VF: improved STAT table patch

misc/fontbuildlib/stat.py

@@ -1,34 +1,61 @@
-# from fontTools.designspaceLib import DesignSpaceDocument
-# from fontTools.ttLib.tables import otTables as ot
-# from fontTools.ttLib import ttFont
 from fontTools.otlLib.builder import buildStatTable
 
+
+# [from OpenType spec on STAT, flags]
+# If set, it indicates that the axis value represents the “normal” value
+# for the axis and may be omitted when composing name strings.
+OT_ELIDABLE_AXIS_VALUE_NAME = 0x0002
+
 def rebuildStatTable(font, designspace):
   if not 'fvar' in font:
     raise Exception('missing fvar table in font')
-
   axes = [dict(tag=a.axisTag, name=a.axisNameID) for a in font['fvar'].axes]
-  # axes = []
-  # for a in statTable.DesignAxisRecord.Axis:
-  #   axes.append({ 'tag': a.AxisTag, 'name': a.AxisNameID, 'ordering': a.AxisOrdering })
-
-  axisNameToTag = dict()
+  locations = None
+  if len(axes) > 1:
+    # TODO: Compute locations automatically.
+    # Currently specific to Inter w/ hard-coded values.
+    locations = [
+      { 'name': 'Regular', 'location': { 'wght': 400, 'slnt': 0 },
+        'flags': OT_ELIDABLE_AXIS_VALUE_NAME },
+      { 'name': 'Italic', 'location': { 'wght': 400, 'slnt': -10.0 } },
+    ]
+  axisTagToName = dict()
   for axis in designspace.axes:
-    axisNameToTag[axis.name] = axis.tag
-
-  locations = []
+    axisTagToName[axis.tag] = axis.name
+  weightAxisName = axisTagToName['wght']
+  slantAxisName = axisTagToName.get('slnt', 'Slant')
+  weightAxis = None
+  for a in axes:
+    if a['tag'] == 'wght':
+      weightAxis = a
+      break
+  weightValues = []
   for instance in designspace.instances:
-    location = dict()
     for axisName, value in instance.location.items():
-      tag = axisNameToTag[axisName]
-      location[tag] = value
-    locations.append({ 'name': instance.styleName, 'location': location })
+      if axisName == slantAxisName:
+        # skip italic/oblique/slant
+        continue
+      weightValue = {
+        'name':  instance.styleName,
+        'value': instance.location[weightAxisName],
+      }
+      if weightValue['value'] == 400:
+        weightValue['flags'] = OT_ELIDABLE_AXIS_VALUE_NAME
+      weightValues.append(weightValue)
+  weightAxis['values'] = weightValues
+
+  # axisNameToTag = dict()
+  # for axis in designspace.axes:
+  #   axisNameToTag[axis.name] = axis.tag
+  # locations = []
+  # for instance in designspace.instances:
+  #   location = dict()
+  #   for axisName, value in instance.location.items():
+  #     tag = axisNameToTag[axisName]
+  #     location[tag] = value
+  #   loc = { 'name': instance.styleName, 'location': location }
+  #   if instance.styleName == "Regular":
+  #     loc['flags'] = OT_ELIDABLE_AXIS_VALUE_NAME
+  #   locations.append(loc)
 
   buildStatTable(font, axes, locations)
-
-
-# font = ttFont.TTFont("build/fonts/var/Inter.var.ttf")
-# designspace = DesignSpaceDocument.fromfile('build/ufo/inter.designspace')
-# rebuildStatTable(font, designspace)
-# print("write build/tmp/Inter.var-patched.ttf")
-# font.save("build/tmp/Inter.var-patched.ttf")