Controling/adding colormaps in colormap widget

[pierre-sepulchre]

Would it be possible to add more colormaps in the dedicated widget, i.e. using custom colormaps defined earlier in the notebooks ? In : # Colormap choice widget colormap = Dropdown( options=colormaps, description='colormap:' )

For now colormaps is :

{'BrBG': 0, 'PRGn': 1, 'PiYG': 2, 'PuOr': 3, 'RdBu': 4, 'RdGy': 5, 'RdYlBu': 6, 'RdYlGn': 7, 'Spectral': 8, 'BuGn': 9, 'BuPu': 10, 'GnBu': 11, 'OrRd': 12, 'PuBuGn': 13, 'PuBu': 14, 'PuRd': 15, 'RdPu': 16, 'YlGnBu': 17, 'YlGn': 18, 'YlOrBr': 19, 'YlOrRd': 20, 'Blues': 21, 'Greens': 22, 'Greys': 23, 'Purples': 24, 'Reds': 25, 'Oranges': 26, 'Cividis': 27, 'CubehelixDefault': 28, 'Rainbow': 29, 'Warm': 30, 'Cool': 31, 'Sinebow': 32, 'Turbo': 33, 'Viridis': 34, 'Magma': 35, 'Inferno': 36, 'Plasma': 37}

[WesleyTheGeolien]

I'm guessing:

class IsoColorModel extends EffectModel {

  defaults() {
    return {...super.defaults(),
      _model_name: IsoColorModel.model_name,
      min: 0.,
      max: 0.,
      range: [0., 0.],
      colormap: 34,
      type: 'linear',
    };
  }

this is getting passed to this w:

function deserialize_float32array (data: any, manager: any) {
    return new Float32Array(data.data.buffer);
}

which is somehow changing the colormap?

I saw something about d3 in the commit log as well ....

Could an option be to interpret the python (or other) colormap then pass the data array through to the javascript somehow?

[martinRenou]

I started some work in draft PRs (see https://github.com/QuantStack/ipygany/pull/23 and https://github.com/QuantStack/GanyJS/pull/9) to add Paraview colormaps support, and my idea was that at some point users could define their own colormaps with a list of colors and control points, just like in Paraview.

This is not possible yet though.

[martinRenou]

Could an option be to interpret the python (or other) colormap then pass the data array through to the javascript somehow?

The IsoColor is not using deserialize_float32array, it is just passing the colormap index (34 by default for Viridis), that the JavaScript side is able to map to the right colormap in GanyJS.