Trajectories rendered as snapshots

[mattwthompson]

For at least the trajectories I've look at on my machine today, pressing the "play" button results in the slider moving along but no changes to atomic positions:

Timestep 0:

Timestep 5:

I happen to see the same thing with the GROMACS XTC trajectory at the end of the example.

[Yoshanuikabundi]

This is a long standing problem unfortunately. NGLView is designed to pass trajectory frames one at a time from Python world to JavaScript world, and only the JavaScript world can be embedded in a browser. Each time the UI requests a new frame, the old one is discarded and the new one sent over from Python world, so the browser only has one frame at a time, and so entire trajectories cannot be embedded (without embedding a Python interpreter).

NGL (the JS library) does support loading several trajectory formats, so it would be theoretically possible to thread the needle just right so it works, but unless something's changed upstream in the last year or so this would require substantial contributions to NGLView (the Python library) and code changes in all the examples that use trajectories.

[hainm]

This is a long standing problem unfortunately. NGLView is designed to pass trajectory frames one at a time from Python world to JavaScript world, and only the JavaScript world can be embedded in a browser. Each time the UI requests a new frame, the old one is discarded and the new one sent over from Python world, so the browser only has one frame at a time, and so entire trajectories cannot be embedded (without embedding a Python interpreter).

@Yoshanuikabundi you could embed a subset of frames but while saving the HTML, you have to use frame_range:
(I forget this sometimes)

https://github.com/nglviewer/nglview/blob/09a6e232839aa8db3cbaf9633218b2fdcfd8d64e/nglview/widget.py#L65

[hainm]

nglviewer/nglview#687