[instancer] Don't produce triples outside <-1,0,+1>

Fixes #3350
fonttools · Dec 6, 2023 · 8728789 · 8728789
1 parent 4dbf534
commit 8728789
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Showing 3 changed files with 25 additions and 8 deletions.
diff --git a/Lib/fontTools/varLib/instancer/solver.py b/Lib/fontTools/varLib/instancer/solver.py
@@ -178,7 +178,9 @@ def _solve(tent, axisLimit, negative=False):
         #
         newUpper = peak + (1 - gain) * (upper - peak)
         assert axisMax <= newUpper  # Because outGain > gain
-        if newUpper <= axisDef + (axisMax - axisDef) * 2:
+        # Disabled because ots doesn't like us:
+        # https://github.com/fonttools/fonttools/issues/3350
+        if False and newUpper <= axisDef + (axisMax - axisDef) * 2:
             upper = newUpper
             if not negative and axisDef + (axisMax - axisDef) * MAX_F2DOT14 < upper:
                 # we clamp +2.0 to the max F2Dot14 (~1.99994) for convenience

diff --git a/Tests/varLib/instancer/instancer_test.py b/Tests/varLib/instancer/instancer_test.py
@@ -1986,7 +1986,10 @@ def check_limit_single_var_axis_range(self, var, axisTag, axisRange, expected):
                 TupleVariation({"wght": (0.0, 0.5, 1.0)}, [100, 100]),
                 "wght",
                 0.6,
-                [TupleVariation({"wght": (0.0, 0.833334, 1.666667)}, [100, 100])],
+                [
+                    TupleVariation({"wght": (0.0, 0.833334, 1.0)}, [100, 100]),
+                    TupleVariation({"wght": (0.833334, 1.0, 1.0)}, [80, 80]),
+                ],
             ),
             (
                 TupleVariation({"wght": (0.0, 0.2, 1.0)}, [100, 100]),
@@ -2001,7 +2004,10 @@ def check_limit_single_var_axis_range(self, var, axisTag, axisRange, expected):
                 TupleVariation({"wght": (0.0, 0.2, 1.0)}, [100, 100]),
                 "wght",
                 0.5,
-                [TupleVariation({"wght": (0.0, 0.4, 1.99994)}, [100, 100])],
+                [
+                    TupleVariation({"wght": (0.0, 0.4, 1)}, [100, 100]),
+                    TupleVariation({"wght": (0.4, 1, 1)}, [62.5, 62.5]),
+                ],
             ),
             (
                 TupleVariation({"wght": (0.5, 0.5, 1.0)}, [100, 100]),
@@ -2065,7 +2071,10 @@ def test_positive_var(self, var, axisTag, newMax, expected):
                 TupleVariation({"wght": (-1.0, -0.5, 0.0)}, [100, 100]),
                 "wght",
                 -0.6,
-                [TupleVariation({"wght": (-1.666667, -0.833334, 0.0)}, [100, 100])],
+                [
+                    TupleVariation({"wght": (-1.0, -0.833334, 0.0)}, [100, 100]),
+                    TupleVariation({"wght": (-1.0, -1.0, -0.833334)}, [80, 80]),
+                ],
             ),
             (
                 TupleVariation({"wght": (-1.0, -0.2, 0.0)}, [100, 100]),
@@ -2080,7 +2089,10 @@ def test_positive_var(self, var, axisTag, newMax, expected):
                 TupleVariation({"wght": (-1.0, -0.2, 0.0)}, [100, 100]),
                 "wght",
                 -0.5,
-                [TupleVariation({"wght": (-2.0, -0.4, 0.0)}, [100, 100])],
+                [
+                    TupleVariation({"wght": (-1.0, -0.4, 0.0)}, [100, 100]),
+                    TupleVariation({"wght": (-1.0, -1.0, -0.4)}, [62.5, 62.5]),
+                ],
             ),
             (
                 TupleVariation({"wght": (-1.0, -0.5, -0.5)}, [100, 100]),

diff --git a/Tests/varLib/instancer/solver_test.py b/Tests/varLib/instancer/solver_test.py
@@ -43,15 +43,17 @@ class RebaseTentTest(object):
                 (0, 0.2, 1),
                 (-1, 0, 0.8),
                 [
-                    (1, (0, 0.25, 1.25)),
+                    (1, (0, 0.25, 1)),
+                    (0.25, (0.25, 1, 1)),
                 ],
             ),
             # Case 3 boundary
             pytest.param(
                 (0, 0.4, 1),
                 (-1, 0, 0.5),
                 [
-                    (1, (0, 0.8, 1.99994)),
+                    (1, (0, 0.8, 1)),
+                    (2.5 / 3, (0.8, 1, 1)),
                 ],
             ),
             # Case 4
@@ -234,7 +236,8 @@ class RebaseTentTest(object):
                 (0, 0.2, 1),
                 (0, 0, 0.5),
                 [
-                    (1, (0, 0.4, 1.99994)),
+                    (1, (0, 0.4, 1)),
+                    (0.625, (0.4, 1, 1)),
                 ],
             ),
             # https://github.com/fonttools/fonttools/issues/3139