearEasingPoint> points)
: points_(std::move(points)) {}
LinearTimingFunction::~LinearTimingFunction() = default;
LinearTimingFunction::LinearTimingFunction(const LinearTimingFunction& other) {
points_ = other.points_;
}
std::unique_ptr<LinearTimingFunction> LinearTimingFunction::Create() {
return base::WrapUnique(new LinearTimingFunction());
}
std::unique_ptr<LinearTimingFunction> LinearTimingFunction::Create(
std::vector<LinearEasingPoint> points) {
DCHECK(points.size() >= 2);
return base::WrapUnique(new LinearTimingFunction(std::move(points)));
}
TimingFunction::Type LinearTimingFunction::GetType() const {
return Type::LINEAR;
}
std::unique_ptr<TimingFunction> LinearTimingFunction::Clone() const {
return base::WrapUnique(new LinearTimingFunction(*this));
}
double LinearTimingFunction::Velocity(double x) const {
return 0;
}
double LinearTimingFunction::GetValue(double input_progress,
LimitDirection limit_direction) const {
if (IsTrivial()) {
return input_progress;
}
// https://w3c.github.io/csswg-drafts/css-easing/#linear-easing-function-output
// 1. Let points be linearEasingFunction’s points.
// 2. Let pointAIndex be index of the last item in points with an input
// less than or equal to inputProgress, or 0 if there is no match.
auto it = std::upper_bound(points_.cbegin(), points_.cend(), input_progress,
[](double progress, const auto& point) {
return 100 * progress < point.input;
});
it = it == points_.cend() ? std::prev(it) : it;
auto point_a = it == points_.cbegin() ? it : std::prev(it);
// 3. If pointAIndex is equal to points size minus 1, decrement pointAIndex
// by 1.
point_a = std::next(point_a) == points_.cend() ? std::prev(point_a) : point_a;
// 4. Let pointA be points[pointAIndex].
// 5. Let pointB be points[pointAIndex + 1].
const auto& point_b = std::next(point_a);
// 6. If pointA’s input is equal to pointB’s input, return pointB’s output.
if (point_a->input == point_b->input) {
return point_b->output;
}
// 7. Let progressFromPointA be inputProgress minus pointA’s input.
const double progress_from_point_a = input_progress - point_a->input / 100;
// 8. Let pointInputRange be pointB’s input minus pointA’s input.
const double point_input_range = (point_b->input - point_a->input) / 100;
// 9. Let progressBetweenPoints be progressFromPointA divided by
// pointInputRange.
const double progress_between_points =
progress_from_point_a / point_input_range;
// 10. Let pointOutputRange be pointB’s output minus pointA’s output.
const double point_output_range = point_b->output - point_a->output;
// 11. Let outputFromLastPoint be progressBetweenPoints multiplied by
// pointOutputRange.
const double output_from_last_point =
progress_between_points * point_output_range;
// 12. Return pointA’s output plus outputFromLastPoint.
return point_a->output + output_from_last_point;
}
} // namespace gfx
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