src/com/owncloud/android/utils/BitmapUtils.java

   1 /* ownCloud Android client application
   2  *   Copyright (C) 2012-2014 ownCloud Inc.
   3  *
   4  *   This program is free software: you can redistribute it and/or modify
   5  *   it under the terms of the GNU General Public License version 2,
   6  *   as published by the Free Software Foundation.
   7  *
   8  *   This program is distributed in the hope that it will be useful,
   9  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  *   GNU General Public License for more details.
  12  *
  13  *   You should have received a copy of the GNU General Public License
  14  *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  *
  16  */
  17 package com.owncloud.android.utils;
  18
  19 import com.owncloud.android.lib.common.utils.Log_OC;
  20
  21 import android.graphics.Bitmap;
  22 import android.graphics.BitmapFactory;
  23 import android.graphics.Matrix;
  24 import android.graphics.BitmapFactory.Options;
  25 import android.media.ExifInterface;
  26 import android.net.Uri;
  27 import android.webkit.MimeTypeMap;
  28
  29 import java.io.File;
  30
  31 /**
  32  * Utility class with methods for decoding Bitmaps.
  33  *
  34  * @author David A. Velasco
  35  */
  36 public class BitmapUtils {
  37
  38
  39     /**
  40      * Decodes a bitmap from a file containing it minimizing the memory use, known that the bitmap
  41      * will be drawn in a surface of reqWidth x reqHeight
  42      *
  43      * @param srcPath       Absolute path to the file containing the image.
  44      * @param reqWidth      Width of the surface where the Bitmap will be drawn on, in pixels.
  45      * @param reqHeight     Height of the surface where the Bitmap will be drawn on, in pixels.
  46      * @return
  47      */
  48     public static Bitmap decodeSampledBitmapFromFile(String srcPath, int reqWidth, int reqHeight) {
  49
  50         // set desired options that will affect the size of the bitmap
  51         final Options options = new Options();
  52         options.inScaled = true;
  53         options.inPurgeable = true;
  54         if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.GINGERBREAD_MR1) {
  55             options.inPreferQualityOverSpeed = false;
  56         }
  57         if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.HONEYCOMB) {
  58             options.inMutable = false;
  59         }
  60
  61         // make a false load of the bitmap to get its dimensions
  62         options.inJustDecodeBounds = true;
  63
  64         BitmapFactory.decodeFile(srcPath, options);
  65
  66         // calculate factor to subsample the bitmap
  67         options.inSampleSize = calculateSampleFactor(options, reqWidth, reqHeight);
  68
  69         // decode bitmap with inSampleSize set
  70         options.inJustDecodeBounds = false;
  71         return BitmapFactory.decodeFile(srcPath, options);
  72
  73     }
  74
  75
  76     /**
  77      * Calculates a proper value for options.inSampleSize in order to decode a Bitmap minimizing
  78      * the memory overload and covering a target surface of reqWidth x reqHeight if the original
  79      * image is big enough.
  80      *
  81      * @param options       Bitmap decoding options; options.outHeight and options.inHeight should
  82      *                      be set.
  83      * @param reqWidth      Width of the surface where the Bitmap will be drawn on, in pixels.
  84      * @param reqHeight     Height of the surface where the Bitmap will be drawn on, in pixels.
  85      * @return              The largest inSampleSize value that is a power of 2 and keeps both
  86      *                      height and width larger than reqWidth and reqHeight.
  87      */
  88     private static int calculateSampleFactor(Options options, int reqWidth, int reqHeight) {
  89
  90         final int height = options.outHeight;
  91         final int width = options.outWidth;
  92         int inSampleSize = 1;
  93
  94         if (height > reqHeight || width > reqWidth) {
  95             final int halfHeight = height / 2;
  96             final int halfWidth = width / 2;
  97
  98             while ((halfHeight / inSampleSize) > reqHeight
  99                     && (halfWidth / inSampleSize) > reqWidth) {
 100                 inSampleSize *= 2;
 101             }
 102         }
 103
 104         return inSampleSize;
 105     }
 106
 107     /**
 108      * Rotate bitmap according to EXIF orientation.
 109      * Cf. http://www.daveperrett.com/articles/2012/07/28/exif-orientation-handling-is-a-ghetto/
 110      * @param bitmap Bitmap to be rotated
 111      * @param storagePath Path to source file of bitmap. Needed for EXIF information.
 112      * @return correctly EXIF-rotated bitmap
 113      */
 114     public static Bitmap rotateImage(Bitmap bitmap, String storagePath){
 115         Bitmap resultBitmap = bitmap;
 116
 117         try
 118         {
 119             ExifInterface exifInterface = new ExifInterface(storagePath);
 120             int orientation = exifInterface.getAttributeInt(ExifInterface.TAG_ORIENTATION, 1);
 121
 122             Matrix matrix = new Matrix();
 123
 124             // 1: nothing to do
 125
 126             // 2
 127             if (orientation == ExifInterface.ORIENTATION_FLIP_HORIZONTAL)
 128             {
 129                 matrix.postScale(-1.0f, 1.0f);
 130             }
 131             // 3
 132             else if (orientation == ExifInterface.ORIENTATION_ROTATE_180)
 133             {
 134                 matrix.postRotate(180);
 135             }
 136             // 4
 137             else if (orientation == ExifInterface.ORIENTATION_FLIP_VERTICAL)
 138             {
 139                 matrix.postScale(1.0f, -1.0f);
 140             }
 141             // 5
 142             else if (orientation == ExifInterface.ORIENTATION_TRANSPOSE)
 143             {
 144                 matrix.postRotate(-90);
 145                 matrix.postScale(1.0f, -1.0f);
 146             }
 147             // 6
 148             else if (orientation == ExifInterface.ORIENTATION_ROTATE_90)
 149             {
 150                 matrix.postRotate(90);
 151             }
 152             // 7
 153             else if (orientation == ExifInterface.ORIENTATION_TRANSVERSE)
 154             {
 155                 matrix.postRotate(90);
 156                 matrix.postScale(1.0f, -1.0f);
 157             }
 158             // 8
 159             else if (orientation == ExifInterface.ORIENTATION_ROTATE_270)
 160             {
 161                 matrix.postRotate(270);
 162             }
 163
 164             // Rotate the bitmap
 165             resultBitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
 166             if (resultBitmap != bitmap) {
 167                 bitmap.recycle();
 168             }
 169         }
 170         catch (Exception exception)
 171         {
 172             Log_OC.e("BitmapUtil", "Could not rotate the image: " + storagePath);
 173         }
 174         return resultBitmap;
 175     }
 176
 177     /**
 178      * Checks if file passed is an image
 179      * @param file
 180      * @return true/false
 181      */
 182     public static boolean isImage(File file) {
 183         Uri selectedUri = Uri.fromFile(file);
 184         String fileExtension = MimeTypeMap.getFileExtensionFromUrl(selectedUri.toString().toLowerCase());
 185         String mimeType = MimeTypeMap.getSingleton().getMimeTypeFromExtension(fileExtension);
 186
 187         return (mimeType != null && mimeType.startsWith("image/"));
 188     }
 189
 190 }