Add an option to control the discretization of colormap

[xyont]

Context F3D is able to display data using a color map. By default, the discretization of the colormap is 256. It would be nice to add a way to control that discretization.

Suggested Solution

• Add a CLI option (--colormap-discretization) in F3DOptionParser
• Add a libf3d option (model.scivis.discretization) in options
• Add a dedicated member in vtkF3DRendererWithColoring and takes it into account in ConfigureRangeAndCTFForColoring

Original Issue

dear Developers,

i did not know is this feature available yet or not, several times i read the documentation but i can not find for such purpose.

Paraview has capability to setting number of color discretization, hopefully is not complex things and F3D also capable to do the same. it's a common in engineering representation.

best regards, SN

[mwestphal]

What about using Step color space ?

[Meakk]

I think it's unrelated to step color space, just the number of computed colors in the lookup table.
We could use vtkDiscretizableColorTransferFunction and add a new option to set the number of colors.

[mwestphal]

Indeed, but being able to choose the step color space resolve the usecase in a different way and open the door to other color spaces.

[mwestphal]

That being said, adding the number of colors should be quite an easy feature to add. Feel free to contribute if you can @xyont

[xyont]

i'm new to graphics especially in VTK, not a really programmer also. however, it's interesting subject in which lead me to start learn something.

[mwestphal]

Added context and suggested solution.

[MarcosDanielTorres]

Hi! Maybe I can take this?

[mwestphal]

Sure!

[gapry]

@mwestphal I'd like to work on this issue. Could you please assign it to me?

[mwestphal]

Of course! Feel free to join our discord if you want :)

https://discord.f3d.app