[vtk-developers] Charts API: Color by LUT

[Eric E. Monson]

Hey Marcus,

No problem -- I know you're busy. I'm basically just setting a LUT that the plot owns, and then passing an array of colors and using glColorPointer in an alternate DrawPointSprites routine to efficiently draw the points. I'm trying to keep the API as simple as possible, leaving the range setting, etc, in the LUT so it won't get as complicated as vtkMapper. I'll try extending it to the parallel coordinates plot since that's the other case I need, and then I'll try to push it to Gerrit for you to peruse.

I'm curious how you're integrating the color transfer function editor into your system. As long as you don't _have_ to use it to define a simple colormap for the scatter & pc plots, it sounds great. It would be nice to have a CTF editor outside of ParaView, and if it let's you also define the alpha map, that's very cool.

Good luck with your stuff and I'll talk to you later,
-Eric


On Nov 5, 2010, at 4:56 PM, Marcus D. Hanwell wrote:

> Hi Eric,
> 
> Apologies for not getting back to you, I am busy preparing for a trip and getting some things finished up. I have some work getting ready for inclusion with 2D histograms, and they are colored by scalars. I was thinking about applying the same technique to scatter/line plots, but I am certainly interested in the approach you are using.
> 
> We have the color transfer function editor, and the approach I am using will tie in with that. I am not 100% clear on what you are doing, but would love to take a look. have a screenshot of my own on another system showing a 2D histogram colored by a scalar field. Do you want to push it to Gerrit at some point?
> 
> I have a backlog to get through, but would certainly like to get this functionality into the charts.
> 
> Marcus
> 
> On Nov 5, 2010, at 4:42 PM, Eric E. Monson wrote:
> 
>> Hey Marcus,
>> 
>> I'm making some progress with pretty basic functionality in the points plot for now. I'll probably try to get it working for parallel coordinates on Monday, and then run a patch by you to see if you think I'm on the right track.
>> 
>> Thanks,
>> -Eric
>> 
>> <ScatterColorByArray_rev1.png>
>> 
>> On Nov 4, 2010, at 2:12 PM, Eric E. Monson wrote:
>> 
>>> Hey Marcus,
>>> 
>>> Back in August someone brought up the issue of coloring points in a plot (e.g. scatter) according to the values in another array. I've never done any OpenGL programming, but I think I see how it can be done efficiently. Before I start playing around with it, though, I wanted to check whether this is something you guys are already implementing for near-term deployment? (I'm going to need it soon for a project.)
>>> 
>>> Talk to you later,
>>> -Eric
>>> 
>>> ------------------------------------------------------
>>> Eric E Monson
>>> Duke Visualization Technology Group
>>> 
> 

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