TruncateToWidth, the middle "front...back" ellipsis for addresses, pool
URLs, paths, labels and the status bar, cut at byte offsets: a
multi-byte character at either cut was split into invalid UTF-8 and
drawn as replacement characters (e.g. a translated Cyrillic or CJK
status). It also tried front lengths from n/2 down until one fit,
building and measuring a new string for each: up to O(n^2) per
truncated label per frame.
util::textfit::middleEllipsis keeps the same contract and is
byte-identical for ASCII, but snaps the front cut down and the back cut
up to code-point boundaries, and finds the largest fitting front length
by bisection into one reused buffer: O(log n) measures for single-line
text. Text containing a newline keeps the linear scan, because its
measured width (the widest line) does not grow steadily with the cut.
text_fit.h also gains largestFittingPrefix, a bisection over code-point
boundaries; its first caller is the node-status banner in a following
change.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>