I have been working with very recent SVN/CVS versions of FOP, Batik and JEuclid. I have embedded a small fragment of MathML in an XSL-FO document (actually output from Docbook source by xsltproc):
<fo:instream-foreign-object> <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"; overflow="scroll"> <mml:mrow> <mml:mo>∑</mml:mo> <mml:mn>4</mml:mn> <mml:mo>+</mml:mo> <mml:mi>x</mml:mi> </mml:mrow> </mml:math> </fo:instream-foreign-object> I needed two patches to the examples/mathml directory to get this to work: First, the constructor for MathBase and DOMMathBuilder have changed in recent JEuclid (fop-svn-jeuclid-svn.patch). Secondly, the scaling of the image is completely wrong, because of the extreme complexity of the dimension handling. I have found great difficulty in understanding this because of the levels of nesting, the interaction of JEuclid, Batik and FOP, and the fact that attributes such as height and width are copied so frequently from one object to another. Width and height seem to come from two different sources which are inconsistent. The size of the viewport seems to come from InstreamForeignObject.prepareIntrinsicSize(), which calls MathMLElement.getDimension(), which calls MathMLElement.convertToSVG() which calls MathBase.getWidth() and MathBase.getHeight(). This seems to be the actual extent of the rendered text. However, later in Batik's SVGSVGElementBridge.createGraphicsNode(), the "width" and "height" attributes are read from the SVG document: float w = se.getWidth().getAnimVal().getValue() etc. I found that while the actual size of the math text was 48x10 points, the w and h here were 100x100 - this seems to be a default value. As a result the math was squashed by a factor of 0.48x0.1 - not what I want. It appears that this happens because the MathMLElement class in FOP's examples/mathml directory does not place the generated <svg> element at the root of the SVG document, but places it as a child of ANOTHER <svg> element. Therefore the "width"/"height" attributes are not processed by Batik. There is a comment in MathMLElement.java to the effect that "this should be done in a better way". This patch puts the generated node at the root where it should be, and makes the text the right size (fop-svn-mathml-root.patch). I hope that my analysis may be of interest to anyone working on the FOP/JEuclid integration. Peter
diff -u -r fop-svn-old/examples/mathml/src/org/apache/fop/mathml/MathMLElement.java fop-svn/examples/mathml/src/org/apache/fop/mathml/MathMLElement.java
--- fop-svn-old/examples/mathml/src/org/apache/fop/mathml/MathMLElement.java 2006-09-20 20:12:33.000000000 +0100
+++ fop-svn/examples/mathml/src/org/apache/fop/mathml/MathMLElement.java 2006-09-20 20:14:28.000000000 +0100
@@ -20,9 +20,12 @@
package org.apache.fop.mathml;
import java.awt.Color;
+import java.awt.Font;
import java.awt.Dimension;
import java.awt.geom.Point2D;
+import org.apache.avalon.framework.logger.ConsoleLogger;
+
import org.apache.fop.apps.FOPException;
import org.apache.fop.fo.FONode;
import org.apache.fop.fo.PropertyList;
@@ -81,10 +84,9 @@
int displayfontsize = 12;
int inlinefontsize = 12;
- MathBase base = new MathBase(
- (new DOMMathBuilder(doc)).getMathRootElement(),
- fontname, fontstyle, inlinefontsize,
- displayfontsize);
+ MathBase base = new MathBase(new Font(fontname, fontstyle, inlinefontsize));
+
+ new DOMMathBuilder(doc, new ConsoleLogger(), base);
base.setDebug(false);
diff -u -r fop-svn-old/examples/mathml/src/org/apache/fop/mathml/MathMLElementMapping.java fop-svn/examples/mathml/src/org/apache/fop/mathml/MathMLElementMapping.java
--- fop-svn-old/examples/mathml/src/org/apache/fop/mathml/MathMLElementMapping.java 2006-09-20 20:12:33.000000000 +0100
+++ fop-svn/examples/mathml/src/org/apache/fop/mathml/MathMLElementMapping.java 2006-09-20 20:14:20.000000000 +0100
@@ -19,6 +19,10 @@
package org.apache.fop.mathml;
+import java.awt.Font;
+
+import org.apache.avalon.framework.logger.ConsoleLogger;
+
import org.apache.fop.fo.FONode;
import org.apache.fop.fo.ElementMapping;
import org.apache.fop.image.analyser.XMLReader;
@@ -82,10 +86,9 @@
int inlinefontsize = 12;
int displayfontsize = 12;
- MathBase base = new MathBase(
- (new DOMMathBuilder(doc)).getMathRootElement(),
- fontname, fontstyle, inlinefontsize,
- displayfontsize);
+ MathBase base = new MathBase(new Font(fontname, fontstyle, inlinefontsize));
+
+ new DOMMathBuilder(doc, new ConsoleLogger(), base);
base.setDebug(false);
diff -u -r fop-svn-old/examples/mathml/src/org/apache/fop/mathml/MathMLElement.java fop-svn/examples/mathml/src/org/apache/fop/mathml/MathMLElement.java
--- fop-svn-old/examples/mathml/src/org/apache/fop/mathml/MathMLElement.java 2006-09-20 20:15:44.000000000 +0100
+++ fop-svn/examples/mathml/src/org/apache/fop/mathml/MathMLElement.java 2006-09-20 20:16:56.000000000 +0100
@@ -43,6 +43,10 @@
import net.sourceforge.jeuclid.MathBase;
import net.sourceforge.jeuclid.DOMMathBuilder;
+import java.io.Writer;
+import java.io.OutputStreamWriter;
+import org.apache.batik.dom.util.DOMUtilities;
+
/**
* Defines the top-level element for MathML.
*/
@@ -134,10 +138,9 @@
// this should be done in a better way
Element root = g.getRoot();
- svgdocument = impl.createDocument(svgNS, "svg", null);
+ svgdocument = impl.createDocument(svgNS, null, null);
Node node = svgdocument.importNode(root, true);
- ((org.apache.batik.dom.svg.SVGOMDocument) svgdocument).
- getRootElement().appendChild(node);
+ svgdocument.appendChild(node);
return svgdocument;
signature.asc
Description: This is a digitally signed message part
