image

Determine if an image has transparent pixels

In this tutorial we shall show you how to check if an Image has transparent pixels. This example shows the basic techniques in order to gain very detailed information about your images.

In short,  to determine if an image has transparent  pixels, one has to take the following steps:

  • Load an image using ImageIcon and getImage method
  • If the Image is a BufferedImage the color model is already available, so you simply have to check the return value of getColorModel().hasAlpha() methods.
  • If the Image is not buffered, you have to use a PixelGrabber to retrieve the image’s color model (grabbing a single pixel is usually sufficient)
  • Then use the ColorModel class to get the color model from the PixelGrabber
  • And simply paint the buffered image in a new Frame
Let’s see how the code looks like:
package com.javacodegeeks.snippets.desktop;

import java.awt.Image;
import java.awt.image.BufferedImage;
import java.awt.image.ColorModel;
import java.awt.image.PixelGrabber;

public class ImageAlpha {

    public static void main(String[] args) {

  // Create frame with specific title

  boolean hasAlpha = false;

  // Get image - change to where your image file is located

  Image image = new ImageIcon("image.png").getImage();

  // If buffered image, the color model is readily available

  if (image instanceof BufferedImage) {

BufferedImage bimage = (BufferedImage) image;

hasAlpha =  bimage.getColorModel().hasAlpha();

  } else {

// Use a pixel grabber to retrieve the image's color model; grabbing a single pixel is usually sufficient

  PixelGrabber pg = new PixelGrabber(image, 0, 0, 1, 1, false);

try {

    pg.grabPixels();

} catch (InterruptedException e) {

    System.out.println("Could not grab image pixels " + e.getMessage());

}

// Get the image's color model

ColorModel cm = pg.getColorModel();

hasAlpha = cm.hasAlpha();

  }

  System.out.println("Has Alpha ? " + hasAlpha);

    }

}

 
This was an example on how to determine if an image has transparent pixels.

Byron Kiourtzoglou

Byron is a master software engineer working in the IT and Telecom domains. He is an applications developer in a wide variety of applications/services. He is currently acting as the team leader and technical architect for a proprietary service creation and integration platform for both the IT and Telecom industries in addition to a in-house big data real-time analytics solution. He is always fascinated by SOA, middleware services and mobile development. Byron is co-founder and Executive Editor at Java Code Geeks.
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