Question

I am getting an image via URL from the Internet and trying to resize (to a smaller size) before saving it. I managed to save it, but I’m unable to resize it. How could I do that? Here is the code:

URL url = new URL(LogoURL);

InputStream input = url.openStream();
try {
    OutputStream output = new FileOutputStream("data/data/com.android.mylogo/logo.jpg");
    try {
        //byte[] buffer = new byte[aReasonableSize];     
        int bytesRead = 0;
        System.out.println("Buffer Length is \t:-" + buffer.length);
        while ((bytesRead = input.read(buffer, 0, buffer.length)) >= 0) {
            System.out.println("inside while");
            output.write(buffer, 0, bytesRead);
        }
    } finally {
        output.close();
        System.out.println("saved image");
    }
} finally {
    input.close();
}

Answer 1

If you want to downscale the image to particular dimensions, you can use the following code:

HttpClient client = new DefaultHttpClient();
HttpGet request = new HttpGet(LogoURL);

try {
    HttpResponse response = client.execute(request);
    final int statusCode = response.getStatusLine().getStatusCode();
    if (statusCode != HttpStatus.SC_OK) {
        Log.w(LOG_TAG, "Error " + statusCode + " while retrieving bitmap from " + url);
        return null;
    }

    HttpEntity entity = response.getEntity();
    if (entity != null) {

        InputStream is = null;
        BufferedInputStream bis = null;
        try {
            is = url.openStream();
            bis = new BufferedInputStream(is);

            int sampleSize = 1;

            bis.mark(Integer.MAX_VALUE);

            Options bounds = new Options();
            bounds.inJustDecodeBounds = true;
            BitmapFactory.decodeStream(bis, null, bounds);
            if (bounds.outWidth != -1) {
                int width = bounds.outWidth;
                int height = bounds.outHeight;
                boolean withinBounds = width <= YOUR_DESIRED_WIDTH && height <= YOUR_DESIRED_HEIGHT;

                int newWidth = width;
                int newHeight = height;
                while (!withinBounds) {
                    newWidth /= 2;
                    newHeight /= 2;
                    sampleSize *= 2;
                    withinBounds = newWidth <= YOUR_DESIRED_WIDTH && newHeight <= YOUR_DESIRED_HEIGHT;
                }
            } else {
                Log.w(LOG_TAG, "Can't open bitmap at " + url);
                return null;
            }

            try {
                bis.reset();
            } catch (IOException e) {
                if(is != null){
                    is.close();
                }

                if(bis != null){
                    bis.close();
                }

                if(!entity.isRepeatable()){
                    entity.consumeContent();
                    response = client.execute(request);
                    entity = response.getEntity();
                }

                is = entity.getContent();
                bis = new BufferedInputStream(is);
            }

            Options opts = new Options();
            opts.inSampleSize = sampleSize;
            Bitmap bm = BitmapFactory.decodeStream(bis, null, opts);

            return bm;
        } finally {
            if (is != null) {
                is.close();
            }               

            if (bis != null) {
                bis.close();
            }

            entity.consumeContent();
        }
    }
} catch (IOException e) {
    request.abort();
    Log.w(LOG_TAG, "I/O error while retrieving bitmap from " + url, e);
} catch (IllegalStateException e) {
    request.abort();
    Log.w(LOG_TAG, "Incorrect URL: " + url);
} catch (Exception e) {
    request.abort();
    Log.w(LOG_TAG, "Error while retrieving bitmap from " + url, e);
}

When you open the image with Options bounds = new Options(); bounds.inJustDecodeBounds = true;, then the image data won’t be downloaded, only the size of the image. I use this size to calculate the new scale ratio to get the desired width and height.

With the option Options opts = new Options(); opts.inSampleSize = sampleSize; the BitmapFactory will download an already resized image. You save memory, and bandwidth this way.

Note, that the sampleSize values should be powers of 2. It works with different numbers as well, but this is much more efficient.