1 /* 2 * Copyright (C) 2017 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file 5 * except in compliance with the License. You may obtain a copy of the License at 6 * 7 * http://www.apache.org/licenses/LICENSE-2.0 8 * 9 * Unless required by applicable law or agreed to in writing, software distributed under the 10 * License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 11 * KIND, either express or implied. See the License for the specific language governing 12 * permissions and limitations under the License. 13 */ 14 15 package com.android.egg.octo; 16 17 import android.graphics.Canvas; 18 import android.graphics.Paint; 19 import android.graphics.Path; 20 import android.graphics.PathMeasure; 21 import android.os.Debug; 22 23 import java.util.Arrays; 24 25 public class TaperedPathStroke { 26 static float sMinStepPx = 4f; 27 static PathMeasure pm = new PathMeasure(); 28 static float[] pos = {0,0}; 29 static float[] tan = {0,0}; lerp(float t, float a, float b)30 static float lerp(float t, float a, float b) { 31 return a + t*(b-a); 32 } setMinStep(float px)33 public static void setMinStep(float px) { 34 sMinStepPx = px; 35 } 36 37 // it's the variable-width brush algorithm from the Markers app, basically drawPath(Canvas c, Path p, float r1, float r2, Paint pt)38 public static void drawPath(Canvas c, Path p, float r1, float r2, Paint pt) { 39 pm.setPath(p,false); 40 final float len = pm.getLength(); 41 float t=0; 42 boolean last=false; 43 while (true) { 44 if (t>=len) { 45 t=len; 46 last=true; 47 } 48 pm.getPosTan(t, pos, tan); 49 float r = len > 0 ? lerp(t/len, r1, r2) : r1; 50 c.drawCircle(pos[0], pos[1], r, pt); 51 t += Math.max(r*0.25f, sMinStepPx); // walk forward 1/4 radius, not too small though 52 if (last) break; 53 } 54 } 55 } 56