Merge pull request #971 from googlefonts/interpolate-components-with-…

…intermediate

Build intermediate layers with non-intermediate components

Lib/glyphsLib/builder/__init__.py

@@ -12,11 +12,13 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import copy
 import logging
 
 from glyphsLib import classes
 
 from .builders import UFOBuilder, GlyphsBuilder
+from .transformations import TRANSFORMATIONS
 
 logger = logging.getLogger(__name__)
 
@@ -34,11 +36,13 @@ def to_ufos(
     expand_includes=False,
     minimal=False,
     glyph_data=None,
+    preserve_original=False,
 ):
     """Take a GSFont object and convert it into one UFO per master.
 
     Takes in data as Glyphs.app-compatible classes, as documented at
-    https://docu.glyphsapp.com/
+    https://docu.glyphsapp.com/. The input ``GSFont`` object is modified
+    unless ``preserve_original`` is true.
 
     If include_instances is True, also returns the parsed instance data.
 
@@ -54,9 +58,14 @@ def to_ufos(
     If minimal is True, it is assumed that the UFOs will only be used in
     font production, and unnecessary steps (e.g. converting background layers)
     will be skipped.
+
+    If preserve_original is True, this works on a copy of the font object
+    to avoid modifying the original object.
     """
+    if preserve_original:
+        font = copy.deepcopy(font)
     builder = UFOBuilder(
-        font,
+        preflight_glyphs(font),
         ufo_module=ufo_module,
         family_name=family_name,
         propagate_anchors=propagate_anchors,
@@ -89,13 +98,16 @@ def to_designspace(
     expand_includes=False,
     minimal=False,
     glyph_data=None,
+    preserve_original=False,
 ):
     """Take a GSFont object and convert it into a Designspace Document + UFOS.
     The UFOs are available as the attribute `font` of each SourceDescriptor of
     the DesignspaceDocument:
 
         ufos = [source.font for source in designspace.sources]
 
+    The input object is modified unless ``preserve_original`` is true.
+
     The designspace and the UFOs are not written anywhere by default, they
     are all in-memory. If you want to write them to the disk, consider using
     the `filename` attribute of the DesignspaceDocument and of its
@@ -111,9 +123,15 @@ def to_designspace(
 
     If generate_GDEF is True, write a `table GDEF {...}` statement in the
     UFO's features.fea, containing GlyphClassDef and LigatureCaretByPos.
+
+    If preserve_original is True, this works on a copy of the font object
+    to avoid modifying the original object.
     """
+    if preserve_original:
+        font = copy.deepcopy(font)
+
     builder = UFOBuilder(
-        font,
+        preflight_glyphs(font),
         ufo_module=ufo_module,
         family_name=family_name,
         instance_dir=instance_dir,
@@ -130,6 +148,15 @@ def to_designspace(
     return builder.designspace
 
 
+def preflight_glyphs(font):
+    """Run a set of transformations over a GSFont object to make
+    it easier to convert to UFO; resolve all the "smart stuff"."""
+
+    for transform in TRANSFORMATIONS:
+        transform(font)
+    return font
+
+
 def to_glyphs(
     ufos_or_designspace,
     glyphs_module=classes,

Lib/glyphsLib/builder/builders.py

@@ -54,7 +54,9 @@ def __init__(
         """Create a builder that goes from Glyphs to UFO + designspace.
 
         Keyword arguments:
-        font -- The GSFont object to transform into UFOs
+        font -- The GSFont object to transform into UFOs. We expect this GSFont
+                object to have been pre-processed with
+                ``glyphsLib.builder.preflight_glyphs``.
         ufo_module -- A Python module to use to build UFO objects (you can pass
                       a custom module that has the same classes as ufoLib2 or
                       defcon to get instances of your own classes). Default: ufoLib2

Lib/glyphsLib/builder/transformations/__init__.py

@@ -0,0 +1,4 @@
+from .intermediate_layers import resolve_intermediate_components
+
+
+TRANSFORMATIONS = [resolve_intermediate_components]

