Remove "Display" named-instances from variable font

A lot of software gets confused when there are named instances that differ
only by opsz. This change removes all "Display" instances from the fvar table
and makes opsz=32 the default, so that software without automatic opsz-to-size
mapping displays the "Display" styles instead of the text styles by default.
This is the same approach taken by Apple San Francisco Pro.

Closes #519

1 files changed, 68 insertions, 0 deletions

diff --git a/misc/tools/gen-var-designspace.py b/misc/tools/gen-var-designspace.py
new file mode 100644
index 000000000..7b3e4b757
--- /dev/null
+++ b/misc/tools/gen-var-designspace.py
@@ -0,0 +1,68 @@
+import sys, argparse, re
+from fontTools.designspaceLib import DesignSpaceDocument
+
+
+WHITESPACE_RE = re.compile(r'\s+')
+
+
+def remove_whitespace(s):
+  return WHITESPACE_RE.sub("", s)
+
+
+def fixup_instances_text(designspace):
+  # makes the "text" (non-display) instances the default ones
+  i = len(designspace.instances)
+  while i > 0:
+    i -= 1
+    instance = designspace.instances[i]
+    if instance.name.find('Inter Display') != -1:
+      del designspace.instances[i]
+
+
+def fixup_instances_display(designspace):
+  # makes the display instances the default ones
+  i = len(designspace.instances)
+  while i > 0:
+    i -= 1
+    instance = designspace.instances[i]
+    if instance.name.find('Inter Display') != -1:
+      if instance.styleName == 'Display':
+        instance.styleName = 'Regular'
+      else:
+        instance.styleName = instance.styleName.replace('Display ', '')
+    else:
+      del designspace.instances[i]
+  # change default opsz value
+  for a in designspace.axes:
+    if a.tag == "opsz":
+      a.default = a.maximum
+      break
+
+
+def fixup_postscript_instance_names(designspace):
+  # make sure there are PostScript names assigned (fontmake does not create these)
+  psFamilyName = remove_whitespace(designspace.instances[0].familyName)
+  for instance in designspace.instances:
+    instance.postScriptFontName = psFamilyName + remove_whitespace(instance.styleName)
+
+
+def main(argv):
+  ap = argparse.ArgumentParser(description=
+    'Generate designspace file for variable font from generic designspace file')
+  ap.add_argument("input_designspace", help="Path to generic designspace file")
+  ap.add_argument("output_designspace", help="Path for output designspace file")
+
+  args = ap.parse_args()
+
+  designspace = DesignSpaceDocument.fromfile(args.input_designspace)
+
+  # fixup_instances_text(designspace)
+  fixup_instances_display(designspace)
+
+  fixup_postscript_instance_names(designspace)
+
+  designspace.write(args.output_designspace)
+
+
+if __name__ == '__main__':
+  main(sys.argv)