1 files changed, 75 insertions, 0 deletions
diff --git a/lib/silfont/scripts/psfcheckinterpolatable.py b/lib/silfont/scripts/psfcheckinterpolatable.py
new file mode 100644
index 0000000..abcf526
--- /dev/null
+++ b/lib/silfont/scripts/psfcheckinterpolatable.py
@@ -0,0 +1,75 @@
+#!/usr/bin/env python
+__doc__ = '''Check that the ufos in a designspace file are interpolatable'''
+__url__ = 'http://github.com/silnrsi/pysilfont'
+__copyright__ = 'Copyright (c) 2021 SIL International (http://www.sil.org)'
+__license__ = 'Released under the MIT License (http://opensource.org/licenses/MIT)'
+__author__ = 'David Raymond'
+
+from silfont.core import execute
+from fontParts.world import OpenFont
+import fontTools.designspaceLib as DSD
+
+argspec = [
+    ('designspace', {'help': 'Design space file'}, {'type': 'filename'}),
+    ('-l','--log', {'help': 'Log file'}, {'type': 'outfile', 'def': '_checkinterp.log'}),
+    ]
+
+def doit(args) :
+    logger = args.logger
+
+    ds = DSD.DesignSpaceDocument()
+    ds.read(args.designspace)
+    if len(ds.sources) == 1: logger.log("The design space file has only one source UFO", "S")
+
+    # Find all the UFOs from the DS Sources.  Where there are more than 2, the primary one will be considered to be
+    # the one where info copy="1" is set (as per psfsyncmasters).  If not set for any, use the first ufo.
+    pufo = None
+    otherfonts = {}
+    for source in ds.sources:
+        ufo = source.path
+        try:
+            font = OpenFont(ufo)
+        except Exception as e:
+            logger.log("Unable to open " + ufo, "S")
+        if source.copyInfo:
+            if pufo: logger.log('Multiple fonts with <info copy="1" />', "S")
+            pufo = ufo
+            pfont = font
+        else:
+            otherfonts[ufo] = font
+    if pufo is None: # If we can't identify the primary font by conyInfo, just use the first one
+        pufo = ds.sources[0].path
+        pfont = otherfonts[pufo]
+        del otherfonts[pufo]
+
+    pinventory = set(glyph.name for glyph in pfont)
+    
+    for oufo in otherfonts:      
+        logger.log(f'Comparing {pufo} with {oufo}', 'P')
+        ofont = otherfonts[oufo]
+        oinventory = set(glyph.name for glyph in ofont)
+    
+        if pinventory != oinventory:
+            logger.log("The glyph inventories in the two UFOs differ", "E")
+            for glyphn in sorted(pinventory - oinventory):
+                logger.log(f'{glyphn} is only in {pufo}', "W")
+            for glyphn in sorted(oinventory - pinventory):
+                logger.log(f'{glyphn} is only in {oufo}', "W")
+        else:
+            logger.log("The UFOs have the same glyph inventories", "P")
+        # Are glyphs compatible for interpolation
+        incompatibles = {}
+        for glyphn in pinventory & oinventory:
+            compatible, report = pfont[glyphn].isCompatible(ofont[glyphn])
+            if not compatible: incompatibles[glyphn] = report
+        if incompatibles:
+            logger.log(f'{len(incompatibles)} glyphs are not interpolatable', 'E')
+            for glyphn in sorted(incompatibles):
+                logger.log(f'{glyphn} is not interpolatable', 'W')
+                logger.log(incompatibles[glyphn], "I")
+            if logger.scrlevel == "W": logger.log("To see detailed reports run with scrlevel and/or loglevel set to I")
+        else:
+            logger.log("All the glyphs are interpolatable", "P")
+
+def cmd() : execute(None,doit, argspec)
+if __name__ == "__main__": cmd()