fop/src/org/apache/fop/render/pdf/PDFRenderer.java

/*
 * $Id$
 * Copyright (C) 2001 The Apache Software Foundation. All rights reserved.
 * For details on use and redistribution please refer to the
 * LICENSE file included with these sources.
 */

package org.apache.fop.render.pdf;

// FOP
import org.apache.fop.render.PrintRenderer;
import org.apache.fop.image.ImageArea;
import org.apache.fop.image.FopImage;
import org.apache.fop.apps.FOPException;
import org.apache.fop.fo.properties.*;
import org.apache.fop.layout.inline.*;
import org.apache.fop.datatypes.*;
import org.apache.fop.svg.*;
import org.apache.fop.pdf.*;
import org.apache.fop.layout.*;
import org.apache.fop.image.*;
import org.apache.fop.extensions.*;
import org.apache.fop.datatypes.IDReferences;
import org.apache.fop.render.pdf.fonts.LazyFont;

import org.apache.batik.bridge.*;
import org.apache.batik.swing.svg.*;
import org.apache.batik.swing.gvt.*;
import org.apache.batik.gvt.*;
import org.apache.batik.gvt.renderer.*;
import org.apache.batik.gvt.filter.*;
import org.apache.batik.gvt.event.*;

import org.w3c.dom.*;
import org.w3c.dom.svg.*;
import org.w3c.dom.css.*;
import org.w3c.dom.svg.SVGLength;

// Java
import java.io.IOException;
import java.io.OutputStream;
import java.util.Enumeration;
import java.util.Vector;
import java.util.Hashtable;
import java.awt.geom.AffineTransform;
import java.awt.geom.Dimension2D;
import java.awt.Point;
import java.awt.RenderingHints;
import java.awt.font.FontRenderContext;
import java.awt.Dimension;

/**
 * Renderer that renders areas to PDF
 *
 * Modified by Mark Lillywhite, mark-fop@inomial.com to use the
 * new Renderer interface. The PDF renderer is by far the trickiest
 * renderer and the best supported by FOP. It also required some
 * reworking in the way that Pages, Catalogs and the Root object
 * were written to the stream. The output document should now still
 * be a 100% compatible PDF document, but hte order of the document
 * writing is significantly different. See also the changes
 * to PDFPage, PDFPages and PDFRoot.
 */
public class PDFRenderer extends PrintRenderer {

    /**
     * the PDF Document being created
     */
    protected PDFDocument pdfDoc;

    /**
     * the /Resources object of the PDF document being created
     */
    protected PDFResources pdfResources;

    /**
     * the current stream to add PDF commands to
     */
    PDFStream currentStream;

    /**
     * the current annotation list to add annotations to
     */
    PDFAnnotList currentAnnotList;

    /**
     * the current page to add annotations to
     */
    PDFPage currentPage;

    PDFColor currentColor;

    /**
     * true if a TJ command is left to be written
     */
    boolean textOpen = false;

    /**
     * the previous Y coordinate of the last word written.
     * Used to decide if we can draw the next word on the same line.
     */
    int prevWordY = 0;

    /**
     * the previous X coordinate of the last word written.
     * used to calculate how much space between two words
     */
    int prevWordX = 0;

    /**
     * The  width of the previous word. Used to calculate space between
     */
    int prevWordWidth = 0;

    /**
     * reusable word area string buffer to reduce memory usage
     */
    private StringBuffer _wordAreaPDF = new StringBuffer();

    /**
     * options
     */
    protected Hashtable options;

    /**
     * create the PDF renderer
     */
    public PDFRenderer() {
        this.pdfDoc = new PDFDocument();
    }

    /**
     * set up renderer options
     */
    public void setOptions(Hashtable options) {
        this.options = options;
    }

    /**
     * set the PDF document's producer
     *
     * @param producer string indicating application producing PDF
     */
    public void setProducer(String producer) {
        this.pdfDoc.setProducer(producer);
    }

    public void startRenderer(OutputStream stream)
    throws IOException {
        pdfDoc.outputHeader(stream);
    }

    public void stopRenderer(OutputStream stream)
    throws IOException {
        FontSetup.addToResources(this.pdfDoc, fontInfo);
        pdfDoc.outputTrailer(stream);
    }

