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Posted to batik-users@xmlgraphics.apache.org by "Nierop, P. van" <p....@vu.nl> on 2012/11/22 12:04:35 UTC

Problem using path objects (SVGOMPathElement) parsed from svg file

Hello,

I have only recently started using Batik and this is my first post to the Batik maillist.

I am experiencing problems working with paths. This step-by-step description gives you an idea about what I am trying to achieve.

1. I read an exisiting svg file that contains a path element
2. Get path information
3. Draw shapes along the path

This is my svg file (named "basedrawing.svg", generated with inkscape, but modifed to remove all clutter):
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg
   xmlns:dc="http://purl.org/dc/elements/1.1/"
   xmlns:cc="http://creativecommons.org/ns#"
   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
   xmlns:svg="http://www.w3.org/2000/svg"
   xmlns="http://www.w3.org/2000/svg"
   >
    <path
        id="test"
        d="m 162.875,146.15625 -0.0312,1 c 162.80372,4.28431 255.5724,32.82885 307.625,60.28125 26.0263,13.7262 41.8838,27.18577 51.21875,37.1875 9.33495,10.00173 12.125,16.5 12.125,16.5 l 0.9375,-0.375 c 0,0 -2.9287,-6.72495 -12.34375,-16.8125 -9.4151,-10.08755 -25.35224,-23.6012 -51.4688,-37.375 C 418.70439,179.0149 325.78557,150.44337 162.875,146.15625 z"
    />
</svg>
This file is rendered correctly in the Firefox webbrowser.

My next goal is to read in this svg file and generate a object representation of the path element (try to make it a valid SVGOMPathElement instance) This is the java code with which I try to read the svg:

import java.io.File;
import java.io.IOException;
import java.net.URI;
import org.apache.batik.dom.svg.SAXSVGDocumentFactory;
import org.apache.batik.dom.svg.SVGOMPathElement;
import org.apache.batik.util.XMLResourceDescriptor;
import org.w3c.dom.Element;
import org.w3c.dom.svg.SVGDocument;

public class TestSVGDomParser {

    public static void main(String[] args) throws IOException {

        URI fileURI = new File("basedrawing.svg").toURI();

        String parser = XMLResourceDescriptor.getXMLParserClassName();
        SAXSVGDocumentFactory f = new SAXSVGDocumentFactory(parser);
        SVGDocument doc = (SVGDocument) f.createDocument( fileURI.toString() );

        // try to get a path using the unique identifier
        Element e = doc.getElementById("test");

        // cast to path
        SVGOMPathElement path = (SVGOMPathElement) e;

        // works fine
        System.out.println( path.getAttribute("d") );

        // does not work, throws a null pointer exception
        System.out.println( path.getTotalLength() );
    }

}
The problem I think is that the cast of the e (instance of Element) to path (instance of SVGOMPathElement) does not trigger the internal interpretation of the 'd' attribute. I conclude from this that I do not follow the proper procedures to build the object representation of the svg document.

Could someone advise me on how to proceed?

Thanks in advance,

Pim


--
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-

   Pim van Nierop

   Center for Neurogenomics and Cognitive Research
   Faculty of Earth and Life Sciences
   Vrije Universiteit
   Amsterdam
   Email    pim.van.nierop@cncr.vu.nl
   Tel.     +31 (0)20 5987114
   Fax.     +31 (0)20 5987112

*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-


RE: Problem using path objects (SVGOMPathElement) parsed from svg file

Posted by "Nierop, P. van" <p....@vu.nl>.
Thanks a lot! This was the information that I missed.

All the best,

Pim

--
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-

   Pim van Nierop

   Center for Neurogenomics and Cognitive Research
   Faculty of Earth and Life Sciences
   Vrije Universiteit
   Amsterdam
   Email    pim.van.nierop@cncr.vu.nl
   Tel.     +31 (0)20 5987114
   Fax.     +31 (0)20 5987112

*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-

________________________________
From: Thomas DeWeese [thomas.deweese@gmail.com]
Sent: 24 November 2012 13:14
To: batik-users@xmlgraphics.apache.org
Subject: Re: Problem using path objects (SVGOMPathElement) parsed from svg file

