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// Copyright 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 "base/logging.h"
#include "base/memory/scoped_ptr.h"
#include "cc/animation/timing_function.h"
#include "cc/base/math_util.h"
namespace cc {
TimingFunction::TimingFunction() {}
TimingFunction::~TimingFunction() {}
scoped_ptr<CubicBezierTimingFunction> CubicBezierTimingFunction::Create(
double x1, double y1, double x2, double y2) {
return make_scoped_ptr(new CubicBezierTimingFunction(x1, y1, x2, y2));
}
CubicBezierTimingFunction::CubicBezierTimingFunction(double x1,
double y1,
double x2,
double y2)
: bezier_(x1, y1, x2, y2) {}
CubicBezierTimingFunction::~CubicBezierTimingFunction() {}
float CubicBezierTimingFunction::GetValue(double x) const {
return static_cast<float>(bezier_.Solve(x));
}
float CubicBezierTimingFunction::Velocity(double x) const {
return static_cast<float>(bezier_.Slope(x));
}
void CubicBezierTimingFunction::Range(float* min, float* max) const {
double min_d = 0;
double max_d = 1;
bezier_.Range(&min_d, &max_d);
*min = static_cast<float>(min_d);
*max = static_cast<float>(max_d);
}
scoped_ptr<TimingFunction> CubicBezierTimingFunction::Clone() const {
return make_scoped_ptr(new CubicBezierTimingFunction(*this));
}
// These numbers come from
// http://www.w3.org/TR/css3-transitions/#transition-timing-function_tag.
scoped_ptr<TimingFunction> EaseTimingFunction::Create() {
return CubicBezierTimingFunction::Create(0.25, 0.1, 0.25, 1.0);
}
scoped_ptr<TimingFunction> EaseInTimingFunction::Create() {
return CubicBezierTimingFunction::Create(0.42, 0.0, 1.0, 1.0);
}
scoped_ptr<TimingFunction> EaseOutTimingFunction::Create() {
return CubicBezierTimingFunction::Create(0.0, 0.0, 0.58, 1.0);
}
scoped_ptr<TimingFunction> EaseInOutTimingFunction::Create() {
return CubicBezierTimingFunction::Create(0.42, 0.0, 0.58, 1);
}
scoped_ptr<StepsTimingFunction> StepsTimingFunction::Create(
int steps,
float steps_start_offset) {
return make_scoped_ptr(new StepsTimingFunction(steps, steps_start_offset));
}
StepsTimingFunction::StepsTimingFunction(int steps, float steps_start_offset)
: steps_(steps), steps_start_offset_(steps_start_offset) {
// Restrict it to CSS presets: step_start, step_end and step_middle.
// See the Web Animations specification, 3.12.4. Timing in discrete steps.
DCHECK(steps_start_offset_ == 0 || steps_start_offset_ == 1 ||
steps_start_offset_ == 0.5);
}
StepsTimingFunction::~StepsTimingFunction() {
}
float StepsTimingFunction::GetValue(double t) const {
const double steps = static_cast<double>(steps_);
const double value = MathUtil::ClampToRange(
std::floor((steps * t) + steps_start_offset_) / steps, 0.0, 1.0);
return static_cast<float>(value);
}
scoped_ptr<TimingFunction> StepsTimingFunction::Clone() const {
return make_scoped_ptr(new StepsTimingFunction(*this));
}
void StepsTimingFunction::Range(float* min, float* max) const {
*min = 0.0f;
*max = 1.0f;
}
float StepsTimingFunction::Velocity(double x) const {
return 0.0f;
}
} // namespace cc
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