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plotter-app/venv/lib/python3.8/site-packages/fontTools/varLib/interpolate_layout.py

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+"""
+Interpolate OpenType Layout tables (GDEF / GPOS / GSUB).
+"""
+
+from fontTools.ttLib import TTFont
+from fontTools.varLib import models, VarLibError, load_designspace, load_masters
+from fontTools.varLib.merger import InstancerMerger
+import os.path
+import logging
+from copy import deepcopy
+from pprint import pformat
+
+log = logging.getLogger("fontTools.varLib.interpolate_layout")
+
+
+def interpolate_layout(designspace, loc, master_finder=lambda s: s, mapped=False):
+    """
+    Interpolate GPOS from a designspace file and location.
+
+    If master_finder is set, it should be a callable that takes master
+    filename as found in designspace file and map it to master font
+    binary as to be opened (eg. .ttf or .otf).
+
+    If mapped is False (default), then location is mapped using the
+    map element of the axes in designspace file.  If mapped is True,
+    it is assumed that location is in designspace's internal space and
+    no mapping is performed.
+    """
+    if hasattr(designspace, "sources"):  # Assume a DesignspaceDocument
+        pass
+    else:  # Assume a file path
+        from fontTools.designspaceLib import DesignSpaceDocument
+
+        designspace = DesignSpaceDocument.fromfile(designspace)
+
+    ds = load_designspace(designspace)
+    log.info("Building interpolated font")
+
+    log.info("Loading master fonts")
+    master_fonts = load_masters(designspace, master_finder)
+    font = deepcopy(master_fonts[ds.base_idx])
+
+    log.info("Location: %s", pformat(loc))
+    if not mapped:
+        loc = {name: ds.axes[name].map_forward(v) for name, v in loc.items()}
+    log.info("Internal location: %s", pformat(loc))
+    loc = models.normalizeLocation(loc, ds.internal_axis_supports)
+    log.info("Normalized location: %s", pformat(loc))
+
+    # Assume single-model for now.
+    model = models.VariationModel(ds.normalized_master_locs)
+    assert 0 == model.mapping[ds.base_idx]
+
+    merger = InstancerMerger(font, model, loc)
+
+    log.info("Building interpolated tables")
+    # TODO GSUB/GDEF
+    merger.mergeTables(font, master_fonts, ["GPOS"])
+    return font
+
+
+def main(args=None):
+    """Interpolate GDEF/GPOS/GSUB tables for a point on a designspace"""
+    from fontTools import configLogger
+    import argparse
+    import sys
+
+    parser = argparse.ArgumentParser(
+        "fonttools varLib.interpolate_layout",
+        description=main.__doc__,
+    )
+    parser.add_argument(
+        "designspace_filename", metavar="DESIGNSPACE", help="Input TTF files"
+    )
+    parser.add_argument(
+        "locations",
+        metavar="LOCATION",
+        type=str,
+        nargs="+",
+        help="Axis locations (e.g. wdth=120",
+    )
+    parser.add_argument(
+        "-o",
+        "--output",
+        metavar="OUTPUT",
+        help="Output font file (defaults to <designspacename>-instance.ttf)",
+    )
+    parser.add_argument(
+        "-l",
+        "--loglevel",
+        metavar="LEVEL",
+        default="INFO",
+        help="Logging level (defaults to INFO)",
+    )
+
+    args = parser.parse_args(args)
+
+    if not args.output:
+        args.output = os.path.splitext(args.designspace_filename)[0] + "-instance.ttf"
+
+    configLogger(level=args.loglevel)
+
+    finder = lambda s: s.replace("master_ufo", "master_ttf_interpolatable").replace(
+        ".ufo", ".ttf"
+    )
+
+    loc = {}
+    for arg in args.locations:
+        tag, val = arg.split("=")
+        loc[tag] = float(val)
+
+    font = interpolate_layout(args.designspace_filename, loc, finder)
+    log.info("Saving font %s", args.output)
+    font.save(args.output)
+
+
+if __name__ == "__main__":
+    import sys
+
+    if len(sys.argv) > 1:
+        sys.exit(main())
+    import doctest
+
+    sys.exit(doctest.testmod().failed)