Main.java Source code

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Here is the source code for Main.java

Source

//package com.java2s;
/*
 * Jitsi, the OpenSource Java VoIP and Instant Messaging client.
 *
 * Copyright @ 2015 Atlassian Pty Ltd
 *
 * 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.content.*;

import android.graphics.*;

import android.net.*;
import java.io.*;

public class Main {
    /**
     * Reads <tt>Bitmap</tt> from given <tt>uri</tt> using
     * <tt>ContentResolver</tt>. Output image is scaled to given
     * <tt>reqWidth</tt> and <tt>reqHeight</tt>. Output size is not guaranteed
     * to match exact given values, because only powers of 2 are used as scale
     * factor. Algorithm tries to scale image down as long as the output size
     * stays larger than requested value.
     *
     * @param ctx the context used to create <tt>ContentResolver</tt>.
     * @param uri the <tt>Uri</tt> that points to the image.
     * @param reqWidth requested width.
     * @param reqHeight requested height.
     * @return <tt>Bitmap</tt> from given <tt>uri</tt> retrieved using
     * <tt>ContentResolver</tt> and down sampled as close as possible to match
     * requested width and height.
     * @throws IOException
     */
    public static Bitmap scaledBitmapFromContentUri(Context ctx, Uri uri, int reqWidth, int reqHeight)
            throws IOException {
        InputStream imageStream = null;
        try {
            // First decode with inJustDecodeBounds=true to check dimensions
            imageStream = ctx.getContentResolver().openInputStream(uri);
            if (imageStream == null)
                return null;

            final BitmapFactory.Options options = new BitmapFactory.Options();
            options.inJustDecodeBounds = true;
            BitmapFactory.decodeStream(imageStream, null, options);
            imageStream.close();

            // Calculate inSampleSize
            options.inSampleSize = calculateInSampleSize(options, reqWidth, reqHeight);

            // Decode bitmap with inSampleSize set
            options.inJustDecodeBounds = false;
            imageStream = ctx.getContentResolver().openInputStream(uri);

            return BitmapFactory.decodeStream(imageStream, null, options);
        } finally {
            if (imageStream != null) {
                imageStream.close();
            }
        }
    }

    /**
     * Calculates <tt>options.inSampleSize</tt> for requested width and height.
     * @param options the <tt>Options</tt> object that contains image
     *                <tt>outWidth</tt> and <tt>outHeight</tt>.
     * @param reqWidth requested width.
     * @param reqHeight requested height.
     * @return <tt>options.inSampleSize</tt> for requested width and height.
     */
    public static int calculateInSampleSize(BitmapFactory.Options options, int reqWidth, int reqHeight) {
        // Raw height and width of image
        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;

            // Calculate the largest inSampleSize value that is a power of 2
            // and keeps both height and width larger than the requested height
            // and width.
            while ((halfHeight / inSampleSize) > reqHeight && (halfWidth / inSampleSize) > reqWidth) {
                inSampleSize *= 2;
            }
        }

        return inSampleSize;
    }
}