Merge pull request #3155 from fonttools/fix-drop-implied-oncurves

fix a bug in dropImpliedOnCurvePoints
fonttools · Jun 6, 2023 · 66ce7c0 · 66ce7c0
2 parents 6559819 + 0761508
commit 66ce7c0
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Showing 2 changed files with 30 additions and 6 deletions.
diff --git a/Lib/fontTools/ttLib/tables/_g_l_y_f.py b/Lib/fontTools/ttLib/tables/_g_l_y_f.py
@@ -1602,6 +1602,7 @@ def dropImpliedOnCurvePoints(*interpolatable_glyphs: Glyph) -> Set[int]:
                     continue
 
                 may_drop.add(i)
+            start = last + 1
         # we only want to drop if ALL interpolatable glyphs have the same implied oncurves
         if drop is None:
             drop = may_drop

diff --git a/Tests/ttLib/tables/_g_l_y_f_test.py b/Tests/ttLib/tables/_g_l_y_f_test.py
@@ -856,20 +856,43 @@ def test_dropImpliedOnCurvePoints_all_quad_off_curves():
                 ((-1, -1), 0),
                 ((-1, 0), flagOnCurve),
                 ((-1, 1), 0),
-            ]
+            ],
+            [
+                ((0, 2), flagOnCurve),
+                ((2, 2), 0),
+                ((2, 0), flagOnCurve),
+                ((2, -2), 0),
+                ((0, -2), flagOnCurve),
+                ((-2, -2), 0),
+                ((-2, 0), flagOnCurve),
+                ((-2, 2), 0),
+            ],
         ],
         Transform().scale(2.0),
     )
     # also add an empty glyph (will be ignored); we use this trick for 'sparse' masters
     glyph3 = Glyph()
     glyph3.numberOfContours = 0
 
-    assert dropImpliedOnCurvePoints(glyph1, glyph2, glyph3) == {0, 2, 4, 6}
+    assert dropImpliedOnCurvePoints(glyph1, glyph2, glyph3) == {
+        0,
+        2,
+        4,
+        6,
+        8,
+        10,
+        12,
+        14,
+    }
 
-    assert glyph1.flags == glyph2.flags == array.array("B", [0, 0, 0, 0])
-    assert glyph1.coordinates == GlyphCoordinates([(1, 1), (1, -1), (-1, -1), (-1, 1)])
-    assert glyph2.coordinates == GlyphCoordinates([(2, 2), (2, -2), (-2, -2), (-2, 2)])
-    assert glyph1.endPtsOfContours == glyph2.endPtsOfContours == [3]
+    assert glyph1.flags == glyph2.flags == array.array("B", [0, 0, 0, 0, 0, 0, 0, 0])
+    assert glyph1.coordinates == GlyphCoordinates(
+        [(1, 1), (1, -1), (-1, -1), (-1, 1), (2, 2), (2, -2), (-2, -2), (-2, 2)]
+    )
+    assert glyph2.coordinates == GlyphCoordinates(
+        [(2, 2), (2, -2), (-2, -2), (-2, 2), (4, 4), (4, -4), (-4, -4), (-4, 4)]
+    )
+    assert glyph1.endPtsOfContours == glyph2.endPtsOfContours == [3, 7]
     assert glyph3.numberOfContours == 0