|
1 | | -# Conversions between RGB and YIQ color spaces. |
2 | 1 | # |
3 | | -# R, G, B are amounts of Red, Green and Blue; |
4 | | -# Y, I, Q are intensity (Y) and two difference signals (I, Q). |
5 | | - |
| 2 | +# Module color - do color conversions |
| 3 | +# |
6 | 4 |
|
7 | | -# Convert a (R, G, B) triple to (Y, I, Q). |
8 | | -# Scale is arbitrary (output uses the same scale as input). |
| 5 | +ONE_THIRD=1.0/3.0 |
| 6 | +ONE_SIXTH=1.0/6.0 |
| 7 | +TWO_THIRD=2.0/3.0 |
9 | 8 |
|
10 | | -def rgb_to_yiq(r, g, b): |
11 | | - y = 0.30*r + 0.59*g + 0.11*b |
12 | | - i = 0.60*r - 0.28*g - 0.32*b |
13 | | - q = 0.21*r - 0.52*g + 0.31*b |
14 | | - return y, i, q |
| 9 | +def rgb_to_yiq(r,g,b): |
| 10 | + y = 0.3*r + 0.59*g + 0.11*b |
| 11 | + i = 0.6*r - 0.28*g - 0.32*b |
| 12 | + q = 0.21*r- 0.52*g + 0.31*b |
| 13 | + return (y,i,q) |
| 14 | +def yiq_to_rgb(y,i,q): |
| 15 | + r = y + 0.948262*i + 0.624013*q |
| 16 | + g = y - 0.276066*i - 0.639810*q |
| 17 | + b = y - 1.105450*i + 1.729860*q |
| 18 | + if r < 0.0: r = 0.0 |
| 19 | + if g < 0.0: g = 0.0 |
| 20 | + if b < 0.0: b = 0.0 |
| 21 | + if r > 1.0: r = 1.0 |
| 22 | + if g > 1.0: g = 1.0 |
| 23 | + if b > 1.0: b = 1.0 |
| 24 | + return (r,g,b) |
15 | 25 |
|
| 26 | +def _v(m1,m2,hue): |
| 27 | + if hue >= 1.0: hue = hue - 1.0 |
| 28 | + if hue < 0.0: hue = hue + 1.0 |
| 29 | + if hue < ONE_SIXTH: |
| 30 | + return m1 + (m2-m1)*hue*6.0 |
| 31 | + if hue < 0.5: |
| 32 | + return m2 |
| 33 | + if hue < TWO_THIRD: |
| 34 | + return m1 + (m2-m1)*(TWO_THIRD-hue)*6.0 |
| 35 | + return m1 |
16 | 36 |
|
17 | | -# Convert a (Y, I, Q) triple to (R, G, B). |
18 | | -# Input and output values are in the interval [0.0 ... 1.0]. |
| 37 | +def rgb_to_hls(r,g,b): |
| 38 | + maxc = max(r,g,b) |
| 39 | + minc = min(r,g,b) |
| 40 | + l = (minc+maxc)/2.0 |
| 41 | + if minc == maxc: |
| 42 | + return 0.0, l, 0.0 |
| 43 | + if l <= 0.5: |
| 44 | + s = (maxc-minc)/(maxc+minc) |
| 45 | + else: |
| 46 | + s = (maxc-minc)/(2-maxc-minc) |
| 47 | + rc = (maxc-r)/(maxc-minc) |
| 48 | + gc = (maxc-g)/(maxc-minc) |
| 49 | + bc = (maxc-b)/(maxc-minc) |
| 50 | + if r == maxc: |
| 51 | + h = bc-gc |
| 52 | + elif g == maxc: |
| 53 | + h = 2.0+rc-bc |
| 54 | + else: |
| 55 | + h = 4.0+gc-rc |
| 56 | + h = h/6.0 |
| 57 | + if h < 0.0: |
| 58 | + h = h + 1.0 |
| 59 | + return h,l,s |
| 60 | +def hls_to_rgb(h,l,s): |
| 61 | + if s == 0.0: |
| 62 | + return l,l,l |
| 63 | + if l <= 0.5: |
| 64 | + m2 = l * (1.0+s) |
| 65 | + else: |
| 66 | + m2 = l+s-(l*s) |
| 67 | + m1 = 2.0*l - m2 |
| 68 | + return (_v(m1,m2,h+ONE_THIRD), _v(m1,m2,h), _v(m1,m2,h-ONE_THIRD)) |
19 | 69 |
|
20 | | -def yiq_to_rgb(y, i, q): |
21 | | - r = y + 0.948262*i + 0.624013*q |
22 | | - g = y - 0.276066*i - 0.639810*q |
23 | | - b = y - 1.105450*i + 1.729860*q |
24 | | - if r < 0.0: r = 0.0 |
25 | | - if g < 0.0: g = 0.0 |
26 | | - if b < 0.0: b = 0.0 |
27 | | - if r > 1.0: r = 1.0 |
28 | | - if g > 1.0: g = 1.0 |
29 | | - if b > 1.0: b = 1.0 |
30 | | - return r, g, b |
| 70 | +def rgb_to_hsv(r,g,b): |
| 71 | + maxc = max(r,g,b) |
| 72 | + minc = min(r,g,b) |
| 73 | + v = maxc |
| 74 | + if minc == maxc: |
| 75 | + return 0.0, 0.0, v |
| 76 | + s = (maxc-minc)/maxc |
| 77 | + rc = (maxc-r)/(maxc-minc) |
| 78 | + gc = (maxc-g)/(maxc-minc) |
| 79 | + bc = (maxc-b)/(maxc-minc) |
| 80 | + if r == maxc: |
| 81 | + h = bc-gc |
| 82 | + elif g == maxc: |
| 83 | + h = 2.0+rc-bc |
| 84 | + else: |
| 85 | + h = 4.0+gc-rc |
| 86 | + h = h/6.0 |
| 87 | + if h < 0.0: |
| 88 | + h = h + 1.0 |
| 89 | + return h,s,v |
| 90 | +def hsv_to_rgb(h,s,v): |
| 91 | + if s == 0.0: |
| 92 | + return v,v,v |
| 93 | + i = int(h*6.0) |
| 94 | + f = (h*6.0)-i |
| 95 | + p = v*(1.0-s) |
| 96 | + q = v*(1.0-s*f) |
| 97 | + t = v*(1.0-s*(1.0-f)) |
| 98 | + if i in (0,6): return v,t,p |
| 99 | + if i = 1: return q,v,p |
| 100 | + if i = 2: return p,v,t |
| 101 | + if i = 3: return p,q,v |
| 102 | + if i = 4: return t,p,v |
| 103 | + if i = 5: return v,p,q |
| 104 | + print i, h, f |
| 105 | + print h, s, v |
| 106 | + raise 'Bad color' |
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