CustomLine repeats across RadChart

[Willem]

When using the CustomLine drawn using RadChart annotations we are experiencing an issue if the slope of the line is very small and intercepts with the visible y-axis. 

The line will either repeat many times across the chart or disappear entirely.

To reproduce this issue please modify the sample from http://www.telerik.com/community/forums/silverlight/chart/annotation-text-on-customline.aspx  with the following sample data and line definition

MainPage.xaml.cs

dataCollection.Add(new DummyDataItem {XValue = 1, YValue = 0.02 });
dataCollection.Add(new DummyDataItem { XValue = 2, YValue = 0.01873752 });
dataCollection.Add(new DummyDataItem { XValue = 3, YValue = 0.01813006 });
dataCollection.Add(new DummyDataItem { XValue = 4, YValue = 0.01697080 });
dataCollection.Add(new DummyDataItem { XValue = 5, YValue = 0.01771891 });
dataCollection.Add(new DummyDataItem { XValue = 6, YValue = 0.01513730 });
dataCollection.Add(new DummyDataItem { XValue = 7, YValue = 0.01590351 });
dataCollection.Add(new DummyDataItem { XValue = 8, YValue = 0.01746018 });
dataCollection.Add(new DummyDataItem { XValue = 9, YValue = 0.01691618 });
dataCollection.Add(new DummyDataItem { XValue = 10, YValue = 0.01466685 });
dataCollection.Add(new DummyDataItem { XValue = 11, YValue = 0.01528516 });
dataCollection.Add(new DummyDataItem { XValue = 12, YValue = 0.01634741 });
dataCollection.Add(new DummyDataItem { XValue = 13, YValue = 0.01529021 });

MainPage.xaml

<telerik:CustomLine Style="{StaticResource gridLineStyle}"
                    DataContext="Test" Stroke="Red" Slope="0.0000030000000000001089" YIntercept="0.019997" />

[Missing User]

Hi Willem,

This kind of behavior is caused by a well-known limitation in Silverlight - Silverlight uses a 16-bit integer to calculate sizes. In your case, the CustomLine is rendered with a size greater than the max value of Int16 and this causes Silverlight to render it in multiple rows. As a work around, I can suggest that you set the line's Slope property to 0.

All the best,
Ivan N.
the Telerik team