/*

   Copyright 2001-2003  The Apache Software Foundation 

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

 */
package org.apache.batik.svggen;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.FontMetrics;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.GraphicsConfiguration;
import java.awt.Image;
import java.awt.Shape;
import java.awt.Stroke;
import java.awt.font.GlyphVector;
import java.awt.font.TextLayout;
import java.awt.geom.AffineTransform;
import java.awt.geom.NoninvertibleTransformException;
import java.awt.image.BufferedImage;
import java.awt.image.BufferedImageOp;
import java.awt.image.ImageObserver;
import java.awt.image.RenderedImage;
import java.awt.image.renderable.RenderableImage;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.text.AttributedCharacterIterator;

import org.apache.batik.ext.awt.g2d.AbstractGraphics2D;
import org.apache.batik.ext.awt.g2d.GraphicContext;
import org.apache.batik.util.XMLConstants;
import org.w3c.dom.Document;
import org.w3c.dom.DocumentFragment;
import org.w3c.dom.Element;
import org.w3c.dom.Node;

/**
 * This implementation of the java.awt.Graphics2D abstract class
 * allows users to generate SVG (Scalable Vector Graphics) content
 * from Java code.
 *
 * SVGGraphics2D generates a DOM tree whose root is obtained through
 * the getRoot method. Refer to the DOMTreeManager and DOMGroupManager
 * documentation for details on the structure of the generated
 * DOM tree.
 *
 * The SVGGraphics2D class can produce a DOM tree using any implementation
 * that conforms to the W3C DOM 1.0 specification (see http://www.w3.org).
 * At construction time, the SVGGraphics2D must be given a org.w3.dom.Document
 * instance that is used as a factory to create the various nodes in the
 * DOM tree it generates.
 *
 * The various graphic context attributes (e.g., AffineTransform,
 * Paint) are managed by a GraphicContext object.
 *
 *
 * @author <a href="mailto:vincent.hardy@eng.sun.com">Vincent Hardy</a>
 * @version $Id: SVGGraphics2D.java,v 1.42 2005/04/02 12:58:17 deweese Exp $
 * @see                org.apache.batik.ext.awt.g2d.GraphicContext
 * @see                org.apache.batik.svggen.DOMTreeManager
 * @see                org.apache.batik.svggen.DOMGroupManager
 * @see                org.apache.batik.svggen.ImageHandler
 * @see                org.apache.batik.svggen.ExtensionHandler
 * @see                org.w3c.dom.Document
 */
public class SVGGraphics2D extends AbstractGraphics2D
    implements Cloneable, SVGSyntax, XMLConstants, ErrorConstants {
    /*
     * Constants definitions
     */
    public static final String DEFAULT_XML_ENCODING = "ISO-8859-1";

    /**
     * Controls the policy for grouping nodes. Once the number of attributes
     * overridden by a child element is greater than DEFAULT_MAX_GC_OVERRIDES,
     * a new group is created.
     *
     * @see org.apache.batik.svggen.DOMTreeManager
     */
    public static final int DEFAULT_MAX_GC_OVERRIDES = 3;


    /**
     * The DOMTreeManager manages the process of creating
     * and growing the SVG tree. This SVGGraphics2D relies on
     * the DOMTreeManager to process attributes based on the
     * GraphicContext state and create groups when needed.
     */
    protected DOMTreeManager domTreeManager;

    /**
     * The DOMGroupManager manages additions to the current group
     * node associated for this Graphics2D object. Once a group
     * is complete, the group manager appends it to the DOM tree
     * through the DOMTreeManager.
     * Note that each SVGGraphics2D instance has its own DOMGroupManager
     * (i.e., its own current group) but that all SVGGraphics2D
     * originating from the same SVGGraphics2D through various
     * createGraphics calls share the same DOMTreeManager.
     */
    protected DOMGroupManager domGroupManager;

    /**
     * Contains some information for SVG generation.
     */
    protected SVGGeneratorContext generatorCtx;

    /**
     * Used to convert Java 2D API Shape objects to equivalent SVG
     * elements
     */
    protected SVGShape shapeConverter;

    /**
     * SVG Canvas size
     */
    protected Dimension svgCanvasSize;

    /**
     * Used to create proper font metrics
     */
    protected Graphics2D fmg;

    {
        final BufferedImage bi
            = new BufferedImage(1, 1, BufferedImage.TYPE_INT_ARGB);

        this.fmg = bi.createGraphics();
    }

    /**
     * @return SVG Canvas size, as set in the root svg element
     */
    public final Dimension getSVGCanvasSize(){
        return this.svgCanvasSize;
    }

    /**
     * Set the Canvas size, this is used to set the width and
     * height attributes on the outermost 'svg' element.
     * @param svgCanvasSize SVG Canvas size. May be null (equivalent
     * to 100%, 100%)
     */
    public final void setSVGCanvasSize(final Dimension svgCanvasSize) {
        this.svgCanvasSize = new Dimension(svgCanvasSize);
    }

    /**
     * @return the SVGGeneratorContext used by this SVGGraphics2D instance.
     */
    public final SVGGeneratorContext getGeneratorContext() {
        return this.generatorCtx;
    }

    /**
     * @return the SVGShape used by this SVGGraphics2D instance to
     *         turn Java2D shapes into SVG Shape objects.
     */ 
    public final SVGShape getShapeConverter() {
        return this.shapeConverter;
    }

    /**
     * @return the DOMTreeManager used by this SVGGraphics2D instance
     */
    public final DOMTreeManager getDOMTreeManager(){
        return this.domTreeManager;
    }

