howto: colorbar in FigureFactory.create_trisurf()

[ntfrgl]

For many applications, a colour bar is essential for visual interpretation, but I couldn't find a parameter or example in the documentation indicating how to add one to a trisurf rendering. Based on the documentation on trisurf, surface coloring and meshes, I guessed that adding a colour bar dict into the Mesh3d data could do the job, but this was ineffectual. What would be the right way?

Below is an example for ipython notebook using a mesh from the FAUST dataset, the trimesh library and the default trisurf colouring (z-value). The line before the last is my failed attempt.

import trimesh
mesh = trimesh.load_mesh('tr_reg_003.ply')
x, y, z = mesh.vertices.T
size = (mesh.vertices.max(axis=0) - mesh.vertices.min(axis=0)).T

import plotly.offline as py
import plotly.graph_objs as go
from plotly.tools import FigureFactory as ff
py.init_notebook_mode()
fig = ff.create_trisurf(
    x=x, y=y, z=z, simplices=mesh.faces, colormap='Viridis',
    aspectratio={'x': size[0], 'y': size[1], 'z': size[2]})
fig.data[0].update(colorbar=go.ColorBar(title='z'))
py.iplot(fig)

Also, an option for create_trisurf() setting the aspect ratio based on the mesh extent (as done above manually) would be useful.

[Kully]

@ntfrgl I am looking at it now. I swear I remember a colorbar already being in create_trisurf. I think I may be able to add it.

[ntfrgl]

Any news on this?

[Kully]

Hi there, I think I already added the colorbar. Just download the latest package of plotly and it should be there. I apologize for not responding to this sooner.

[ntfrgl]

Could you please be more specific, e.g. pointing to a commit? The example still doesn't produce a colorbar, and I couldn't find a new relevant option or documentation example for create_trisurf().

[Kully]

Hi again. Yes, the PR was this: #518

A test related to the 2d-density part of it is still failing, so I have to tend to it. I don't know if that has anything the colorbar not showing up (it should be there) but I'll figure it out hopefully today.

[ntfrgl]

I see, thank you.

Unfortunately, this still doesn't solve my problem, because create_trisurf() hasn't been touched by this PR. Looking at the new _make_linear_colorscale(), I tried the following, in analogy to the failed approach shown above:

fig.data[0].update(colorscale=ff._make_linear_colorscale(ff._validate_colors('Viridis', 'rgb')))

And again, although the mesh3d data structure is augmented, no colorbar is displayed. So what I hope for is the following:

• A way to manipulate the data structure s.t. a colorbar is shown. There seems to be some glue missing between the Python API and the JS API.
• A simple parameter for create_trisurf() to do exactly this.
• Documentation for these.

[Kully]

A PR is on the way. Tests need to pass first. #531

[Kully]

@ntfrgl ^^^^

[Kully]

@ntfrgl Alright, version 1.12.5 is available now with a visible colorbar in create_trisurf: