[vtkusers] abnormal chart using scatter points

[Eric E. Monson]

Hello,

Which version of VTK are you using? I've definitely drawn scatter plots using the Charts API that had more than 40,000 points, and this is something the Charts are supposed to be good at, so it will be interesting to see what has gone wrong in your case. The VTK version is important because a lot of development has gone on in the Charts since 5.6, so if you're using 5.6 the bug may already have been fixed.

Otherwise, if you're using the development head and this is still happening, maybe you can pass along a minimal piece of code that demonstrates the problem and we can help figure out what's going on.

Talk to you later,
-Eric

· · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · ·
Eric E Monson
Duke Visualization Technology Group


On Mar 28, 2011, at 1:43 AM, liuxy wrote:

> I used vtkChart API to draw a line: y=sin(x) using "scatter points",
> 
> the chart is abnormal when the number of points are more than 40,000.  
> 
> just like pictrue a.jpg in enclosure.
> 
> but if the points are less than 40,000 or using "Line" to draw y=sin(x),
> 
> the chart is correct. Just like pictrue b.jpg.
> 
> I want to know how to use "scatter points" in drawing charts with huge scale of points ?
> 
> or vtkChart may be not applicable in this situation ?
> 
> 
> P.S:
> 
> By reading the source Code of vtkChart,
> 
> I found when drawing in "scatter points", 
> 
> it used function 'DrawPointSprites'.
> 
> if replaced it with function 'DrawPoints',the chart shows correctly,
> 
> even number of points more than 40,000.
> <a.JPG><b.JPG>_______________________________________________
> Powered by www.kitware.com
> 
> Visit other Kitware open-source projects at http://www.kitware.com/opensource/opensource.html
> 
> Please keep messages on-topic and check the VTK FAQ at: http://www.vtk.org/Wiki/VTK_FAQ
> 
> Follow this link to subscribe/unsubscribe:
> http://www.vtk.org/mailman/listinfo/vtkusers