Merge pull request #814 from googlefonts/component-hash-ttf

Check glyph hashes more thoroughly

Lib/ufo2ft/instructionCompiler.py

@@ -2,10 +2,13 @@
 
 import array
 import logging
+from functools import partial
 from typing import TYPE_CHECKING, Optional
 
 from fontTools import ttLib
+from fontTools.misc.fixedTools import floatToFixedToFloat
 from fontTools.pens.hashPointPen import HashPointPen
+from fontTools.pens.roundingPen import RoundingPointPen
 from fontTools.ttLib import newTable
 from fontTools.ttLib.tables._g_l_y_f import (
  OVERLAP_COMPOUND,
@@ -42,27 +45,28 @@ def __init__(
  self.autoUseMyMetrics = lambda ttGlyph, glyphName: None
 
  def _check_glyph_hash(
- self, glyphName: str, ttglyph: TTGlyph, glyph_hash: Optional[str]
+ self, glyph: Glyph, ttglyph: TTGlyph, stored_hash: Optional[str]
  ) -> bool:
- """Check if the supplied glyph hash from the ufo matches the current outlines."""
- if glyph_hash is None:
+ """Check if the supplied stored glyph hash from the ufo matches the TTGlyph."""
+ if stored_hash is None:
  # The glyph hash is required
  logger.error(
- f"Glyph hash missing, glyph '{glyphName}' will have "
+ f"Glyph hash missing, glyph '{glyph.name}' will have "
  "no instructions in font."
  )
  return False
 
- # Check the glyph hash against the TTGlyph that is being built
-
- ttwidth = self.otf["hmtx"][glyphName][0]
+ ttwidth = self.otf["hmtx"][glyph.name][0]
  hash_pen = HashPointPen(ttwidth, self.otf.getGlyphSet())
- ttglyph.drawPoints(hash_pen, self.otf["glyf"])
+ round_pen = RoundingPointPen(
+ hash_pen, transformRoundFunc=partial(floatToFixedToFloat, precisionBits=14)
+ )
+ ttglyph.drawPoints(round_pen, self.otf["glyf"])
 
- if glyph_hash != hash_pen.hash:
+ if stored_hash != hash_pen.hash:
  logger.error(
- f"The stored hash for glyph '{glyphName}' does not match the TrueType "
- "output glyph. Glyph will have no instructions in the font."
+ f"The stored hash for glyph '{glyph.name}' does not match the "
+ "TrueType output glyph. Glyph will have no instructions in the font."
  )
  return False
  return True
@@ -132,7 +136,7 @@ def _compile_tt_glyph_program(
  ) -> None:
  self._check_tt_data_format(ttdata, f"glyph '{glyph.name}'")
  glyph_hash = ttdata.get("id", None)
- if not self._check_glyph_hash(glyph.name, ttglyph, glyph_hash):
+ if not self._check_glyph_hash(glyph, ttglyph, glyph_hash):
  return
 
  # Compile the glyph program

tests/infoCompiler_test.py

@@ -20,7 +20,6 @@ def testufo(FontClass):
 
 
 class InfoCompilerTest:
-
  def test_head(self, testttf, testufo):
  info = {"versionMajor": 5, "versionMinor": 6}
  compiler = InfoCompiler(testttf, testufo, info)

tests/instructionCompiler_test.py

@@ -1,8 +1,11 @@
 import logging
+from functools import partial
 
 import pytest
 from fontTools.cu2qu.ufo import font_to_quadratic
+from fontTools.misc.fixedTools import floatToFixedToFloat
 from fontTools.pens.hashPointPen import HashPointPen
+from fontTools.pens.roundingPen import RoundingPointPen
 from fontTools.ttLib.tables._g_l_y_f import (
  OVERLAP_COMPOUND,
  ROUND_XY_TO_GRID,
@@ -40,7 +43,10 @@ def expect_maxp(
 
 def get_hash_ufo(glyph, ufo):
  hash_pen = HashPointPen(glyph.width, ufo)
- glyph.drawPoints(hash_pen)
+ round_pen = RoundingPointPen(
+ hash_pen, transformRoundFunc=partial(floatToFixedToFloat, precisionBits=14)
+ )
+ glyph.drawPoints(round_pen)
  return hash_pen.hash
 
 
@@ -89,15 +95,15 @@ def test_check_glyph_hash_match(self, quaduforeversed, quadfont):
  ttglyph = quadfont["glyf"]["a"]
 
  ic = InstructionCompiler(quaduforeversed, quadfont)
- result = ic._check_glyph_hash(glyph.name, ttglyph, ufo_hash)
+ result = ic._check_glyph_hash(glyph, ttglyph, ufo_hash)
  assert result
 
  def test_check_glyph_hash_missing(self, quaduforeversed, quadfont):
  glyph = quaduforeversed["a"]
 
  ic = InstructionCompiler(quaduforeversed, quadfont)
  result = ic._check_glyph_hash(
- glyph.name,
+ glyph,
  quadfont["glyf"]["a"],
  None,
  )
@@ -113,7 +119,7 @@ def test_check_glyph_hash_mismatch(self, testufo, quadfont):
 
  ic = InstructionCompiler(testufo, quadfont)
  result = ic._check_glyph_hash(
- glyph.name,
+ glyph,
  ttglyph,
  ufo_hash,
  )
@@ -129,7 +135,7 @@ def test_check_glyph_hash_mismatch_composite(self, testufo, quadfont):
 
  ic = InstructionCompiler(testufo, quadfont)
  result = ic._check_glyph_hash(
- glyph.name,
+ glyph,
  ttglyph,
  ufo_hash,
  )
@@ -146,7 +152,7 @@ def test_check_glyph_hash_mismatch_width(self, quaduforeversed, quadfont):
 
  ic = InstructionCompiler(quaduforeversed, quadfont)
  result = ic._check_glyph_hash(
- glyph.name,
+ glyph,
  ttglyph,
  ufo_hash,
  )