This method first examines if the thumbnail embedded in EXIF is bigger than our target size. - Android Graphics

Description

This method first examines if the thumbnail embedded in EXIF is bigger than our target size.

Demo Code

/*//from   w ww . j av a  2  s.  c  o m
 * 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 java.io.FileDescriptor;
import java.io.IOException;
import java.io.OutputStream;
import android.content.ContentResolver;
import android.content.ContentUris;
import android.content.ContentValues;
import android.database.Cursor;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Rect;
import android.net.Uri;
import android.os.ParcelFileDescriptor;
import android.provider.BaseColumns;
import android.provider.MediaStore.Images;
import android.provider.MediaStore.Images.Thumbnails;
import android.util.Log;

public class Main{
    private static final String TAG = "ThumbnailUtil";
    public static final boolean RECYCLE_INPUT = true;
    public static final boolean NO_NATIVE = false;
    public static final int THUMBNAIL_TARGET_SIZE = 320;
    public static final int MINI_THUMB_TARGET_SIZE = 96;
    public static final int THUMBNAIL_MAX_NUM_PIXELS = 512 * 384;
    public static final int MINI_THUMB_MAX_NUM_PIXELS = 128 * 128;
    public static final int UNCONSTRAINED = -1;
    private static final String[] THUMB_PROJECTION = new String[] { BaseColumns._ID // 0
    };
    /**
     * This method first examines if the thumbnail embedded in EXIF is bigger than our target
     * size. If not, then it'll create a thumbnail from original image. Due to efficiency
     * consideration, we want to let MediaThumbRequest avoid calling this method twice for
     * both kinds, so it only requests for MICRO_KIND and set saveImage to true.
     *
     * This method always returns a "square thumbnail" for MICRO_KIND thumbnail.
     *
     * @param cr ContentResolver
     * @param filePath file path needed by EXIF interface
     * @param uri URI of original image
     * @param origId image id
     * @param kind either MINI_KIND or MICRO_KIND
     * @param saveImage Whether to save MINI_KIND thumbnail obtained in this method.
     * @return Bitmap
     */
    public static Bitmap createImageThumbnail(ContentResolver cr,
            String filePath, Uri uri, long origId, int kind,
            boolean saveMini) {
        final boolean wantMini = (kind == Images.Thumbnails.MINI_KIND || saveMini);
        final int targetSize = wantMini ? ThumbnailUtil.THUMBNAIL_TARGET_SIZE
                : ThumbnailUtil.MINI_THUMB_TARGET_SIZE;
        final int maxPixels = wantMini ? ThumbnailUtil.THUMBNAIL_MAX_NUM_PIXELS
                : ThumbnailUtil.MINI_THUMB_MAX_NUM_PIXELS;
        final byte[] thumbData = createThumbnailFromEXIF(filePath,
                targetSize);
        Bitmap bitmap = null;

        if (thumbData != null) {
            final BitmapFactory.Options options = new BitmapFactory.Options();
            options.inSampleSize = computeSampleSize(options, targetSize,
                    maxPixels);
            options.inDither = false;
            options.inPreferredConfig = Bitmap.Config.ARGB_8888;
            options.inJustDecodeBounds = false;
            bitmap = BitmapFactory.decodeByteArray(thumbData, 0,
                    thumbData.length, options);
        }

        if (bitmap == null) {
            bitmap = ThumbnailUtil.makeBitmap(targetSize, maxPixels, uri,
                    cr);
        }

        if (bitmap == null) {
            return null;
        }

        if (saveMini) {
            if (thumbData != null) {
                ThumbnailUtil.storeThumbnail(cr, origId, thumbData,
                        bitmap.getWidth(), bitmap.getHeight());
            } else {
                ThumbnailUtil.storeThumbnail(cr, origId, bitmap);
            }
        }

        if (kind == Images.Thumbnails.MICRO_KIND) {
            // now we make it a "square thumbnail" for MICRO_KIND thumbnail
            bitmap = ThumbnailUtil.extractMiniThumb(bitmap,
                    ThumbnailUtil.MINI_THUMB_TARGET_SIZE,
                    ThumbnailUtil.MINI_THUMB_TARGET_SIZE,
                    ThumbnailUtil.RECYCLE_INPUT);
        }
        return bitmap;
    }
    static byte[] createThumbnailFromEXIF(String filePath, int targetSize) {
        if (filePath == null) {
            return null;
        }

        try {
            final ExifInterface exif = new ExifInterface(filePath);
            if (exif == null) {
                return null;
            }
            final byte[] thumbData = exif.getThumbnail();
            if (thumbData == null) {
                return null;
            }
            // Sniff the size of the EXIF thumbnail before decoding it. Photos
            // from the device will pass, but images that are side loaded from
            // other cameras may not.
            final BitmapFactory.Options options = new BitmapFactory.Options();
            options.inJustDecodeBounds = true;
            BitmapFactory.decodeByteArray(thumbData, 0, thumbData.length,
                    options);

            final int width = options.outWidth;
            final int height = options.outHeight;

