1 /* 2 * Copyright (C) 2017 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 package com.android.launcher3.graphics; 17 18 import android.graphics.Bitmap; 19 import android.graphics.Canvas; 20 import android.graphics.Paint; 21 import android.graphics.Rect; 22 import android.graphics.RectF; 23 24 /** 25 * Utility class which draws a bitmap by dissecting it into 3 segments and stretching 26 * the middle segment. 27 */ 28 public class NinePatchDrawHelper { 29 30 // The extra width used for the bitmap. This portion of the bitmap is stretched to match the 31 // width of the draw region. Randomly chosen, any value > 4 will be sufficient. 32 public static final int EXTENSION_PX = 20; 33 34 private final Rect mSrc = new Rect(); 35 private final RectF mDst = new RectF(); 36 public final Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG); 37 38 /** 39 * Draws the bitmap split into three parts horizontally, with the middle part having width 40 * as {@link #EXTENSION_PX} in the center of the bitmap. 41 */ draw(Bitmap bitmap, Canvas canvas, float left, float top, float right)42 public void draw(Bitmap bitmap, Canvas canvas, float left, float top, float right) { 43 int height = bitmap.getHeight(); 44 45 mSrc.top = 0; 46 mSrc.bottom = height; 47 mDst.top = top; 48 mDst.bottom = top + height; 49 draw3Patch(bitmap, canvas, left, right); 50 } 51 52 53 /** 54 * Draws the bitmap split horizontally into 3 parts (same as {@link #draw}) and split 55 * vertically into two parts, bottom part of size {@link #EXTENSION_PX} / 2 which is 56 * stretched vertically. 57 */ drawVerticallyStretched(Bitmap bitmap, Canvas canvas, float left, float top, float right, float bottom)58 public void drawVerticallyStretched(Bitmap bitmap, Canvas canvas, float left, float top, 59 float right, float bottom) { 60 draw(bitmap, canvas, left, top, right); 61 62 // Draw bottom stretched region. 63 int height = bitmap.getHeight(); 64 mSrc.top = height - EXTENSION_PX / 4; 65 mSrc.bottom = height; 66 mDst.top = top + height; 67 mDst.bottom = bottom; 68 draw3Patch(bitmap, canvas, left, right); 69 } 70 71 72 draw3Patch(Bitmap bitmap, Canvas canvas, float left, float right)73 private void draw3Patch(Bitmap bitmap, Canvas canvas, float left, float right) { 74 int width = bitmap.getWidth(); 75 int halfWidth = width / 2; 76 77 // Draw left edge 78 drawRegion(bitmap, canvas, 0, halfWidth, left, left + halfWidth); 79 80 // Draw right edge 81 drawRegion(bitmap, canvas, halfWidth, width, right - halfWidth, right); 82 83 // Draw middle stretched region 84 int halfExt = EXTENSION_PX / 4; 85 drawRegion(bitmap, canvas, halfWidth - halfExt, halfWidth + halfExt, 86 left + halfWidth, right - halfWidth); 87 } 88 drawRegion(Bitmap bitmap, Canvas c, int srcLeft, int srcRight, float dstLeft, float dstRight)89 private void drawRegion(Bitmap bitmap, Canvas c, 90 int srcLeft, int srcRight, float dstLeft, float dstRight) { 91 mSrc.left = srcLeft; 92 mSrc.right = srcRight; 93 94 mDst.left = dstLeft; 95 mDst.right = dstRight; 96 c.drawBitmap(bitmap, mSrc, mDst, paint); 97 } 98 } 99