italicize.py

import fontforge
import sys
import math

if len(sys.argv) != 8:
    print("Usage: python italicize.py <input-font> <output-font> <font-name> <family-name> <full-name> <font-weight> <italic-degree>")
    sys.exit(1)

input_font = sys.argv[1]
output_font = sys.argv[2]
font_name = sys.argv[3]
family_name = sys.argv[4]
full_name = sys.argv[5]
font_weight = sys.argv[6]
italic_degree = float(sys.argv[7])

font = fontforge.open(input_font)

slant_value = math.tan(math.radians(italic_degree))

font.selection.all()
font.transform((1, 0, slant_value, 1, 0, 0))

font.fontname = font_name
font.familyname = family_name
font.fullname = full_name
font.weight = font_weight

font.generate(output_font)

font.close()