1 /* 2 * Copyright (C) 2011 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.phone; 18 19 import android.graphics.Bitmap; 20 import android.os.SystemClock; 21 import android.os.SystemProperties; 22 import android.util.Log; 23 24 25 /** 26 * Image effects used by the in-call UI. 27 */ 28 public class BitmapUtils { 29 private static final String TAG = "BitmapUtils"; 30 private static final boolean DBG = 31 (PhoneApp.DBG_LEVEL >= 1) && (SystemProperties.getInt("ro.debuggable", 0) == 1); 32 33 /** This class is never instantiated. */ 34 private BitmapUtils() { 35 } 36 37 // 38 // Gaussian blur effect 39 // 40 // gaussianBlur() and related methods are borrowed from 41 // BackgroundUtils.java in the Music2 code (which itself was based on 42 // code from the old Cooliris android Gallery app.) 43 // 44 // TODO: possibly consider caching previously-generated blurred bitmaps; 45 // see getAdaptedBitmap() and mAdaptedBitmapCache in the music app code. 46 // 47 48 private static final int RED_MASK = 0xff0000; 49 private static final int RED_MASK_SHIFT = 16; 50 private static final int GREEN_MASK = 0x00ff00; 51 private static final int GREEN_MASK_SHIFT = 8; 52 private static final int BLUE_MASK = 0x0000ff; 53 54 /** 55 * Creates a blurred version of the given Bitmap. 56 * 57 * @param bitmap the input bitmap, presumably a 96x96 pixel contact 58 * thumbnail. 59 */ 60 public static Bitmap createBlurredBitmap(Bitmap bitmap) { 61 if (DBG) log("createBlurredBitmap()..."); 62 long startTime = SystemClock.uptimeMillis(); 63 if (bitmap == null) { 64 Log.w(TAG, "createBlurredBitmap: null bitmap"); 65 return null; 66 } 67 68 if (DBG) log("- input bitmap: " + bitmap.getWidth() + " x " + bitmap.getHeight()); 69 70 // The bitmap we pass to gaussianBlur() needs to have a width 71 // that's a power of 2, so scale up to 128x128. 72 final int scaledSize = 128; 73 bitmap = Bitmap.createScaledBitmap(bitmap, 74 scaledSize, scaledSize, 75 true /* filter */); 76 if (DBG) log("- after resize: " + bitmap.getWidth() + " x " + bitmap.getHeight()); 77 78 bitmap = gaussianBlur(bitmap); 79 if (DBG) log("- after blur: " + bitmap.getWidth() + " x " + bitmap.getHeight()); 80 81 long endTime = SystemClock.uptimeMillis(); 82 if (DBG) log("createBlurredBitmap() done (elapsed = " + (endTime - startTime) + " msec)"); 83 return bitmap; 84 } 85 86 /** 87 * Apply a gaussian blur filter, and return a new (blurred) bitmap 88 * that's the same size as the input bitmap. 89 * 90 * @param source input bitmap, whose width must be a power of 2 91 */ 92 public static Bitmap gaussianBlur(Bitmap source) { 93 int width = source.getWidth(); 94 int height = source.getHeight(); 95 if (DBG) log("gaussianBlur(): input: " + width + " x " + height); 96 97 // Create a source and destination buffer for the image. 98 int numPixels = width * height; 99 int[] in = new int[numPixels]; 100 int[] tmp = new int[numPixels]; 101 102 // Get the source pixels as 32-bit ARGB. 103 source.getPixels(in, 0, width, 0, 0, width, height); 104 105 // Gaussian is a separable kernel, so it is decomposed into a horizontal 106 // and vertical pass. 107 // The filter function applies the kernel across each row and transposes 108 // the output. 109 // Hence we apply it twice to provide efficient horizontal and vertical 110 // convolution. 111 // The filter discards the alpha channel. 112 gaussianBlurFilter(in, tmp, width, height); 113 gaussianBlurFilter(tmp, in, width, height); 114 115 // Return a bitmap scaled to the desired size. 116 Bitmap filtered = Bitmap.createBitmap(in, width, height, Bitmap.Config.ARGB_8888); 117 source.recycle(); 118 return filtered; 119 } 120 121 private static void gaussianBlurFilter(int[] in, int[] out, int width, int height) { 122 // This function is currently hardcoded to blur with RADIUS = 4. 123 // (If you change RADIUS, you'll have to change the weights[] too.) 124 final int RADIUS = 4; 125 final int[] weights = { 13, 23, 32, 39, 42, 39, 32, 23, 13}; // Adds up to 256 126 int inPos = 0; 127 int widthMask = width - 1; // width must be a power of two. 128 for (int y = 0; y < height; ++y) { 129 // Compute the alpha value. 130 int alpha = 0xff; 131 // Compute output values for the row. 132 int outPos = y; 133 for (int x = 0; x < width; ++x) { 134 int red = 0; 135 int green = 0; 136 int blue = 0; 137 for (int i = -RADIUS; i <= RADIUS; ++i) { 138 int argb = in[inPos + (widthMask & (x + i))]; 139 int weight = weights[i+RADIUS]; 140 red += weight *((argb & RED_MASK) >> RED_MASK_SHIFT); 141 green += weight *((argb & GREEN_MASK) >> GREEN_MASK_SHIFT); 142 blue += weight *(argb & BLUE_MASK); 143 } 144 // Output the current pixel. 145 out[outPos] = (alpha << 24) | ((red >> 8) << RED_MASK_SHIFT) 146 | ((green >> 8) << GREEN_MASK_SHIFT) 147 | (blue >> 8); 148 outPos += height; 149 } 150 inPos += width; 151 } 152 } 153 154 // 155 // Debugging 156 // 157 158 private static void log(String msg) { 159 Log.d(TAG, msg); 160 } 161 } 162
