The current behavior of rendering `?` for an unknown Unicode character
can be hard to distinguish from a typo. Use the standard Unicode
"replacement character" instead, that's what it's designed for:
https://en.wikipedia.org/wiki/Specials_(Unicode_block)
I'm making this PR as a draft because I'm not sure I did everything that
was needed to change the character set covered by the fonts. Running
that script is in its own commit. If this is proper, I'll rebase/squash
into one commit and un-draft.
Co-authored-by: Maeve Andrews <maeve@git.mail.maeveandrews.com>
Replace linear O(n) search with binary search O(log n) for unicode
interval lookup. Korean fonts have many intervals (~30,000+ glyphs), so
this improves text rendering performance during page navigation.
## Summary
* **What is the goal of this PR?** (e.g., Fixes a bug in the user
authentication module, Implements the new feature for
file uploading.)
Replace linear `O(n)` glyph lookup with binary search `O(log n)` to
improve text rendering performance during page navigation.
* **What changes are included?**
- Modified `EpdFont::getGlyph()` to use binary search instead of linear
search for unicode interval lookup
- Added early return for empty interval count
## Additional Context
* Add any other information that might be helpful for the reviewer
(e.g., performance implications, potential risks, specific areas to
focus on).
- Performance implications: Fonts with many unicode intervals benefit
the most. Korean fonts have ~30,000+ glyphs across multiple intervals,
but any font with significant glyph coverage (CJK, extended Latin,
emoji, etc.) will see improvement.
- Complexity: from `O(n)` to `O(log n)` where n = number of unicode
intervals. For fonts with 10+ intervals, this reduces lookup iterations
significantly.
- Risk: Low - the binary search logic is straightforward and the
intervals are already sorted by unicode codepoint (required for the
original early-exit optimization).
