/*
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* Copyright (C) 2015 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License
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*/
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package com.android.systemui.classifier;
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public class Point {
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public float x;
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public float y;
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public long timeOffsetNano;
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public Point(float x, float y) {
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this.x = x;
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this.y = y;
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this.timeOffsetNano = 0;
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}
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public Point(float x, float y, long timeOffsetNano) {
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this.x = x;
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this.y = y;
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this.timeOffsetNano = timeOffsetNano;
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}
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public boolean equals(Point p) {
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return x == p.x && y == p.y;
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}
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public float dist(Point a) {
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return (float) Math.hypot(a.x - x, a.y - y);
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}
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/**
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* Calculates the cross product of vec(this, a) and vec(this, b) where vec(x,y) is the
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* vector from point x to point y
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*/
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public float crossProduct(Point a, Point b) {
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return (a.x - x) * (b.y - y) - (a.y - y) * (b.x - x);
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}
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/**
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* Calculates the dot product of vec(this, a) and vec(this, b) where vec(x,y) is the
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* vector from point x to point y
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*/
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public float dotProduct(Point a, Point b) {
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return (a.x - x) * (b.x - x) + (a.y - y) * (b.y - y);
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}
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/**
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* Calculates the angle in radians created by points (a, this, b). If any two of these points
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* are the same, the method will return 0.0f
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*
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* @return the angle in radians
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*/
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public float getAngle(Point a, Point b) {
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float dist1 = dist(a);
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float dist2 = dist(b);
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if (dist1 == 0.0f || dist2 == 0.0f) {
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return 0.0f;
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}
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float crossProduct = crossProduct(a, b);
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float dotProduct = dotProduct(a, b);
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float cos = Math.min(1.0f, Math.max(-1.0f, dotProduct / dist1 / dist2));
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float angle = (float) Math.acos(cos);
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if (crossProduct < 0.0) {
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angle = 2.0f * (float) Math.PI - angle;
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}
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return angle;
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}
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}
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