Re: rendering directly to java.awt.Graphics2D

Hi Mike,

  I've seen variations of this type thing before...  in my case a top level
svg that contains an <image> who's xlink:href references another document
(svg in my case).  The referenced svg document had an id'd gradient that was
in the <defs>...when the gradient was referenced by a shape's fill, the
transcode would fail. Seems once the DOM (GVT) is booted the calls out to
the xlnk:href are resolved. The uri for the embedded document seemed to be
null (null#id on reference)You can try to setDocumentURI("something") on the
parent...I think I tried that with no success, but needed to work-around
(base64 data uri worked fine) and move on. I can probably reproduce this
behavior in a test case if you think it will help resolve your issue.  I
have not had time to debug it further, but it is on the (long) list.

On Thu, Aug 4, 2011 at 4:36 PM, Mike Jarmy <[email protected]> wrote:

> On Wed, Aug 3, 2011 at 3:39 PM, Mike Jarmy <[email protected]> wrote:
> > On Wed, Aug 3, 2011 at 1:03 PM, Mike Jarmy <[email protected]> wrote:
> >> I'm working with a custom widget toolkit that is built directly on top
> >> of java.awt -- in other words I'm not using Swing, or SWT, or anything
> >> other than a framework built on plain old AWT.
> >>
> >> I'd like to be able to render (and animate) SVG drawings directly onto
> >> a java.awt.Graphics2D instance.  However, I'm having a bit of trouble
> >> figuring out how exactly to do that with batik.  I *think* that I need
> >> to decode my SVG drawing into a GVT tree, and then render the tree.
> >> However I can't figure out which part of batik I need in order to do
> >> the rendering.  Transcoder and SVGGraphics2D do not seem to be quite
> >> what I want. Actually, I haven't yet figured out the
> >> decoding-to-GVT-step either, but I'm assuming that's pretty
> >> straightforward.
> >>
> >> So can anyone give me a pointer on how to do this?  Perhaps just point
> >> me to an existing example?  My first goal is to just get static images
> >> rendering.
> >>
> >> After that, I'll need to get animation working.  I'm assuming that
> >> supporting animation will entail updating the drawing's current time
> >> every so oftern on a separate thread, via the AnimationEngine, and
> >> then re-rendering the updated GVT?
> >>
> >> I *could* do all this by rendering into a static java.awt.Image, and
> >> then bliting the Image (i.e. roll my own double-buffering), but I'd
> >> prefer to figure out how to just draw directly onto a Graphics2D
> >> instance first.  That's because the framework I'm using already has
> >> some double-buffering, so I most likely wont need to do that with the
> >> SVG rendering.
> >>
> >> Thanks,
> >> Mike Jarmy
> >>
> >> P.S. FYI, I'll probably never need to support handling interactive user
> input.
> >>
> >
> > OK, I have discovered the GraphicsNode.paint(Graphics2D g2d)  method,
> > which may be all I need to call once I actually get a valid GVT build.
> >  However, I'm having trouble building a GVT from a
> > java.io.InputStream.  Here is the code I'm using:
> >
> >            String parser = XMLResourceDescriptor.getXMLParserClassName();
> >            SAXSVGDocumentFactory f = new SAXSVGDocumentFactory(parser);
> > //            String uri = "http://www.example.org/document.svg";
> >            Document document = f.createDocument(null, inputStream);
> >
> >            UserAgent userAgent = new UserAgentAdapter();
> >            DocumentLoader loader = new DocumentLoader(userAgent);
> >            BridgeContext bctx = new BridgeContext(userAgent, loader);
> >            bctx.setDynamicState( BridgeContext.DYNAMIC );
> >            GVTBuilder builder = new GVTBuilder();
> >            this.gvtRoot = builder.build(bctx, document);
> >
> > This code fails at the call to GVTBuilder.build(), with the following
> error:
> >
> > Invalid CSS document.
> > Unable to make sense of URL for connection