            if (width >= targetSize && height >= targetSize) {
                return thumbData;
            }
        } catch (final IOException ex) {
            Log.w(TAG, ex);
        }
        return null;
    }
    public static int computeSampleSize(BitmapFactory.Options options,
            int minSideLength, int maxNumOfPixels) {
        final 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;
    }
    /**
     * Make a bitmap from a given Uri.
     *
     * @param uri
     */
    public static Bitmap makeBitmap(int minSideLength, int maxNumOfPixels,
            Uri uri, ContentResolver cr) {
        return makeBitmap(minSideLength, maxNumOfPixels, uri, cr, NO_NATIVE);
    }
    public static Bitmap makeBitmap(int minSideLength, int maxNumOfPixels,
            Uri uri, ContentResolver cr, boolean useNative) {
        ParcelFileDescriptor input = null;
        try {
            input = cr.openFileDescriptor(uri, "r");
            BitmapFactory.Options options = null;
            if (useNative) {
                options = createNativeAllocOptions();
            }
            return makeBitmap(minSideLength, maxNumOfPixels, uri, cr,
                    input, options);
        } catch (final IOException ex) {
            Log.e(TAG, "", ex);
            return null;
        } finally {
            closeSilently(input);
        }
    }
    public static Bitmap makeBitmap(int minSideLength, int maxNumOfPixels,
            Uri uri, ContentResolver cr, ParcelFileDescriptor pfd,
            BitmapFactory.Options options) {
        Bitmap b = null;
        try {
            if (pfd == null) {
                pfd = makeInputStream(uri, cr);
            }
            if (pfd == null) {
                return null;
            }
            if (options == null) {
                options = new BitmapFactory.Options();
            }

            final FileDescriptor fd = pfd.getFileDescriptor();
            options.inSampleSize = 1;
            options.inJustDecodeBounds = true;
            BitmapFactory.decodeFileDescriptor(fd, null, options);
            if (options.mCancel || options.outWidth == -1
                    || options.outHeight == -1) {
                return null;
            }
            options.inSampleSize = computeSampleSize(options,
                    minSideLength, maxNumOfPixels);
            options.inJustDecodeBounds = false;

            options.inDither = false;
            options.inPreferredConfig = Bitmap.Config.ARGB_8888;
            b = BitmapFactory.decodeFileDescriptor(fd, null, options);
        } catch (final OutOfMemoryError ex) {
            Log.e(TAG, "Got oom exception ", ex);
            return null;
        } finally {
            closeSilently(pfd);
        }
        return b;
    }
    /**
     * Store a given thumbnail in the database. (Bitmap)
     */
    private static boolean storeThumbnail(ContentResolver cr, long origId,
            Bitmap thumb) {
        if (thumb == null) {
            return false;
        }
        try {
            final Uri uri = getImageThumbnailUri(cr, origId,
                    thumb.getWidth(), thumb.getHeight());
            final OutputStream thumbOut = cr.openOutputStream(uri);
            thumb.compress(Bitmap.CompressFormat.JPEG, 85, thumbOut);
            thumbOut.close();
            return true;
        } catch (final Throwable t) {
            Log.e(TAG, "Unable to store thumbnail", t);
            return false;
        }
    }
    /**
     * Store a given thumbnail in the database. (byte array)
     */
    private static boolean storeThumbnail(ContentResolver cr, long origId,
            byte[] jpegThumbnail, int width, int height) {
        if (jpegThumbnail == null) {
            return false;
        }

        final Uri uri = getImageThumbnailUri(cr, origId, width, height);
        if (uri == null) {
            return false;
        }
        try {
            final OutputStream thumbOut = cr.openOutputStream(uri);
            thumbOut.write(jpegThumbnail);
            thumbOut.close();
            return true;
        } catch (final Throwable t) {
            Log.e(TAG, "Unable to store thumbnail", t);
            return false;
        }
    }
    /**
     * Creates a centered bitmap of the desired size.
     * @param source
     * @param recycle whether we want to recycle the input
     */
    public static Bitmap extractMiniThumb(Bitmap source, int width,
            int height, boolean recycle) {
        if (source == null) {
            return null;
        }

        float scale;
        if (source.getWidth() < source.getHeight()) {
            scale = width / (float) source.getWidth();
        } else {
            scale = height / (float) source.getHeight();
        }
        final Matrix matrix = new Matrix();
        matrix.setScale(scale, scale);
        final Bitmap miniThumbnail = transform(matrix, source, width,
                height, true, recycle);
        return miniThumbnail;
    }
    private static int computeInitialSampleSize(
            BitmapFactory.Options options, int minSideLength,
            int maxNumOfPixels) {
        final double w = options.outWidth;
        final double h = options.outHeight;

