fix: fit backdrops on navigation instead of forcing 100% zoom

[charlesangus]

Problem

Navigating to a backdrop with Alt+A zoomed in too far on large backdrops, while small ones looked fine — an inconsistent "sometimes" framing. Selecting the same backdrop and running zoomToFitSelected() in the Script Editor framed it correctly.

This is a pre-existing bug, independent of the #61 / #62 / #63 module-margin work.

Root cause

navigate_to_backdrop() called nuke.zoom(1.0, [center_x, center_y]). The first argument is an absolute zoom scale (100% — one node-grid unit per screen pixel), not a fit. So it always jumped to 100% regardless of backdrop size:

• Large backdrop → 100% is far more zoomed-in than fit → too far in.
• Small backdrop (~viewport-sized at 100%) → happens to look right.

The center math was correct; only the hardcoded scale was wrong.

Fix

Select the backdrop and call nuke.zoomToFitSelected(), so the scale adapts to the backdrop's size — the same thing that works from the Script Editor.

nukescripts.clear_selection_recursive()
backdrop_node['selected'].setValue(True)
nuke.zoomToFitSelected()
nukescripts.clear_selection_recursive()

The old docstring justified avoiding zoomToFitSelected() to target a Group's internal DAG panel rather than the root DAG. That reasoning is obsolete: navigation is dispatched after the picker closes via QtCore.QTimer.singleShot (_anchor_navigate_invoke), so the focused panel is already active — the exact path navigate_to_anchor() already uses with zoomToFitSelected().

Tests

• Updated test_navigate_to_backdrop_selects_and_zooms to assert zoomToFitSelected() is called.
• Added test_navigate_to_backdrop_does_not_force_fixed_zoom — asserts no absolute zoom scale is set.

Full suite: 486 passed.

UAT

Pending — to be performed in Nuke by the maintainer:

• Navigate to a large backdrop with Alt+A → confirm it now fits (no longer zoomed in too far).
• Navigate to a small backdrop → still framed sensibly.
• Confirm backdrops inside a Group's node graph also fit correctly (the panel-targeting case the old docstring worried about).

[Copilot]

Copilot encountered an error and was unable to review this pull request. You can try again by re-requesting a review.

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.