change-font-line-spacing.py

#!/usr/bin/env python

import sys
import fontforge

if __name__ == '__main__':
  if len(sys.argv) != 5:
    print 'usage: %s <input-font> <output-font> <hhead-ascent> <hhead-descent>' % sys.argv[0]
  else:
    font = fontforge.open(sys.argv[1])
    font.hhea_ascent = int(sys.argv[3])
    font.hhea_descent = int(sys.argv[4])
    font.generate(sys.argv[2])
    font.close()