Viewer UI

The viewer shows a small on-canvas UI so you can control the scene without writing code for every action.

You use it to:

• reset the camera,

• toggle fullscreen and background mode,

• start/stop simple animations (spin/swing),

• navigate trajectories (when available),

• open a synced popout view (when enabled).

Control buttons

The on-canvas buttons are:

• Reset: reset the camera view.

• Full: toggle fullscreen.

• Bg: toggle light/dark background.

• Spin: toggle continuous spin animation.

• Swing: toggle rocking animation.

• Pop: open a synced popout window (only when enabled).

Trajectory bar (structures)

If your molecular system has multiple structures, the viewer exposes a small trajectory bar. It stays disabled when there is only one structure.

You can:

• Step backward/forward by step using the − and + buttons.

• Play/pause using the play button (▶ / ⏸).

• Scrub to a structure index using the slider.

• Read the current position as current / total (1-based).

• Set the step size and playback FPS with the numeric fields.

Tip

• In MolSysViewer, “multiple structures” can be a trajectory (time-ordered) or an ensemble/model set.

Show/hide and placement

You can hide the on-canvas UI entirely:

view.set_controls_visible(False)

You can also enable autohide and configure placement:

view.set_controls_visible(
    True,
    autohide=True,
    position=["top", "right"],
    position_fullscreen=["bottom", "right"],
)

Defaults come from molsysviewer.config:

• molsysviewer.config.show_controls

• molsysviewer.config.autohide_controls

• molsysviewer.config.controls_position

• molsysviewer.config.controls_position_fullscreen

Popout

When the popout button is enabled, the popout viewer stays synced with the host:

• camera changes,

• spin/swing toggles,

• and scene operations (load, shapes, regions, layers).

Notes

• In docs-light exports (write_html(..., mode="lite")), popout requires a runtime URL and is controlled by include_popout.