    /**
     * add a line to the current stream
     *
     * @param x1 the start x location in millipoints
     * @param y1 the start y location in millipoints
     * @param x2 the end x location in millipoints
     * @param y2 the end y location in millipoints
     * @param th the thickness in millipoints
     * @param r the red component
     * @param g the green component
     * @param b the blue component
     */
    protected void addLine(int x1, int y1, int x2, int y2, int th,
                           PDFPathPaint stroke) {
        closeText();

        currentStream.add("ET\nq\n" + stroke.getColorSpaceOut(false)
                          + (x1 / 1000f) + " " + (y1 / 1000f) + " m "
                          + (x2 / 1000f) + " " + (y2 / 1000f) + " l "
                          + (th / 1000f) + " w S\n" + "Q\nBT\n");
    }

    /**
     * add a line to the current stream
     *
     * @param x1 the start x location in millipoints
     * @param y1 the start y location in millipoints
     * @param x2 the end x location in millipoints
     * @param y2 the end y location in millipoints
     * @param th the thickness in millipoints
     * @param rs the rule style
     * @param r the red component
     * @param g the green component
     * @param b the blue component
     */
    protected void addLine(int x1, int y1, int x2, int y2, int th, int rs,
                           PDFPathPaint stroke) {
        closeText();
        currentStream.add("ET\nq\n" + stroke.getColorSpaceOut(false)
                          + setRuleStylePattern(rs) + (x1 / 1000f) + " "
                          + (y1 / 1000f) + " m " + (x2 / 1000f) + " "
                          + (y2 / 1000f) + " l " + (th / 1000f) + " w S\n"
                          + "Q\nBT\n");
    }

    /**
     * add a rectangle to the current stream
     *
     * @param x the x position of left edge in millipoints
     * @param y the y position of top edge in millipoints
     * @param w the width in millipoints
     * @param h the height in millipoints
     * @param stroke the stroke color/gradient
     */
    protected void addRect(int x, int y, int w, int h, PDFPathPaint stroke) {
        closeText();
        currentStream.add("ET\nq\n" + stroke.getColorSpaceOut(false)
                          + (x / 1000f) + " " + (y / 1000f) + " "
                          + (w / 1000f) + " " + (h / 1000f) + " re s\n"
                          + "Q\nBT\n");
    }

    /**
     * add a filled rectangle to the current stream
     *
     * @param x the x position of left edge in millipoints
     * @param y the y position of top edge in millipoints
     * @param w the width in millipoints
     * @param h the height in millipoints
     * @param fill the fill color/gradient
     * @param stroke the stroke color/gradient
     */
    protected void addRect(int x, int y, int w, int h, PDFPathPaint stroke,
                           PDFPathPaint fill) {
        closeText();
        currentStream.add("ET\nq\n" + fill.getColorSpaceOut(true)
                          + stroke.getColorSpaceOut(false) + (x / 1000f)
                          + " " + (y / 1000f) + " " + (w / 1000f) + " "
                          + (h / 1000f) + " re b\n" + "Q\nBT\n");
    }

    /**
     * add a filled rectangle to the current stream
     *
     * @param x the x position of left edge in millipoints
     * @param y the y position of top edge in millipoints
     * @param w the width in millipoints
     * @param h the height in millipoints
     * @param fill the fill color/gradient
     */
    protected void addFilledRect(int x, int y, int w, int h,
                                 PDFPathPaint fill) {
        closeText();
        currentStream.add("ET\nq\n" + fill.getColorSpaceOut(true)
                          + (x / 1000f) + " " + (y / 1000f) + " "
                          + (w / 1000f) + " " + (h / 1000f) + " re f\n"
                          + "Q\nBT\n");
    }

