Question

I want to be able to prevent users from uploading low quality images to my website.

I’d thought about doing this through restricting DPI thresholds, but it seems this isn’t too easy to do.

Does anyone know any tricks to do this? I’m happy for it to be imprecise, i.e. a modelled DPI, or occasionally wrong. Also happy for it to only apply to some image types.

Basically anything to improve the user generated content would help!

Ideally the solution will be in Java, but I’ll consider any tech, as long as it can be wrapped in a web service.

Answer 1

Did you try following API’s to acheive this ?

com.sun.image.codec.jpeg
com.sun.media.jai.codec

Here is the sample code

import java.net.MalformedURLException;
import java.net.URL;

import javax.media.jai.JAI;
import javax.media.jai.PlanarImage;

class CheckResolution {
  String imageURL = "test.png";

  public static void main(String[] args) throws MalformedURLException {
     CheckResolution cr = new CheckResolution();
     URL imageurl = new URL(cr.imageURL);
     PlanarImage pi = JAI.create("url", imageurl);
     int imagewidth = pi.getWidth();
     int imageheight = pi.getHeight();
     System.out.println("Image Width:" + imagewidth + " --- Image Height:" + imageheight);
  }
}