Skip to main content


Eclipse Community Forums
Forum Search:

Search      Help    Register    Login    Home
Home » Eclipse Projects » Nebula » Possible Error in XYGraph(Certain values for points in a trace trigger ArrayIndexOutOfBounds exceptions.)
Possible Error in XYGraph [message #1619044] Mon, 16 February 2015 09:49 Go to next message
Alex Clayton is currently offline Alex ClaytonFriend
Messages: 8
Registered: February 2015
Junior Member
Hi

I think I may of discovered a possible error in Visualization XYGraph package. Namely certain combination of points and axes results in an ArrayIndexOutOfBounds exception when the graph is drawn.

The simplest example I could find to replicate it was:

public class ErrorExample {

	public static void main(String[] args) {
		final Shell shell = new Shell();
		shell.setSize(300, 250);
	    shell.open();
	    
	    //use LightweightSystem to create the bridge between SWT and draw2D
		final LightweightSystem lws = new LightweightSystem(shell);
		
		//create a new XY Graph.
		XYGraph xyGraph = new XYGraph();
		xyGraph.setTitle("Error Example");
		xyGraph.primaryYAxis.setTitle("Y - axis");
		xyGraph.primaryXAxis.setTitle("X - axis");
		xyGraph.primaryYAxis.setAutoScale(false);
		xyGraph.primaryXAxis.setAutoScale(false);
		xyGraph.primaryXAxis.setShowMajorGrid(true);
		xyGraph.primaryYAxis.setShowMajorGrid(true);
		xyGraph.primaryXAxis.setRange(new Range(0.0,5.0));
		xyGraph.primaryYAxis.setRange(new Range(0.0,10.0));
		//set it as the content of LightwightSystem
		lws.setContents(xyGraph);
		
		//create a trace data provider, which will provide the data to the trace.
		CircularBufferDataProvider traceDataProvider = new CircularBufferDataProvider(false);
		traceDataProvider.setBufferSize(100);	
		traceDataProvider.addSample(new Sample(-1, 11));
		traceDataProvider.addSample(new Sample(6,4));
		
		//create the trace
		Trace trace = new Trace("Trace1-XY Plot", 
				xyGraph.primaryXAxis, xyGraph.primaryYAxis, traceDataProvider);
		
		//set trace property
		trace.setPointStyle(PointStyle.XCROSS);

		//add the trace to xyGraph
		xyGraph.addTrace(trace);
					
	   
	    Display display = Display.getDefault();
	    while (!shell.isDisposed()) {
	      if (!display.readAndDispatch())
	        display.sleep();
	    }
	   
	}

}


When run this crashes with the following stack trace.

Exception in thread "main" org.eclipse.swt.SWTException: Failed to execute runnable (java.lang.ArrayIndexOutOfBoundsException: 2)
	at org.eclipse.swt.SWT.error(Unknown Source)
	at org.eclipse.swt.SWT.error(Unknown Source)
	at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Unknown Source)
	at org.eclipse.swt.widgets.Display.runAsyncMessages(Unknown Source)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Unknown Source)
	at com.example.ErrorExample.main(ErrorExample.java:56)
Caused by: java.lang.ArrayIndexOutOfBoundsException: 2
	at org.eclipse.nebula.visualization.xygraph.figures.Trace.getStraightLineIntersection(Trace.java:1091)
	at org.eclipse.nebula.visualization.xygraph.figures.Trace.getIntersection(Trace.java:1033)
	at org.eclipse.nebula.visualization.xygraph.figures.Trace.paintFigure(Trace.java:700)
	at org.eclipse.draw2d.Figure.paint(Figure.java:1115)
	at org.eclipse.draw2d.Figure.paintChildren(Figure.java:1167)
	at org.eclipse.draw2d.Figure.paintClientArea(Figure.java:1202)
	at org.eclipse.nebula.visualization.xygraph.figures.PlotArea.paintClientArea(PlotArea.java:232)
	at org.eclipse.draw2d.Figure.paint(Figure.java:1117)
	at org.eclipse.draw2d.Figure.paintChildren(Figure.java:1167)
	at org.eclipse.draw2d.Figure.paintClientArea(Figure.java:1202)
	at org.eclipse.draw2d.Figure.paint(Figure.java:1117)
	at org.eclipse.draw2d.Figure.paintChildren(Figure.java:1167)
	at org.eclipse.draw2d.Figure.paintClientArea(Figure.java:1202)
	at org.eclipse.draw2d.Figure.paint(Figure.java:1117)
	at org.eclipse.draw2d.DeferredUpdateManager.paint(DeferredUpdateManager.java:165)
	at org.eclipse.draw2d.LightweightSystem.paint(LightweightSystem.java:203)
	at org.eclipse.draw2d.LightweightSystem$2.handleEvent(LightweightSystem.java:110)
	at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
	at org.eclipse.swt.widgets.Display.sendEvent(Unknown Source)
	at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
	at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
	at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
	at org.eclipse.swt.widgets.Control.drawWidget(Unknown Source)
	at org.eclipse.swt.widgets.Canvas.drawWidget(Unknown Source)
	at org.eclipse.swt.widgets.Widget.drawRect(Unknown Source)
	at org.eclipse.swt.widgets.Canvas.drawRect(Unknown Source)
	at org.eclipse.swt.widgets.Display.windowProc(Unknown Source)
	at org.eclipse.swt.internal.cocoa.OS.objc_msgSend(Native Method)
	at org.eclipse.swt.internal.cocoa.NSView.displayIfNeeded(Unknown Source)
	at org.eclipse.swt.widgets.Control.update(Unknown Source)
	at org.eclipse.swt.widgets.Control.update(Unknown Source)
	at org.eclipse.draw2d.NativeGraphicsSource.getGraphics(NativeGraphicsSource.java:48)
	at org.eclipse.draw2d.DeferredUpdateManager.getGraphics(DeferredUpdateManager.java:147)
	at org.eclipse.draw2d.DeferredUpdateManager.repairDamage(DeferredUpdateManager.java:310)
	at org.eclipse.draw2d.DeferredUpdateManager.performUpdate(DeferredUpdateManager.java:192)
	at org.eclipse.draw2d.DeferredUpdateManager$UpdateRequest.run(DeferredUpdateManager.java:44)
	at org.eclipse.swt.widgets.RunnableLock.run(Unknown Source)
	... 4 more