    /**
     * render image area to PDF
     *
     * @param area the image area to render
     */
    public void renderImageArea(ImageArea area) {
        // adapted from contribution by BoBoGi
        int x = this.currentXPosition + area.getXOffset();
        int y = this.currentYPosition;
        int w = area.getContentWidth();
        int h = area.getHeight();

        this.currentYPosition -= h;

        FopImage img = area.getImage();
        if (img instanceof SVGImage) {
            try {
                closeText();

                SVGDocument svg = ((SVGImage)img).getSVGDocument();
                currentStream.add("ET\nq\n");
                renderSVGDocument(svg, (int)x, (int)y, area.getFontState());
                currentStream.add("Q\nBT\n");
            } catch (FopImageException e) {}

        } else {
            int xObjectNum = this.pdfDoc.addImage(img);
            closeText();

            currentStream.add("ET\nq\n" + (((float)w) / 1000f) + " 0 0 "
                              + (((float)h) / 1000f) + " "
                              + (((float)x) / 1000f) + " "
                              + (((float)(y - h)) / 1000f) + " cm\n" + "/Im"
                              + xObjectNum + " Do\nQ\nBT\n");
        }
        this.currentXPosition += area.getContentWidth();
    }

    /**
     * render a foreign object area
     */
    public void renderForeignObjectArea(ForeignObjectArea area) {
        // if necessary need to scale and align the content
        this.currentXPosition = this.currentXPosition + area.getXOffset();
        this.currentYPosition = this.currentYPosition;
        switch (area.getAlign()) {
        case TextAlign.START:
            break;
        case TextAlign.END:
            break;
        case TextAlign.CENTER:
        case TextAlign.JUSTIFY:
            break;
        }
        switch (area.getVerticalAlign()) {
        case VerticalAlign.BASELINE:
            break;
        case VerticalAlign.MIDDLE:
            break;
        case VerticalAlign.SUB:
            break;
        case VerticalAlign.SUPER:
            break;
        case VerticalAlign.TEXT_TOP:
            break;
        case VerticalAlign.TEXT_BOTTOM:
            break;
        case VerticalAlign.TOP:
            break;
        case VerticalAlign.BOTTOM:
            break;
        }
        closeText();

        // in general the content will not be text
        currentStream.add("ET\n");
        // align and scale
        currentStream.add("q\n");
        switch (area.scalingMethod()) {
        case Scaling.UNIFORM:
            break;
        case Scaling.NON_UNIFORM:
            break;
        }
        // if the overflow is auto (default), scroll or visible
        // then the contents should not be clipped, since this
        // is considered a printing medium.
        switch (area.getOverflow()) {
        case Overflow.VISIBLE:
        case Overflow.SCROLL:
        case Overflow.AUTO:
            break;
        case Overflow.HIDDEN:
            break;
        }

        area.getObject().render(this);
        currentStream.add("Q\n");
        currentStream.add("BT\n");
        this.currentXPosition += area.getEffectiveWidth();
        // this.currentYPosition -= area.getEffectiveHeight();
    }

    /**
     * render SVG area to PDF
     *
     * @param area the SVG area to render
     */
    public void renderSVGArea(SVGArea area) {
        // place at the current instream offset
        int x = this.currentXPosition;
        int y = this.currentYPosition;
        renderSVGDocument(area.getSVGDocument(), x, y, area.getFontState());
    }

    protected void renderSVGDocument(Document doc, int x, int y,
                                     FontState fs) {
        SVGSVGElement svg = ((SVGDocument)doc).getRootElement();
        int w = (int)(svg.getWidth().getBaseVal().getValue() * 1000);
        int h = (int)(svg.getHeight().getBaseVal().getValue() * 1000);
        float sx = 1, sy = -1;
        int xOffset = x, yOffset = y;