    /** 
     * Set a DOM Tree manager for the SVGGraphics2D.
     * @param treeMgr the new DOM Tree manager this SVGGraphics2D should use
     */
     protected final void setDOMTreeManager(final DOMTreeManager treeMgr) {
        this.domTreeManager = treeMgr;
        this.generatorCtx.genericImageHandler.setDOMTreeManager(this.domTreeManager);
    }

     /**
     * @return the DOMGroupManager used by this SVGGraphics2D instance
     */
    protected final DOMGroupManager getDOMGroupManager(){
        return this.domGroupManager;
    }

    /** 
     * Set a new DOM Group manager for this SVGGraphics2D.
     * @param groupMgr the new DOM Group manager this SVGGraphics2D should use
     */
     protected final void setDOMGroupManager(final DOMGroupManager groupMgr) {
	this.domGroupManager = groupMgr;
    }

    /**
     * @return the Document used as a DOM object factory by this
     *         SVGGraphics2D instance
     */
    public final Document getDOMFactory(){
        return this.generatorCtx.domFactory;
    }

    /**
     * @return the ImageHandler used by this SVGGraphics2D instance
     */
    public final ImageHandler getImageHandler(){
        return this.generatorCtx.imageHandler;
    }

    /**
     * @return the GenericImageHandler used by this SVGGraphics2D instance
     */
    public final GenericImageHandler getGenericImageHandler(){
        return this.generatorCtx.genericImageHandler;
    }

    /**
     * @return the extension handler used by this SVGGraphics2D instance
     */
    public final ExtensionHandler getExtensionHandler(){
        return this.generatorCtx.extensionHandler;
    }

    /**
     * @param extensionHandler new extension handler this SVGGraphics2D
     *        should use
     */
    public final void setExtensionHandler(final ExtensionHandler extensionHandler) {
        this.generatorCtx.setExtensionHandler(extensionHandler);
    }

    /**
     * @param domFactory Factory which will produce Elements for the DOM tree
     *        this Graphics2D generates.
     * @exception SVGGraphics2DRuntimeException if domFactory is null.
     */
    public SVGGraphics2D(final Document domFactory) {
        this(SVGGeneratorContext.createDefault(domFactory), false);
    }

    /**
     * @param domFactory Factory which will produce Elements for the DOM tree
     *                   this Graphics2D generates.
     * @param imageHandler defines how images are referenced in the
     *                     generated SVG fragment
     * @param extensionHandler defines how Java 2D API extensions map
     *                         to SVG Nodes.
     * @param textAsShapes if true, all text is turned into SVG shapes in the
     *        convertion. No SVG text is output.
     *
     * @exception SVGGraphics2DRuntimeException if domFactory is null.
     */
    public SVGGraphics2D(final Document domFactory,
                         final ImageHandler imageHandler,
                         final ExtensionHandler extensionHandler,
                         final boolean textAsShapes) {
        this(buildSVGGeneratorContext(domFactory,
                                      imageHandler,
                                      extensionHandler),
             textAsShapes);
    }

    /**
     * Helper method to create an <tt>SVGGeneratorContext</tt> from the 
     * constructor parameters.
     */
    public static SVGGeneratorContext 
        buildSVGGeneratorContext(final Document domFactory,
                                 final ImageHandler imageHandler,
                                 final ExtensionHandler extensionHandler){

        final SVGGeneratorContext generatorCtx = new SVGGeneratorContext(domFactory);
        generatorCtx.setIDGenerator(new SVGIDGenerator());
        generatorCtx.setExtensionHandler(extensionHandler);
        generatorCtx.setImageHandler(imageHandler);
        generatorCtx.setStyleHandler(new DefaultStyleHandler());
        generatorCtx.setComment("Generated by the Batik Graphics2D SVG Generator");
        generatorCtx.setErrorHandler(new DefaultErrorHandler());

        return generatorCtx;
    }

    /**
     * Creates a new SVGGraphics2D object.
     * @param generatorCtx the <code>SVGGeneratorContext</code> instance
     * that will provide all useful information to the generator.
     * @param textAsShapes if true, all text is turned into SVG shapes in the
     *        convertion. No SVG text is output.
     *
     * @exception SVGGraphics2DRuntimeException if generatorContext is null.
     */
    public SVGGraphics2D(final SVGGeneratorContext generatorCtx,
                         final boolean textAsShapes) {
        super(textAsShapes);

        if (generatorCtx == null)
            // no error handler here as we don't have the ctx...
            throw new SVGGraphics2DRuntimeException(ERR_CONTEXT_NULL);

        this.setGeneratorContext(generatorCtx);
    }

    /**
     * Sets an non null <code>SVGGeneratorContext</code>.
     */
    protected void setGeneratorContext(final SVGGeneratorContext generatorCtx) {
        this.generatorCtx = generatorCtx;

        this.gc = new GraphicContext(new AffineTransform());

        final SVGGeneratorContext.GraphicContextDefaults gcDefaults =
            generatorCtx.getGraphicContextDefaults();

        if(gcDefaults != null){
            if(gcDefaults.getPaint() != null){
                this.gc.setPaint(gcDefaults.getPaint());
            }
            if(gcDefaults.getStroke() != null){
                this.gc.setStroke(gcDefaults.getStroke());
            }
            if(gcDefaults.getComposite() != null){
                this.gc.setComposite(gcDefaults.getComposite());
            }
            if(gcDefaults.getClip() != null){
                this.gc.setClip(gcDefaults.getClip());
            }
            if(gcDefaults.getRenderingHints() != null){
                this.gc.setRenderingHints(gcDefaults.getRenderingHints());
            }
            if(gcDefaults.getFont() != null){
                this.gc.setFont(gcDefaults.getFont());
            }
            if(gcDefaults.getBackground() != null){
                this.gc.setBackground(gcDefaults.getBackground());
            }
        }

