Convert SVG to PNG Java Example

Apache Batik – SVG to PNG Conversion

In this example, we will explain how to convert a SVG Image to PNG, in Java, by using Apache Batik library. We will provide a Java Program to do this transcoding, and provide the output of the code to check the conversion. This example is on the same lines as of our earlier tutorial on SVG to JPEG transformation.

Input SVG File

We will use the same SVG file that we used in the SVG to JPEG tutorial. You may wish to take a copy of the file from the previous post, or you can alternatively, use your own SVG Image for the example. We will now provide the step by step guide for this conversion.

Read SVG Image to TranscoderInput

This is the first step in the program and in this we use Java NIO (you can still use java.io.File if you are running a older version of Java) to accept the file in TranscoderInput object. The code fragment is provided below:

        //Step -1: We read the input SVG document into Transcoder Input
        //We use Java NIO for this purpose
        String svg_URI_input = Paths.get("chessboard.svg").toUri().toURL().toString();
        TranscoderInput input_svg_image = new TranscoderInput(svg_URI_input);        

Set Output PNG Image

In this step, we create TranscoderOutput object, that maps to the output PNG image. We will create an OutputStream object and pass this to TranscoderOutput constructor.This sets the output definition right and we can then use PNGTranscoder to set the output PNG image properties.

        //Step-2: Define OutputStream to PNG Image and attach to TranscoderOutput
        OutputStream png_ostream = new FileOutputStream("chessboard.png");
        TranscoderOutput output_png_image = new TranscoderOutput(png_ostream);              

Create PNG Transcoder

We create a blank PNG Transcoder object which will do the conversion for us. For this tutorial, we are not going to set any properties against the PNG file. But you can specify properties that include Gamma correction key as an example.

        // Step-3: Create PNGTranscoder and define hints if required
        PNGTranscoder my_converter = new PNGTranscoder();        

Convert SVG to PNG

In this step, we invoke the “transcode” method in PNGTranscoder class and pass the input and output objects created earlier. This step converts SVG Image to PNG Image file and generates the output file.

        // Step-4: Convert and Write output
        my_converter.transcode(input_svg_image, output_png_image);

At the end of the step, you can close the flush the outputstream.

Batik – SVG to PNG – Complete Java Program

The complete Java program that converts SVG Image to PNG using Apache Batik is provided below:

import java.io.*;
import org.apache.batik.transcoder.image.PNGTranscoder;
import org.apache.batik.transcoder.TranscoderInput;
import org.apache.batik.transcoder.TranscoderOutput;
import java.nio.file.Paths;
import java.nio.file.Path;
public class svg2png {
    public static void main(String[] args) throws Exception {
        //Step -1: We read the input SVG document into Transcoder Input
        //We use Java NIO for this purpose
        String svg_URI_input = Paths.get("chessboard.svg").toUri().toURL().toString();
        TranscoderInput input_svg_image = new TranscoderInput(svg_URI_input);        
        //Step-2: Define OutputStream to PNG Image and attach to TranscoderOutput
        OutputStream png_ostream = new FileOutputStream("chessboard.png");
        TranscoderOutput output_png_image = new TranscoderOutput(png_ostream);              
        // Step-3: Create PNGTranscoder and define hints if required
        PNGTranscoder my_converter = new PNGTranscoder();        
        // Step-4: Convert and Write output
        my_converter.transcode(input_svg_image, output_png_image);
        // Step 5- close / flush Output Stream
        png_ostream.flush();
        png_ostream.close();        
    }
}

To compile this program you need batik-transcoder.jar file. To run the program, you need quite a number of Batik JAR files. A sample command line is given below:

java  -classpath .;batik-transcoder.jar;batik-dom.jar;batik-bridge
.jar;batik-css.jar;batik-gvt.jar;batik-util.jar;batik-svg-dom.jar;xml-apis-ext.j
ar;xml-apis.jar;batik-ext.jar;batik-xml.jar;batik-anim.jar;batik-parser.jar;bati
k-script.jar;batik-awt-util.jar;batik-codec.jar svg2png

The program generates the output PNG images successfully upon execution. That completes a quick tutorial to convert SVG to PNG in Java, using Batik library. Post your comment / exception if any, and we will have a look.