chromium/remoting/client/ui/fling_tracker.cc

// Copyright 2017 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "remoting/client/ui/fling_tracker.h"

#include <cmath>

namespace remoting {

namespace {

const float kSecToMs = …;

// TODO(yuweih): May need to tweak these numbers to get better smoothness.

// Stop flinging if the speed drops below this. This is a small speed to make
// sure the animation stops smoothly.
const float kMinTrackSpeed = …;

// The minimum displacement needed to trigger the fling animation. This is to
// prevent unintentional fling with low velocity.
const float kMinDisplacement = …;

float GetDisplacement(float time_constant,
                      float initial_speed_rate,
                      float time_elapsed) { … }

// Returns the time needed for the object to get to the stable state where the
// speed drops below kMinTrackSpeed.
float GetDuration(float time_constant, float initial_speed_rate) { … }

}  // namespace

FlingTracker::FlingTracker(float time_constant)
    : … { … }

FlingTracker::~FlingTracker() = default;

void FlingTracker::StartFling(float velocity_x, float velocity_y) { … }

void FlingTracker::StopFling() { … }

bool FlingTracker::IsFlingInProgress() const { … }

bool FlingTracker::TrackMovement(base::TimeDelta time_elapsed,
                                 float* dx,
                                 float* dy) { … }

}  // namespace remoting