BitmapUtil.java

/*****************************************************************************
 * BitmapUtil.java
 *****************************************************************************
 * Copyright © 2011-2014 VLC authors and VideoLAN
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

package org.videolan.vlc.util;

import android.annotation.TargetApi;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.net.Uri;
import android.os.Build;

import org.videolan.libvlc.util.AndroidUtil;
import org.videolan.vlc.MediaDatabase;
import org.videolan.vlc.MediaWrapper;
import org.videolan.vlc.R;
import org.videolan.vlc.VLCApplication;

public class BitmapUtil {
    public final static String TAG = "VLC/Util/BitmapUtil";

    public static Bitmap cropBorders(Bitmap bitmap, int width, int height)
    {
        int top = 0;
        for (int i = 0; i < height / 2; i++) {
            int pixel1 = bitmap.getPixel(width / 2, i);
            int pixel2 = bitmap.getPixel(width / 2, height - i - 1);
            if ((pixel1 == 0 || pixel1 == -16777216) &&
                (pixel2 == 0 || pixel2 == -16777216)) {
                top = i;
            } else {
                break;
            }
        }

        int left = 0;
        for (int i = 0; i < width / 2; i++) {
            int pixel1 = bitmap.getPixel(i, height / 2);
            int pixel2 = bitmap.getPixel(width - i - 1, height / 2);
            if ((pixel1 == 0 || pixel1 == -16777216) &&
                (pixel2 == 0 || pixel2 == -16777216)) {
                left = i;
            } else {
                break;
            }
        }

        if (left >= width / 2 - 10 || top >= height / 2 - 10)
            return bitmap;

        // Cut off the transparency on the borders
        return Bitmap.createBitmap(bitmap, left, top,
                (width - (2 * left)), (height - (2 * top)));
    }

    public static Bitmap scaleDownBitmap(Context context, Bitmap bitmap, int width) {
        /*
         * This method can lead to OutOfMemoryError!
         * If the source size is more than twice the target size use
         * the optimized version available in AudioUtil::readCoverBitmap
         */
        if (bitmap != null) {
            final float densityMultiplier = context.getResources().getDisplayMetrics().density;
            int w = (int) (width * densityMultiplier);
            int h = (int) (w * bitmap.getHeight() / ((double) bitmap.getWidth()));
            bitmap = Bitmap.createScaledBitmap(bitmap, w, h, true);
        }
        return bitmap;
    }

    public static Bitmap getPictureFromCache(MediaWrapper media) {
        // mPicture is not null only if passed through
        // the ctor which is deprecated by now.
        Bitmap b = media.getPicture();
        if (b == null) {
            final BitmapCache cache = BitmapCache.getInstance();
            return cache.getBitmapFromMemCache(media.getLocation());
        } else {
            return b;
        }
    }

    public static Bitmap fetchPicture(MediaWrapper media) {
        final BitmapCache cache = BitmapCache.getInstance();

        Bitmap picture = readCoverBitmap(media.getArtworkURL());
        if (picture == null) {
            picture = MediaDatabase.getInstance().getPicture(media.getUri());
        }
        cache.addBitmapToMemCache(media.getLocation(), picture);
        return picture;
    }

    public static Bitmap getPicture(MediaWrapper media) {
        final Bitmap picture = getPictureFromCache(media);
        if (picture != null)
            return picture;
        else
            return fetchPicture(media);
    }

    private static Bitmap readCoverBitmap(String path) {
        if (path == null)
            return null;
        Resources res = VLCApplication.getAppResources();
        String uri = Uri.decode(path);
        if (uri.startsWith("file://"))
            uri = uri.substring(7);
        Bitmap cover = null;
        BitmapFactory.Options options = new BitmapFactory.Options();
        int height = res.getDimensionPixelSize(R.dimen.grid_card_thumb_height);
        int width = res.getDimensionPixelSize(R.dimen.grid_card_thumb_width);

        /* Get the resolution of the bitmap without allocating the memory */
        options.inJustDecodeBounds = true;
        BitmapFactory.decodeFile(uri, options);

        if (options.outWidth > 0 && options.outHeight > 0) {
            if (options.outWidth > width){
                options.outWidth = width;
                options.outHeight = height;
            }
            options.inJustDecodeBounds = false;

            // Decode the file (with memory allocation this time)
            try {
                cover = BitmapFactory.decodeFile(uri, options);
            } catch (OutOfMemoryError e) {
                cover = null;
            }
        }

        return cover;
    }

    @TargetApi(Build.VERSION_CODES.KITKAT)
    static boolean canUseForInBitmap(
            Bitmap candidate, BitmapFactory.Options targetOptions) {

        if (candidate == null)
            return false;

        if (AndroidUtil.isKitKatOrLater()) {
            if (targetOptions.inSampleSize == 0)
                return false;
            // From Android 4.4 (KitKat) onward we can re-use if the byte size of
            // the new bitmap is smaller than the reusable bitmap candidate
            // allocation byte count.
            int width = targetOptions.outWidth / targetOptions.inSampleSize;
            int height = targetOptions.outHeight /  targetOptions.inSampleSize;
            int byteCount = width * height * getBytesPerPixel(candidate.getConfig());
            return byteCount <= candidate.getAllocationByteCount();
        }

        // On earlier versions, the dimensions must match exactly and the inSampleSize must be 1
        return candidate.getWidth() == targetOptions.outWidth
                && candidate.getHeight() == targetOptions.outHeight
                && targetOptions.inSampleSize == 1;
    }

    /**
     * A helper function to return the byte usage per pixel of a bitmap based on its configuration.
     */
    static int getBytesPerPixel(Bitmap.Config config) {
        if (config == Bitmap.Config.ARGB_8888) {
            return 4;
        } else if (config == Bitmap.Config.RGB_565) {
            return 2;
        } else if (config == Bitmap.Config.ARGB_4444) {
            return 2;
        } else if (config == Bitmap.Config.ALPHA_8) {
            return 1;
        }
        return 1;
    }

    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
    public static void setInBitmap(BitmapFactory.Options options){
        if (!AndroidUtil.isHoneycombOrLater())
            return;
        Bitmap inBitmap = BitmapCache.getInstance().getReusableBitmap(options);
        if (inBitmap != null) {
            options.inBitmap = inBitmap;
        }
    }
}