        /*
         * Clip to the svg area.
         * Note: To have the svg overlay (under) a text area then use
         * an fo:block-container
         */
        currentStream.add("q\n");
        if (w != 0 && h != 0) {
            currentStream.add(x / 1000f + " " + y / 1000f + " m\n");
            currentStream.add((x + w) / 1000f + " " + y / 1000f + " l\n");
            currentStream.add((x + w) / 1000f + " " + (y - h) / 1000f
                              + " l\n");
            currentStream.add(x / 1000f + " " + (y - h) / 1000f + " l\n");
            currentStream.add("h\n");
            currentStream.add("W\n");
            currentStream.add("n\n");
        }
        // transform so that the coordinates (0,0) is from the top left
        // and positive is down and to the right. (0,0) is where the
        // viewBox puts it.
        currentStream.add(sx + " 0 0 " + sy + " " + xOffset / 1000f + " "
                          + yOffset / 1000f + " cm\n");


        UserAgent userAgent = new MUserAgent(new AffineTransform());

        GVTBuilder builder = new GVTBuilder();
        GraphicsNodeRenderContext rc = getRenderContext(fs);
        BridgeContext ctx = new BridgeContext(userAgent, rc);
        PDFAElementBridge aBridge = new PDFAElementBridge();
        ctx.putBridge(aBridge);
        GraphicsNode root;
        PDFGraphics2D graphics = new PDFGraphics2D(true, fs, pdfDoc,
                                 currentFontName,
                                 currentFontSize,
                                 currentXPosition,
                                 currentYPosition);
        graphics.setGraphicContext(new org.apache.batik.ext.awt.g2d.GraphicContext());
        graphics.setRenderingHints(rc.getRenderingHints());
        aBridge.setCurrentTransform(new AffineTransform(sx, 0, 0, sy, xOffset / 1000f, yOffset / 1000f));
        try {
            root = builder.build(ctx, doc);
            root.paint(graphics, rc);
            currentStream.add(graphics.getString());
        } catch (Exception e) {
            log.error("svg graphic could not be rendered: "
                                   + e.getMessage(), e);
        }

        currentAnnotList = graphics.getAnnotList();

        currentStream.add("Q\n");
    }

    public GraphicsNodeRenderContext getRenderContext(FontState fs) {
        GraphicsNodeRenderContext nodeRenderContext = null;
        if (nodeRenderContext == null) {
            RenderingHints hints = new RenderingHints(null);
            hints.put(RenderingHints.KEY_ANTIALIASING,
                      RenderingHints.VALUE_ANTIALIAS_ON);

            hints.put(RenderingHints.KEY_INTERPOLATION,
                      RenderingHints.VALUE_INTERPOLATION_BILINEAR);

            FontRenderContext fontRenderContext =
                new FontRenderContext(new AffineTransform(), true, true);

            TextPainter textPainter = null;
            Boolean bl =
                org.apache.fop.configuration.Configuration.getBooleanValue("strokeSVGText");
            if (bl == null || bl.booleanValue()) {
                textPainter = new StrokingTextPainter();
            } else {
                textPainter = new PDFTextPainter(fs);
            }
            GraphicsNodeRableFactory gnrFactory =
                new ConcreteGraphicsNodeRableFactory();

            nodeRenderContext =
                new GraphicsNodeRenderContext(new AffineTransform(), null,
                                              hints, fontRenderContext,
                                              textPainter, gnrFactory);
            nodeRenderContext.setTextPainter(textPainter);
        }

        return nodeRenderContext;
    }

    /**
     * render inline area to PDF
     *
     * @param area inline area to render
     */
    public void renderWordArea(WordArea area) {
        synchronized (_wordAreaPDF) {
            StringBuffer pdf = _wordAreaPDF;
            pdf.setLength(0);

            Hashtable kerning = null;
            boolean kerningAvailable = false;

            kerning = area.getFontState().getKerning();
            if (kerning != null &&!kerning.isEmpty()) {
                kerningAvailable = true;
            }

            String name = area.getFontState().getFontName();
            int size = area.getFontState().getFontSize();

