Multi-resolution image API was introduced in Java 9. This API supports multiple images with different resolution variants. This API allows a set of images with different resolution to be used as a single multi-resolution image.

Consider the following images.

These are three images of a logo with different sizes.

Now in order to work with these three images, Java 9 onwards, Multi-resolution Image API can be used as single API to get all variants or a particular variant to be displayed.

// read all images into one multiresolution image
MultiResolutionImage multiResolutionImage = 
   new BaseMultiResolutionImage(images.toArray(new Image[0]));

Here MultiResolutionImage and BaseMultiResolutionImage classes are part of java.awt.image package.

Following are major operations of multi-resolution image.

• Image getResolutionVariant(double destImageWidth, double destImageHeight) − Gets a specific image which is best variant to represent this logical image at the indicated size.

• List<Image> getResolutionVariants() − Gets a readable list of all resolution variants.

Example – Get All variants

In this example, we”ve loaded three images and store them in MultiResolutionImage. Then using getResolutionVariants() method, we”re checking all the available image variants in this multi-resolution image and printing it.

package com.tutorialspoint;

import java.awt.Image;
import java.awt.image.BaseMultiResolutionImage;
import java.awt.image.MultiResolutionImage;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

import javax.imageio.ImageIO;

public class Tester {
   public static void main(String[] args) throws IOException, MalformedURLException {

	  // prepare a list of urls of all images
      List<String> imgUrls = List.of("http://www.tutorialspoint.com/java9/images/logo.png",
         "http://www.tutorialspoint.com/java9/images/mini_logo.png",
         "http://www.tutorialspoint.com/java9/images/large_logo.png");

      // create a list of Image object
      List<Image> images = new ArrayList<Image>();

      // Create image objects using image urls
      for (String url : imgUrls) {
         images.add(ImageIO.read(new URL(url)));
      }

      // read all images into one multiresolution image
      MultiResolutionImage multiResolutionImage = 
         new BaseMultiResolutionImage(images.toArray(new Image[0]));

      // get all variants of images
      List<Image> variants = multiResolutionImage.getResolutionVariants();

     
      System.out.println("Total number of images: " + variants.size());
     
      // print all the images
      for (Image img : variants) {
         System.out.println(img);
      }     
   }  
}

Output

Let us compile and run the above program, this will produce the following result −

Total number of images: 3
BufferedImage@7ce6a65d: type = 6 ColorModel: #pixelBits = 32 numComponents = 4 
color space =java.awt.color.ICC_ColorSpace@548ad73b transparency = 3 
has alpha = true isAlphaPre = false ByteInterleavedRaster: width =311 
height = 89 #numDataElements 4 dataOff[0] = 3

BufferedImage@4c762604: type = 6 ColorModel: #pixelBits = 32 numComponents = 4 
color space =java.awt.color.ICC_ColorSpace@548ad73b transparency = 3 
has alpha = true isAlphaPre = false ByteInterleavedRaster: width =156 
height = 45 #numDataElements 4 dataOff[0] = 3

BufferedImage@2641e737: type = 6 ColorModel: #pixelBits = 32 numComponents = 4 
color space =java.awt.color.ICC_ColorSpace@548ad73b transparency = 3 
has alpha = true isAlphaPre = false ByteInterleavedRaster: width =622 
height = 178 #numDataElements 4 dataOff[0] = 3

Example – Get Specific variant

In this example, we”ve loaded three images and store them in MultiResolutionImage. Then using getResolutionVariant() method, we”re getting specific image variant as per the provided resolution in this multi-resolution image and printing it. In case resoltution is not exact match, this method returns the neares t resolution image.

package com.tutorialspoint;

import java.awt.Image;
import java.awt.image.BaseMultiResolutionImage;
import java.awt.image.MultiResolutionImage;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

import javax.imageio.ImageIO;

public class Tester {
   public static void main(String[] args) throws IOException, MalformedURLException {

	  // prepare a list of urls of all images
      List<String> imgUrls = List.of("http://www.tutorialspoint.com/java9/images/logo.png",
         "http://www.tutorialspoint.com/java9/images/mini_logo.png",
         "http://www.tutorialspoint.com/java9/images/large_logo.png");

      // create a list of Image object
      List<Image> images = new ArrayList<Image>();

      // Create image objects using image urls
      for (String url : imgUrls) {
         images.add(ImageIO.read(new URL(url)));
      }

      // read all images into one multiresolution image
      MultiResolutionImage multiResolutionImage = 
         new BaseMultiResolutionImage(images.toArray(new Image[0]));

      // get all variants of images
      List<Image> variants = multiResolutionImage.getResolutionVariants();

     
      System.out.println("Total number of images: " + variants.size());
     
      // get a resolution-specific image variant for each indicated size
      Image variant1 = multiResolutionImage.getResolutionVariant(156, 45);
      System.out.printf("nImage for destination[%d,%d]: [%d,%d]", 
         156, 45, variant1.getWidth(null), variant1.getHeight(null));

      Image variant2 = multiResolutionImage.getResolutionVariant(311, 89);
      System.out.printf("nImage for destination[%d,%d]: [%d,%d]", 311, 89, 
         variant2.getWidth(null), variant2.getHeight(null));

      Image variant3 = multiResolutionImage.getResolutionVariant(622, 178);
      System.out.printf("nImage for destination[%d,%d]: [%d,%d]", 622, 178, 
         variant3.getWidth(null), variant3.getHeight(null));

      Image variant4 = multiResolutionImage.getResolutionVariant(300, 300);
      System.out.printf("nImage for destination[%d,%d]: [%d,%d]", 300, 300, 
         variant4.getWidth(null), variant4.getHeight(null));
   }  
} 

Output

Let us compile and run the above program, this will produce the following result −

Total number of images: 3
Image for destination[156,45]: [311,89]
Image for destination[311,89]: [311,89]
Image for destination[622,178]: [622,178]
Image for destination[300,300]: [622,178]