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
17package com.example.android.bitmapfun.util;
18
19import android.annotation.TargetApi;
20import android.content.Context;
21import android.content.res.Resources;
22import android.graphics.Bitmap;
23import android.graphics.BitmapFactory;
24import android.os.Build;
25import android.util.Log;
26
27import com.example.android.bitmapfun.BuildConfig;
28
29import 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 */
36public 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        // First decode with inJustDecodeBounds=true to check dimensions
119        final BitmapFactory.Options options = new BitmapFactory.Options();
120        options.inJustDecodeBounds = true;
121        BitmapFactory.decodeResource(res, resId, options);
122
123        // Calculate inSampleSize
124        options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
125
126        // If we're running on Honeycomb or newer, try to use inBitmap
127        if (Utils.hasHoneycomb()) {
128            addInBitmapOptions(options, cache);
129        }
130
131        // Decode bitmap with inSampleSize set
132        options.inJustDecodeBounds = false;
133        return BitmapFactory.decodeResource(res, resId, options);
134    }
135
136    /**
137     * Decode and sample down a bitmap from a file to the requested width and height.
138     *
139     * @param filename The full path of the file to decode
140     * @param reqWidth The requested width of the resulting bitmap
141     * @param reqHeight The requested height of the resulting bitmap
142     * @param cache The ImageCache used to find candidate bitmaps for use with inBitmap
143     * @return A bitmap sampled down from the original with the same aspect ratio and dimensions
144     *         that are equal to or greater than the requested width and height
145     */
146    public static Bitmap decodeSampledBitmapFromFile(String filename,
147            int reqWidth, int reqHeight, ImageCache cache) {
148
149        // First decode with inJustDecodeBounds=true to check dimensions
150        final BitmapFactory.Options options = new BitmapFactory.Options();
151        options.inJustDecodeBounds = true;
152        BitmapFactory.decodeFile(filename, options);
153
154        // Calculate inSampleSize
155        options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
156
157        // If we're running on Honeycomb or newer, try to use inBitmap
158        if (Utils.hasHoneycomb()) {
159            addInBitmapOptions(options, cache);
160        }
161
162        // Decode bitmap with inSampleSize set
163        options.inJustDecodeBounds = false;
164        return BitmapFactory.decodeFile(filename, options);
165    }
166
167    /**
168     * Decode and sample down a bitmap from a file input stream to the requested width and height.
169     *
170     * @param fileDescriptor The file descriptor to read from
171     * @param reqWidth The requested width of the resulting bitmap
172     * @param reqHeight The requested height of the resulting bitmap
173     * @param cache The ImageCache used to find candidate bitmaps for use with inBitmap
174     * @return A bitmap sampled down from the original with the same aspect ratio and dimensions
175     *         that are equal to or greater than the requested width and height
176     */
177    public static Bitmap decodeSampledBitmapFromDescriptor(
178            FileDescriptor fileDescriptor, int reqWidth, int reqHeight, ImageCache cache) {
179
180        // First decode with inJustDecodeBounds=true to check dimensions
181        final BitmapFactory.Options options = new BitmapFactory.Options();
182        options.inJustDecodeBounds = true;
183        BitmapFactory.decodeFileDescriptor(fileDescriptor, null, options);
184
185        // Calculate inSampleSize
186        options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);
187
188        // Decode bitmap with inSampleSize set
189        options.inJustDecodeBounds = false;
190
191        // If we're running on Honeycomb or newer, try to use inBitmap
192        if (Utils.hasHoneycomb()) {
193            addInBitmapOptions(options, cache);
194        }
195
196        return BitmapFactory.decodeFileDescriptor(fileDescriptor, null, options);
197    }
198
199    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
200    private static void addInBitmapOptions(BitmapFactory.Options options, ImageCache cache) {
201        // inBitmap only works with mutable bitmaps so force the decoder to
202        // return mutable bitmaps.
203        options.inMutable = true;
204
205        if (cache != null) {
206            // Try and find a bitmap to use for inBitmap
207            Bitmap inBitmap = cache.getBitmapFromReusableSet(options);
208
209            if (inBitmap != null) {
210                if (BuildConfig.DEBUG) {
211                    Log.d(TAG, "Found bitmap to use for inBitmap");
212                }
213                options.inBitmap = inBitmap;
214            }
215        }
216    }
217
218    /**
219     * Calculate an inSampleSize for use in a {@link BitmapFactory.Options} object when decoding
220     * bitmaps using the decode* methods from {@link BitmapFactory}. This implementation calculates
221     * the closest inSampleSize that will result in the final decoded bitmap having a width and
222     * height equal to or larger than the requested width and height. This implementation does not
223     * ensure a power of 2 is returned for inSampleSize which can be faster when decoding but
224     * results in a larger bitmap which isn't as useful for caching purposes.
225     *
226     * @param options An options object with out* params already populated (run through a decode*
227     *            method with inJustDecodeBounds==true
228     * @param reqWidth The requested width of the resulting bitmap
229     * @param reqHeight The requested height of the resulting bitmap
230     * @return The value to be used for inSampleSize
231     */
232    public static int calculateInSampleSize(BitmapFactory.Options options,
233            int reqWidth, int reqHeight) {
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            // Calculate ratios of height and width to requested height and width
242            final int heightRatio = Math.round((float) height / (float) reqHeight);
243            final int widthRatio = Math.round((float) width / (float) reqWidth);
244
245            // Choose the smallest ratio as inSampleSize value, this will guarantee a final image
246            // with both dimensions larger than or equal to the requested height and width.
247            inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
248
249            // This offers some additional logic in case the image has a strange
250            // aspect ratio. For example, a panorama may have a much larger
251            // width than height. In these cases the total pixels might still
252            // end up being too large to fit comfortably in memory, so we should
253            // be more aggressive with sample down the image (=larger inSampleSize).
254
255            final float totalPixels = width * height;
256
257            // Anything more than 2x the requested pixels we'll sample down further
258            final float totalReqPixelsCap = reqWidth * reqHeight * 2;
259
260            while (totalPixels / (inSampleSize * inSampleSize) > totalReqPixelsCap) {
261                inSampleSize++;
262            }
263        }
264        return inSampleSize;
265    }
266}
267