# Python code coverage for Lib/colorsys.py

# | count | content |
---|---|---|

1 | n/a | """Conversion functions between RGB and other color systems. |

2 | n/a | |

3 | n/a | This modules provides two functions for each color system ABC: |

4 | n/a | |

5 | n/a | rgb_to_abc(r, g, b) --> a, b, c |

6 | n/a | abc_to_rgb(a, b, c) --> r, g, b |

7 | n/a | |

8 | n/a | All inputs and outputs are triples of floats in the range [0.0...1.0] |

9 | n/a | (with the exception of I and Q, which covers a slightly larger range). |

10 | n/a | Inputs outside the valid range may cause exceptions or invalid outputs. |

11 | n/a | |

12 | n/a | Supported color systems: |

13 | n/a | RGB: Red, Green, Blue components |

14 | n/a | YIQ: Luminance, Chrominance (used by composite video signals) |

15 | n/a | HLS: Hue, Luminance, Saturation |

16 | n/a | HSV: Hue, Saturation, Value |

17 | n/a | """ |

18 | n/a | |

19 | n/a | # References: |

20 | n/a | # http://en.wikipedia.org/wiki/YIQ |

21 | n/a | # http://en.wikipedia.org/wiki/HLS_color_space |

22 | n/a | # http://en.wikipedia.org/wiki/HSV_color_space |

23 | n/a | |

24 | n/a | __all__ = ["rgb_to_yiq","yiq_to_rgb","rgb_to_hls","hls_to_rgb", |

25 | n/a | "rgb_to_hsv","hsv_to_rgb"] |

26 | n/a | |

27 | n/a | # Some floating point constants |

28 | n/a | |

29 | n/a | ONE_THIRD = 1.0/3.0 |

30 | n/a | ONE_SIXTH = 1.0/6.0 |

31 | n/a | TWO_THIRD = 2.0/3.0 |

32 | n/a | |

33 | n/a | # YIQ: used by composite video signals (linear combinations of RGB) |

34 | n/a | # Y: perceived grey level (0.0 == black, 1.0 == white) |

35 | n/a | # I, Q: color components |

36 | n/a | # |

37 | n/a | # There are a great many versions of the constants used in these formulae. |

38 | n/a | # The ones in this library uses constants from the FCC version of NTSC. |