        this.shapeConverter = new SVGShape(generatorCtx);
        this.domTreeManager = new DOMTreeManager(this.gc,
                                                 generatorCtx,
                                                 DEFAULT_MAX_GC_OVERRIDES);
        this.domGroupManager = new DOMGroupManager(this.gc, this.domTreeManager);
        this.domTreeManager.addGroupManager(this.domGroupManager);
        generatorCtx.genericImageHandler.setDOMTreeManager(this.domTreeManager);
    }

    /**
     * This constructor is used in create()
     *
     * @see #create
     */
    public SVGGraphics2D(final SVGGraphics2D g) {
        super(g);
        this.generatorCtx = g.generatorCtx;
        this.gc.validateTransformStack();
        this.shapeConverter = g.shapeConverter;
        this.domTreeManager = g.domTreeManager;
        this.domGroupManager = new DOMGroupManager(this.gc, this.domTreeManager);
        this.domTreeManager.addGroupManager(this.domGroupManager);
    }

    /**
     * @param svgFileName name of the file where SVG content
     *        should be written
     */
    public void stream(final String svgFileName) throws SVGGraphics2DIOException {
        this.stream(svgFileName, false);
    }

    /**
     * @param svgFileName name of the file where SVG content
     *        should be written
     * @param useCss defines whether the output SVG should use CSS style
     * properties as opposed to plain attributes.
     */
    public void stream(final String svgFileName, final boolean useCss)
        throws SVGGraphics2DIOException {
        try {
            final OutputStreamWriter writer =
                new OutputStreamWriter(new FileOutputStream(svgFileName),
                                       DEFAULT_XML_ENCODING);
            this.stream(writer, useCss);
            writer.flush();
            writer.close();
        } catch (final SVGGraphics2DIOException io) {
            // this one as already been handled in stream(Writer, boolean)
            // method => rethrow it in all cases
            throw io;
        } catch (final IOException e) {
            this.generatorCtx.errorHandler.
                handleError(new SVGGraphics2DIOException(e));
        }
    }

    /**
     * @param writer used to writer out the SVG content
     */
    public void stream(final Writer writer) throws SVGGraphics2DIOException {
        this.stream(writer, false);
    }

    /**
     * @param writer used to writer out the SVG content
     * @param useCss defines whether the output SVG should use CSS
     * style properties as opposed to plain attributes.
     */
    public void stream(final Writer writer, final boolean useCss)
        throws SVGGraphics2DIOException {
        final Element svgRoot = this.getRoot();
        this.stream(svgRoot, writer, useCss);
    }

    /**
     * @param svgRoot root element to stream out
     */
    public void stream(final Element svgRoot, final Writer writer)
        throws SVGGraphics2DIOException {
        this.stream(svgRoot, writer, false);
    }

    /**
     * @param svgRoot root element to stream out
     * @param writer output
     * @param useCss defines whether the output SVG should use CSS style
     * properties as opposed to plain attributes.
     */
    public void stream(final Element svgRoot, final Writer writer, final boolean useCss)
        throws SVGGraphics2DIOException {
        final Node rootParent = svgRoot.getParentNode();
        final Node nextSibling = svgRoot.getNextSibling();

        try {
            //
            // Enforce that the default and xlink namespace
            // declarations appear on the root element
            //
            svgRoot.setAttributeNS(XMLNS_NAMESPACE_URI,
                                   XMLNS_PREFIX,
                                   SVG_NAMESPACE_URI);

            svgRoot.setAttributeNS(XMLNS_NAMESPACE_URI,
                                   XMLNS_PREFIX + ":" + XLINK_PREFIX,
                                   XLINK_NAMESPACE_URI);

            final DocumentFragment svgDocument =
                svgRoot.getOwnerDocument().createDocumentFragment();
            svgDocument.appendChild(svgRoot);

            if (useCss)
                SVGCSSStyler.style(svgDocument);

            XmlWriter.writeXml(svgDocument, writer);
            writer.flush();
        } catch (final SVGGraphics2DIOException e) {
            // this catch prevents from catching an SVGGraphics2DIOException
            // and wrapping it again in another SVGGraphics2DIOException
            // as would do the second catch (XmlWriter throws SVGGraphics2DIO
            // Exception but flush throws IOException)
            this.generatorCtx.errorHandler.
                handleError(e);
        } catch (final IOException io) {
            this.generatorCtx.errorHandler.
                handleError(new SVGGraphics2DIOException(io));
        } finally {
            // Restore the svgRoot to its original tree position
            if (rootParent != null) {
                if (nextSibling == null) {
                    rootParent.appendChild(svgRoot);
                } else {
                    rootParent.insertBefore(svgRoot, nextSibling);
                }
            }
        }
    }

    /**
     * Invoking this method will return a set of definition element that
     * contain all the definitions referenced by the attributes generated by
     * the various converters. This also resets the converters.
     */
    public java.util.List getDefinitionSet(){
        return this.domTreeManager.getDefinitionSet();
    }

