FNS_TimelineRegistry

Timeline Registry #

TouchDesigner's timeline bar is a fixed piece of chrome. This registry makes it extensible: a tool publishes a panel COMP and it appears in the bar, in a zone it picks, without that tool knowing anything about the dialog's layout.

Nothing stock is moved or re-expressed. Contributions are shown through Select COMP mirrors anchored to TD's own blocks, and /ui is never saved with a project, so the whole surface is rebuilt on every load — the registry re-registers rather than restoring.

It ships as its own core package, promoted to /sys (global shortcut op.FNS_TIMELINEREGISTRY), alongside the other surface registries.

With nothing contributed it claims nothing at all. The surface appears with the first registration and disappears with the last, and the bar returns to its stock height.

The three zones #

• transport — beside TD's own play controls, in the existing row.
• properties — with the time-properties block at the left.
• background — a full-width strip in the frame-ruler band, drawn underneath the ruler numbers (TD's own ruler background is transparent, so it shows through).

background is a grow zone: rather than taking its height out of the transport row and clipping the controls, it makes the bar taller by its own height and the bar's fixed-height blocks follow. The dialog height is always recomputed as base plus growth, never incremented — the bar's height is saved in the .toe while /sys is not, so an increment-and-restore scheme would creep taller every session.

For tool authors #

A tool that wants a timeline widget ships a small host copy of this registry, the same shape as a toolbar or navbar entry. The host's Registration page names the contribution: the tool COMP, a canonical name, the zone, order, and whether it is displayed.

From Python, op.FNS_TIMELINEREGISTRY.RegisterWidget(comp, 'mytool', zone='transport', order=20) does the same, with UnregisterWidget() and SetWidgetZone() as the rest of the API.

Registration is not instantaneous: the entry is stored first and its zone arrives with the host's parameter a frame later, so anything that depends on the final zone settles across a frame rather than asserting in the same pass.

FNS_TimelineTools is the reference consumer — it uses transport for its own controls and background for the media strip.