            // This assumes that *all* CIDFonts use a /ToUnicode mapping
            boolean useMultiByte = false;
            Font f =
                (Font)area.getFontState().getFontInfo().getFonts().get(name);
            if (f instanceof LazyFont){
                if(((LazyFont) f).getRealFont() instanceof CIDFont){
                    useMultiByte = true;
                }
            }else if (f instanceof CIDFont){
                useMultiByte = true;
            }
            // String startText = useMultiByte ? "<FEFF" : "(";
            String startText = useMultiByte ? "<" : "(";
            String endText = useMultiByte ? "> " : ") ";

            if ((!name.equals(this.currentFontName))
                    || (size != this.currentFontSize)) {
                closeText();

                this.currentFontName = name;
                this.currentFontSize = size;
                pdf = pdf.append("/" + name + " " + (size / 1000) + " Tf\n");
            }

            PDFColor areaColor = null;
            if (this.currentFill instanceof PDFColor) {
                areaColor = (PDFColor)this.currentFill;
            }

            if (areaColor == null || areaColor.red() != (double)area.getRed()
                    || areaColor.green() != (double)area.getGreen()
                    || areaColor.blue() != (double)area.getBlue()) {

                areaColor = new PDFColor((double)area.getRed(),
                                         (double)area.getGreen(),
                                         (double)area.getBlue());


                closeText();
                this.currentFill = areaColor;
                pdf.append(this.currentFill.getColorSpaceOut(true));
            }


            int rx = this.currentXPosition;
            int bl = this.currentYPosition;

            addWordLines(area, rx, bl, size, areaColor);


            if (!textOpen || bl != prevWordY) {
                closeText();

                pdf.append("1 0 0 1 " + (rx / 1000f) + " " + (bl / 1000f)
                           + " Tm [" + startText);
                prevWordY = bl;
                textOpen = true;
            } else {
                // express the space between words in thousandths of an em
                int space = prevWordX - rx + prevWordWidth;
                float emDiff = (float)space / (float)currentFontSize * 1000f;
                // this prevents a problem in Acrobat Reader where large
                // numbers cause text to disappear or default to a limit
                if (emDiff < -33000) {
                    closeText();

                    pdf.append("1 0 0 1 " + (rx / 1000f) + " " + (bl / 1000f)
                               + " Tm [" + startText);
                    textOpen = true;
                } else {
                    pdf.append(Float.toString(emDiff));
                    pdf.append(" ");
                    pdf.append(startText);
                }
            }
            prevWordWidth = area.getContentWidth();
            prevWordX = rx;


            String s;
            if (area.getPageNumberID()
                    != null) {    // this text is a page number, so resolve it
                s = idReferences.getPageNumber(area.getPageNumberID());
                if (s == null) {
                    s = "";
                }
            } else {
                s = area.getText();
            }

            int l = s.length();

            for (int i = 0; i < l; i++) {
                char ch = area.getFontState().mapChar(s.charAt(i));

                if (!useMultiByte) {
                    if (ch > 127) {
                        pdf.append("\\");
                        pdf.append(Integer.toOctalString((int)ch));

                    } else {
                        switch (ch) {
                        case '(':
                        case ')':
                        case '\\':
                            pdf.append("\\");
                            break;
                        }
                        pdf.append(ch);
                    }
                } else {
                    pdf.append(getUnicodeString(ch));
                }

                if (kerningAvailable && (i + 1) < l) {
                    addKerning(pdf, (new Integer((int)ch)),
                               (new Integer((int)area.getFontState().mapChar(s.charAt(i + 1)))),
                               kerning, startText, endText);
                }

            }
            pdf.append(endText);

            currentStream.add(pdf.toString());

            this.currentXPosition += area.getContentWidth();

        }
    }



    /**
     * Convert a char to a multibyte hex representation
     */
    private String getUnicodeString(char c) {

        StringBuffer buf = new StringBuffer(4);

        byte[] uniBytes = null;
        try {
            char[] a = {
                c
            };
            uniBytes = new String(a).getBytes("UnicodeBigUnmarked");
        } catch (Exception e) {
            // This should never fail
        }


        for (int i = 0; i < uniBytes.length; i++) {
            int b = (uniBytes[i] < 0) ? (int)(256 + uniBytes[i])
                    : (int)uniBytes[i];

