Third stage of the adaptive tool area (shrink -> compact -> collapse).
When even the compact panels don't fit, DensitySwap picks a new
CollapsePanels widget that keeps a left prefix of panels inline and
collapses the rest to buttons; clicking a button opens the full panel as
an overlay flyout anchored below it (closes on outside press, mirroring
color_select's Floating).
A collapsed panel's button shows a live representative tool — the panel's
last-used tool (tracked per panel in Ribbon::note_panel_tool on every
tool click), defaulting to its first — rendered as a large icon. To
support this, render_small now also renders Large* items small and
render_large now renders plain Tool/Dropdown items large. Large dropdowns
render as icon + label + a bottom arrow strip via a shared
render_large_dropdown helper, used in both the full ribbon and collapsed
panels.
Ribbon dropdowns (tool dropdowns + undo/redo history) now anchor their
overlay directly below their widget at any size: a transparent PosReport
wrapper records each dropdown button's screen bounds into a thread-local
map on draw, and the overlays read it via Ribbon::dd_anchor instead of the
layout-estimating compute_*_left helpers.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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