Alexander Lucas | 97842ff | 2014-03-07 14:56:55 -0800 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2012 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.example.android.displayingbitmaps.util; |
| 18 | |
| 19 | import android.annotation.TargetApi; |
| 20 | import android.content.Context; |
| 21 | import android.content.res.Resources; |
| 22 | import android.graphics.Bitmap; |
| 23 | import android.graphics.BitmapFactory; |
| 24 | import android.os.Build; |
| 25 | |
| 26 | import com.example.android.common.logger.Log; |
| 27 | import com.example.android.displayingbitmaps.BuildConfig; |
| 28 | |
| 29 | import java.io.FileDescriptor; |
| 30 | |
| 31 | /** |
| 32 | * A simple subclass of {@link ImageWorker} that resizes images from resources given a target width |
| 33 | * and height. Useful for when the input images might be too large to simply load directly into |
| 34 | * memory. |
| 35 | */ |
| 36 | public class ImageResizer extends ImageWorker { |
| 37 | private static final String TAG = "ImageResizer"; |
| 38 | protected int mImageWidth; |
| 39 | protected int mImageHeight; |
| 40 | |
| 41 | /** |
| 42 | * Initialize providing a single target image size (used for both width and height); |
| 43 | * |
| 44 | * @param context |
| 45 | * @param imageWidth |
| 46 | * @param imageHeight |
| 47 | */ |
| 48 | public ImageResizer(Context context, int imageWidth, int imageHeight) { |
| 49 | super(context); |
| 50 | setImageSize(imageWidth, imageHeight); |
| 51 | } |
| 52 | |
| 53 | /** |
| 54 | * Initialize providing a single target image size (used for both width and height); |
| 55 | * |
| 56 | * @param context |
| 57 | * @param imageSize |
| 58 | */ |
| 59 | public ImageResizer(Context context, int imageSize) { |
| 60 | super(context); |
| 61 | setImageSize(imageSize); |
| 62 | } |
| 63 | |
| 64 | /** |
| 65 | * Set the target image width and height. |
| 66 | * |
| 67 | * @param width |
| 68 | * @param height |
| 69 | */ |
| 70 | public void setImageSize(int width, int height) { |
| 71 | mImageWidth = width; |
| 72 | mImageHeight = height; |
| 73 | } |
| 74 | |
| 75 | /** |
| 76 | * Set the target image size (width and height will be the same). |
| 77 | * |
| 78 | * @param size |
| 79 | */ |
| 80 | public void setImageSize(int size) { |
| 81 | setImageSize(size, size); |
| 82 | } |
| 83 | |
| 84 | /** |
| 85 | * The main processing method. This happens in a background task. In this case we are just |
| 86 | * sampling down the bitmap and returning it from a resource. |
| 87 | * |
| 88 | * @param resId |
| 89 | * @return |
| 90 | */ |
| 91 | private Bitmap processBitmap(int resId) { |
| 92 | if (BuildConfig.DEBUG) { |
| 93 | Log.d(TAG, "processBitmap - " + resId); |
| 94 | } |
| 95 | return decodeSampledBitmapFromResource(mResources, resId, mImageWidth, |
| 96 | mImageHeight, getImageCache()); |
| 97 | } |
| 98 | |
| 99 | @Override |
| 100 | protected Bitmap processBitmap(Object data) { |
| 101 | return processBitmap(Integer.parseInt(String.valueOf(data))); |
| 102 | } |
| 103 | |
| 104 | /** |
| 105 | * Decode and sample down a bitmap from resources to the requested width and height. |
| 106 | * |
| 107 | * @param res The resources object containing the image data |
| 108 | * @param resId The resource id of the image data |
| 109 | * @param reqWidth The requested width of the resulting bitmap |
| 110 | * @param reqHeight The requested height of the resulting bitmap |
| 111 | * @param cache The ImageCache used to find candidate bitmaps for use with inBitmap |
| 112 | * @return A bitmap sampled down from the original with the same aspect ratio and dimensions |
| 113 | * that are equal to or greater than the requested width and height |