        final int lowerBound = (maxNumOfPixels == UNCONSTRAINED) ? 1
                : (int) Math.ceil(Math.sqrt(w * h / maxNumOfPixels));
        final int upperBound = (minSideLength == UNCONSTRAINED) ? 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 == UNCONSTRAINED)
                && (minSideLength == UNCONSTRAINED)) {
            return 1;
        } else if (minSideLength == UNCONSTRAINED) {
            return lowerBound;
        } else {
            return upperBound;
        }
    }
    public static BitmapFactory.Options createNativeAllocOptions() {
        final BitmapFactory.Options options = new BitmapFactory.Options();
        //options.inNativeAlloc = true;

        return options;
    }
    private static void closeSilently(ParcelFileDescriptor c) {
        if (c == null) {
            return;
        }
        try {
            c.close();
        } catch (final Throwable t) {
            // do nothing
        }
    }
    private static ParcelFileDescriptor makeInputStream(Uri uri,
            ContentResolver cr) {
        try {
            return cr.openFileDescriptor(uri, "r");
        } catch (final IOException ex) {
            return null;
        }
    }
    /**
     * Look up thumbnail uri by given imageId, it will be automatically created if it's not created
     * yet. Most of the time imageId is identical to thumbId, but it's not always true.
     * @param req
     * @param width
     * @param height
     * @return Uri Thumbnail uri
     */
    private static Uri getImageThumbnailUri(ContentResolver cr,
            long origId, int width, int height) {
        final Uri thumbUri = Images.Thumbnails.EXTERNAL_CONTENT_URI;
        final Cursor c = cr.query(thumbUri, THUMB_PROJECTION,
                Thumbnails.IMAGE_ID + "=?",
                new String[] { String.valueOf(origId) }, null);
        try {
            if (c.moveToNext()) {
                return ContentUris.withAppendedId(thumbUri, c.getLong(0));
            }
        } finally {
            if (c != null) {
                c.close();
            }
        }

        final ContentValues values = new ContentValues(4);
        values.put(Thumbnails.KIND, Thumbnails.MINI_KIND);
        values.put(Thumbnails.IMAGE_ID, origId);
        values.put(Thumbnails.HEIGHT, height);
        values.put(Thumbnails.WIDTH, width);
        try {
            return cr.insert(thumbUri, values);
        } catch (final Exception ex) {
            Log.w(TAG, ex);
            return null;
        }
    }
    public static Bitmap transform(Matrix scaler, Bitmap source,
            int targetWidth, int targetHeight, boolean scaleUp,
            boolean recycle) {

        final int deltaX = source.getWidth() - targetWidth;
        final int deltaY = source.getHeight() - targetHeight;
        if (!scaleUp && (deltaX < 0 || deltaY < 0)) {
            /*
             * In this case the bitmap is smaller, at least in one dimension,
             * than the target.  Transform it by placing as much of the image
             * as possible into the target and leaving the top/bottom or
             * left/right (or both) black.
             */
            final Bitmap b2 = Bitmap.createBitmap(targetWidth,
                    targetHeight, Bitmap.Config.ARGB_8888);
            final Canvas c = new Canvas(b2);

            final int deltaXHalf = Math.max(0, deltaX / 2);
            final int deltaYHalf = Math.max(0, deltaY / 2);
            final Rect src = new Rect(deltaXHalf, deltaYHalf, deltaXHalf
                    + Math.min(targetWidth, source.getWidth()), deltaYHalf
                    + Math.min(targetHeight, source.getHeight()));
            final int dstX = (targetWidth - src.width()) / 2;
            final int dstY = (targetHeight - src.height()) / 2;
            final Rect dst = new Rect(dstX, dstY, targetWidth - dstX,
                    targetHeight - dstY);
            c.drawBitmap(source, src, dst, null);
            if (recycle) {
                source.recycle();
            }
            return b2;
        }
        final float bitmapWidthF = source.getWidth();
        final float bitmapHeightF = source.getHeight();

        final float bitmapAspect = bitmapWidthF / bitmapHeightF;
        final float viewAspect = (float) targetWidth / targetHeight;

        if (bitmapAspect > viewAspect) {
            final float scale = targetHeight / bitmapHeightF;
            if (scale < .9F || scale > 1F) {
                scaler.setScale(scale, scale);
            } else {
                scaler = null;
            }
        } else {
            final float scale = targetWidth / bitmapWidthF;
            if (scale < .9F || scale > 1F) {
                scaler.setScale(scale, scale);
            } else {
                scaler = null;
            }
        }

        Bitmap b1;
        if (scaler != null) {
            // this is used for minithumb and crop, so we want to filter here.
            b1 = Bitmap.createBitmap(source, 0, 0, source.getWidth(),
                    source.getHeight(), scaler, true);
        } else {
            b1 = source;
        }

        if (recycle && b1 != source) {
            source.recycle();
        }

        final int dx1 = Math.max(0, b1.getWidth() - targetWidth);
        final int dy1 = Math.max(0, b1.getHeight() - targetHeight);

        final Bitmap b2 = Bitmap.createBitmap(b1, dx1 / 2, dy1 / 2,
                targetWidth, targetHeight);

        if (b2 != b1) {
            if (recycle || b1 != source) {
                b1.recycle();
            }
        }

        return b2;
    }
}

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