#!/usr/bin/env python

import sys
import cgi
import cgitb
import urllib
import Image, ImageDraw, ImageFont

cgitb.enable()

form = cgi.FieldStorage()
img = form["i"].value

if not img.startswith("http:"):
	raise ValueError("%s not an HTTP url" % img)

im = Image.open(urllib.urlretrieve(img)[0])

if "c" in form:
	cap = form["c"].value
	font = ImageFont.truetype("fonts/LiberationSans-Regular.ttf", 12)
	(w, h) = font.getsize(cap)

	draw = ImageDraw.Draw(im)
	(left, top, right, bottom) = im.getbbox()
	box = (0, bottom - 30, right, bottom)
	mask = Image.new("L", (right, 30), 111)
	im.paste("black", box, mask)

	center = (right - left ) / 2
	x = center - (w/2)
	if x < 0:
		x = 3
	draw.text((x, bottom - 20), cap, font=font)
	del draw

fmt = "png"
print "Content-type: image/%s" % fmt
print
print im.save(sys.stdout, format=fmt)