| 114 | */ |
| 115 | public static Bitmap decodeSampledBitmapFromResource(Resources res, int resId, |
| 116 | int reqWidth, int reqHeight, ImageCache cache) { |
| 117 | |
| 118 | // BEGIN_INCLUDE (read_bitmap_dimensions) |
| 119 | // First decode with inJustDecodeBounds=true to check dimensions |
| 120 | final BitmapFactory.Options options = new BitmapFactory.Options(); |
| 121 | options.inJustDecodeBounds = true; |
| 122 | BitmapFactory.decodeResource(res, resId, options); |
| 123 | |
| 124 | // Calculate inSampleSize |
| 125 | options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight); |
| 126 | // END_INCLUDE (read_bitmap_dimensions) |
| 127 | |
| 128 | // If we're running on Honeycomb or newer, try to use inBitmap |
| 129 | if (Utils.hasHoneycomb()) { |
| 130 | addInBitmapOptions(options, cache); |
| 131 | } |
| 132 | |
| 133 | // Decode bitmap with inSampleSize set |
| 134 | options.inJustDecodeBounds = false; |
| 135 | return BitmapFactory.decodeResource(res, resId, options); |
| 136 | } |
| 137 | |
| 138 | /** |
| 139 | * Decode and sample down a bitmap from a file to the requested width and height. |
| 140 | * |
| 141 | * @param filename The full path of the file to decode |
| 142 | * @param reqWidth The requested width of the resulting bitmap |
| 143 | * @param reqHeight The requested height of the resulting bitmap |
| 144 | * @param cache The ImageCache used to find candidate bitmaps for use with inBitmap |
| 145 | * @return A bitmap sampled down from the original with the same aspect ratio and dimensions |
| 146 | * that are equal to or greater than the requested width and height |
| 147 | */ |
| 148 | public static Bitmap decodeSampledBitmapFromFile(String filename, |
| 149 | int reqWidth, int reqHeight, ImageCache cache) { |
| 150 | |
| 151 | // First decode with inJustDecodeBounds=true to check dimensions |
| 152 | final BitmapFactory.Options options = new BitmapFactory.Options(); |
| 153 | options.inJustDecodeBounds = true; |
| 154 | BitmapFactory.decodeFile(filename, options); |
| 155 | |
| 156 | // Calculate inSampleSize |
| 157 | options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight); |
| 158 | |
| 159 | // If we're running on Honeycomb or newer, try to use inBitmap |
| 160 | if (Utils.hasHoneycomb()) { |
| 161 | addInBitmapOptions(options, cache); |
| 162 | } |
| 163 | |
| 164 | // Decode bitmap with inSampleSize set |
| 165 | options.inJustDecodeBounds = false; |
| 166 | return BitmapFactory.decodeFile(filename, options); |
| 167 | } |
| 168 | |
| 169 | /** |
| 170 | * Decode and sample down a bitmap from a file input stream to the requested width and height. |
| 171 | * |
| 172 | * @param fileDescriptor The file descriptor to read from |
| 173 | * @param reqWidth The requested width of the resulting bitmap |
| 174 | * @param reqHeight The requested height of the resulting bitmap |
| 175 | * @param cache The ImageCache used to find candidate bitmaps for use with inBitmap |
| 176 | * @return A bitmap sampled down from the original with the same aspect ratio and dimensions |
| 177 | * that are equal to or greater than the requested width and height |
| 178 | */ |
| 179 | public static Bitmap decodeSampledBitmapFromDescriptor( |
| 180 | FileDescriptor fileDescriptor, int reqWidth, int reqHeight, ImageCache cache) { |
| 181 | |
| 182 | // First decode with inJustDecodeBounds=true to check dimensions |
| 183 | final BitmapFactory.Options options = new BitmapFactory.Options(); |
| 184 | options.inJustDecodeBounds = true; |
| 185 | BitmapFactory.decodeFileDescriptor(fileDescriptor, null, options); |
| 186 | |
| 187 | // Calculate inSampleSize |
