Android Bitmap Create makeBitmap(int minSideLength, int maxNumOfPixels, Uri uri, ContentResolver cr, ParcelFileDescriptor pfd, BitmapFactory.Options options)

Description

Make a bitmap from a given Uri, minimal side length, and maximum number of pixels.

Declaration

private static Bitmap makeBitmap(int minSideLength, int maxNumOfPixels,
        Uri uri, ContentResolver cr, ParcelFileDescriptor pfd,
        BitmapFactory.Options options) 

Method Source Code

//package com.java2s;
import java.io.FileDescriptor;
import java.io.IOException;
import android.content.ContentResolver;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;

import android.net.Uri;
import android.os.ParcelFileDescriptor;

import android.util.Log;

public class Main {
    private static final String TAG = "ThumbnailUtils";
    private static final int UNCONSTRAINED = -1;

    /**/*from   w  w w  .  j a  v  a2 s .c o m*/
     * Make a bitmap from a given Uri, minimal side length, and maximum number
     * of pixels. The image data will be read from specified pfd if it's not
     * null, otherwise a new input stream will be created using specified
     * ContentResolver.
     * 
     * Clients are allowed to pass their own BitmapFactory.Options used for
     * bitmap decoding. A new BitmapFactory.Options will be created if options
     * is null.
     */
    private 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;
    }

    private static ParcelFileDescriptor makeInputStream(Uri uri,
            ContentResolver cr) {
        try {
            return cr.openFileDescriptor(uri, "r");
        } catch (IOException ex) {
            return null;
        }
    }

    private 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;
    }

    private static void closeSilently(ParcelFileDescriptor c) {
        if (c == null)
            return;
        try {
            c.close();
        } catch (Throwable t) {
            // do nothing
        }
    }

    private static int computeInitialSampleSize(
            BitmapFactory.Options options, int minSideLength,
            int maxNumOfPixels) {
        double w = options.outWidth;
        double h = options.outHeight;
        int lowerBound = (maxNumOfPixels == UNCONSTRAINED) ? 1 : (int) Math
                .ceil(Math.sqrt(w * h / maxNumOfPixels));
        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;
        }
    }
}

Related

1. getBitmap(int resId, Context ctx)
2. getBitmapFromImageView(ImageView theImage)
3. getBitmapFromResource(Resources resources, int resourceId, int reqWidth, int reqHeight)
4. getBitmapFromURI(Context context, Uri uri)
5. getBackground(int bgcolor)
6. generateBitmap(int width, int height)