Re: Repainting a JSVGCanvas

> Von: aaaa aaaa <scorefande@...>
> Betreff: Re: Repainting a JSVGCanvas
> An: batik-users@...
> Datum: Mittwoch, 28. Mai 2008, 11:02
> Hi,
> not the resizing triggers the exception. The occurance of
> the exception seems completely arbitrary to me and is not
> reproduced easily.
>
> I think it only occurs when I move the cursor over an svg
> element where the set attribute is used so that the fill
> attribute changes. Resizing repaints the canvas. So my
> first (and dirty) solution was to make this kind of repaint
> when the variable is null.
>
> Of course it would be better when I would understand why I
> get this NullPointer Exception.
>
>
> I have following classes (SVGArea and SVGAreaPainter) which
> displays the document. The SVGArea is used by the
> SVGAreaPainter. The SVGAreaPainter has a lot methods. The
> one that makes the mouseover effect for some elements is
>
> private void addMouseOverEffect(Element el, String color)
> {
> Element mouseOver = doc.createElementNS(svgNS,
> "set");
> mouseOver.setAttributeNS(null, "attributeName",
> "fill");
> mouseOver.setAttributeNS(null, "attributeType",
> "XML");
> mouseOver.setAttributeNS(null, "to", color);
> mouseOver.setAttributeNS(null, "begin",
> "mouseover");
> el.appendChild(mouseOver);
> Element mouseOut = doc.createElementNS(svgNS,
> "set");
> mouseOut.setAttributeNS(null, "attributeName",
> "fill");
> mouseOut.setAttributeNS(null, "attributeType",
> "XML");
> mouseOut.setAttributeNS(null, "to",
> el.getAttribute("fill"));
> mouseOut.setAttributeNS(null, "begin",
> "mouseout");
> el.appendChild(mouseOut);
> }
> ----------------------------------------------------------------
> SVGArea class:
>
> package de.unidue.inf.xmlvis.gui.svg;
>
> import java.awt.event.MouseWheelEvent;
> import java.awt.event.MouseWheelListener;
>
> import javax.swing.SwingUtilities;
>
> import org.apache.batik.dom.svg.SVGDOMImplementation;
> import org.apache.batik.swing.JSVGCanvas;
> import org.apache.batik.swing.gvt.GVTTreeRendererEvent;
> import org.apache.batik.swing.gvt.GVTTreeRendererListener;
> import org.apache.batik.swing.svg.GVTTreeBuilderEvent;
> import org.apache.batik.swing.svg.GVTTreeBuilderListener;
> import
> org.apache.batik.swing.svg.SVGLoadEventDispatcherEvent;
> import
> org.apache.batik.swing.svg.SVGLoadEventDispatcherListener;
> import org.apache.log4j.Logger;
> import org.w3c.dom.DOMImplementation;
> import org.w3c.dom.Document;
> import org.w3c.dom.Element;
> import org.w3c.dom.svg.SVGDocument;
>
> import de.unidue.inf.xmlvis.gui.StatusBarManager;
>
> public class SVGArea extends JSVGCanvas implements
> SVGLoadEventDispatcherListener, GVTTreeRendererListener,
> GVTTreeBuilderListener,
> MouseWheelListener {
>
> private static final long serialVersionUID =
> -4835732750510548844L;
> @SuppressWarnings("unused")
> private static final Logger logger =
> Logger.getLogger(SVGArea.class);
> private static final String svgNS =
> SVGDOMImplementation.SVG_NAMESPACE_URI;
> private static final DOMImplementation impl =
> SVGDOMImplementation.getDOMImplementation();
> private int width;
> private int height;
> private Document doc = null;
> private Element svgRoot;
> private JSVGScrollPane scroll;
>
> public SVGArea() {
> super(null, true, false);
> addSVGLoadEventDispatcherListener(this);
> addGVTTreeRendererListener(this);
> addGVTTreeBuilderListener(this);
> addMouseWheelListener(this);
> setDocumentState(JSVGCanvas.ALWAYS_DYNAMIC);
> doc = impl.createDocument(svgNS, "svg", null);
> svgRoot = doc.getDocumentElement();
> }
>
> public void setDocument() {
> setSVGDocument((SVGDocument) doc);
> }
>
> public Document getDocument() {
> return doc;
> }
>
> public void resetSVGDocument() {
> doc = impl.createDocument(svgNS, "svg", null);
