create And Store Image Thumbnail - Android Graphics

Description

create And Store Image Thumbnail

Demo Code

/*/* w  w w. j  ava2s  .  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.File;
import java.io.FileDescriptor;
import java.io.IOException;
import java.io.OutputStream;
import java.text.SimpleDateFormat;
import android.content.ContentResolver;
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.Environment;
import android.os.ParcelFileDescriptor;
import android.util.Log;

public class Main{
    private static final String TAG = "ThumbnailUtil";
    public static final File PICTURES_THUMB_DIR = new File(
            Environment.getExternalStorageDirectory(),
            "financisto/pictures/thumb");
    public static final boolean RECYCLE_INPUT = true;
    public static final boolean NO_NATIVE = false;
    public static final int MINI_THUMB_TARGET_SIZE = 96;
    public static final int MICRO_THUMB_TARGET_SIZE = 64;
    public static final int MINI_THUMB_MAX_NUM_PIXELS = 128 * 128;
    public static Bitmap createAndStoreImageThumbnail(ContentResolver cr,
            File originalImage) {
        File thumbFile = new File(PICTURES_THUMB_DIR,
                originalImage.getName());
        if (thumbFile.exists()) {
            return loadThumbnail(thumbFile);
        } else {
            Bitmap thumb = createImageThumbnail(cr, originalImage);
            saveThumbnail(cr, thumbFile, thumb);
            return thumb;
        }
    }
    public static Bitmap loadThumbnail(String originalImage) {
        if (originalImage == null) {
            return null;
        }
        File thumbFile = new File(PICTURES_THUMB_DIR, originalImage);
        if (thumbFile.exists()) {
            return loadThumbnail(thumbFile);
        }
        return null;
    }
    private static Bitmap loadThumbnail(File thumbFile) {
        return BitmapFactory.decodeFile(thumbFile.getAbsolutePath());
    }
    /**
     * This method always returns a "square thumbnail" for MICRO_KIND thumbnail.
     *
     * @param cr ContentResolver
     * @param file original image
     * @return Bitmap
     */
    public static Bitmap createImageThumbnail(ContentResolver cr,
            File originalFile) {
        int targetSize = ThumbnailUtil.MINI_THUMB_TARGET_SIZE;
        int maxPixels = ThumbnailUtil.MINI_THUMB_MAX_NUM_PIXELS;

        Uri uri = Uri.fromFile(originalFile);
        Bitmap bitmap = ThumbnailUtil.makeBitmap(targetSize, maxPixels,
                uri, cr);

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

        // now we make it a "square thumbnail" for MICRO_KIND thumbnail
        bitmap = ThumbnailUtil.extractMiniThumb(bitmap,
                ThumbnailUtil.MICRO_THUMB_TARGET_SIZE,
                ThumbnailUtil.MICRO_THUMB_TARGET_SIZE,
                ThumbnailUtil.RECYCLE_INPUT);
        return bitmap;
    }
    private static boolean saveThumbnail(ContentResolver cr,
            File thumbFile, Bitmap thumb) {
        if (thumb == null)
            return false;
        try {
            Uri uri = Uri.fromFile(thumbFile);
            OutputStream thumbOut = cr.openOutputStream(uri);
            thumb.compress(Bitmap.CompressFormat.JPEG, 85, thumbOut);
            thumbOut.close();
            return true;
        } catch (Throwable t) {
            Log.e(TAG, "Unable to store thumbnail", t);
            return false;
        }
    }
    /**
     * 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 (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();

            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 (OutOfMemoryError ex) {
            Log.e(TAG, "Got oom exception ", ex);
            return null;
        } finally {
            closeSilently(pfd);
        }
        return b;
    }
    /**
     * 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();
        }
        Matrix matrix = new Matrix();
        matrix.setScale(scale, scale);
        Bitmap miniThumbnail = transform(matrix, source, width, height,
                true, recycle);
        return miniThumbnail;
    }
    public static BitmapFactory.Options createNativeAllocOptions() {
        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 (Throwable t) {
            // do nothing
        }
    }
    private static ParcelFileDescriptor makeInputStream(Uri uri,
            ContentResolver cr) {
        try {
            return cr.openFileDescriptor(uri, "r");
        } catch (IOException 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;
    }
    public static Bitmap transform(Matrix scaler, Bitmap source,
            int targetWidth, int targetHeight, boolean scaleUp,
            boolean recycle) {

        int deltaX = source.getWidth() - targetWidth;
        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.
             */
            Bitmap b2 = Bitmap.createBitmap(targetWidth, targetHeight,
                    Bitmap.Config.ARGB_8888);
            Canvas c = new Canvas(b2);

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

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

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

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

        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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