Street names got rarer the further you zoomed in, which is backwards.
A line label anchored to the midpoint of the feature as the *tile* drew
it -- a fixed geographic point, not a point in your view -- and the
tighter the view, the less likely that point was still on screen. Of the
265 named streets in the Montréal fixture, 37 anchors landed on a 53x26
canvas at zoom 14 and 6 at zoom 16, of which 2 survived collision.
The line is now clipped to the canvas first and the label goes on the
longest piece that survives, so the anchor is always somewhere you are
actually looking. Clipping rather than testing the endpoints matters:
at high zoom a street often crosses the whole view with both of its ends
outside it, and that is exactly the street you most want named. The
next-longest pieces are kept as alternates and tried in turn when the
first spot is already taken, so a street whose middle sits under a node
marker still gets named further along. A feature with nothing on screen
queues nothing at all.
That made a second bug visible: OpenStreetMap splits a long street into
several named features, and once each one anchored to its own visible
stretch, René-Lévesque was drawn twice on one screen. A name is now drawn
once per frame -- on a terminal's worth of columns the second copy only
ever takes space from a street that has none.
Zoom 16 goes 2 -> 6 street names at 53x26 and 2 -> 8 at 72x24; zoom 15
goes 10 -> 13. Waterway labels take the same path and improve with it.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Jean-Pierre MartineauandClaude Opus 5
fd312db8b9