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Revision as of 04:28, 7 April 2004 editChinasaur (talk | contribs)Extended confirmed users3,353 edits Did my best to touch things up for HSV. Dunno Py, so may need tweaking to get it to run.← Previous edit Revision as of 04:32, 7 April 2004 edit undoChinasaur (talk | contribs)Extended confirmed users3,353 editsm Changed all my added comments to "# -->" so you can find themNext edit →
Line 30: Line 30:
MIN=min(r,g,b) MIN=min(r,g,b)


# Using negatives for this generally not a good idea. In most # --> Using negatives for this generally not a good idea. In most
# languages, you'd want to use a special value like "undef" or # --> languages, you'd want to use a special value like "undef" or
# "null". I think Python has "none" but I don't know Python so # --> "null". I think Python has "none" but I don't know Python so
# I'm not sure if that's what you'd use. # --> I'm not sure if that's what you'd use.
# Especially not a good idea in this case since h is actually supposed # --> Especially not a good idea in this case since h is actually
# to be able to go negative (see below and my new revision to the # --> supposed to be able to go negative (see below and my new
# HSV color space article. # --> revision to the HSV color space article.
# And anyway, using the else statement is a better way to arrange the # --> And anyway, using the else statement is a better way to arrange
# logic. Easier to read, and one less comparison so probably more # --> the logic; easier to read, and one less comparison so probably
# efficient. # --> more efficient.
# h=-1 # h=-1
# s=-1 # s=-1
Line 52: Line 52:
if r == MAX: h=(0.0+( (g-b)/(MAX-MIN) ))*60 if r == MAX: h=(0.0+( (g-b)/(MAX-MIN) ))*60


# This was wrong in the article; reversed the minus # --> This was wrong in the article; reversed the minus
if g == MAX: h=(2.0+( (b-r)/(MAX-MIN) ))*60 if g == MAX: h=(2.0+( (b-r)/(MAX-MIN) ))*60
if b == MAX: h=(4.0+( (r-g)/(MAX-MIN) ))*60 if b == MAX: h=(4.0+( (r-g)/(MAX-MIN) ))*60
# Actually h should be undefined in this case; you might want to # --> Actually h should be undefined in this case; you might want to
# set it to "none" if that's the way Python works. In practice # --> set it to "none" if that's the way Python works. In practice
# there's nothing wrong with making it zero though. # --> there's nothing wrong with making it zero though.
else: h = 0 else: h = 0


Line 64: Line 64:
V=int(v*100) V=int(v*100)
# H will intentionally come out < 0 for purples; have to wrap around # --> H will intentionally come out < 0 for purples; have to wrap around
# if H<0: H="undefined" # if H<0: H="undefined"
if H < 0: H += 360 if H < 0: H += 360


# Shouldn't be possible for S < 0; at most throw an error here but # --> Shouldn't be possible for S < 0 anymore
# I'd just cut it.
# if S<0: S="undefined" # if S<0: S="undefined"


Revision as of 04:32, 7 April 2004

#!/usr/bin/python
# Diclaimer: 
# I only just picked up python. No apologies are made for this code.
def hextriplet2rgb(triplet) :
        # assuming the triplet *isn't* prefixed with 0x
        value=eval("0x"+triplet)
        r=(value & 0xFF0000) / 0x10000
        g=(value & 0x00FF00) /   0x100
        b=(value & 0x0000FF) 
        return (r,g,b)
# from http://en.wikipedia.org/CMYK
def rgb2cmyk (rgb) :
        r,g,b=rgb
        c,m,y=(1 - r / 255.0,1 - g / 255.0,1 - b / 255.0)
        C,M,Y,K= (c-min(c,m,y),m-min(c,m,y),y-min(c,m,y),min(c,m,y))
        # and additionally, *255 to convert proportion up to 8bits
        return tuple(map (lambda proportion: int(proportion*255), ))
# from http://en.wikipedia.org/HSV_color_space
def rgb2hsv (rgb) :
        # formula takes fp, bother!
        r,g,b = map (lambda x : x/255.0, rgb)
        MAX=max(r,g,b)
        MIN=min(r,g,b)
        # --> Using negatives for this generally not a good idea.  In most
        # --> languages, you'd want to use a special value like "undef" or 
        # --> "null".  I think Python has "none" but I don't know Python so
        # --> I'm not sure if that's what you'd use.
        # --> Especially not a good idea in this case since h is actually 
        # --> supposed to be able to go negative (see below and my new 
        # --> revision to the HSV color space article.
        # --> And anyway, using the else statement is a better way to arrange 
        # --> the logic; easier to read, and one less comparison so probably 
        # --> more efficient.
        # h=-1
        # s=-1
        v=MAX
        if (v > 0) :
                s = (MAX - MIN) / MAX 
        else: s = 0
        if (s > 0) :
                if r == MAX: h=(0.0+( (g-b)/(MAX-MIN) ))*60
                # --> This was wrong in the article; reversed the minus
                if g == MAX: h=(2.0+( (b-r)/(MAX-MIN) ))*60
                if b == MAX: h=(4.0+( (r-g)/(MAX-MIN) ))*60
        # --> Actually h should be undefined in this case; you might want to 
        # --> set it to "none" if that's the way Python works.  In practice
        # --> there's nothing wrong with making it zero though.
        else: h = 0
        H=int(h)
        S=int(s*100)
        V=int(v*100)
        # --> H will intentionally come out < 0 for purples; have to wrap around
        # if H<0: H="undefined"
        if H < 0: H += 360
        # --> Shouldn't be possible for S < 0 anymore
        # if S<0: S="undefined"
        return (H,S,V)
while True:
        print "\n\n"
        print "== Color Coordinates =="
        hextriplet = raw_input(" \'\'\']\'\'\' = #")
        rgb=hextriplet2rgb(hextriplet)
        print " \'\'\']\'\'\'    (r, g, b)    = ",rgb
        print " \'\'\']\'\'\'   (c, m, y, k) = ",rgb2cmyk(rgb)
        print " \'\'\']\'\'\'    (h, s, v)    = ",rgb2hsv(rgb)