[qu2cu.cli] Add --all-cubic

Lib/fontTools/qu2cu/cli.py

@@ -19,6 +19,7 @@ def _font_to_cubic(input_path, output_path=None, **kwargs):
     qu2cu_kwargs = {
         "stats": stats,
         "max_err": kwargs["max_err_em"] * font["head"].unitsPerEm,
+        "all_cubic": kwargs["all_cubic"],
     }
 
     assert "gvar" not in font, "Cannot convert variable font"
@@ -59,6 +60,14 @@ def main(args=None):
         default=0.001,
         help="maxiumum approximation error measured in EM (default: 0.001)",
     )
+    parser.add_argument(
+        "-c",
+        "--all-cubic",
+        type=bool,
+        default=False,
+        action="store_true",
+        help="whether to only use cubic curves",
+    )
 
     output_parser = parser.add_mutually_exclusive_group()
     output_parser.add_argument(
@@ -109,6 +118,7 @@ def main(args=None):
     kwargs = dict(
         dump_stats=options.verbose > 0,
         max_err_em=options.conversion_error,
+        all_cubic=options.all_cubic,
     )
 
     for input_path, output_path in zip(options.infiles, output_paths):