Merge pull request #2382 from fonttools/ignore-overlap-errors-option

instancer: add --ignore-overlap-errors option

Lib/fontTools/ttLib/removeOverlaps.py

@@ -115,6 +115,7 @@ def _simplify(path: pathops.Path, debugGlyphName: str) -> pathops.Path:
         )
         return path
     except pathops.PathOpsError as e:
+        if log.isEnabledFor(logging.DEBUG):
             path.dump()
         raise RemoveOverlapsError(
             f"Failed to remove overlaps from glyph {debugGlyphName!r}"
@@ -162,6 +163,7 @@ def removeOverlaps(
     font: ttFont.TTFont,
     glyphNames: Optional[Iterable[str]] = None,
     removeHinting: bool = True,
+    ignoreErrors=False,
 ) -> None:
     """Simplify glyphs in TTFont by merging overlapping contours.
 
@@ -179,6 +181,8 @@ def removeOverlaps(
         glyphNames: optional iterable of glyph names (str) to remove overlaps from.
             By default, all glyphs in the font are processed.
         removeHinting (bool): set to False to keep hinting for unmodified glyphs.
+        ignoreErrors (bool): set to True to ignore errors while removing overlaps,
+            thus keeping the tricky glyphs unchanged (fonttools/fonttools#2363).
     """
     try:
         glyfTable = font["glyf"]
@@ -206,10 +210,15 @@ def removeOverlaps(
     )
     modified = set()
     for glyphName in glyphNames:
+        try:
             if removeTTGlyphOverlaps(
                 glyphName, glyphSet, glyfTable, hmtxTable, removeHinting
             ):
                 modified.add(glyphName)
+        except RemoveOverlapsError:
+            if not ignoreErrors:
+                raise
+            log.error("Failed to remove overlaps for '%s'", glyphName)
 
     log.debug("Removed overlaps for %s glyphs:\n%s", len(modified), " ".join(modified))
 

Lib/fontTools/varLib/instancer/__init__.py

@@ -127,6 +127,7 @@ class OverlapMode(IntEnum):
     KEEP_AND_DONT_SET_FLAGS = 0
     KEEP_AND_SET_FLAGS = 1
     REMOVE = 2
+    REMOVE_AND_IGNORE_ERRORS = 3
 
 
 def instantiateTupleVariationStore(
@@ -1185,7 +1186,8 @@ def instantiateVariableFont(
             on all glyphs to maximise cross-compatibility of the generated instance.
             You can disable this by passing OverlapMode.KEEP_AND_DONT_SET_FLAGS.
             If you want to remove the overlaps altogether and merge overlapping
-            contours and components, you can pass OverlapMode.REMOVE. Note that this
+            contours and components, you can pass OverlapMode.REMOVE (or
+            REMOVE_AND_IGNORE_ERRORS to not hard-fail on tricky glyphs). Note that this
             requires the skia-pathops package (available to pip install).
             The overlap parameter only has effect when generating full static instances.
         updateFontNames (bool): if True, update the instantiated font's name table using
@@ -1244,11 +1246,14 @@ def instantiateVariableFont(
         if "glyf" in varfont:
             if overlap == OverlapMode.KEEP_AND_SET_FLAGS:
                 setMacOverlapFlags(varfont["glyf"])
-            elif overlap == OverlapMode.REMOVE:
+            elif overlap in (OverlapMode.REMOVE, OverlapMode.REMOVE_AND_IGNORE_ERRORS):
                 from fontTools.ttLib.removeOverlaps import removeOverlaps
 
                 log.info("Removing overlaps from glyf table")
-                removeOverlaps(varfont)
+                removeOverlaps(
+                    varfont,
+                    ignoreErrors=(overlap == OverlapMode.REMOVE_AND_IGNORE_ERRORS),
+                )
 
     varLib.set_default_weight_width_slant(
         varfont,
@@ -1355,6 +1360,12 @@ def parseArgs(args):
         help="Merge overlapping contours and components (only applicable "
         "when generating a full instance). Requires skia-pathops",
     )
+    parser.add_argument(
+        "--ignore-overlap-errors",
+        dest="ignore_overlap_errors",
+        action="store_true",
+        help="Don't crash if the remove-overlaps operation fails for some glyphs.",
+    )
     parser.add_argument(
         "--update-name-table",
         action="store_true",
@@ -1371,6 +1382,9 @@ def parseArgs(args):
     options = parser.parse_args(args)
 
     if options.remove_overlaps:
+        if options.ignore_overlap_errors:
+            options.overlap = OverlapMode.REMOVE_AND_IGNORE_ERRORS
+        else:
             options.overlap = OverlapMode.REMOVE
     else:
         options.overlap = OverlapMode(int(options.overlap))