| 188 | options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight); |
| 189 | |
| 190 | // Decode bitmap with inSampleSize set |
| 191 | options.inJustDecodeBounds = false; |
| 192 | |
| 193 | // If we're running on Honeycomb or newer, try to use inBitmap |
| 194 | if (Utils.hasHoneycomb()) { |
| 195 | addInBitmapOptions(options, cache); |
| 196 | } |
| 197 | |
| 198 | return BitmapFactory.decodeFileDescriptor(fileDescriptor, null, options); |
| 199 | } |
| 200 | |
| 201 | @TargetApi(Build.VERSION_CODES.HONEYCOMB) |
| 202 | private static void addInBitmapOptions(BitmapFactory.Options options, ImageCache cache) { |
| 203 | //BEGIN_INCLUDE(add_bitmap_options) |
| 204 | // inBitmap only works with mutable bitmaps so force the decoder to |
| 205 | // return mutable bitmaps. |
| 206 | options.inMutable = true; |
| 207 | |
| 208 | if (cache != null) { |
| 209 | // Try and find a bitmap to use for inBitmap |
| 210 | Bitmap inBitmap = cache.getBitmapFromReusableSet(options); |
| 211 | |
| 212 | if (inBitmap != null) { |
| 213 | options.inBitmap = inBitmap; |
| 214 | } |
| 215 | } |
| 216 | //END_INCLUDE(add_bitmap_options) |
| 217 | } |
| 218 | |
| 219 | /** |
| 220 | * Calculate an inSampleSize for use in a {@link android.graphics.BitmapFactory.Options} object when decoding |
| 221 | * bitmaps using the decode* methods from {@link android.graphics.BitmapFactory}. This implementation calculates |
| 222 | * the closest inSampleSize that is a power of 2 and will result in the final decoded bitmap |
| 223 | * having a width and height equal to or larger than the requested width and height. |
| 224 | * |
| 225 | * @param options An options object with out* params already populated (run through a decode* |
| 226 | * method with inJustDecodeBounds==true |
| 227 | * @param reqWidth The requested width of the resulting bitmap |
| 228 | * @param reqHeight The requested height of the resulting bitmap |
| 229 | * @return The value to be used for inSampleSize |
| 230 | */ |
| 231 | public static int calculateInSampleSize(BitmapFactory.Options options, |
| 232 | int reqWidth, int reqHeight) { |
| 233 | // BEGIN_INCLUDE (calculate_sample_size) |
| 234 | // Raw height and width of image |
| 235 | final int height = options.outHeight; |
| 236 | final int width = options.outWidth; |
| 237 | int inSampleSize = 1; |
| 238 | |
| 239 | if (height > reqHeight || width > reqWidth) { |
| 240 | |
| 241 | final int halfHeight = height / 2; |
| 242 | final int halfWidth = width / 2; |
| 243 | |
| 244 | // Calculate the largest inSampleSize value that is a power of 2 and keeps both |
| 245 | // height and width larger than the requested height and width. |
| 246 | while ((halfHeight / inSampleSize) > reqHeight |
| 247 | && (halfWidth / inSampleSize) > reqWidth) { |
| 248 | inSampleSize *= 2; |
| 249 | } |
| 250 | |
| 251 | // This offers some additional logic in case the image has a strange |
| 252 | // aspect ratio. For example, a panorama may have a much larger |
| 253 | // width than height. In these cases the total pixels might still |
| 254 | // end up being too large to fit comfortably in memory, so we should |
| 255 | // be more aggressive with sample down the image (=larger inSampleSize). |
| 256 | |
| 257 | long totalPixels = width * height / inSampleSize; |
| 258 | |
| 259 | // Anything more than 2x the requested pixels we'll sample down further |
| 260 | final long totalReqPixelsCap = reqWidth * reqHeight * 2; |
| 261 | |
| 262 | while (totalPixels > totalReqPixelsCap) { |
| 263 | inSampleSize *= 2; |
| 264 | totalPixels /= 2; |
| 265 | } |
| 266 | } |
| 267 | return inSampleSize; |
| 268 | // END_INCLUDE (calculate_sample_size) |
| 269 | } |
| 270 | } |