[instancer/L4] Misc fixes and fix tests

Lib/fontTools/varLib/instancer/__init__.py

@@ -204,8 +204,8 @@ def expand(
         default = None
         if n == 2:
             minimum, maximum = v
-        elif n == 3:
-            minimum, default, maximum = v
+        elif n >= 3:
+            return cls(*v)
         else:
             raise ValueError(f"expected sequence of 2 or 3; got {n}: {v!r}")
         return cls(minimum, default, maximum)
@@ -234,14 +234,14 @@ def limitRangeAndPopulateDefault(self, fvarTriple) -> "AxisTriple":
 
 
 @dataclasses.dataclass(frozen=True, order=True, repr=False)
-class NormalizedAxisTriple(AxisTriple):
+class NormalizedAxisTripleAndDistances(AxisTriple):
     """A triple of (min, default, max) normalized axis values."""
 
     minimum: float
     default: float
     maximum: float
-    distanceNegative: float
-    distancePositive: float
+    distanceNegative: Optional[float] = 1
+    distancePositive: Optional[float] = 1
 
     def __post_init__(self):
         if self.default is None:
@@ -256,15 +256,18 @@ def reverse_negate(self):
         v = self
         return self.__class__(-v[2], -v[1], -v[0], v[4], v[3])
 
-    def normalizeValue(self, v):
+    def normalizeValue(self, v, extrapolate=True):
         lower, default, upper, distanceNegative, distancePositive = self
         assert lower <= default <= upper
 
+        if not extrapolate:
+            v = max(lower, min(upper, v))
+
         if v == default:
             return 0
 
         if default < 0:
-            return -self.reverse_negate().normalizeValue(-v)
+            return -self.reverse_negate().normalizeValue(-v, extrapolate=extrapolate)
 
         # default >= 0 and v != default
 
@@ -285,6 +288,12 @@ def normalizeValue(self, v):
         else:
             vDistance = -v * distanceNegative + distancePositive * default
 
+        if totalDistance == 0:
+            # This happens
+            if default == 0:
+                return -v / lower
+            return 0  # Shouldn't happen
+
         return -vDistance / totalDistance
 
 
@@ -375,7 +384,7 @@ def normalize(self, varfont, usingAvar=True) -> "NormalizedAxisLimits":
             distancePositive = triple[2] - triple[1]
 
             if self[axis_tag] is None:
-                normalizedLimits[axis_tag] = NormalizedAxisTriple(
+                normalizedLimits[axis_tag] = NormalizedAxisTripleAndDistances(
                     0, 0, 0, distanceNegative, distancePositive
                 )
                 continue
@@ -386,7 +395,7 @@ def normalize(self, varfont, usingAvar=True) -> "NormalizedAxisLimits":
                 defaultV = triple[1]
 
             avarMapping = avarSegments.get(axis_tag, None)
-            normalizedLimits[axis_tag] = NormalizedAxisTriple(
+            normalizedLimits[axis_tag] = NormalizedAxisTripleAndDistances(
                 *(normalize(v, triple, avarMapping) for v in (minV, defaultV, maxV)),
                 distanceNegative,
                 distancePositive,
@@ -402,7 +411,7 @@ def __init__(self, *args, **kwargs):
         self._data = data = {}
         for k, v in dict(*args, **kwargs).items():
             try:
-                triple = NormalizedAxisTriple.expand(v)
+                triple = NormalizedAxisTripleAndDistances.expand(v)
             except ValueError as e:
                 raise ValueError(f"Invalid axis limits for {k!r}: {v!r}") from e
             data[k] = triple
@@ -486,7 +495,7 @@ def changeTupleVariationsAxisLimits(variations, axisLimits):
 
 
 def changeTupleVariationAxisLimit(var, axisTag, axisLimit):
-    assert isinstance(axisLimit, NormalizedAxisTriple)
+    assert isinstance(axisLimit, NormalizedAxisTripleAndDistances)
 
     # Skip when current axis is missing (i.e. doesn't participate),
     lower, peak, upper = var.axes.get(axisTag, (-1, 0, 1))
@@ -549,7 +558,7 @@ def _instantiateGvarGlyph(
                         "Instancing accross VarComposite axes with variation is not supported."
                     )
                 limits = axisLimits[tag]
-                loc = limits.normalizeValue(loc)
+                loc = limits.normalizeValue(loc, extrapolate=False)
                 newLocation[tag] = loc
             component.location = newLocation
 
@@ -969,7 +978,7 @@ def instantiateAvar(varfont, axisLimits):
             mappedMax = floatToFixedToFloat(
                 piecewiseLinearMap(axisRange.maximum, mapping), 14
             )
-            mappedAxisLimit = NormalizedAxisTriple(
+            mappedAxisLimit = NormalizedAxisTripleAndDistances(
                 mappedMin,
                 mappedDef,
                 mappedMax,

