Java tutorial
//package com.java2s; /* * Copyright (C) 2009 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.util.Log; public class Main { private static final String TAG = "Util"; public static Bitmap makeBitmap(byte[] jpegData, int maxNumOfPixels) { try { BitmapFactory.Options options = new BitmapFactory.Options(); options.inJustDecodeBounds = true; BitmapFactory.decodeByteArray(jpegData, 0, jpegData.length, options); if (options.mCancel || options.outWidth == -1 || options.outHeight == -1) { return null; } options.inSampleSize = computeSampleSize(options, -1, maxNumOfPixels); options.inJustDecodeBounds = false; options.inDither = false; options.inPreferredConfig = Bitmap.Config.ARGB_8888; return BitmapFactory.decodeByteArray(jpegData, 0, jpegData.length, options); } catch (OutOfMemoryError ex) { Log.e(TAG, "Got oom exception ", ex); return null; } } public static int computeSampleSize(BitmapFactory.Options options, int minSideLength, int maxNumOfPixels) { int initialSize = computeInitialSampleSize(options, minSideLength, maxNumOfPixels); int roundedSize; if (initialSize <= 8) { roundedSize = 1; while (roundedSize < initialSize) { roundedSize <<= 1; } } else { roundedSize = (initialSize + 7) / 8 * 8; } return roundedSize; } private static int computeInitialSampleSize(BitmapFactory.Options options, int minSideLength, int maxNumOfPixels) { double w = options.outWidth; double h = options.outHeight; int lowerBound = (maxNumOfPixels < 0) ? 1 : (int) Math.ceil(Math.sqrt(w * h / maxNumOfPixels)); int upperBound = (minSideLength < 0) ? 128 : (int) Math.min(Math.floor(w / minSideLength), Math.floor(h / minSideLength)); if (upperBound < lowerBound) { // return the larger one when there is no overlapping zone. return lowerBound; } if (maxNumOfPixels < 0 && minSideLength < 0) { return 1; } else if (minSideLength < 0) { return lowerBound; } else { return upperBound; } } }