    /**
     * Invoking this method will return a reference to the topLevelGroup
     * Element managed by this object. It will also cause this object
     * to start working with a new topLevelGroup.
     *
     * @return top level group
     */
    public Element getTopLevelGroup(){
        return this.getTopLevelGroup(true);
    }

    /**
     * Invoking this method will return a reference to the topLevelGroup
     * Element managed by this object. It will also cause this object
     * to start working with a new topLevelGroup.
     *
     * @param includeDefinitionSet if true, the definition set is included and
     *        the converters are reset (i.e., they start with an empty set
     *        of definitions).
     * @return top level group
     */
    public Element getTopLevelGroup(final boolean includeDefinitionSet){
        return this.domTreeManager.getTopLevelGroup(includeDefinitionSet);
    }

    /**
     * Sets the topLevelGroup to the input element. This will throw an exception
     * if the input element is not of type 'g' or if it is null.
     */
    public void setTopLevelGroup(final Element topLevelGroup){
        this.domTreeManager.setTopLevelGroup(topLevelGroup);
    }

    /**
     * @return the svg root node of the SVG document associated with this
     *         object
     */
    public Element getRoot(){
        return this.getRoot(null);
    }

    /**
     * This version of the getRoot method will append the input svgRoot
     * and set its attributes.
     *
     * @param svgRoot an SVG element underwhich the content should 
     *        be appended.
     * @return the svg root node of the SVG document associated with 
     *         this object.
     */
    public Element getRoot(Element svgRoot) {
        svgRoot = this.domTreeManager.getRoot(svgRoot);
        if (this.svgCanvasSize != null){
            svgRoot.setAttributeNS(null, SVG_WIDTH_ATTRIBUTE,
                                   "" + this.svgCanvasSize.width);
            svgRoot.setAttributeNS(null, SVG_HEIGHT_ATTRIBUTE,
                                   "" + this.svgCanvasSize.height);
        }
        return svgRoot;
    }

    /**
     * Creates a new <code>Graphics</code> object that is
     * a copy of this <code>Graphics</code> object.
     * @return     a new graphics context that is a copy of
     *             this graphics context.
     */
    public Graphics create(){
        return new SVGGraphics2D(this);
    }


    /**
     * Sets the paint mode of this graphics context to alternate between
     * this graphics context's current color and the new specified color.
     * This specifies that logical pixel operations are performed in the
     * XOR mode, which alternates pixels between the current color and
     * a specified XOR color.
     * <p>
     * When drawing operations are performed, pixels which are the
     * current color are changed to the specified color, and vice versa.
     * <p>
     * Pixels that are of colors other than those two colors are changed
     * in an unpredictable but reversible manner; if the same figure is
     * drawn twice, then all pixels are restored to their original values.
     * @param     c1 the XOR alternation color
     */
    public void setXORMode(final Color c1) {
        this.generatorCtx.errorHandler.
            handleError(new SVGGraphics2DRuntimeException(ERR_XOR));
    }

    /**
     * Gets the font metrics for the specified font.
     * @return    the font metrics for the specified font.
     * @param     f the specified font
     * @see       java.awt.Graphics#getFont
     * @see       java.awt.FontMetrics
     * @see       java.awt.Graphics#getFontMetrics()
     */
    public FontMetrics getFontMetrics(final Font f){
        return this.fmg.getFontMetrics(f);
    }

    /**
     * Copies an area of the component by a distance specified by
     * <code>dx</code> and <code>dy</code>. From the point specified
     * by <code>x</code> and <code>y</code>, this method
     * copies downwards and to the right.  To copy an area of the
     * component to the left or upwards, specify a negative value for
     * <code>dx</code> or <code>dy</code>.
     * If a portion of the source rectangle lies outside the bounds
     * of the component, or is obscured by another window or component,
     * <code>copyArea</code> will be unable to copy the associated
     * pixels. The area that is omitted can be refreshed by calling
     * the component's <code>paint</code> method.
     * @param       x the <i>x</i> coordinate of the source rectangle.
     * @param       y the <i>y</i> coordinate of the source rectangle.
     * @param       width the width of the source rectangle.
     * @param       height the height of the source rectangle.
     * @param       dx the horizontal distance to copy the pixels.
     * @param       dy the vertical distance to copy the pixels.
     */
    public void copyArea(final int x, final int y, final int width, final int height,
                         final int dx, final int dy){
        // No-op
    }

    /**
     * Draws as much of the specified image as is currently available.
     * The image is drawn with its top-left corner at
     * (<i>x</i>,&nbsp;<i>y</i>) in this graphics context's coordinate
     * space. Transparent pixels in the image do not affect whatever
     * pixels are already there.
     * <p>
     * This method returns immediately in all cases, even if the
     * complete image has not yet been loaded, and it has not been dithered
     * and converted for the current output device.
     * <p>
     * If the image has not yet been completely loaded, then
     * <code>drawImage</code> returns <code>false</code>. As more of
     * the image becomes available, the process that draws the image notifies
     * the specified image observer.
     * @param    img the specified image to be drawn.
     * @param    x   the <i>x</i> coordinate.
     * @param    y   the <i>y</i> coordinate.
     * @param    observer    object to be notified as more of
     *                          the image is converted.
     * @see      java.awt.Image
     * @see      java.awt.image.ImageObserver
     * @see      java.awt.image.ImageObserver#imageUpdate(java.awt.Image, int, int, int, int, int)
     */
    public boolean drawImage(final Image img, final int x, final int y,
                             final ImageObserver observer) {
        final Element imageElement =
            this.getGenericImageHandler().createElement(this.getGeneratorContext());
        final AffineTransform xform = this.getGenericImageHandler().handleImage(
                                                         img, imageElement,
                                                         x, y,
                                                         img.getWidth(null),
                                                         img.getHeight(null),
                                                         this.getGeneratorContext());
        
        if (xform == null) {
            this.domGroupManager.addElement(imageElement);
        } else {
            AffineTransform inverseTransform = null;
            try {
                inverseTransform = xform.createInverse();
            } catch(final NoninvertibleTransformException e) {
                // This should never happen since handleImage
                // always returns invertible transform
                throw new SVGGraphics2DRuntimeException(ERR_UNEXPECTED);
            }
            this.gc.transform(xform);
            this.domGroupManager.addElement(imageElement);
            this.gc.transform(inverseTransform);
        }
        return true;
    }

