Python 3 compatibility: use print function

In the future, we may want to switch to Python 3 to be able to use
things like type annotation (via mypy). The only thing that holds us
back is that the Fontforge Python library is Python 2.x-only. But it
costs us little to start preparing for the changeover now.

Author: rmunn

dataconvert.py

@@ -1,4 +1,4 @@
-from __future__ import division
+from __future__ import division, print_function
 
 """Library for converting lines and polygons between various formats
 
@@ -95,7 +95,7 @@ def any_to_linestring(pointlist):
     try:
         return LineString(any_to_polyline(pointlist))
     except ValueError:
-        print str(list(pointlist))
+        print(str(list(pointlist)))
         raise
 
 def any_to_polygon(outside, holes):

extractpoints.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 
-from __future__ import division
+from __future__ import division, print_function
 
 import fontforge
 import time
@@ -427,7 +427,7 @@ def find_centerpoint(edgepoint):
         # it earlier in the next_point(curpt) call.
         start_from = find_centerpoint(curpt)
         if start_from is None:
-            print "find_centerpoint({}) failed...".format(curpt)
+            print("find_centerpoint({}) failed...".format(curpt))
             start_from = curpt
             edit_line_after_recording = False
         else:
@@ -519,17 +519,17 @@ def create_dotted_font(fname):
         glyph = input_font[glyphname]
         new_glyph = new_font[glyphname]
         new_glyph.clear()
-        print "Processing glyph at codepoint U+{:04X} named {}".format(glyph.encoding, glyphname)
+        print("Processing glyph at codepoint U+{:04X} named {}".format(glyph.encoding, glyphname))
         glyph.unlinkRef()
         copy_glyph(glyph, new_glyph)
     font_type = args.output.lower().rsplit('.', 1)[-1]
     if font_type == 'sfd':
         new_font.save(args.output)
     else:
         new_font.generate(args.output)
-    print "Dotted font created as", args.output
+    print("Dotted font created as", args.output)
     if args.visualize:
-        print "Press any key to exit"
+        print("Press any key to exit")
         import visualization
         visualization.wait_for_keypress(args.em, args.zoom)
 
@@ -546,7 +546,7 @@ def extraction_demo(fname, letter):
     glyph = font[codepoint]
     glyph.unlinkRef()
     dots = extract_dots(glyph, args.visualize)
-    print "{} dots found".format(len(dots))
+    print("{} dots found".format(len(dots)))
     if args.visualize:
         import visualization
         visualization.wait_for_keypress(args.em, args.zoom)
@@ -674,9 +674,9 @@ def debug(s, *args, **kwargs):
     if not DEBUG:
         return
     if not args and not kwargs:
-        print s
+        print(s)
     else:
-        print s.format(*args, **kwargs)
+        print(s.format(*args, **kwargs))
 
 def parse_args():
     "Parse the arguments the user passed in"

generalfuncs.py

@@ -1,4 +1,4 @@
-from __future__ import division
+from __future__ import division, print_function
 
 """Library for generally useful functions
 

visualization.py

@@ -1,4 +1,4 @@
-from __future__ import division
+from __future__ import division, print_function
 
 """Library for visualizing our results"""
 
@@ -35,7 +35,7 @@ def wait_for_keypress(emsize = 1024, zoom = 1.0):
             # Reconstruct glyph coords from screen coords
             x = float(x) / zoom
             y = emsize-(float(y) / zoom)
-            print (x, y)
+            print((x, y))
             import sys
             sys.stdout.flush()
             continue
@@ -126,7 +126,7 @@ def draw_midlines(screen, polylines, midpoints, emsize = 1024, zoom = 1.0, polyl
     #for m in midpoints:
         #x = int(m[0] * zoom)
         #y = int((emsize-m[1]) * zoom)
-        #print (x, y)
+        #print((x, y))
         #pixel(screen, x, y, midpointcolor)
 
     # Close the polylines loop again prior to drawing