            String hexString = Integer.toHexString(b);
            if (hexString.length() == 1)
                buf = buf.append("0" + hexString);
            else
                buf = buf.append(hexString);
        }

        return buf.toString();

    }


    /**
     * Checks to see if we have some text rendering commands open
     * still and writes out the TJ command to the stream if we do
     */
    private void closeText() {
        if (textOpen) {
            currentStream.add("] TJ\n");
            textOpen = false;
            prevWordX = 0;
            prevWordY = 0;
        }
    }

    private void addKerning(StringBuffer buf, Integer ch1, Integer ch2,
                            Hashtable kerning, String startText,
                            String endText) {
        Hashtable kernPair = (Hashtable)kerning.get(ch1);

        if (kernPair != null) {
            Integer width = (Integer)kernPair.get(ch2);
            if (width != null) {
                buf.append(endText).append(-(width.intValue())).append(' ').append(startText);
            }
        }
    }

    public void render(Page page, OutputStream outputStream)
    throws FOPException, IOException {
        // log.debug("rendering single page to PDF");
        this.idReferences = page.getIDReferences();
        this.pdfResources = this.pdfDoc.getResources();
        this.pdfDoc.setIDReferences(idReferences);
        this.renderPage(page);

        //FontSetup.addToResources(this.pdfDoc, fontInfo);

        // TODO: this needs to be implemented
        renderRootExtensions(page);

        // log.debug("writing out PDF");
        this.pdfDoc.output(outputStream);
    }

    /**
     * render page into PDF
     *
     * @param page page to render
     */
    public void renderPage(Page page) {
        BodyAreaContainer body;
        AreaContainer before, after, start, end;

        currentStream = this.pdfDoc.makeStream();
        body = page.getBody();
        before = page.getBefore();
        after = page.getAfter();
        start = page.getStart();
        end = page.getEnd();

        this.currentFontName = "";
        this.currentFontSize = 0;

        currentStream.add("BT\n");

        renderBodyAreaContainer(body);

        if (before != null) {
            renderAreaContainer(before);
        }

        if (after != null) {
            renderAreaContainer(after);
        }

        if (start != null) {
            renderAreaContainer(start);
        }

        if (end != null) {
            renderAreaContainer(end);
        }
        closeText();

        float w = page.getWidth();
        float h = page.getHeight();
        currentStream.add("ET\n");

        currentPage = this.pdfDoc.makePage(this.pdfResources, currentStream,
                                           Math.round(w / 1000),
                                           Math.round(h / 1000), page);

        if (page.hasLinks() || currentAnnotList != null) {
            if(currentAnnotList == null) {
                currentAnnotList = this.pdfDoc.makeAnnotList();
            }
            currentPage.setAnnotList(currentAnnotList);

            Enumeration e = page.getLinkSets().elements();
            while (e.hasMoreElements()) {
                LinkSet linkSet = (LinkSet)e.nextElement();

                linkSet.align();
                String dest = linkSet.getDest();
                int linkType = linkSet.getLinkType();
                Enumeration f = linkSet.getRects().elements();
                while (f.hasMoreElements()) {
                    LinkedRectangle lrect = (LinkedRectangle)f.nextElement();
                    currentAnnotList.addLink(this.pdfDoc.makeLink(lrect.getRectangle(),
                                             dest, linkType));
                }
            }
            currentAnnotList = null;
        } else {
            // just to be on the safe side
            currentAnnotList = null;
        }

        // ensures that color is properly reset for blocks that carry over pages
        this.currentFill = null;
    }

