joxl/gradient.py

## gradient.py
#!/usr/bin/env python

import argparse
import colorsys

HTML_TEMPLATE = """<!DOCTYPE html>
<html>
  <head>
    <style>
      body {
        background: linear-gradient(to right, %s);
      }
    </style>
  </head>
  <body>
  </body>
<html>"""


class Color(object):

    VALID = set("0123456789abcdef")

    def __init__(self, hex_str):
        hex_str = hex_str.lower()
        if len(hex_str) != 6 or not set(hex_str).issubset(self.VALID):
            raise ValueError(hex_str)
        self._hex_str = hex_str

    @classmethod
    def from_hsv(cls, hue, sat, val):
        def perc2byte(perc):
            return int(round(perc * 255, 0))
        r, g, b = colorsys.hsv_to_rgb(hue, sat, val)
        hex_str = "%02x%02x%02x" % (perc2byte(r), perc2byte(g), perc2byte(b))
        return cls(hex_str)

    @property
    def hex_str(self):
        return self._hex_str

    @property
    def rgb(self):
        def hex2color(hexval):
            return int(hexval, 16) / 255.0
        red   = hex2color(self.hex_str[0:2])
        green = hex2color(self.hex_str[2:4])
        blue  = hex2color(self.hex_str[4:6])
        return red, green, blue

    @property
    def hsv(self):
        return colorsys.rgb_to_hsv(*self.rgb)

    def __repr__(self):
        return "<Color hex='%s'>" % (self.hex_str,)


def gradient(src, dst, samples, reverse=False):
    assert samples >= 2, "Must have at least 2 samples"

    def ilerp(it1, it2):
        step = (it2 - it1) / (samples - 1)
        for index in xrange(samples):
            yield it1 + (step * index)

    def ilerp_hue(hue1, hue2, reverse):
        if not reverse and hue1 > hue2:
            # wrap foward (e.g 300..360..0..50)
            for hue in ilerp(hue1, hue2 + 1.0):
                if hue <= 1.0:
                    yield hue
                else:
                    yield hue - 1.0
        elif reverse and hue1 < hue2:
            # wrap backward (e.g 50..0..360..300)
            for hue in ilerp(hue1, hue2 - 1.0):
                if hue >= 0.0:
                    yield hue
                else:
                    yield hue + 1.0
        else:
            for hue in ilerp(hue1, hue2):
                yield hue

    hue1, sat1, val1 = src.hsv
    hue2, sat2, val2 = dst.hsv

    return map(Color.from_hsv,
        ilerp_hue(hue1, hue2, reverse),
        ilerp(sat1, sat2),
        ilerp(val1, val2),
    )


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument("source", metavar="SRC_HEX",
        help="source color (in hex format, e.g. FF0000)")
    parser.add_argument("dest", metavar="DST_HEX",
        help="destination color (in hex format, e.g. 0000FF)")
    parser.add_argument("-s", "--samples", metavar="N", default=10, type=int,
        help="generate %(metavar)s gradient color samples (default=%(default)s)")
    parser.add_argument("-r", "--reverse", action="store_true", default=False,
        help="perform reverse gradient in the hue spectrum")
    parser.add_argument("--html", action="store_true", default=False,
        help="Output HTML code for viewing gradient")

    opts = parser.parse_args()

    # validate args
    if opts.samples < 2:
        parser.error("Must have at least 2 samples")
    try:
        src = Color(opts.source)
        dst = Color(opts.dest)
    except ValueError:
        parser.error("Invalid source/destination colors (%s/%s)" % (opts.source,
                                                                    opts.dest))

    # calculate gradient colors
    colors = gradient(src, dst, opts.samples, opts.reverse)

    # output results
    if opts.html:
        # in html
        css = []
        for color in colors:
            css.append("#%s" % (color.hex_str,))
        print(HTML_TEMPLATE % (",".join(css),))
    else:
        # just raw color hex strings
        for color in colors:
            print(color.hex_str)


if __name__ == "__main__":
    main()
	#!/usr/bin/env python

	import argparse
	import colorsys

	HTML_TEMPLATE = """<!DOCTYPE html>
	<html>
	<head>
	<style>
	body {
	background: linear-gradient(to right, %s);
	}
	</style>
	</head>
	<body>
	</body>
	<html>"""


	class Color(object):

