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      */
ImageResizer(Context context, int imageWidth, int imageHeight)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      */
ImageResizer(Context context, int imageSize)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      */
setImageSize(int width, int height)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      */
setImageSize(int size)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      */
processBitmap(int resId)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
processBitmap(Object data)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      */
decodeSampledBitmapFromResource(Resources res, int resId, int reqWidth, int reqHeight, ImageCache cache)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      */
decodeSampledBitmapFromFile(String filename, int reqWidth, int reqHeight, ImageCache cache)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      */
decodeSampledBitmapFromDescriptor( FileDescriptor fileDescriptor, int reqWidth, int reqHeight, ImageCache cache)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)
addInBitmapOptions(BitmapFactory.Options options, ImageCache cache)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      */
calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight)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 }
271