39 | n/a | |

40 | n/a | def rgb_to_yiq(r, g, b): |

41 | n/a | y = 0.30*r + 0.59*g + 0.11*b |

42 | n/a | i = 0.74*(r-y) - 0.27*(b-y) |

43 | n/a | q = 0.48*(r-y) + 0.41*(b-y) |

44 | n/a | return (y, i, q) |

45 | n/a | |

46 | n/a | def yiq_to_rgb(y, i, q): |

47 | n/a | # r = y + (0.27*q + 0.41*i) / (0.74*0.41 + 0.27*0.48) |

48 | n/a | # b = y + (0.74*q - 0.48*i) / (0.74*0.41 + 0.27*0.48) |

49 | n/a | # g = y - (0.30*(r-y) + 0.11*(b-y)) / 0.59 |

50 | n/a | |

51 | n/a | r = y + 0.9468822170900693*i + 0.6235565819861433*q |

52 | n/a | g = y - 0.27478764629897834*i - 0.6356910791873801*q |

53 | n/a | b = y - 1.1085450346420322*i + 1.7090069284064666*q |

54 | n/a | |

55 | n/a | if r < 0.0: |

56 | n/a | r = 0.0 |

57 | n/a | if g < 0.0: |

58 | n/a | g = 0.0 |

59 | n/a | if b < 0.0: |

60 | n/a | b = 0.0 |

61 | n/a | if r > 1.0: |

62 | n/a | r = 1.0 |

63 | n/a | if g > 1.0: |

64 | n/a | g = 1.0 |

65 | n/a | if b > 1.0: |

66 | n/a | b = 1.0 |

67 | n/a | return (r, g, b) |

68 | n/a | |

69 | n/a | |

70 | n/a | # HLS: Hue, Luminance, Saturation |

71 | n/a | # H: position in the spectrum |

72 | n/a | # L: color lightness |

73 | n/a | # S: color saturation |

74 | n/a | |

75 | n/a | def rgb_to_hls(r, g, b): |

76 | n/a | maxc = max(r, g, b) |

77 | n/a | minc = min(r, g, b) |

78 | n/a | # XXX Can optimize (maxc+minc) and (maxc-minc) |

79 | n/a | l = (minc+maxc)/2.0 |

80 | n/a | if minc == maxc: |

81 | n/a | return 0.0, l, 0.0 |

82 | n/a | if l <= 0.5: |

83 | n/a | s = (maxc-minc) / (maxc+minc) |

84 | n/a | else: |

85 | n/a | s = (maxc-minc) / (2.0-maxc-minc) |

86 | n/a | rc = (maxc-r) / (maxc-minc) |

87 | n/a | gc = (maxc-g) / (maxc-minc) |

88 | n/a | bc = (maxc-b) / (maxc-minc) |

89 | n/a | if r == maxc: |

90 | n/a | h = bc-gc |

91 | n/a | elif g == maxc: |

92 | n/a | h = 2.0+rc-bc |

93 | n/a | else: |

94 | n/a | h = 4.0+gc-rc |

95 | n/a | h = (h/6.0) % 1.0 |

96 | n/a | return h, l, s |

97 | n/a | |

98 | n/a | def hls_to_rgb(h, l, s): |

99 | n/a | if s == 0.0: |

100 | n/a | return l, l, l |

101 | n/a | if l <= 0.5: |

102 | n/a | m2 = l * (1.0+s) |

103 | n/a | else: |

104 | n/a | m2 = l+s-(l*s) |

105 | n/a | m1 = 2.0*l - m2 |

106 | n/a | return (_v(m1, m2, h+ONE_THIRD), _v(m1, m2, h), _v(m1, m2, h-ONE_THIRD)) |

107 | n/a | |

108 | n/a | def _v(m1, m2, hue): |

109 | n/a | hue = hue % 1.0 |

110 | n/a | if hue < ONE_SIXTH: |

111 | n/a | return m1 + (m2-m1)*hue*6.0 |

112 | n/a | if hue < 0.5: |

113 | n/a | return m2 |

114 | n/a | if hue < TWO_THIRD: |

115 | n/a | return m1 + (m2-m1)*(TWO_THIRD-hue)*6.0 |

116 | n/a | return m1 |

117 | n/a | |

118 | n/a | |

119 | n/a | # HSV: Hue, Saturation, Value |

120 | n/a | # H: position in the spectrum |

121 | n/a | # S: color saturation ("purity") |

122 | n/a | # V: color brightness |

123 | n/a | |

124 | n/a | def rgb_to_hsv(r, g, b): |

125 | n/a | maxc = max(r, g, b) |

126 | n/a | minc = min(r, g, b) |

127 | n/a | v = maxc |

128 | n/a | if minc == maxc: |

129 | n/a | return 0.0, 0.0, v |

130 | n/a | s = (maxc-minc) / maxc |

131 | n/a | rc = (maxc-r) / (maxc-minc) |

132 | n/a | gc = (maxc-g) / (maxc-minc) |

133 | n/a | bc = (maxc-b) / (maxc-minc) |

134 | n/a | if r == maxc: |

135 | n/a | h = bc-gc |

136 | n/a | elif g == maxc: |

137 | n/a | h = 2.0+rc-bc |

138 | n/a | else: |

139 | n/a | h = 4.0+gc-rc |

140 | n/a | h = (h/6.0) % 1.0 |

141 | n/a | return h, s, v |

142 | n/a | |

143 | n/a | def hsv_to_rgb(h, s, v): |

144 | n/a | if s == 0.0: |

145 | n/a | return v, v, v |

146 | n/a | i = int(h*6.0) # XXX assume int() truncates! |

147 | n/a | f = (h*6.0) - i |

148 | n/a | p = v*(1.0 - s) |

149 | n/a | q = v*(1.0 - s*f) |

150 | n/a | t = v*(1.0 - s*(1.0-f)) |

151 | n/a | i = i%6 |

152 | n/a | if i == 0: |

153 | n/a | return v, t, p |

154 | n/a | if i == 1: |

155 | n/a | return q, v, p |

156 | n/a | if i == 2: |

157 | n/a | return p, v, t |

158 | n/a | if i == 3: |

159 | n/a | return p, q, v |

160 | n/a | if i == 4: |

161 | n/a | return t, p, v |

162 | n/a | if i == 5: |

163 | n/a | return v, p, q |

164 | n/a | # Cannot get here |