Lib/glyphsLib/builder/transformations/intermediate_layers.py

@@ -0,0 +1,129 @@
+import logging
+import uuid
+
+from fontTools.varLib.models import VariationModel, normalizeValue
+
+from glyphsLib.classes import GSLayer, GSNode, GSPath
+from glyphsLib.builder.axes import get_regular_master
+
+
+logger = logging.getLogger(__name__)
+
+
+def resolve_intermediate_components(font):
+    for glyph in font.glyphs:
+        for layer in glyph.layers:
+            if layer._is_brace_layer():
+                # First, let's find glyphs with intermediate layers
+                # which have components which don't have intermediate layers
+                for shape in layer.components:
+                    ensure_component_has_sparse_layer(font, shape, layer)
+
+
+def variation_model(font, locations):
+    tags = [axis.axisTag for axis in font.axes]
+    limits = {tag: (min(x), max(x)) for tag, x in zip(tags, (zip(*locations)))}
+    master_locations = []
+    default_location = get_regular_master(font).axes
+    for loc in locations:
+        this_loc = {}
+        for ix, axisTag in enumerate(tags):
+            axismin, axismax = limits[axisTag]
+            this_loc[axisTag] = normalizeValue(
+                loc[ix], (axismin, default_location[ix], axismax)
+            )
+        master_locations.append(this_loc)
+    return VariationModel(master_locations, axisOrder=tags), limits
+
+
+def ensure_component_has_sparse_layer(font, component, parent_layer):
+    tags = [axis.axisTag for axis in font.axes]
+    master_locations = [x.axes for x in font.masters]
+    _, limits = variation_model(font, master_locations)
+    location = tuple(parent_layer._brace_coordinates())
+    default_location = get_regular_master(font).axes
+    normalized_location = {
+        axisTag: normalizeValue(
+            location[ix], (limits[axisTag][0], default_location[ix], limits[axisTag][1])
+        )
+        for ix, axisTag in enumerate(tags)
+    }
+    componentglyph = component.component
+    for layer in componentglyph.layers:
+        if layer.layerId == parent_layer.layerId:
+            return
+        if "coordinates" in layer.attributes and layer._brace_coordinates() == location:
+            return
+
+    # We'll add the appropriate intermediate layer to the component, that'll fix it
+    logger.info(
+        "Adding intermediate layer to %s to support %s %s",
+        componentglyph.name,
+        parent_layer.parent.name,
+        parent_layer.name,
+    )
+    layer = GSLayer()
+    layer.attributes["coordinates"] = location
+    layer.layerId = str(uuid.uuid4())
+    layer.associatedMasterId = parent_layer.associatedMasterId
+    layer.name = parent_layer.name
+    # Create a glyph-level variation model for the component glyph,
+    # including any intermediate layers
+    interpolatable_layers = []
+    locations = []
+    for l in componentglyph.layers:
+        if l._is_brace_layer():
+            locations.append(l.attributes["coordinates"])
+            interpolatable_layers.append(l)
+        if l._is_master_layer:
+            locations.append(font.masters[l.associatedMasterId].axes)
+            interpolatable_layers.append(l)
+    glyph_level_model, _ = variation_model(font, locations)
+
+    # Interpolate new layer width
+    all_widths = [l.width for l in interpolatable_layers]
+    layer.width = glyph_level_model.interpolateFromMasters(
+        normalized_location, all_widths
+    )
+
+    # Interpolate layer shapes
+    for ix, shape in enumerate(componentglyph.layers[0].shapes):
+        all_shapes = [l.shapes[ix] for l in interpolatable_layers]
+        if isinstance(shape, GSPath):
+            # We are making big assumptions about compatibility here
+            layer.shapes.append(
+                interpolate_path(all_shapes, glyph_level_model, normalized_location)
+            )
+        else:
+            ensure_component_has_sparse_layer(font, shape, parent_layer)
+            layer.shapes.append(
+                interpolate_component(
+                    all_shapes, glyph_level_model, normalized_location
+                )
+            )
+    componentglyph.layers.append(layer)
+
+
+def interpolate_path(paths, model, location):
+    path = GSPath()
+    for master_nodes in zip(*[p.nodes for p in paths]):
+        node = GSNode()
+        node.type = master_nodes[0].type
+        node.smooth = master_nodes[0].smooth
+        xs = [n.position.x for n in master_nodes]
+        ys = [n.position.y for n in master_nodes]
+        node.position.x = model.interpolateFromMasters(location, xs)
+        node.position.y = model.interpolateFromMasters(location, ys)
+        path.nodes.append(node)
+    return path
+
+
+def interpolate_component(components, model, location):
+    component = components[0].clone()
+    if all(c.transform == component.transform for c in components):
+        return component
+    transforms = [c.transform for c in components]
+    for element in range(6):
+        values = [t[element] for t in transforms]
+        component.transform[element] = model.interpolateFromMasters(location, values)
+    return component

Lib/glyphsLib/classes.py

@@ -3699,7 +3699,7 @@ def __repr__(self):
         return f'<{self.__class__.__name__} "{name}" ({parent})>'
 
     def __lt__(self, other):
-        if self.master and other.master and self.associatedMasterId == self.layerId:
+        if self.master and other.master and self._is_master_layer:
             return (
                 self.master.weightValue < other.master.weightValue
                 or self.master.widthValue < other.master.widthValue
@@ -3734,13 +3734,13 @@ def master(self):
             master = self.parent.parent.masterForId(self.associatedMasterId)
             return master
 
+    @property
+    def _is_master_layer(self):
+        return self.associatedMasterId == self.layerId
+
     @property
     def name(self):
-        if (
-            self.associatedMasterId
-            and self.associatedMasterId == self.layerId
-            and self.parent
-        ):
+        if self.associatedMasterId and self._is_master_layer and self.parent:
             master = self.parent.parent.masterForId(self.associatedMasterId)
             if master:
                 return master.name

tests/builder/preflight_test.py

@@ -0,0 +1,9 @@
+import glyphsLib
+from glyphsLib.builder.transformations import resolve_intermediate_components
+
+
+def test_intermediates_with_components_without_intermediates(datadir):
+    font = glyphsLib.GSFont(str(datadir.join("ComponentsWithIntermediates.glyphs")))
+    assert len(font.glyphs["A"].layers) != len(font.glyphs["Astroke"].layers)
+    resolve_intermediate_components(font)
+    assert len(font.glyphs["A"].layers) == len(font.glyphs["Astroke"].layers)