    /**
     * Draws as much of the specified image as has already been scaled
     * to fit inside the specified rectangle.
     * <p>
     * The image is drawn inside the specified rectangle of this
     * graphics context's coordinate space, and is scaled if
     * necessary. Transparent pixels do not affect whatever pixels
     * are already there.
     * <p>
     * This method returns immediately in all cases, even if the
     * entire image has not yet been scaled, dithered, and converted
     * for the current output device.
     * If the current output representation is not yet complete, then
     * <code>drawImage</code> returns <code>false</code>. As more of
     * the image becomes available, the process that draws the image notifies
     * the image observer by calling its <code>imageUpdate</code> method.
     * <p>
     * A scaled version of an image will not necessarily be
     * available immediately just because an unscaled version of the
     * image has been constructed for this output device.  Each size of
     * the image may be cached separately and generated from the original
     * data in a separate image production sequence.
     * @param    img    the specified image to be drawn.
     * @param    x      the <i>x</i> coordinate.
     * @param    y      the <i>y</i> coordinate.
     * @param    width  the width of the rectangle.
     * @param    height the height of the rectangle.
     * @param    observer    object to be notified as more of
     *                          the image is converted.
     * @see      java.awt.Image
     * @see      java.awt.image.ImageObserver
     * @see      java.awt.image.ImageObserver#imageUpdate(java.awt.Image, int, int, int, int, int)
     */
    public boolean drawImage(final Image img, final int x, final int y,
                             final int width, final int height,
                             final ImageObserver observer){
        final Element imageElement =
            this.getGenericImageHandler().createElement(this.getGeneratorContext());
        final AffineTransform xform 
            = this.getGenericImageHandler().handleImage(
                                       img, imageElement,
                                       x, y,
                                       width, height,
                                       this.getGeneratorContext());
        
        if (xform == null) {
            this.domGroupManager.addElement(imageElement);
        } else {
            AffineTransform inverseTransform = null;
            try {
                inverseTransform = xform.createInverse();
            } catch(final NoninvertibleTransformException e) {
                // This should never happen since handleImage
                // always returns invertible transform
                throw new SVGGraphics2DRuntimeException(ERR_UNEXPECTED);
            }
            this.gc.transform(xform);
            this.domGroupManager.addElement(imageElement);
            this.gc.transform(inverseTransform);
        }
        return true;
    }

    /**
     * Disposes of this graphics context and releases
     * any system resources that it is using.
     * A <code>Graphics</code> object cannot be used after
     * <code>dispose</code>has been called.
     * <p>
     * When a Java program runs, a large number of <code>Graphics</code>
     * objects can be created within a short time frame.
     * Although the finalization process of the garbage collector
     * also disposes of the same system resources, it is preferable
     * to manually free the associated resources by calling this
     * method rather than to rely on a finalization process which
     * may not run to completion for a long period of time.
     * <p>
     * Graphics objects which are provided as arguments to the
     * <code>paint</code> and <code>update</code> methods
     * of components are automatically released by the system when
     * those methods return. For efficiency, programmers should
     * call <code>dispose</code> when finished using
     * a <code>Graphics</code> object only if it was created
     * directly from a component or another <code>Graphics</code> object.
     * @see         java.awt.Graphics#finalize
     * @see         java.awt.Component#paint
     * @see         java.awt.Component#update
     * @see         java.awt.Component#getGraphics
     * @see         java.awt.Graphics#create
     */
    public void dispose() {
        this.domTreeManager.removeGroupManager(this.domGroupManager);
    }

    /**
     * Strokes the outline of a <code>Shape</code> using the settings of the
     * current <code>Graphics2D</code> context.  The rendering attributes
     * applied include the <code>Clip</code>, <code>Transform</code>,
     * <code>Paint</code>, <code>Composite</code> and
     * <code>Stroke</code> attributes.
     * @param s the <code>Shape</code> to be rendered
     * @see #setStroke
     * @see #setPaint
     * @see java.awt.Graphics#setColor
     * @see #transform
     * @see #setTransform
     * @see #clip
     * @see #setClip
     * @see #setComposite
     */
    public void draw(final Shape s) {
        // Only BasicStroke can be converted to an SVG attribute equivalent.
        // If the GraphicContext's Stroke is not an instance of BasicStroke,
        // then the stroked outline is filled.
        final Stroke stroke = this.gc.getStroke();
        if (stroke instanceof BasicStroke) {
            final Element svgShape = this.shapeConverter.toSVG(s);
            if (svgShape != null) {
                this.domGroupManager.addElement(svgShape, DOMGroupManager.DRAW);
            }
        } else {
            final Shape strokedShape = stroke.createStrokedShape(s);
            this.fill(strokedShape);
        }
    }