Lib/fontTools/varLib/instancer/featureVars.py

@@ -1,5 +1,4 @@
 from fontTools.ttLib.tables import otTables as ot
-from fontTools.varLib.models import normalizeValue
 from copy import deepcopy
 import logging
 
@@ -41,7 +40,9 @@ def _limitFeatureVariationConditionRange(condition, axisLimit):
         # condition invalid or out of range
         return
 
-    return tuple(axisLimit.normalizeValue(v) for v in (minValue, maxValue))
+    return tuple(
+        axisLimit.normalizeValue(v, extrapolate=False) for v in (minValue, maxValue)
+    )
 
 
 def _instantiateFeatureVariationRecord(
@@ -50,9 +51,9 @@ def _instantiateFeatureVariationRecord(
     applies = True
     shouldKeep = False
     newConditions = []
-    from fontTools.varLib.instancer import NormalizedAxisTriple
+    from fontTools.varLib.instancer import NormalizedAxisTripleAndDistances
 
-    default_triple = NormalizedAxisTriple(-1, 0, +1, 0, 0)
+    default_triple = NormalizedAxisTripleAndDistances(-1, 0, +1, 0, 0)
     for i, condition in enumerate(record.ConditionSet.ConditionTable):
         if condition.Format == 1:
             axisIdx = condition.AxisIndex

Tests/varLib/instancer/instancer_test.py

@@ -1950,7 +1950,7 @@ def check_limit_single_var_axis_range(self, var, axisTag, axisRange, expected):
         ],
     )
     def test_positive_var(self, var, axisTag, newMax, expected):
-        axisRange = instancer.NormalizedAxisTriple(0, 0, newMax)
+        axisRange = instancer.NormalizedAxisTripleAndDistances(0, 0, newMax, 1, 1)
         self.check_limit_single_var_axis_range(var, axisTag, axisRange, expected)
 
     @pytest.mark.parametrize(
@@ -2029,7 +2029,7 @@ def test_positive_var(self, var, axisTag, newMax, expected):
         ],
     )
     def test_negative_var(self, var, axisTag, newMin, expected):
-        axisRange = instancer.NormalizedAxisTriple(newMin, 0, 0)
+        axisRange = instancer.NormalizedAxisTripleAndDistances(newMin, 0, 0, 1, 1)
         self.check_limit_single_var_axis_range(var, axisTag, axisRange, expected)
 
 
@@ -2052,7 +2052,7 @@ def test_limitFeatureVariationConditionRange(oldRange, newLimit, expected):
     condition = featureVars.buildConditionTable(0, *oldRange)
 
     result = instancer.featureVars._limitFeatureVariationConditionRange(
-        condition, instancer.NormalizedAxisTriple(*newLimit)
+        condition, instancer.NormalizedAxisTripleAndDistances(*newLimit, 1, 1)
     )
 
     assert result == expected
@@ -2094,9 +2094,9 @@ def test_parseLimits_invalid(limits):
 @pytest.mark.parametrize(
     "limits, expected",
     [
-        ({"wght": (100, 400)}, {"wght": (-1.0, 0, 0)}),
-        ({"wght": (100, 400, 400)}, {"wght": (-1.0, 0, 0)}),
-        ({"wght": (100, 300, 400)}, {"wght": (-1.0, -0.5, 0)}),
+        ({"wght": (100, 400)}, {"wght": (-1.0, 0, 0, 300, 500)}),
+        ({"wght": (100, 400, 400)}, {"wght": (-1.0, 0, 0, 300, 500)}),
+        ({"wght": (100, 300, 400)}, {"wght": (-1.0, -0.5, 0, 300, 500)}),
     ],
 )
 def test_normalizeAxisLimits(varfont, limits, expected):
@@ -2113,7 +2113,7 @@ def test_normalizeAxisLimits_no_avar(varfont):
     limits = instancer.AxisLimits(wght=(400, 400, 500))
     normalized = limits.normalize(varfont)
 
-    assert normalized["wght"] == pytest.approx((0, 0, 0.2), 1e-4)
+    assert normalized["wght"] == pytest.approx((0, 0, 0.2, 300, 500), 1e-4)
 
 
 def test_normalizeAxisLimits_missing_from_fvar(varfont):

Tests/varLib/instancer/solver_test.py

@@ -1,4 +1,5 @@
 from fontTools.varLib.instancer import solver
+from fontTools.varLib.instancer import NormalizedAxisTripleAndDistances
 import pytest
 
 
@@ -245,6 +246,10 @@ class RebaseTentTest(object):
         ],
     )
     def test_rebaseTent(self, tent, axisRange, expected):
+        if len(axisRange) < 5:
+            axisRange += (1, 1)
+        axisRange = NormalizedAxisTripleAndDistances(*axisRange)
+
         sol = solver.rebaseTent(tent, axisRange)
 
         a = pytest.approx