Pillow/Tests/test_format_hsv.py

from .helper import PillowTestCase, hopper

from PIL import Image
from PIL._util import py3

import colorsys
import itertools


class TestFormatHSV(PillowTestCase):

    def int_to_float(self, i):
        return float(i)/255.0

    def str_to_float(self, i):
        return float(ord(i))/255.0

    def tuple_to_ints(self, tp):
        x, y, z = tp
        return int(x*255.0), int(y*255.0), int(z*255.0)

    def test_sanity(self):
        Image.new('HSV', (100, 100))

    def wedge(self):
        w = Image._wedge()
        w90 = w.rotate(90)

        (px, h) = w.size

        r = Image.new('L', (px*3, h))
        g = r.copy()
        b = r.copy()

        r.paste(w, (0, 0))
        r.paste(w90, (px, 0))

        g.paste(w90, (0, 0))
        g.paste(w,  (2*px, 0))

        b.paste(w, (px, 0))
        b.paste(w90, (2*px, 0))

        img = Image.merge('RGB', (r, g, b))

        return img

    def to_xxx_colorsys(self, im, func, mode):
        # convert the hard way using the library colorsys routines.

        (r, g, b) = im.split()

        if py3:
            conv_func = self.int_to_float
        else:
            conv_func = self.str_to_float

        if hasattr(itertools, 'izip'):
            iter_helper = itertools.izip
        else:
            iter_helper = itertools.zip_longest

        converted = [self.tuple_to_ints(func(conv_func(_r), conv_func(_g),
                                             conv_func(_b)))
                     for (_r, _g, _b) in iter_helper(r.tobytes(), g.tobytes(),
                                                     b.tobytes())]

        if py3:
            new_bytes = b''.join(bytes(chr(h)+chr(s)+chr(v), 'latin-1') for (
                h, s, v) in converted)
        else:
            new_bytes = b''.join(chr(h)+chr(s)+chr(v) for (
                h, s, v) in converted)

        hsv = Image.frombytes(mode, r.size, new_bytes)

        return hsv

    def to_hsv_colorsys(self, im):
        return self.to_xxx_colorsys(im, colorsys.rgb_to_hsv, 'HSV')

    def to_rgb_colorsys(self, im):
        return self.to_xxx_colorsys(im, colorsys.hsv_to_rgb, 'RGB')

    def test_wedge(self):
        src = self.wedge().resize((3*32, 32), Image.BILINEAR)
        im = src.convert('HSV')
        comparable = self.to_hsv_colorsys(src)

        self.assert_image_similar(im.getchannel(0), comparable.getchannel(0),
                                  1, "Hue conversion is wrong")
        self.assert_image_similar(im.getchannel(1), comparable.getchannel(1),
                                  1, "Saturation conversion is wrong")
        self.assert_image_similar(im.getchannel(2), comparable.getchannel(2),
                                  1, "Value conversion is wrong")

        comparable = src
        im = im.convert('RGB')

        self.assert_image_similar(im.getchannel(0), comparable.getchannel(0),
                                  3, "R conversion is wrong")
        self.assert_image_similar(im.getchannel(1), comparable.getchannel(1),
                                  3, "G conversion is wrong")
        self.assert_image_similar(im.getchannel(2), comparable.getchannel(2),
                                  3, "B conversion is wrong")

    def test_convert(self):
        im = hopper('RGB').convert('HSV')
        comparable = self.to_hsv_colorsys(hopper('RGB'))

        self.assert_image_similar(im.getchannel(0), comparable.getchannel(0),
                                  1, "Hue conversion is wrong")
        self.assert_image_similar(im.getchannel(1), comparable.getchannel(1),
                                  1, "Saturation conversion is wrong")
        self.assert_image_similar(im.getchannel(2), comparable.getchannel(2),
                                  1, "Value conversion is wrong")

    def test_hsv_to_rgb(self):
        comparable = self.to_hsv_colorsys(hopper('RGB'))
        converted = comparable.convert('RGB')
        comparable = self.to_rgb_colorsys(comparable)

        self.assert_image_similar(converted.getchannel(0),
                                  comparable.getchannel(0),
                                  3, "R conversion is wrong")
        self.assert_image_similar(converted.getchannel(1),
                                  comparable.getchannel(1),
                                  3, "G conversion is wrong")
        self.assert_image_similar(converted.getchannel(2),
                                  comparable.getchannel(2),
                                  3, "B conversion is wrong")