    /**
     * Renders an image, applying a transform from image space into user space
     * before drawing.
     * The transformation from user space into device space is done with
     * the current <code>Transform</code> in the <code>Graphics2D</code>.
     * The specified transformation is applied to the image before the
     * transform attribute in the <code>Graphics2D</code> context is applied.
     * The rendering attributes applied include the <code>Clip</code>,
     * <code>Transform</code>, and <code>Composite</code> attributes.
     * Note that no rendering is done if the specified transform is
     * noninvertible.
     * @param img the <code>Image</code> to be rendered
     * @param xform the transformation from image space into user space
     * @param obs the {@link ImageObserver}
     * to be notified as more of the <code>Image</code>
     * is converted
     * @return <code>true</code> if the <code>Image</code> is
     * fully loaded and completely rendered;
     * <code>false</code> if the <code>Image</code> is still being loaded.
     * @see #transform
     * @see #setTransform
     * @see #setComposite
     * @see #clip
     * @see #setClip
     */
    public boolean drawImage(final Image img,
                             final AffineTransform xform,
                             final ImageObserver obs){
        boolean retVal = true;

        if (xform == null) {
            retVal = this.drawImage(img, 0, 0, null);
        } else if(xform.getDeterminant() != 0){
            AffineTransform inverseTransform = null;
            try{
                inverseTransform = xform.createInverse();
            }   catch(final NoninvertibleTransformException e){
                // Should never happen since we checked the
                // matrix determinant
                throw new SVGGraphics2DRuntimeException(ERR_UNEXPECTED);
            }

            this.gc.transform(xform);
            retVal = this.drawImage(img, 0, 0, null);
            this.gc.transform(inverseTransform);
        } else {
            final AffineTransform savTransform = new AffineTransform(this.gc.getTransform());
            this.gc.transform(xform);
            retVal = this.drawImage(img, 0, 0, null);
            this.gc.setTransform(savTransform);
        }

        return retVal;

    }


    /**
     * Renders a <code>BufferedImage</code> that is
     * filtered with a
     * {@link BufferedImageOp}.
     * The rendering attributes applied include the <code>Clip</code>,
     * <code>Transform</code>
     * and <code>Composite</code> attributes.  This is equivalent to:
     * <pre>
     * img1 = op.filter(img, null);
     * drawImage(img1, new AffineTransform(1f,0f,0f,1f,x,y), null);
     * </pre>
     * @param op the filter to be applied to the image before rendering
     * @param img the <code>BufferedImage</code> to be rendered
     * @param x the x coordinate in user space where the upper left
     *          corner of the image is rendered
     * @param y the y coordinate in user space where the upper left
     *          corner of the image is rendered
     * @see #transform
     * @see #setTransform
     * @see #setComposite
     * @see #clip
     * @see #setClip
     */
    public void drawImage(BufferedImage img,
                          final BufferedImageOp op,
                          final int x,
                          final int y){
        //
        // Only convert if the input image is of type sRGB
        // non-premultiplied
        //
        /*if(img.getType() == BufferedImage.TYPE_INT_ARGB){
            //
            // There are two special cases: AffineTransformOp and
            // ColorConvertOp. If the input op is not one of these
            // two, then SVGBufferedImageOp is requested to map the
            // filter to an SVG equivalent.
            //
            if(op instanceof AffineTransformOp){
                AffineTransformOp transformOp = (AffineTransformOp)op;
                AffineTransform transform = transformOp.getTransform();

                if(transform.getDeterminant() != 0){
                    AffineTransform inverseTransform = null;
                    try{
                        inverseTransform = transform.createInverse();
                    }catch(NoninvertibleTransformException e){
                        // This should never happen since we checked the
                        // matrix determinant
                        throw new SVGGraphics2DRuntimeException(ERR_UNEXPECTED);
                    }
                    gc.transform(transform);
                    drawImage(img, x, y, null);
                    gc.transform(inverseTransform);
                }
                else{
                    AffineTransform savTransform =
                    new AffineTransform(gc.getTransform());
                    gc.transform(transform);
                    drawImage(img, x, y, null);
                    gc.setTransform(savTransform);
                }
            }
            else if(op instanceof ColorConvertOp){
                img = op.filter(img, null);
                drawImage(img, x, y, null);
            }
            else{
                //
                // Try and convert to an SVG filter
                //
                SVGFilterDescriptor filterDesc =
                domTreeManager.getFilterConverter().toSVG(op, null);
                if(filterDesc != null){
                //
                // Because other filters may be needed to represent the
                // composite that applies to this image, a group is created that
                // contains the image element.
                //
                Element imageElement =
                getDOMFactory().
                createElementNS(SVG_NAMESPACE_URI, SVG_IMAGE_TAG);
                getImageHandler().handleImage((Image)img, imageElement,
                generatorCtx);
                imageElement.setAttributeNS(null, SVG_X_ATTRIBUTE,
                Integer.toString(x));
                imageElement.setAttributeNS(null, SVG_Y_ATTRIBUTE,
                Integer.toString(y));
                imageElement.setAttributeNS(null, SVG_WIDTH_ATTRIBUTE,
                Integer.toString(img.getWidth(null)));
                imageElement.setAttributeNS(null, SVG_HEIGHT_ATTRIBUTE,
                Integer.toString(img.getHeight(null)));
                imageElement.setAttributeNS(null, SVG_FILTER_ATTRIBUTE,
                filterDesc.getFilterValue());
                Element imageGroup = generatorCtx.domFactory.createElementNS(SVG_NAMESPACE_URI,
                SVG_G_TAG);
                imageGroup.appendChild(imageElement);

                    domGroupManager.addElement(imageGroup);
                }
                else{
                    //
                    // Could not convert to an equivalent SVG filter:
                    // filter now and draw resulting image
                    //
                    img = op.filter(img, null);
                    drawImage(img, x, y, null);
                }
            }
        }
        else{*/
            //
            // Input image is not sRGB non premultiplied.
            // Do not try conversion: apply filter and paint
            //
        img = op.filter(img, null);
        this.drawImage(img, x, y, null);
            // }
    }


