Add snippet to remove overlaps on TTF with skia-pathops

Snippets/remove-overlaps.py

@@ -0,0 +1,76 @@
+#! /usr/bin/env python3
+
+# Example script to remove overlaps in TTF using skia-pathops
+
+
+import sys
+from fontTools.ttLib import TTFont
+from fontTools.pens.recordingPen import DecomposingRecordingPen
+from fontTools.pens.ttGlyphPen import TTGlyphPen
+
+try:
+    import pathops
+except ImportError:
+    sys.exit(
+        "This script requires the skia-pathops module. "
+        "`pip install skia-pathops` and then retry."
+    )
+
+
+def skpath_from_simple_glyph(glyphName, glyphSet):
+    path = pathops.Path()
+    pathPen = path.getPen()
+    glyphSet[glyphName].draw(pathPen)
+    return path
+
+
+def skpath_from_composite_glyph(glyphName, glyphSet):
+    # record TTGlyph outlines without components
+    dcPen = DecomposingRecordingPen(glyphSet)
+    glyphSet[glyphName].draw(dcPen)
+    # replay recording onto a skia-pathops Path
+    path = pathops.Path()
+    pathPen = path.getPen()
+    dcPen.replay(pathPen)
+    return path
+
+
+def tt_glyph_from_skpath(path):
+    ttPen = TTGlyphPen(None)
+    path.draw(ttPen)
+    return ttPen.glyph()
+
+
+def main():
+    if len(sys.argv) != 3:
+        print("usage: remove-overlaps.py fontfile.ttf outfile.ttf")
+        sys.exit(1)
+
+    src = sys.argv[1]
+    dst = sys.argv[2]
+
+    with TTFont(src) as f:
+        glyfTable = f["glyf"]
+        glyphSet = f.getGlyphSet()
+
+        for glyphName in glyphSet.keys():
+            if glyfTable[glyphName].isComposite():
+                path = skpath_from_composite_glyph(glyphName, glyphSet)
+            else:
+                path = skpath_from_simple_glyph(glyphName, glyphSet)
+
+            # duplicate path
+            path2 = pathops.Path(path)
+
+            # remove overlaps
+            path2.simplify()
+
+            # replace TTGlyph if simplified copy is different
+            if path2 != path:
+                glyfTable[glyphName] = tt_glyph_from_skpath(path2)
+
+        f.save(dst)
+
+
+if __name__ == "__main__":
+    main()