> svgRoot = doc.getDocumentElement();
> }
>
> @Override
> public void
> svgLoadEventDispatchCancelled(SVGLoadEventDispatcherEvent
> e) {
> StatusBarManager.svgLoadEventDispatchCancelled();
> }
>
> @Override
> public void
> svgLoadEventDispatchCompleted(SVGLoadEventDispatcherEvent
> e) {
> }
>
> @Override
> public void
> svgLoadEventDispatchFailed(SVGLoadEventDispatcherEvent e) {
> StatusBarManager.svgLoadEventDispatchFailed();
> }
>
> @Override
> public void
> svgLoadEventDispatchStarted(SVGLoadEventDispatcherEvent e)
> {
> StatusBarManager.svgLoadEventDispatchStarted();
> }
>
> @Override
> public void gvtRenderingCancelled(GVTTreeRendererEvent e)
> {
> }
>
> @Override
> public void gvtRenderingCompleted(GVTTreeRendererEvent e)
> {
> StatusBarManager.gvtRenderingCompleted();
> }
>
> @Override
> public void gvtRenderingFailed(GVTTreeRendererEvent e) {
> }
>
> @Override
> public void gvtRenderingPrepare(GVTTreeRendererEvent e) {
> }
>
> @Override
> public void gvtRenderingStarted(GVTTreeRendererEvent e) {
> }
>
> @Override
> public void gvtBuildCancelled(GVTTreeBuilderEvent e) {
> }
>
> @Override
> public void gvtBuildCompleted(GVTTreeBuilderEvent e) {
> }
>
> @Override
> public void gvtBuildFailed(GVTTreeBuilderEvent e) {
> }
>
> @Override
> public void gvtBuildStarted(GVTTreeBuilderEvent e) {
> }
>
> public void setSVGSize(int width, int height) {
> this.width = width;
> this.height = height;
> svgRoot.setAttributeNS(null, "width",
> String.valueOf(width));
> svgRoot.setAttributeNS(null, "height",
> String.valueOf(height));
> SVGAreaPainter painter = new SVGAreaPainter(this);
> painter.drawText(0, 0, ".", 1);
> painter.drawText(width, height, ".", 1);
> }
>
> public float getSVGWidth() {
> return width;
> }
>
> public float getSVGHeight() {
> return height;
> }
>
> @Override
> public void mouseWheelMoved(final MouseWheelEvent e) {
> SwingUtilities.invokeLater(new Runnable() {
>
> @Override
> public void run() {
> // An das passende ScrollPane weiterleiten
> if (scroll != null) {
> scroll.dispatchEvent(e);
> }
> }
>
> });
>
> }
>
> public void setScroll(JSVGScrollPane scroll) {
> this.scroll = scroll;
> }
> }
>
> --- Cameron McCormack <cam@...> schrieb am Mi,
> 28.5.2008:
> Von: Cameron McCormack <cam@...>
> Betreff: Re: Repainting a JSVGCanvas
> An: batik-users@...
> Datum: Mittwoch, 28. Mai 2008, 9:04
>
> aaaa aaaa: > the problem is that I get occasionally a
> NullPointerException in the > ScrollListener of the
> JSVGCanvas. The variable "newview" is null in
> > the updateCompleted method .  Hmm.  I’m not sure
> what would cause getViewBoxRect() to return null if all you
> are doing is resizing, unless there’s a threading issue.
> > Rectangle2D newview = getViewBoxRect(); >  > So
> sometimes the canvas gets white and it has to be repaint.
> It's > immediatly repainted when I resize the frame
> or when I'm using the > scrollbars. But I've
> inserted > > if (newview == null) { >
> canvas.getUpdateManager().getUpdateRunnableQueue().invokeLater(new
> Runnable() { >  > @Override > public void
> run() { > canvas.repaint(); > } >  >
> }); > return; > } >  > and this does
> not have any effect. Another solution maybe would be to >
> avoid to get the Exception. But I don't see what I'm
> doing wrong.  I don’t think calling canvas.repaint() is
> the right
>  thing to fix the problem.  It sounds like there is a
> problem with JSVGScrollPane or JSVGCanvas.  Are you able to
> provide a reduced test case that demonstrates the problem
> (perhaps just loading a small SVG document in a
> JSVGScrollPane/JSVGCanvas, where continually resizing it
> will trigger the bug)?  Thanks,  Cameron  --  Cameron
> McCormack ≝ http://mcc.id.au/ 
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