    /**
     * Renders a {@link RenderedImage},
     * applying a transform from image
     * space into user space before drawing.
     * The transformation from user space into device space is done with
     * the current <code>Transform</code> in the <code>Graphics2D</code>.
     * The specified transformation is applied to the image before the
     * transform attribute in the <code>Graphics2D</code> context is applied.
     * The rendering attributes applied include the <code>Clip</code>,
     * <code>Transform</code>, and <code>Composite</code> attributes. Note
     * that no rendering is done if the specified transform is
     * noninvertible.
     * @param img the image to be rendered
     * @param trans2 the transformation from image space into user space
     * @see #transform
     * @see #setTransform
     * @see #setComposite
     * @see #clip
     * @see #setClip
     */
    public void drawRenderedImage(final RenderedImage img,
                                  final AffineTransform trans2) {

        final Element image =
            this.getGenericImageHandler().createElement(this.getGeneratorContext());
        final AffineTransform trans1 
            = this.getGenericImageHandler().handleImage(
                                       img, image,
                                       img.getMinX(),
                                       img.getMinY(),
                                       img.getWidth(),
                                       img.getHeight(),
                                       this.getGeneratorContext());
        
        AffineTransform xform;
        
        // Concatenate the transformation we receive from the imageHandler
        // to the user-supplied one. Be aware that both may be null.
        if (trans2 == null) {
            xform = trans1;
        } else {
            if(trans1 == null) {
                xform = trans2;
             } else {
                xform = new AffineTransform(trans2);
                xform.concatenate(trans1);
            }
        }

        if(xform == null) {
            this.domGroupManager.addElement(image);
        } else if(xform.getDeterminant() != 0){
            AffineTransform inverseTransform = null;
            try{
                inverseTransform = xform.createInverse();
            }catch(final NoninvertibleTransformException e){
                // This should never happen since we checked
                // the matrix determinant
                throw new SVGGraphics2DRuntimeException(ERR_UNEXPECTED);
            }
            this.gc.transform(xform);
            this.domGroupManager.addElement(image);
            this.gc.transform(inverseTransform);
        } else {
            final AffineTransform savTransform = new AffineTransform(this.gc.getTransform());
            this.gc.transform(xform);
            this.domGroupManager.addElement(image);
            this.gc.setTransform(savTransform);
        }
    }

    /**
     * Renders a
     * {@link RenderableImage},
     * applying a transform from image space into user space before drawing.
     * The transformation from user space into device space is done with
     * the current <code>Transform</code> in the <code>Graphics2D</code>.
     * The specified transformation is applied to the image before the
     * transform attribute in the <code>Graphics2D</code> context is applied.
     * The rendering attributes applied include the <code>Clip</code>,
     * <code>Transform</code>, and <code>Composite</code> attributes. Note
     * that no rendering is done if the specified transform is
     * noninvertible.
     * <p>
     * Rendering hints set on the <code>Graphics2D</code> object might
     * be used in rendering the <code>RenderableImage</code>.
     * If explicit control is required over specific hints recognized by a
     * specific <code>RenderableImage</code>, or if knowledge of which hints
     * are used is required, then a <code>RenderedImage</code> should be
     * obtained directly from the <code>RenderableImage</code>
     * and rendered using
     * {@link #drawRenderedImage(RenderedImage, AffineTransform)}.
     * @param img the image to be rendered
     * @param trans2 the transformation from image space into user space
     * @see #transform
     * @see #setTransform
     * @see #setComposite
     * @see #clip
     * @see #setClip
     * @see #drawRenderedImage
     */
    public void drawRenderableImage(final RenderableImage img,
                                    final AffineTransform trans2){
                                    
        final Element image =
            this.getGenericImageHandler().createElement(this.getGeneratorContext());
        
        final AffineTransform trans1 = 
            this.getGenericImageHandler().handleImage(
                                     img, image,
                                     img.getMinX(),
                                     img.getMinY(),
                                     img.getWidth(),
                                     img.getHeight(),
                                     this.getGeneratorContext());
        
        AffineTransform xform;

        // Concatenate the transformation we receive from the imageHandler
        // to the user-supplied one. Be aware that both may be null.
        if (trans2 == null) {
            xform = trans1;
        } else {
            if(trans1 == null) {
                xform = trans2;
             } else {
                xform = new AffineTransform(trans2);
                xform.concatenate(trans1);
            }
        }

        if (xform == null) {
            this.domGroupManager.addElement(image);
        } else if(xform.getDeterminant() != 0){
            AffineTransform inverseTransform = null;
            try{
                inverseTransform = xform.createInverse();
            }catch(final NoninvertibleTransformException e){
                // This should never happen because we checked the
                // matrix determinant
                throw new SVGGraphics2DRuntimeException(ERR_UNEXPECTED);
            }
            this.gc.transform(xform);
            this.domGroupManager.addElement(image);
            this.gc.transform(inverseTransform);
        } else {
            final AffineTransform savTransform = new AffineTransform(this.gc.getTransform());
            this.gc.transform(xform);
            this.domGroupManager.addElement(image);
            this.gc.setTransform(savTransform);
        }
    }


