[vtk-developers] Charts in VTK and ParaView

[Marcus D. Hanwell]

Hi,

I wanted to give a summary of the progress made with charts in VTK and 
ParaView. Over the last couple of weeks I have been working on integrating the 
new VTK/OpenGL based charts into ParaView. I have the necessary proxies and 
filters in place so that you can now select the columns of the table to be 
plotted. This work is all in VTK/ParaView CVS head.

http://www.vtk.org/Wiki/VTK/Charts/ChartAPI#Newer_Screenshot_in_ParaView

I have been working on achieving feature parity with the existing line charts. 
So the vtkChartXY class now contains functions to add and manage the plots. 
The axes can automatically calculate "pretty numbers" to be used for tick 
locations/marks. I have also added line stippling in addition to the coloring, 
and the mouse interaction features (using vtkContextScene) allow zooming and 
panning as you would expect.

You can also select the X column to be used, or use the index of the array. 
This is all exposed in the ParaView interface under the XY Chart 
(EXPERIMENTAL) view type. I am currently adding some facilities to choose 
colors automatically and place a legend on the chart. This is all exposed in 
the VTK API, and it is possible to do more in that API than can is currently 
exposed in the ParaView GUI.

The classes in VTK/Charts, specifically vtkChart* and vtkPlot* expose much of 
this functionality. Mouse interaction is now handled by the vtkContextScene 
class, with panning and zomming support already present.

Selection support will require some additional hooks, but is something I hope 
to add in soon. Work on a new Mark API should help us to generalize how 
multiple arrays can be mapped onto plots in charts (such as color, mark size, 
etc).

I would appreciate feedback on this work as it currently stands. I will be 
working away to flash out the holes I see for ParaView and a general line chart 
display. I will also be fixing bugs, adding tests, and hopefully exposing a few 
of the new features in the ParaView GUI (such as scientific style axes - at the 
origin as you pan around).

Thanks,

Marcus
-- 
Marcus D. Hanwell, Ph.D.
R&D Engineer, Kitware Inc.
(518) 881-4937