1 /* 2 * Copyright (C) 2015 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.android.camera.ui.motion; 18 19 /** 20 * Represents a discrete linear scale function. 21 */ 22 public final class LinearScale { 23 private final float mDomainA; 24 private final float mDomainB; 25 private final float mRangeA; 26 private final float mRangeB; 27 28 private final float mScale; 29 LinearScale(float domainA, float domainB, float rangeA, float rangeB)30 public LinearScale(float domainA, float domainB, float rangeA, float rangeB) { 31 mDomainA = domainA; 32 mDomainB = domainB; 33 mRangeA = rangeA; 34 mRangeB = rangeB; 35 36 // Precomputed ratio between input domain and output range. 37 float scale = (mRangeB - mRangeA) / (mDomainB - mDomainA); 38 mScale = Float.isNaN(scale) ? 0.0f : scale; 39 } 40 41 /** 42 * Clamp a given domain value to the given domain. 43 */ clamp(float domainValue)44 public float clamp(float domainValue) { 45 if (mDomainA > mDomainB) { 46 return Math.max(mDomainB, Math.min(mDomainA, domainValue)); 47 } 48 49 return Math.max(mDomainA, Math.min(mDomainB, domainValue)); 50 } 51 52 /** 53 * Returns true if the value is within the domain. 54 */ isInDomain(float domainValue)55 public boolean isInDomain(float domainValue) { 56 if (mDomainA > mDomainB) { 57 return domainValue <= mDomainA && domainValue >= mDomainB; 58 } 59 return domainValue >= mDomainA && domainValue <= mDomainB; 60 } 61 62 /** 63 * Linearly scale a given domain value into the output range. 64 */ scale(float domainValue)65 public float scale(float domainValue) { 66 return mRangeA + (domainValue - mDomainA) * mScale; 67 } 68 69 /** 70 * For the current domain and range parameters produce a new scale function 71 * that is the inverse of the current scale function. 72 */ inverse()73 public LinearScale inverse() { 74 return new LinearScale(mRangeA, mRangeB, mDomainA, mDomainB); 75 } 76 77 @Override toString()78 public String toString() { 79 return "LinearScale{" + 80 "mDomainA=" + mDomainA + 81 ", mDomainB=" + mDomainB + 82 ", mRangeA=" + mRangeA + 83 ", mRangeB=" + mRangeB + "}"; 84 } 85 }