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.cts.view; 18 19 /** 20 * Represents coordinates where (x, y) = (0, 0) represents the top-left most point. 21 */ 22 public class Position { 23 private final float mX; 24 private final float mY; 25 Position(float x, float y)26 public Position(float x, float y) { 27 mX = x; 28 mY = y; 29 } 30 getX()31 public float getX() { 32 return mX; 33 } 34 getY()35 public float getY() { 36 return mY; 37 } 38 39 /** 40 * @return The vector dot product between {@code this} and another {@link Position}. 41 */ dotProduct(Position other)42 public double dotProduct(Position other) { 43 return (mX * other.mX) + (mY * other.mY); 44 } 45 46 /** 47 * @return The euclidean distance between {@code this} and the other {@link Position}. 48 */ distanceTo(Position other)49 public double distanceTo(Position other) { 50 return Math.sqrt(Math.pow((mX - other.mX), 2) + Math.pow((mY - other.mY), 2)); 51 } 52 53 /** 54 * Returns the closest double approximation to the smallest angle swept out by an arc from 55 * {@code this} to the other {@link Position}, given the origin of the arc. 56 * 57 * @param origin The {@link Position} to use as the origin of the arc. 58 * @return The angle swept out, in radians within the range {@code [-pi..pi]}. A negative double 59 * indicates that the smallest angle swept out is in the clockwise direction, and a positive 60 * double indicates otherwise. 61 */ arcAngleTo(Position other, Position origin)62 public double arcAngleTo(Position other, Position origin) { 63 // Compute the angle of the polar representation of this and other w.r.t. the arc origin. 64 double originToThisAngle = Math.atan2(origin.mY - mY, mX - origin.mX); 65 double originToOtherAngle = Math.atan2(origin.mY - other.mY, other.mX - origin.mX); 66 double difference = originToOtherAngle - originToThisAngle; 67 68 // If the difference exceeds PI or is less then -PI, then we should compensate to 69 // bring the value back into the [-pi..pi] range by removing/adding a full revolution. 70 if (difference < -Math.PI) { 71 difference += 2 * Math.PI; 72 } else if (difference > Math.PI){ 73 difference -= 2 * Math.PI; 74 } 75 return difference; 76 } 77 78 /** 79 * Returns the closest double approximation to the angle to the other {@link Position}. 80 * 81 * @return The angle swept out, in radians within the range {@code [-pi..pi]}. 82 */ angleTo(Position other)83 public double angleTo(Position other) { 84 return Math.atan2(other.mY - mY, other.mX - mX); 85 } 86 87 /** 88 * Defines equality between pairs of {@link Position}s. 89 * <p> 90 * Two Position instances are defined to be equal if their x and y coordinates are equal. 91 */ 92 @Override equals(Object o)93 public boolean equals(Object o) { 94 if (!(o instanceof Position)) { 95 return false; 96 } 97 Position other = (Position) o; 98 return (Float.compare(other.mX, mX) == 0) && (Float.compare(other.mY, mY) == 0); 99 } 100 101 @Override hashCode()102 public int hashCode() { 103 int result = 17; 104 result = 31 * result + Float.floatToIntBits(mX); 105 result = 31 * result + Float.floatToIntBits(mY); 106 return result; 107 } 108 } 109