[varLib.avar] Test & fix _pruneLocations

Lib/fontTools/varLib/avar.py

@@ -22,15 +22,16 @@ def _pruneLocations(locations, poles, axisTags):
     model = VariationModel(locations, axisTags)
     modelMapping = model.mapping
     modelSupports = model.supports
-    pins = poles.copy()
+    pins = {tuple(k.items()): None for k in poles}
-    for pole in poles.keys():
+    for location in poles:
-        location = dict(pole)
         i = locations.index(location)
         i = modelMapping[i]
         support = modelSupports[i]
         supportAxes = set(support.keys())
-        for supportIndex, (axisTag, (minV, _, maxV)) in enumerate(support.items()):
+        for axisTag, (minV, _, maxV) in support.items():
             for v in (minV, maxV):
+                if v in (-1, 0, 1):
+                    continue
                 for pin in pins.keys():
                     pinLocation = dict(pin)
                     pinAxes = set(pinLocation.keys())
@@ -46,15 +47,21 @@ def _pruneLocations(locations, poles, axisTags):
                     # better because it can find a pin that is close
                     # to the pole in more dimensions, and reducing
                     # the total number of pins needed.
-                for candidateIdx in range(supportIndex - 1, -1, -1):
+                    for candidateIdx in range(i - 1, -1, -1):
                         candidate = modelSupports[candidateIdx]
                         candidateAxes = set(candidate.keys())
                         if candidateAxes != supportAxes:
                             continue
                         if axisTag not in candidateAxes:
                             continue
-                    if candidateLocation[axisTag] == v:
+                        candidate = {
-                        pins[tuple(candidateLocation.items())] = None
+                            k: defaultV for k, (_, defaultV, _) in candidate.items()
+                        }
+                        if candidate[axisTag] == v:
+                            pins[tuple(candidate.items())] = None
+                            break
+                    else:
+                        assert False, "No pin found"
     return [dict(t) for t in pins.keys()]
 
 
@@ -115,7 +122,8 @@ def mappings_from_avar(font, denormalize=True):
                 key=lambda t: (len(t), tuple(axisIndexes[tag] for tag, _ in t)),
             )
         ]
-        inputLocations = _pruneLocations(inputLocations, poles, axisTags)
+        poles = [dict(t) for t in poles.keys()]
+        inputLocations = _pruneLocations(inputLocations, list(poles), axisTags)
 
         # Find the output locations, at input locations
         varIdxMap = avar.table.VarIdxMap
@@ -210,6 +218,7 @@ def main(args=None):
         segments, mappings = mappings_from_avar(font)
         pprint(segments)
         pprint(mappings)
+        print(len(mappings), "mappings")
         return
 
     axisTags = [a.axisTag for a in font["fvar"].axes]

Tests/varLib/avar_test.py

@@ -0,0 +1,59 @@
+from fontTools.varLib.avar import _pruneLocations
+import unittest
+import pytest
+
+
+@pytest.mark.parametrize(
+    "locations, poles, expected",
+    [
+        (
+            [
+                {"wght": 1},
+                {"wght": 0.5},
+            ],
+            [
+                {"wght": 0.5},
+            ],
+            [
+                {"wght": 0.5},
+            ],
+        ),
+        (
+            [
+                {"wght": 1, "wdth": 1},
+                {"wght": 0.5, "wdth": 1},
+            ],
+            [
+                {"wght": 1, "wdth": 1},
+            ],
+            [
+                {"wght": 1, "wdth": 1},
+                {"wght": 0.5, "wdth": 1},
+            ],
+        ),
+        (
+            [
+                {"wght": 1},
+                {"wdth": 1},
+                {"wght": 0.5, "wdth": 0.5},
+            ],
+            [
+                {"wght": 0.5, "wdth": 0.5},
+            ],
+            [
+                {"wght": 0.5, "wdth": 0.5},
+            ],
+        ),
+    ],
+)
+def test_pruneLocations(locations, poles, expected):
+    axisTags = set()
+    for location in locations:
+        axisTags.update(location.keys())
+    axisTags = sorted(axisTags)
+
+    locations = [{}] + locations
+
+    output = _pruneLocations(locations, poles, axisTags)
+
+    assert output == expected, (output, expected)