    /**
     * defines a string containing dashArray and dashPhase for the rule style
     */
    private String setRuleStylePattern(int style) {
        String rs = "";
        switch (style) {
        case org.apache.fop.fo.properties.RuleStyle.SOLID:
            rs = "[] 0 d ";
            break;
        case org.apache.fop.fo.properties.RuleStyle.DASHED:
            rs = "[3 3] 0 d ";
            break;
        case org.apache.fop.fo.properties.RuleStyle.DOTTED:
            rs = "[1 3] 0 d ";
            break;
        case org.apache.fop.fo.properties.RuleStyle.DOUBLE:
            rs = "[] 0 d ";
            break;
        default:
            rs = "[] 0 d ";
        }
        return rs;
    }

    protected void renderRootExtensions(Page page) {
        Vector v = page.getExtensions();
        if (v != null) {
            Enumeration e = v.elements();
            while (e.hasMoreElements()) {
                ExtensionObj ext = (ExtensionObj)e.nextElement();
                if (ext instanceof Outline) {
                    renderOutline((Outline)ext);
                }
            }
        }

    }

    private void renderOutline(Outline outline) {
        PDFOutline outlineRoot = pdfDoc.getOutlineRoot();
        PDFOutline pdfOutline = null;
        Outline parent = outline.getParentOutline();
        if (parent == null) {
            pdfOutline =
                this.pdfDoc.makeOutline(outlineRoot,
                                        outline.getLabel().toString(),
                                        outline.getInternalDestination());
        } else {
            PDFOutline pdfParentOutline =
                (PDFOutline)parent.getRendererObject();
            if (pdfParentOutline == null) {
                log.error("pdfParentOutline is null");
            } else {
                pdfOutline =
                    this.pdfDoc.makeOutline(pdfParentOutline,
                                            outline.getLabel().toString(),
                                            outline.getInternalDestination());
            }

        }
        outline.setRendererObject(pdfOutline);

        // handle sub outlines
        Vector v = outline.getOutlines();
        Enumeration e = v.elements();
        while (e.hasMoreElements()) {
            renderOutline((Outline)e.nextElement());
        }
    }

    protected class MUserAgent implements UserAgent {
        AffineTransform currentTransform = null;

        /**
         * Creates a new SVGUserAgent.
         */
        protected MUserAgent(AffineTransform at) {
            currentTransform = at;
        }

        /**
         * Displays an error message.
         */
        public void displayError(String message) {
            System.err.println(message);
        }

        /**
         * Displays an error resulting from the specified Exception.
         */
        public void displayError(Exception ex) {
            ex.printStackTrace(System.err);
        }

        /**
         * Displays a message in the User Agent interface.
         * The given message is typically displayed in a status bar.
         */
        public void displayMessage(String message) {
            System.out.println(message);
        }

        /**
         * Returns a customized the pixel to mm factor.
         */
        public float getPixelToMM() {
            // this is set to 72dpi as the values in fo are 72dpi
            return 0.35277777777777777778f; // 72 dpi
            // return 0.26458333333333333333333333333333f;    // 96dpi
        }

        /**
         * Returns the language settings.
         */
        public String getLanguages() {
            return "en";    // userLanguages;
        }

        /**
         * Returns the user stylesheet uri.
         * @return null if no user style sheet was specified.
         */
        public String getUserStyleSheetURI() {
            return null;    // userStyleSheetURI;
        }

        /**
         * Returns the class name of the XML parser.
         */
        public String getXMLParserClassName() {
            return org.apache.fop.apps.Driver.getParserClassName();
        }

        /**
         * Opens a link in a new component.
         * @param doc The current document.
         * @param uri The document URI.
         */
        public void openLink(SVGAElement elt) {
            // application.openLink(uri);
        }


        public Point getClientAreaLocationOnScreen() {
            return new Point(0, 0);
        }

        public void setSVGCursor(java.awt.Cursor cursor) {}


        public AffineTransform getTransform() {
            return currentTransform;
        }

        public Dimension2D getViewportSize() {
            return new Dimension(100, 100);
        }

        public EventDispatcher getEventDispatcher() {
            return null;
        }

        public boolean supportExtension(String str) {
            return false;
        }

        public boolean hasFeature(String str) {
            return false;
        }

        public void registerExtension(BridgeExtension be) {}

        public void handleElement(Element elt, Object data) {}


    }
}