Possible rendering anomaly when panning zoomed chart

[John Matthews]

I noticed this report of a possible rendering anomaly when panning a zoomed time series chart. The effect can be reproduced using this example and the release JARs for jfreechart-1.0.14 & jcommon-1.0.17. Can anyone see an obvious flaw in the example?

[david.gilbert]

Can anyone see an obvious flaw in the example?

No, the example is fine - and excellent for reproducing the defect (just be sure to right-click on the chart and select 'Zoom In' > 'Domain Axis' before panning around).

I've spent some time debugging, and the issue is in the RendererUtilities.findLiveItems() method, which is trying to exclude data items that cannot appear on the chart. For the case where the dataset has no guaranteed x-value ordering, and all the x-values are outside the axis range (at least one lower than the lower bound, and at least one higher than the upper bound), the method is not returning the correct item indices. I'm trying to find a good fix for this.

[david.gilbert]

I don't have more time to look at this tonight, but this patch probably solves the issue:

Code: Select all

Index: RendererUtilities.java
--- RendererUtilities.java Remotely Modified (Based On HEAD)
+++ RendererUtilities.java Locally Modified (Based On LOCAL)
@@ -138,7 +138,7 @@
             int index = 0;
             // skip any items that don't need including...
             double x = dataset.getXValue(series, index);
-            while (index < itemCount && (x < xLow || x > xHigh)) {
+            while (index < itemCount && x < xLow) {
                 index++;
                 if (index < itemCount) {
                     x = dataset.getXValue(series, index);
@@ -232,7 +232,7 @@
             int index = itemCount - 1;
             // skip any items that don't need including...
             double x = dataset.getXValue(series, index);
-            while (index >= 0 && (x < xLow || x > xHigh)) {
+            while (index >= 0 && x > xHigh) {
                 index--;
                 if (index >= 0) {
                     x = dataset.getXValue(series, index);

[John Matthews]

Thank you for looking at this! I've cited a link to this thread. Please let me know if I should do anything else, e.g. file a bug report.

[david.gilbert]

The fix has been committed in SVN for the upcoming 1.0.15 release. Thanks for reporting the issue.