fix: build-script bug fixes for fontconvert{,_sdcard}.py (#1910)

Fontconvert_sdcard.py:

* Move face.set_char_size() before any load_glyph() call. The validation
loop runs load_glyph() with FT_LOAD_RENDER, which renders at the
*active* size — calling it before set_char_size() wastes work at the
default size and triggers Invalid_Size_Handle on some fonts.

* Walk bitmap.buffer using bitmap.pitch with negative-pitch handling.
The previous linear iteration assumed pitch == width and a top-down
layout, which silently corrupts output for any padded or bottom-up
bitmap FreeType returns.

* Fix operator-precedence bug in 2-bit tail-padding: px << (4 - … % 4) *
2 evaluated as (px << (4 - … % 4)) * 2 due to << binding tighter than *.
Add the missing outer parens.

* Drop SMP codepoints (> U+FFFF) from kern and ligature tables before
packing — the binary format uses uint16/uint32 codepoint fields and
would raise struct.error otherwise.

* Skip GPOS kern subtables that aren't lookup type 2 (PairPos).
_extract_pairpos_subtable assumes Type-2 layout; cursive attachment and
other types reachable through the kern feature crash inside it.

Fontconvert.py:

* Force UTF-8 stdout so `python fontconvert.py … > foo.h` on Windows
doesn't emit UTF-16 / replacement characters in the generated header.

## Summary

* **What is the goal of this PR?** (e.g., Implements the new feature for
file uploading.)
* **What changes are included?**

## Additional Context

* Add any other information that might be helpful for the reviewer
(e.g., performance implications, potential risks,
  specific areas to focus on).

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This commit is contained in:

jpirnay

2026-05-10 10:54:04 -05:00

committed by

GitHub

parent 5d5533b3d2

commit 5917c561b3

2 changed files with 76 additions and 18 deletions

									
										lib/EpdFont/scripts/fontconvert.py
									
		+6
		
												View File
												
				@@ -8,6 +8,12 @@ import argparse

				from collections import namedtuple

				from fontTools.ttLib import TTFont

				# Force UTF-8 stdout so that `python fontconvert.py … > foo.h` on Windows

				# (default cp1252) doesn't emit UTF-16 LE / replacement chars in the generated

				# header. Wrapped in a hasattr guard so it's a no-op on older Pythons.

				if hasattr(sys.stdout, 'reconfigure'):

				    sys.stdout.reconfigure(encoding='utf-8')

				# Originally from https://github.com/vroland/epdiy

				parser = argparse.ArgumentParser(description="Generate a header file from a font to be used with epdiy.")