From the stack trace I think the problem may be caused by the following method in the Trace class:

private ISample[] getStraightLineIntersection(final ISample dp1,
			final ISample dp2) {
		final double x1 = dp1.getXValue();
		final double y1 = dp1.getYValue();
		final double x2 = dp2.getXValue();
		final double y2 = dp2.getYValue();
		final double dx = x2 - x1;
		final double dy = y2 - y1;
		final ISample[] dpTuple = new Sample[2];
		int count = 0; // number of valid dbTuple entries
		double x, y;

		if (dy != 0.0) { // Intersection with lower xAxis
			final double ymin = yAxis.getRange().getLower();
			x = (ymin - y1) * dx / dy + x1;
			y = ymin;
			if (evalDP(x, y, dp1, dp2))
				dpTuple[count++] = new Sample(x, y);
			// Intersection with upper xAxis
			final double ymax = yAxis.getRange().getUpper();
			x = (ymax - y1) * dx / dy + x1;
			y = ymax;
			if (evalDP(x, y, dp1, dp2))
				dpTuple[count++] = new Sample(x, y);
		}
		// A line that runs diagonally through the plot,
		// hitting for example the lower left as well as upper right corners
		// would cut both X as well as both Y axes.
		// Return only the X axes hits, since Y axes hits are actually the
		// same points.
		if (count == 2)
			return dpTuple;
		if (dx != 0.0) { // Intersection with left yAxis
			final double xmin = xAxis.getRange().getLower();
			x = xmin;
			y = (xmin - x1) * dy / dx + y1;
			if (evalDP(x, y, dp1, dp2))
				dpTuple[count++] = new Sample(x, y);
			// Intersection with right yAxis
			final double xmax = xAxis.getRange().getUpper();
			x = xmax;
			y = (xmax - x1) * dy / dx + y1;
			if (dx != 0 && evalDP(x, y, dp1, dp2))
				dpTuple[count++] = new Sample(x, y);
		}
		return dpTuple;
	}


It seems if you get one match in the 'X Axis' block and then another two
matches in the 'Y Axis' block then the out of bounds error will be triggered.

Is there a bug out for this, I had a brief look on the bugzilla page but could not find any? Do I need to raise one?
Re: Possible Error in XYGraph [message #1622144 is a reply to message #1619044] Wed, 18 February 2015 09:44 Go to previous messageGo to next message
Wim Jongman is currently offline Wim JongmanFriend
Messages: 432
Registered: July 2009
Senior Member

Hi Alex,

Yes this looks like a bug. Thanks for finding it. Please file a bug against Nebula/Visualization [1] and post the bugnumber here.

It would be fantastic if you can supply a solution. We accept patches through Gerrit [2].

Cheers,

Wim

[1] https://bugs.eclipse.org/bugs/enter_bug.cgi?product=Nebula&component=Visualization
[2] http://wiki.eclipse.org/Nebula/Contributions
Re: Possible Error in XYGraph [message #1622161 is a reply to message #1622144] Wed, 18 February 2015 09:55 Go to previous message
Alex Clayton is currently offline Alex ClaytonFriend
Messages: 8
Registered: February 2015
Junior Member
Hi

Thanks for the reply.

I have raised this as bug 460119. (The forum won't let me post a link as I have
fewer then 5 messages)

I think I may have a solution, so will try and submit it via Gerrit later.

Thanks,
Alex
Previous Topic:control width of combo box?
Next Topic:tablecombo showing image and text even if I dispose the table items
Goto Forum:
  


Current Time: Sun Nov 18 21:31:00 GMT 2018

Powered by FUDForum. Page generated in 0.02505 seconds
.:: Contact :: Home ::.

Powered by: FUDforum 3.0.2.
Copyright ©2001-2010 FUDforum Bulletin Board Software

Back to the top