	VALID = set("0123456789abcdef")

	def __init__(self, hex_str):
	hex_str = hex_str.lower()
	if len(hex_str) != 6 or not set(hex_str).issubset(self.VALID):
	raise ValueError(hex_str)
	self._hex_str = hex_str

	@classmethod
	def from_hsv(cls, hue, sat, val):
	def perc2byte(perc):
	return int(round(perc * 255, 0))
	r, g, b = colorsys.hsv_to_rgb(hue, sat, val)
	hex_str = "%02x%02x%02x" % (perc2byte(r), perc2byte(g), perc2byte(b))
	return cls(hex_str)

	@property
	def hex_str(self):
	return self._hex_str

	@property
	def rgb(self):
	def hex2color(hexval):
	return int(hexval, 16) / 255.0
	red = hex2color(self.hex_str[0:2])
	green = hex2color(self.hex_str[2:4])
	blue = hex2color(self.hex_str[4:6])
	return red, green, blue

	@property
	def hsv(self):
	return colorsys.rgb_to_hsv(*self.rgb)

	def __repr__(self):
	return "<Color hex='%s'>" % (self.hex_str,)


	def gradient(src, dst, samples, reverse=False):
	assert samples >= 2, "Must have at least 2 samples"

	def ilerp(it1, it2):
	step = (it2 - it1) / (samples - 1)
	for index in xrange(samples):
	yield it1 + (step * index)

	def ilerp_hue(hue1, hue2, reverse):
	if not reverse and hue1 > hue2:
	# wrap foward (e.g 300..360..0..50)
	for hue in ilerp(hue1, hue2 + 1.0):
	if hue <= 1.0:
	yield hue
	else:
	yield hue - 1.0
	elif reverse and hue1 < hue2:
	# wrap backward (e.g 50..0..360..300)
	for hue in ilerp(hue1, hue2 - 1.0):
	if hue >= 0.0:
	yield hue
	else:
	yield hue + 1.0
	else:
	for hue in ilerp(hue1, hue2):
	yield hue

	hue1, sat1, val1 = src.hsv
	hue2, sat2, val2 = dst.hsv

	return map(Color.from_hsv,
	ilerp_hue(hue1, hue2, reverse),
	ilerp(sat1, sat2),
	ilerp(val1, val2),
	)


	def main():
	parser = argparse.ArgumentParser()
	parser.add_argument("source", metavar="SRC_HEX",
	help="source color (in hex format, e.g. FF0000)")
	parser.add_argument("dest", metavar="DST_HEX",
	help="destination color (in hex format, e.g. 0000FF)")
	parser.add_argument("-s", "--samples", metavar="N", default=10, type=int,
	help="generate %(metavar)s gradient color samples (default=%(default)s)")
	parser.add_argument("-r", "--reverse", action="store_true", default=False,
	help="perform reverse gradient in the hue spectrum")
	parser.add_argument("--html", action="store_true", default=False,
	help="Output HTML code for viewing gradient")

	opts = parser.parse_args()

	# validate args
	if opts.samples < 2:
	parser.error("Must have at least 2 samples")
	try:
	src = Color(opts.source)
	dst = Color(opts.dest)
	except ValueError:
	parser.error("Invalid source/destination colors (%s/%s)" % (opts.source,
	opts.dest))

	# calculate gradient colors
	colors = gradient(src, dst, opts.samples, opts.reverse)

	# output results
	if opts.html:
	# in html
	css = []
	for color in colors:
	css.append("#%s" % (color.hex_str,))
	print(HTML_TEMPLATE % (",".join(css),))
	else:
	# just raw color hex strings
	for color in colors:
	print(color.hex_str)


	if __name__ == "__main__":
	main()