create Image Thumbnail - Android Graphics

Android examples for Graphics:Bitmap Thumbnail

  1. HOME
  2. Android
  3. Graphics
  4. Bitmap Thumbnail

Description

create Image Thumbnail

Demo Code


//package com.java2s;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;

public class Main {
    public static Bitmap createImageThumbnail(Resources res, int id) {
        Bitmap bitmap = null;//from ww w.  j  a  v  a 2  s .  co  m
        BitmapFactory.Options opts = new BitmapFactory.Options();
        opts.inJustDecodeBounds = true;
        BitmapFactory.decodeResource(res, id, opts);
        opts.inSampleSize = computeSampleSize(opts, -1, 128 * 128);
        opts.inJustDecodeBounds = false;

        try {
            bitmap = BitmapFactory.decodeResource(res, id, opts);
        } catch (Exception e) {
            // TODO: handle exception
        }
        return bitmap;
    }

    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;
    }

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

Related Tutorials