    /**
     * Renders the text specified by the specified <code>String</code>,
     * using the current <code>Font</code> and <code>Paint</code> attributes
     * in the <code>Graphics2D</code> context.
     * The baseline of the first character is at position
     * (<i>x</i>,&nbsp;<i>y</i>) in the User Space.
     * The rendering attributes applied include the <code>Clip</code>,
     * <code>Transform</code>, <code>Paint</code>, <code>Font</code> and
     * <code>Composite</code> attributes. For characters in script systems
     * such as Hebrew and Arabic, the glyphs can be rendered from right to
     * left, in which case the coordinate supplied is the location of the
     * leftmost character on the baseline.
     * @param s the <code>String</code> to be rendered
     * @param x the x coordinate where the <code>String</code>
     *          should be rendered
     * @param y the y coordinate where the <code>String</code>
     *          should be rendered
     * @see #setPaint
     * @see java.awt.Graphics#setColor
     * @see java.awt.Graphics#setFont
     * @see #setTransform
     * @see #setComposite
     * @see #setClip
     */
    public void drawString(final String s, float x, float y) {
        if (!this.textAsShapes) {

            if (this.generatorCtx.svgFont) {
                // record that the font is being used to draw this string, this is
                // so that the SVG Font element will only create glyphs for the
                // characters that are needed
                this.domTreeManager.gcConverter.getFontConverter().recordFontUsage(s, this.getFont());
            }

            final Font font = this.getFont();

            // Account for the font transform if there is one
            AffineTransform txtTxf = null;
            final AffineTransform savTxf = this.getTransform();

            if (font != null){
                txtTxf = font.getTransform();
                if (txtTxf != null && !txtTxf.isIdentity()){
                    // 
                    // The additional transform applies about the text's origin
                    //
                    final AffineTransform t = new AffineTransform();
                    t.translate(x, y);
                    t.concatenate(txtTxf);
                    t.translate(-x, -y);
                    this.transform(t);
                } else {
                    txtTxf = null;
                }
            }

            final Element text =
                this.getDOMFactory().createElementNS(SVG_NAMESPACE_URI, SVG_TEXT_TAG);
            text.setAttributeNS(null, SVG_X_ATTRIBUTE,
                                this.generatorCtx.doubleString(x));
            text.setAttributeNS(null, SVG_Y_ATTRIBUTE,
                                this.generatorCtx.doubleString(y));
            text.setAttributeNS(XML_NAMESPACE_URI,
                                XML_SPACE_ATTRIBUTE,
                                XML_PRESERVE_VALUE);
            text.appendChild(this.getDOMFactory().createTextNode(s));
            this.domGroupManager.addElement(text, DOMGroupManager.FILL);

            if (txtTxf != null){
                this.setTransform(savTxf);
            }
                
        } else {
            final GlyphVector gv = this.getFont().
                createGlyphVector(this.getFontRenderContext(), s);
            this.drawGlyphVector(gv, x, y);
        }
    }

    /**
     * Renders the text of the specified iterator, using the
     * <code>Graphics2D</code> context's current <code>Paint</code>. The
     * iterator must specify a font
     * for each character. The baseline of the
     * first character is at position (<i>x</i>,&nbsp;<i>y</i>) in the
     * User Space.
     * The rendering attributes applied include the <code>Clip</code>,
     * <code>Transform</code>, <code>Paint</code>, and
     * <code>Composite</code> attributes.
     * For characters in script systems such as Hebrew and Arabic,
     * the glyphs can be rendered from right to left, in which case the
     * coordinate supplied is the location of the leftmost character
     * on the baseline.<br />
     * 
     * <b>Note</b>: The current implementation turns a drawString call
     * into shapes. Therefore, the generated SVG file will be sub-optimal
     * in terms of size and will have lost semantic (i.e., text is no
     * longer text but shapes), but it is graphically accurate.
     *
     * @param iterator the iterator whose text is to be rendered
     * @param x the x coordinate where the iterator's text is to be rendered
     * @param y the y coordinate where the iterator's text is to be rendered
     * @see #setPaint
     * @see java.awt.Graphics#setColor
     * @see #setTransform
     * @see #setComposite
     * @see #setClip
     */
    public void drawString(final AttributedCharacterIterator iterator,
                           final float x, final float y) {
        final TextLayout layout = new TextLayout(iterator, this.getFontRenderContext());
        layout.draw(this, x, y);
    }


    /**
     * Fills the interior of a <code>Shape</code> using the settings of the
     * <code>Graphics2D</code> context. The rendering attributes applied
     * include the <code>Clip</code>, <code>Transform</code>,
     * <code>Paint</code>, and <code>Composite</code>.
     * @param s the <code>Shape</code> to be filled
     * @see #setPaint
     * @see java.awt.Graphics#setColor
     * @see #transform
     * @see #setTransform
     * @see #setComposite
     * @see #clip
     * @see #setClip
     */
    public void fill(final Shape s) {
        final Element svgShape = this.shapeConverter.toSVG(s);
        if (svgShape != null) {
            this.domGroupManager.addElement(svgShape, DOMGroupManager.FILL);
        }
    }

    /**
     * Returns the device configuration associated with this
     * <code>Graphics2D</code>.
     */
    public GraphicsConfiguration getDeviceConfiguration(){
        // TO BE DONE.
        return null;
    }

}
