#!/usr/bin/env python

################################################################################
# The MIT License
#
# Copyright (c) 2009 Brian Schott (Sir Alaran)
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.
################################################################################


import random
import sys
import getopt

import cairo


def printUsage():
	print "Usage: " + sys.argv[0] + " [options] width height"
	print "  options:"
	print "    -s    --shiny                   Draws a translucent gradient over the result"
	print "    -b    --base-color=NUMBER       Sets the brightness of the metal to NUMBER."
	print "                                    NUMBER can be any number between 0.0 and 1.0"
	print "                                    Default value is 0.8"
	print "    -a    --alpha=NUMBER            Sets the translucency for the gradient overlay"
	print "                                    Has no effect if -s is not specified."
	print "                                    Default value is 0.7"
	print "    -v    --variation=NUMBER        Amound that the color of grooves will vary from"
	print "                                    the base color. Default value is 0.05"
	print "    -g    --grain-strength=NUMBER   The strength of the \"grain\" of the brushing."
	print "                                    Keep this value fairly low. Defaults to 0.05"
	print "    -o    --output-file=FILENAME    Writes the output to a PNG file named FILENAME."
	print "                                    Default is brushed_output.png"


def processOptions(v, a, b, g, shiny, fileName, width, height):
	optlist, args = getopt.getopt(sys.argv[1:], "sb:a:v:o:g:", ["shiny",
		"base-color=", "alpha=", "variation=", "output-file=",
		"grain-strength="])
	for option, argument in optlist:
		if option in ("-s", "--shiny"):
			shiny = True
		elif option in ("-b", "--base-color"):
			try:
				b = float(argument)
			except ValueError:
				print "Error, could not convert " + argument + " to a number."
		elif option in ("-a", "--alpha"):
			try:
				a = float(argument)
			except ValueError:
				print "Error, could not convert " + argument + " to a number."
		elif option in ("-v", "--variation"):
			try:
				v = float(argument)
			except ValueError:
				print "Error, could not convert " + argument + " to a number."
		elif option in ("-g", "--grain-strength"):
			try:
				g = float(argument)
			except ValueError:
				print "Error, could not convert " + argument + " to a number."
		elif option in ("-o", "--output-file"):
			fileName = argument
		else:
			assert False, "Unhandled option"

	try:
		width = int(args[0])
	except ValueError:
		print "Could not convert " + args[0] + " to a width value"

	try:
		height = int(args[1])
	except ValueError:
		print "Could not convert " + args[1] + " to a height value"

	return v, a, b, g, shiny, fileName, width, height


def drawBrushedMetal(context, width, height, baseColor, variation, grain):
	# Base lines
	for i in range(height):
		r = random.randint(0, 1)
		c = baseColor
		if r == 0:
			c = c - (variation * random.random())
		else:
			c = c + (variation * random.random())
		context.set_source_rgba(c, c, c, 1.0)
		context.set_line_width(1.0)
		context.move_to(0, i + 0.5)
		context.line_to(width, i + 0.5)
		context.stroke()

	# Random gradient scratches
	for i in range(max(width, height) // 4):
		r = random.randint(0, 1)
		c = baseColor
		if r == 0:
			c = c - (variation * random.random())
		else:
			c = c + (variation * random.random())
		context.set_source_rgba(c, c, c, 1.0)
		x = random.randint(0, width)
		y = random.randint(0, height)
		w = ((width / 2.0) + (width * random.random() / 5.0))
		g = cairo.LinearGradient(x, y, x + w, y)
		g.add_color_stop_rgba(0.0, c, c, c, 0.0)
		g.add_color_stop_rgba(0.25, c, c, c, 1.0)
		g.add_color_stop_rgba(0.75, c, c, c, 1.0)
		g.add_color_stop_rgba(1.0, c, c, c, 0.0)
		context.set_source(g)
		context.rectangle(x, y, w, 1.0)
		context.fill()

	# Mostly transparent stripes. This improves the look of the result quite a bit
	for i in range(0, height, 2):
		context.set_source_rgba(0.0, 0.0, 0.0, grain)
		context.set_line_width(1.0)
		context.move_to(0, i + 0.5)
		context.line_to(width, i + 0.5)
		context.stroke()


def drawShine(context, shineAlpha, width):
	g = cairo.LinearGradient(0.0, 0.0, width, 0.0)
	g.add_color_stop_rgba(0.0, 1.0, 1.0, 1.0, 0.0)
	g.add_color_stop_rgba(0.3, 1.0, 1.0, 1.0, shineAlpha * 0.75)
	g.add_color_stop_rgba(0.5, 1.0, 1.0, 1.0, shineAlpha)
	g.add_color_stop_rgba(0.7, 1.0, 1.0, 1.0, shineAlpha * 0.75)
	g.add_color_stop_rgba(1.0, 1.0, 1.0, 1.0, 0.0)
	context.set_source(g)
	context.paint()


def main():
	# At least a width and height need to be specified, so quit if we don't have
	# enough arguments
	if len(sys.argv) < 3:
		printUsage()
		sys.exit(1)

	# Option variables
	v = 0.05
	a = 0.7
	b = 0.8
	g = 0.05
	shiny = False
	fileName = "brushed_output.png"
	w = None
	h = None
	v, a, b, g, shiny, fileName, w, h = processOptions(v, a, b, g, shiny,
		fileName, w, h)

	s = cairo.ImageSurface(cairo.FORMAT_ARGB32, w, h)
	context = cairo.Context(s)

	drawBrushedMetal(context, w, h, b, v, g)
	if shiny == True:
		drawShine(context, a, w)

	s.write_to_png(fileName)
	sys.exit(0)

if __name__ == "__main__":
	main()