Hi Nierop,

   I'm fairly sure that the problem is that you haven't booted the SVG DOM.  Please see the following link for information on how to do that:

http://wiki.apache.org/xmlgraphics-batik/BootSvgAndCssDom

On Thu, Nov 22, 2012 at 3:04 AM, Nierop, P. van <p....@vu.nl>> wrote:
My next goal is to read in this svg file and generate a object representation of the path element (try to make it a valid SVGOMPathElement instance) This is the java code with which I try to read the svg:

import java.io.File;
import java.io.IOException;
import java.net.URI;
import org.apache.batik.dom.svg.SAXSVGDocumentFactory;
import org.apache.batik.dom.svg.SVGOMPathElement;
import org.apache.batik.util.XMLResourceDescriptor;
import org.w3c.dom.Element;
import org.w3c.dom.svg.SVGDocument;

public class TestSVGDomParser {

    public static void main(String[] args) throws IOException {

        URI fileURI = new File("basedrawing.svg").toURI();

        String parser = XMLResourceDescriptor.getXMLParserClassName();
        SAXSVGDocumentFactory f = new SAXSVGDocumentFactory(parser);
        SVGDocument doc = (SVGDocument) f.createDocument( fileURI.toString() );

        // try to get a path using the unique identifier
        Element e = doc.getElementById("test");

        // cast to path
        SVGOMPathElement path = (SVGOMPathElement) e;

        // works fine
        System.out.println( path.getAttribute("d") );

        // does not work, throws a null pointer exception
        System.out.println( path.getTotalLength() );
    }

}
The problem I think is that the cast of the e (instance of Element) to path (instance of SVGOMPathElement) does not trigger the internal interpretation of the 'd' attribute. I conclude from this that I do not follow the proper procedures to build the object representation of the svg document.

Could someone advise me on how to proceed?

Thanks in advance,

Pim


--
*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-

   Pim van Nierop

   Center for Neurogenomics and Cognitive Research
   Faculty of Earth and Life Sciences
   Vrije Universiteit
   Amsterdam
   Email    pim.van.nierop@cncr.vu.nl<ma...@cncr.vu.nl>
   Tel.     +31 (0)20 5987114<tel:%2B31%20%280%2920%205987114>
   Fax.     +31 (0)20 5987112<tel:%2B31%20%280%2920%205987112>

*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-



Re: Problem using path objects (SVGOMPathElement) parsed from svg file

Posted by Thomas DeWeese <th...@gmail.com>.
Hi Nierop,

   I'm fairly sure that the problem is that you haven't booted the SVG DOM.
 Please see the following link for information on how to do that:

http://wiki.apache.org/xmlgraphics-*batik*/BootSvgAndCssDom

On Thu, Nov 22, 2012 at 3:04 AM, Nierop, P. van <p....@vu.nl> wrote:

>  My next goal is to read in this svg file and generate a object
> representation of the path element (try to make it a valid SVGOMPathElement
> instance) This is the java code with which I try to read the svg:
>
> import java.io.File;
> import java.io.IOException;
> import java.net.URI;
> import org.apache.batik.dom.svg.SAXSVGDocumentFactory;
> import org.apache.batik.dom.svg.SVGOMPathElement;
> import org.apache.batik.util.XMLResourceDescriptor;
> import org.w3c.dom.Element;
> import org.w3c.dom.svg.SVGDocument;
>
> public class TestSVGDomParser {
>
>     public static void main(String[] args) throws IOException {
>
>         URI fileURI = new File("basedrawing.svg").toURI();
>
>         String parser = XMLResourceDescriptor.getXMLParserClassName();
>         SAXSVGDocumentFactory f = new SAXSVGDocumentFactory(parser);
>         SVGDocument doc = (SVGDocument) f.createDocument(
> fileURI.toString() );
>
>         // try to get a path using the unique identifier
>         Element e = doc.getElementById("test");
>
>         // cast to path
>         SVGOMPathElement path = (SVGOMPathElement) e;
>
>         // works fine
>         System.out.println( path.getAttribute("d") );
>
>         // does not work, throws a null pointer exception
>         System.out.println( path.getTotalLength() );
>     }
>
> }
>
> The problem I think is that the cast of the e (instance of Element) to
> path (instance of SVGOMPathElement) does not trigger the internal
> interpretation of the 'd' attribute. I conclude from this that I do not
> follow the proper procedures to build the object representation of the svg
> document.
>
> Could someone advise me on how to proceed?
>
> Thanks in advance,
>
> Pim
>
>
> --
>
> *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-
>
>    Pim van Nierop
>
>    Center for Neurogenomics and Cognitive Research
>    Faculty of Earth and Life Sciences
>    Vrije Universiteit
>    Amsterdam
>    Email    pim.van.nierop@cncr.vu.nl
>    Tel.     +31 (0)20 5987114
>    Fax.     +31 (0)20 5987112
>
> *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-
>
>
>