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Extend NGLView classes

Structures | Trajectories | Interface class | Register your backend

Structures

import nglview
struc = nglview.PdbIdStructure("3pqr")     # load file from RCSB PDB
view = nglview.NGLWidget(struc)            # create widget
view                                       # display widget

Trajectories

To enable trajectory access pass a second Trajectory argument to the widget constructor or supply a combined Structure/Trajectory object as the first argument.

Seperate Structure and Trajectory objects using FileStructure and SimpletrajStructure (requires the simpletraj package):

import nglview
struc = nglview.FileStructure(nglview.datafiles.GRO)
traj = nglview.SimpletrajStructure(nglview.datafiles.XTC)
nglview.NGLWidget(struc, traj)

Combined Structure/Trajectory object utilizing MDTrajTrajectory which wraps a trajectory loaded with MDTraj:

import nglview
import mdtraj
traj = mdtraj.load(nglview.datafiles.XTC, top=nglview.datafiles.GRO)
ngl_traj = nglview.MDTrajTrajectory(traj)
view = nglview.NGLWidget(ngl_traj)
view

You can also add more trajectories to the widget

ngl_traj2 = nglview.MDTrajTrajectory(traj2)
view.add_trajectory(ngl_traj2)

Interface classes

You can create your own adaptors simply by following the interfaces for Structure and Trajectory, which can also be combined into a single class.

Structure

class MyStructure(nglview.Structure):
    ext = "pdb"  # or gro, cif, mol2, sdf
    params = {}  # loading options passed to NGL
    def get_structure_string(self):
        return "structure in the self.ext format"

Trajectory

class MyTrajectory(nglview.Trajectory):
    def get_coordinates(self, index):
        # return 2D numpy array, shape=(n_atoms, 3)

    @property
    def n_frames(self):
        return 2  # return number of frames

Combined

class MyStructureTrajectory(nglview.Structure, nglview.Trajectory):
    ext = "pdb"  # or gro, cif, mol2, sdf
    params = {}  # loading options passed to NGL

    def get_structure_string(self):
        return "structure in the self.ext format"

    def get_coordinates(self, index):
        # return 2D numpy array, shape=(n_atoms, 3)
        
    def n_frames(self):
        # return total frames

Register your backend

from nglview import register_backend

@register_backend(your_package_name)
class NewTrajectoryClass:
    def __init__(your_traj, *args, **kwargs):
        # define your own implementation here
    ...

# if you already register your class, you can add `your_traj` directly to `view`
# without creating `NewTrajectoryClass` instance.
view.add_trajectory(your_traj)

Further reading: nglview/adaptor.py