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MediaBrowserService / src / com.example.android.mediabrowserservice / utils /

BitmapHelper.java

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/*
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 * Copyright (C) 2014 The Android Open Source Project
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 *
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 * Licensed under the Apache License, Version 2.0 (the "License");
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 * you may not use this file except in compliance with the License.
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 * You may obtain a copy of the License at
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 *
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 *      http://www.apache.org/licenses/LICENSE-2.0
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 *
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 * Unless required by applicable law or agreed to in writing, software
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 * distributed under the License is distributed on an "AS IS" BASIS,
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 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 * See the License for the specific language governing permissions and
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 * limitations under the License.
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 */
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package com.example.android.mediabrowserservice.utils;
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import android.graphics.Bitmap;
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import android.graphics.BitmapFactory;
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import java.io.BufferedInputStream;
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import java.io.IOException;
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import java.io.InputStream;
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import java.net.HttpURLConnection;
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import java.net.URL;
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public class BitmapHelper {
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    private static final String TAG = LogHelper.makeLogTag(BitmapHelper.class);
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    // Max read limit that we allow our input stream to mark/reset.
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    private static final int MAX_READ_LIMIT_PER_IMG = 1024 * 1024;
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    public static Bitmap scaleBitmap(Bitmap src, int maxWidth, int maxHeight) {
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       double scaleFactor = Math.min(
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           ((double) maxWidth)/src.getWidth(), ((double) maxHeight)/src.getHeight());
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        return Bitmap.createScaledBitmap(src,
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            (int) (src.getWidth() * scaleFactor), (int) (src.getHeight() * scaleFactor), false);
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    }
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    public static Bitmap scaleBitmap(int scaleFactor, InputStream is) {
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        // Get the dimensions of the bitmap
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        BitmapFactory.Options bmOptions = new BitmapFactory.Options();
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        // Decode the image file into a Bitmap sized to fill the View
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        bmOptions.inJustDecodeBounds = false;
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        bmOptions.inSampleSize = scaleFactor;
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        return BitmapFactory.decodeStream(is, null, bmOptions);
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    }
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    public static int findScaleFactor(int targetW, int targetH, InputStream is) {
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        // Get the dimensions of the bitmap
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        BitmapFactory.Options bmOptions = new BitmapFactory.Options();
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        bmOptions.inJustDecodeBounds = true;
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        BitmapFactory.decodeStream(is, null, bmOptions);
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        int actualW = bmOptions.outWidth;
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        int actualH = bmOptions.outHeight;
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        // Determine how much to scale down the image
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        return Math.min(actualW/targetW, actualH/targetH);
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    }
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    @SuppressWarnings("SameParameterValue")
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    public static Bitmap fetchAndRescaleBitmap(String uri, int width, int height)
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            throws IOException {
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        URL url = new URL(uri);
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        BufferedInputStream is = null;
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        try {
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            HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
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            is = new BufferedInputStream(urlConnection.getInputStream());
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            is.mark(MAX_READ_LIMIT_PER_IMG);
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            int scaleFactor = findScaleFactor(width, height, is);
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            LogHelper.d(TAG, "Scaling bitmap ", uri, " by factor ", scaleFactor, " to support ",
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                    width, "x", height, "requested dimension");
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            is.reset();
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            return scaleBitmap(scaleFactor, is);
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        } finally {
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            if (is != null) {
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                is.close();
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            }
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        }
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    }
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}
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