| Introduction |
The Document Object Model (DOM) is an API for XML documents. It defines the logical structure of documents and the way a document is accessed and manipulated. This paper shows how to create an SVG document using the DOM API. Getting started Creating a Document Building an SVG Document Creating a Document from an SVG file Rendering an SVG DOM
| Getting started |
The DOM API defines an interface called `DOMImplementation` which represents the boostrap of any DOM implementation. The role of this class is to bootstrap a particular implementation of the DOM by providing a method to create a `Document`. Then, the concrete `Document` represents an XML document and also acts like a factory for the various DOM objects such `Element`, `Attr` or XML content. How to get an instance of the `DOMImplementation` interface depends on the DOM implementation you are using. In Batik, the DOM implementation is located in the package `org.apache.batik.dom.svg` and the class is named `SVGDOMImplementation`. The following example shows how to get a concrete `DOMImplementation` object.
    import org.w3c.dom.DOMImplementation;
    import org.apache.batik.dom.svg.SVGDOMImplementation;

    DOMImplementation impl = SVGDOMImplementation.getDOMImplementation();
Once you have an instance of a `DOMImplementation`, you are not relying on proprietary code anymore and ready to use the DOM API.
| Creating a Document |
Using the `DOMImplementation`, you are now able to create a `Document`. The following example illustrates how to create an SVG document. Note that the Batik's Document Object Model implementation can be used to represent either an SVG document fragment or any kind of XML document. The following code shows how to get a concrete `Document` object using a `DOMImplementation`. Note that by choosing the namespace URI and the local name of the root element of SVG, we are creating an SVG document.
    import org.apache.batik.dom.svg.SVGDOMImplementation;
    import org.w3c.dom.Document;

    DOMImplementation impl = SVGDOMImplementation.getDOMImplementation();
    // we are using a constant available on the SVGDOMImplementation
    // but we could have used "http://www.w3.org/2000/svg"
    String svgNS = SVGDOMImplementation.SVG_NAMESPACE_URI;
    Document doc = impl.createDocument(svgNS, "svg", null);
As we have created an SVG `Document`, we can cast this document to an `SVGDocument` (defined in the `org.w3c.dom.svg` package) if needed.
| Building an SVG Document |
Finally, using the `Document` object, we are now able to construct SVG content. Note that the document created before supports both generic XML and SVG. Though the DOM implementation of Batik is an SVG DOM implementation, the SVG part is not fully implemented yet so only the DOM Level 2 core functions should be used. The following example shows how to create a red rectangle located at (10, 20), with a size of (100, 50) placed in a (400, 450) SVG canvas.
    import org.apache.batik.dom.svg.SVGDOMImplementation;
    import org.w3c.dom.Document;
    import org.w3c.dom.Element;

    DOMImplementation impl = SVGDOMImplementation.getDOMImplementation();
    String svgNS = SVGDOMImplementation.SVG_NAMESPACE_URI;
    Document doc = impl.createDocument(svgNS, "svg", null);

    // get the root element (the svg element)
    Element svgRoot = doc.getDocumentElement();

    // set the width and height attribute on the root svg element
    svgRoot.setAttributeNS(null, "width", "400");
    svgRoot.setAttributeNS(null, "height", "450");

    // create the rectangle
    Element rectangle = doc.createElementNS(svgNS, "rect");
    rectangle.setAttributeNS(null, "x", "10");
    rectangle.setAttributeNS(null, "y", "20");
    rectangle.setAttributeNS(null, "width", "100");
    rectangle.setAttributeNS(null, "height", "50");
    rectangle.setAttributeNS(null, "style", "fill:red");

    // attach the rectangle to the svg root element
    svgRoot.appendChild(rectangle);
The example given has the following equivalent SVG.
    <svg width="400" height="450">
        <rect x="10" y="20" width="100" height="50" style="fill:red"/>
    </svg>
| Creating a Document from an SVG file |
With Batik, you can also create an SVG DOM tree from a URI, an `InputStream`, or a `Reader` - using the `SAXSVGDocumentFactory`. The following example illustrates how to create an SVG document. Note that the Batik's Document Object Model implementation can be used to represent either an SVG document fragment or any kind of XML document. The following code shows how to get a concrete `Document` object using the `SAXSVGDocumentFactory`.
    import java.io.IOException;

    import org.apache.batik.dom.svg.SAXSVGDocumentFactory;
    import org.apache.batik.util.XMLResourceDescriptor;

    import org.w3c.dom.Document;

    try {
        String parser = XMLResourceDescriptor.getXMLParserClassName();
        SAXSVGDocumentFactory f = new SAXSVGDocumentFactory(parser);
        String uri = "http://...";
        Document doc = f.createDocument(uri);
    } catch (IOException ex) {
         // ...
    }
As we have created an SVG `Document`, we can cast this document to an `SVGDocument` (defined in the `org.w3c.dom.svg` package) if needed.
| Rendering an SVG DOM |
Batik provides several ways to use an SVG DOM tree. Two modules can be immediately used to render your SVG document. JSVGCanvas - The `JSVGCanvas` is a swing component that can display SVG document. A SVG document can be specified using a URI or an SVG DOM tree (using the `setSVGDocument` method). For futher informations about the `JSVGCanvas`, see the JSVGCanvas tutorial. ImageTranscoder - The `ImageTranscoder` is a transcoder which can take a URI, an InputStream or an SVG DOM tree and produces a raster image (such JPEG, PNG or Tiff). By creating a `TranscoderInput` with the SVG DOM tree, you will be able to transform your SVG content to a raster image. For futher informations, see the Transcoder tutorial.

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