> >        at
> org.apache.batik.css.engine.CSSEngine.parseStyleSheet(CSSEngine.java:1149)
> >        at
> org.apache.batik.dom.svg.SVGDOMImplementation.createCSSEngine(SVGDOMImplementation.java:117)
> >        at
> org.apache.batik.dom.ExtensibleDOMImplementation.createCSSEngine(ExtensibleDOMImplementation.java:212)
> >        at
> org.apache.batik.bridge.BridgeContext.initializeDocument(BridgeContext.java:378)
> >        at org.apache.batik.bridge.GVTBuilder.build(GVTBuilder.java:55)
> >        at
> com.tridium.svg.ui.BSvgDrawing.loadDrawing(BSvgDrawing.java:305)
> >
> > Could that be because I'm passing a null value in for the URI when I
> > create the document from the InputStream?  I have noticed that I get
> > the same error no matter what I pass in for the URI.  Is there perhaps
> > a better way to construct a Document from an InputStream?
> >
> > Thanks,
> > Mike Jarmy
> >
>
> I have this working now in a simple "hello, world" style, java app,
> using the following approach:
>
>    public static void main(String[] args) throws Exception
>    {
>        // make the file, along with its input stream and URI
>        File file = new File("D:\\aaa\\svg\\samples\\batik70.svg");
>        FileInputStream inputStream = new FileInputStream(file);
>        String uri = file.toURL().toString();
>
> System.out.println("File " + file.getAbsolutePath() + " exists: " +
> file.exists());
>
>        // create the document
>         String parser = XMLResourceDescriptor.getXMLParserClassName();
>        SAXSVGDocumentFactory f = new SAXSVGDocumentFactory(parser);
>         Document document = f.createDocument(uri, inputStream);
>
>        // create the GVT
>         UserAgent userAgent = new UserAgentAdapter();
>        DocumentLoader loader = new DocumentLoader(userAgent);
>        BridgeContext bctx = new BridgeContext(userAgent, loader);
>        bctx.setDynamicState( BridgeContext.DYNAMIC );
>        GVTBuilder builder = new GVTBuilder();
>         GraphicsNode gvtRoot = builder.build(bctx, document);
>
>        AwtApp app = new AwtApp(gvtRoot);
>        app.setVisible(true);
>    }
>
> AwtApp just calls gvtRoot.paint(Graphics2D) from within a custom
> java.awt.Canvas.  This works perfectly.
>
> However, when I run the same code within my company's software
> framework, I'm still getting this:
>
> Invalid CSS document.
> Unable to make sense of URL for connection
>   at
> org.apache.batik.css.engine.CSSEngine.parseStyleSheet(CSSEngine.java:1149)
>   at
> org.apache.batik.dom.svg.SVGDOMImplementation.createCSSEngine(SVGDOMImplementation.java:117)
>   at
> org.apache.batik.dom.ExtensibleDOMImplementation.createCSSEngine(ExtensibleDOMImplementation.java:212)
>   at
> org.apache.batik.bridge.BridgeContext.initializeDocument(BridgeContext.java:378)
>   at org.apache.batik.bridge.GVTBuilder.build(GVTBuilder.java:55)
>    at com.tridium.svg.ui.BSvgDrawing.main(BSvgDrawing.java:535)
>   at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
>   at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
>   at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
>   at java.lang.reflect.Method.invoke(Unknown Source)
>   at com.tridium.sys.Nre.runClass(Nre.java:209)
>   at com.tridium.sys.Nre.main(Nre.java:152)
>
> Obviously this isn't batik's fault, since my test app works just fine
> in a 'normal' vanilla environment.
>
> Clearly the framework is doing something different, but I'm somewhat
> at a loss to say what it could be.  One possibility is that the
> problem could be caused by classloading.  Our framework using custom
> ClassLoaders, one per jar file.  I have all of the batik jar files
> actually stuffed into one big jar file, as per our general approach.
> Could that have something to do with this problem?
>
> Any other ideas?  If not then I'm on my own, since I have batik doing
> what I want it to do in a simple app.
>
> Thanks,
> Mike Jarmy
>
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