+/* ownCloud Android client application
+ * Copyright (C) 2012-2014 ownCloud Inc.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+package com.owncloud.android.utils;
+
+import android.graphics.Bitmap;
+import android.graphics.BitmapFactory;
+import android.graphics.BitmapFactory.Options;
+
+/**
+ * Utility class with methods for decoding Bitmaps.
+ *
+ * @author David A. Velasco
+ */
+public class BitmapUtils {
+
+
+ /**
+ * Decodes a bitmap from a file containing it minimizing the memory use, known that the bitmap
+ * will be drawn in a surface of reqWidth x reqHeight
+ *
+ * @param srcPath Absolute path to the file containing the image.
+ * @param reqWidth Width of the surface where the Bitmap will be drawn on, in pixels.
+ * @param reqHeight Height of the surface where the Bitmap will be drawn on, in pixels.
+ * @return
+ */
+ public static Bitmap decodeSampledBitmapFromFile(String srcPath, int reqWidth, int reqHeight) {
+
+ // set desired options that will affect the size of the bitmap
+ final Options options = new Options();
+ options.inScaled = true;
+ options.inPurgeable = true;
+ if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.GINGERBREAD_MR1) {
+ options.inPreferQualityOverSpeed = false;
+ }
+ if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.HONEYCOMB) {
+ options.inMutable = false;
+ }
+
+ // make a false load of the bitmap to get its dimensions
+ options.inJustDecodeBounds = true;
+
+ BitmapFactory.decodeFile(srcPath, options);
+
+ // calculate factor to subsample the bitmap
+ options.inSampleSize = calculateSampleFactor(options, reqWidth, reqHeight);
+
+ // decode bitmap with inSampleSize set
+ options.inJustDecodeBounds = false;
+ return BitmapFactory.decodeFile(srcPath, options);
+
+ }
+
+
+ /**
+ * Calculates a proper value for options.inSampleSize in order to decode a Bitmap minimizing
+ * the memory overload and covering a target surface of reqWidth x reqHeight if the original
+ * image is big enough.
+ *
+ * @param options Bitmap decoding options; options.outHeight and options.inHeight should
+ * be set.
+ * @param reqWidth Width of the surface where the Bitmap will be drawn on, in pixels.
+ * @param reqHeight Height of the surface where the Bitmap will be drawn on, in pixels.
+ * @return The largest inSampleSize value that is a power of 2 and keeps both
+ * height and width larger than reqWidth and reqHeight.
+ */
+ private static int calculateSampleFactor(Options options, int reqWidth, int reqHeight) {
+
+ final int height = options.outHeight;
+ final int width = options.outWidth;
+ int inSampleSize = 1;
+
+ if (height > reqHeight || width > reqWidth) {
+ final int halfHeight = height / 2;
+ final int halfWidth = width / 2;
+
+ while ((halfHeight / inSampleSize) > reqHeight
+ && (halfWidth / inSampleSize) > reqWidth) {
+ inSampleSize *= 2;
+ }
+ }
+
+ return inSampleSize;
+ }
+
+}
projects / pub / Android / ownCloud.git / commitdiff