| /* |
| * Copyright (C) 2018 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License |
| */ |
| |
| package com.android.systemui.doze.util |
| |
| import android.util.MathUtils |
| |
| private const val MILLIS_PER_MINUTES = 1000 * 60f |
| private const val BURN_IN_PREVENTION_PERIOD_Y = 521f |
| private const val BURN_IN_PREVENTION_PERIOD_X = 83f |
| private const val BURN_IN_PREVENTION_PERIOD_SCALE = 181f |
| private const val BURN_IN_PREVENTION_PERIOD_PROGRESS = 89f |
| |
| /** |
| * Returns the translation offset that should be used to avoid burn in at |
| * the current time (in pixels.) |
| * |
| * @param amplitude Maximum translation that will be interpolated. |
| * @param xAxis If we're moving on X or Y. |
| */ |
| fun getBurnInOffset(amplitude: Int, xAxis: Boolean): Int { |
| return zigzag(System.currentTimeMillis() / MILLIS_PER_MINUTES, |
| amplitude.toFloat(), |
| if (xAxis) BURN_IN_PREVENTION_PERIOD_X else BURN_IN_PREVENTION_PERIOD_Y).toInt() |
| } |
| |
| /** |
| * Returns a progress offset (between 0f and 1.0f) that should be used to avoid burn in at |
| * the current time. |
| */ |
| fun getBurnInProgressOffset(): Float { |
| return zigzag(System.currentTimeMillis() / MILLIS_PER_MINUTES, |
| 1f, BURN_IN_PREVENTION_PERIOD_PROGRESS) |
| } |
| |
| /** |
| * Returns a value to scale a view in order to avoid burn in. |
| */ |
| fun getBurnInScale(): Float { |
| return 0.8f + zigzag(System.currentTimeMillis() / MILLIS_PER_MINUTES, |
| 0.2f, BURN_IN_PREVENTION_PERIOD_SCALE) |
| } |
| |
| /** |
| * Implements a continuous, piecewise linear, periodic zig-zag function |
| * |
| * Can be thought of as a linear approximation of abs(sin(x))) |
| * |
| * @param period period of the function, ie. zigzag(x + period) == zigzag(x) |
| * @param amplitude maximum value of the function |
| * @return a value between 0 and amplitude |
| */ |
| private fun zigzag(x: Float, amplitude: Float, period: Float): Float { |
| val xprime = x % period / (period / 2) |
| val interpolationAmount = if (xprime <= 1) xprime else 2 - xprime |
| return MathUtils.lerp(0f, amplitude, interpolationAmount) |
| } |