From 3ad201cbe5865e3eda63631ff56b759bdb4162f0 Mon Sep 17 00:00:00 2001
From: Cosimo Lupo <clupo@google.com>
Date: Thu, 23 Jul 2020 11:19:45 +0200
Subject: [PATCH] Snippets/decompose-ttf: remove overlaps with skia-pathops

---
 Snippets/decompose-ttf.py | 26 +++++++++++++++++++++++---
 1 file changed, 23 insertions(+), 3 deletions(-)

diff --git a/Snippets/decompose-ttf.py b/Snippets/decompose-ttf.py
index 36f56d218..bccaf72e1 100755
--- a/Snippets/decompose-ttf.py
+++ b/Snippets/decompose-ttf.py
@@ -9,10 +9,18 @@ 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."
+    )
+
 
 if len(sys.argv) != 3:
-	print("usage: decompose-ttf.py fontfile.ttf outfile.ttf")
-	sys.exit(1)
+    print("usage: decompose-ttf.py fontfile.ttf outfile.ttf")
+    sys.exit(1)
 
 src = sys.argv[1]
 dst = sys.argv[2]
@@ -24,10 +32,22 @@ with TTFont(src) as f:
     for glyphName in glyphSet.keys():
         if not glyfTable[glyphName].isComposite():
             continue
+
+        # 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)
+
+        # remove overlaps
+        path.simplify()
+
+        # create new TTGlyph from Path
         ttPen = TTGlyphPen(None)
-        dcPen.replay(ttPen)
+        path.draw(ttPen)
         glyfTable[glyphName] = ttPen.glyph()
 
     f.save(dst)