BBox for text on path

[Andrew Rowlands]

Hi Thomas,

You might remember I mentioned I previously had issues with the bbox when using 
text on path.  The idea was to resize the text so that the entire string would 
fit along the path such that the bbox would be <= a certain width.

Basically, the kind of approach I was taking was as below (no canvas, running 
as servlet under Tomcat).  For certain strings though, bbox didn't seem to 
calculate the bbox correctly.

In the end I used getComputedTextLength() instead which worked out great.. but 
I really would be interested to know any ideas why using bbox didn't work so 
well...

Cheers,
Andrew

---
String parser = XMLResourceDescriptor.getXMLParserClassName();
SAXSVGDocumentFactory factory = new SAXSVGDocumentFactory(parser);
curDocument = factory.createSVGDocument(
               new File(svgFileName).toURL().toString());

UserAgent userAgent = new UserAgentAdapter();
DocumentLoader loader = new DocumentLoader(userAgent);
BridgeContext ctx = new BridgeContext(userAgent, loader);
ctx.setDynamicState(BridgeContext.DYNAMIC);
GVTBuilder builder   = new GVTBuilder();
builder.build(ctx, curDocument);

// Text element to update
Element elem = curDocument.getElementById("text_element");
Node n = elem.getFirstChild();
Text text;

// There is a textPath that wraps the text
text = (Text) n.getFirstChild();
text.setNodeValue("a b c d e f g h i j k l m n");

// Resize text
this.resizeTextSizeToFit("text_element");

// The SVG was then saved using the transcoder
// ...

// Resize function:
public void resizeTextSizeToFit(String elemID) {

       Element elem = curDocument.getElementById(elemID);
       if (elem == null) {
           return;
       }

       SVGLocatable elemLocatable = (SVGLocatable) 
curDocument.getElementById(elemID);
       float currentFontSize;

       SVGRect bbox = elemLocatable.getBBox();
       float width = bbox.getWidth();

       System.out.println("Original width: " + Float.toString(width));

   if (width >= 430) {
      float currentFontSize = Float.parseFloat(elem.getAttribute("font-size"));
       currentFontSize -= 2;
       elem.setAttributeNS(null, "font-size", Float.toString(currentFontSize));
       this.resizeTextSizeToFit(elemID);
   }

}

________________________________________
From: Thomas DeWeese [thomas.dewe...@gmail.com]
Sent: 22 February 2012 10:12
To: 
batik-users@xmlgraphics.apache.org<mailto:batik-users@xmlgraphics.apache.org>
Cc: 
batik-users@xmlgraphics.apache.org<mailto:batik-users@xmlgraphics.apache.org>
Subject: Re: Bounding Box accuracy for text containing ISO (&#198;) characters

   The bbox and other APIs in Batik should always return the right value as 
long as you don't have multiple threads manipulating the tree at the same time.