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.android.contacts.common.util;
18 
19 import android.graphics.Bitmap;
20 import android.graphics.BitmapFactory;
21 import android.graphics.Canvas;
22 import android.graphics.Paint;
23 import android.graphics.PorterDuff.Mode;
24 import android.graphics.PorterDuffXfermode;
25 import android.graphics.Rect;
26 import android.graphics.RectF;
27 import android.graphics.drawable.Drawable;
28 import android.graphics.drawable.BitmapDrawable;
29 
30 /**
31  * Provides static functions to decode bitmaps at the optimal size
32  */
33 public class BitmapUtil {
BitmapUtil()34     private BitmapUtil() {}
35 
36     /**
37      * Returns Width or Height of the picture, depending on which size is smaller. Doesn't actually
38      * decode the picture, so it is pretty efficient to run.
39      */
getSmallerExtentFromBytes(byte[] bytes)40     public static int getSmallerExtentFromBytes(byte[] bytes) {
41         final BitmapFactory.Options options = new BitmapFactory.Options();
42 
43         // don't actually decode the picture, just return its bounds
44         options.inJustDecodeBounds = true;
45         BitmapFactory.decodeByteArray(bytes, 0, bytes.length, options);
46 
47         // test what the best sample size is
48         return Math.min(options.outWidth, options.outHeight);
49     }
50 
51     /**
52      * Finds the optimal sampleSize for loading the picture
53      * @param originalSmallerExtent Width or height of the picture, whichever is smaller
54      * @param targetExtent Width or height of the target view, whichever is bigger.
55      *
56      * If either one of the parameters is 0 or smaller, no sampling is applied
57      */
findOptimalSampleSize(int originalSmallerExtent, int targetExtent)58     public static int findOptimalSampleSize(int originalSmallerExtent, int targetExtent) {
59         // If we don't know sizes, we can't do sampling.
60         if (targetExtent < 1) return 1;
61         if (originalSmallerExtent < 1) return 1;
62 
63         // Test what the best sample size is. To do that, we find the sample size that gives us
64         // the best trade-off between resulting image size and memory requirement. We allow
65         // the down-sampled image to be 20% smaller than the target size. That way we can get around
66         // unfortunate cases where e.g. a 720 picture is requested for 362 and not down-sampled at
67         // all. Why 20%? Why not. Prove me wrong.
68         int extent = originalSmallerExtent;
69         int sampleSize = 1;
70         while ((extent >> 1) >= targetExtent * 0.8f) {
71             sampleSize <<= 1;
72             extent >>= 1;
73         }
74 
75         return sampleSize;
76     }
77 
78     /**
79      * Decodes the bitmap with the given sample size
80      */
decodeBitmapFromBytes(byte[] bytes, int sampleSize)81     public static Bitmap decodeBitmapFromBytes(byte[] bytes, int sampleSize) {
82         final BitmapFactory.Options options;
83         if (sampleSize <= 1) {
84             options = null;
85         } else {
86             options = new BitmapFactory.Options();
87             options.inSampleSize = sampleSize;
88         }
89         return BitmapFactory.decodeByteArray(bytes, 0, bytes.length, options);
90     }
91 
92     /**
93      * Retrieves a copy of the specified drawable resource, rotated by a specified angle.
94      *
95      * @param resources The current resources.
96      * @param resourceId The resource ID of the drawable to rotate.
97      * @param angle The angle of rotation.
98      * @return Rotated drawable.
99      */
getRotatedDrawable( android.content.res.Resources resources, int resourceId, float angle)100     public static Drawable getRotatedDrawable(
101             android.content.res.Resources resources, int resourceId, float angle) {
102 
103         // Get the original drawable and make a copy which will be rotated.
104         Bitmap original = BitmapFactory.decodeResource(resources, resourceId);
105         Bitmap rotated = Bitmap.createBitmap(
106                 original.getWidth(), original.getHeight(), Bitmap.Config.ARGB_8888);
107 
108         // Perform the rotation.
109         Canvas tempCanvas = new Canvas(rotated);
110         tempCanvas.rotate(angle, original.getWidth()/2, original.getHeight()/2);
111         tempCanvas.drawBitmap(original, 0, 0, null);
112 
113         return new BitmapDrawable(resources,rotated);
114     }
115 
116     /**
117      * Given an input bitmap, scales it to the given width/height and makes it round.
118      *
119      * @param input {@link Bitmap} to scale and crop
120      * @param targetWidth desired output width
121      * @param targetHeight desired output height
122      * @return output bitmap scaled to the target width/height and cropped to an oval. The
123      *         cropping algorithm will try to fit as much of the input into the output as possible,
124      *         while preserving the target width/height ratio.
125      */
getRoundedBitmap(Bitmap input, int targetWidth, int targetHeight)126     public static Bitmap getRoundedBitmap(Bitmap input, int targetWidth, int targetHeight) {
127         if (input == null) {
128             return null;
129         }
130         final Bitmap result = Bitmap.createBitmap(targetWidth, targetHeight, input.getConfig());
131         final Canvas canvas = new Canvas(result);
132         final Paint paint = new Paint();
133         canvas.drawARGB(0, 0, 0, 0);
134         paint.setAntiAlias(true);
135         canvas.drawOval(0, 0, targetWidth, targetHeight, paint);
136 
137         // Specifies that only pixels present in the destination (i.e. the drawn oval) should
138         // be overwritten with pixels from the input bitmap.
139         paint.setXfermode(new PorterDuffXfermode(Mode.SRC_IN));
140 
141         final int inputWidth = input.getWidth();
142         final int inputHeight = input.getHeight();
143 
144         // Choose the largest scale factor that will fit inside the dimensions of the
145         // input bitmap.
146         final float scaleBy = Math.min((float) inputWidth / targetWidth,
147             (float) inputHeight / targetHeight);
148 
149         final int xCropAmountHalved = (int) (scaleBy * targetWidth / 2);
150         final int yCropAmountHalved = (int) (scaleBy * targetHeight / 2);
151 
152         final Rect src = new Rect(
153                 inputWidth / 2 - xCropAmountHalved,
154                 inputHeight / 2 - yCropAmountHalved,
155                 inputWidth / 2 + xCropAmountHalved,
156                 inputHeight / 2 + yCropAmountHalved);
157 
158         final RectF dst = new RectF(0, 0, targetWidth, targetHeight);
159         canvas.drawBitmap(input, src, dst, paint);
160         return result;
161     }
162 }
163