POV-Ray : Newsgroups : povray.newusers : Colour conversion - HTML to RGB Server Time
1 Nov 2024 23:17:08 EDT (-0400)
  Colour conversion - HTML to RGB (Message 1 to 9 of 9)  
From: David Robinson
Subject: Colour conversion - HTML to RGB
Date: 1 Nov 2004 11:15:34
Message: <41866126$1@news.povray.org>
I've done a bit of digging around and I can't seem to come up with anything.

What I'm trying to do is use HTML colours instead of RGB values. This is
really for ease of programming, to save me having to split and recalculate
the HTML values into RGB. I don't mind doing it, but is there an option to
supply POV with HTML values? Or will it need a conversion script somewhere?

Thanks,

David


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From: Slime
Subject: Re: Colour conversion - HTML to RGB
Date: 1 Nov 2004 13:00:40
Message: <418679c8$1@news.povray.org>
> What I'm trying to do is use HTML colours instead of RGB values.

You should search this newsgroup (povray.newusers) for the topic "RGB<->HEX"
which was posted on 9/9/2004 8:33 PM.

 - Slime
 [ http://www.slimeland.com/ ]


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From: Mike Williams
Subject: Re: Colour conversion - HTML to RGB
Date: 1 Nov 2004 13:01:08
Message: <JZmaKAAflnhBFwnw@econym.demon.co.uk>
Wasn't it David Robinson who wrote:
>I've done a bit of digging around and I can't seem to come up with anything.
>
>What I'm trying to do is use HTML colours instead of RGB values. This is
>really for ease of programming, to save me having to split and recalculate
>the HTML values into RGB. I don't mind doing it, but is there an option to
>supply POV with HTML values? Or will it need a conversion script somewhere?

If you mean HTML codes like "FF0088", then it's possible to write a
macro. It's not particularly pretty because you've got to perform
arithmetic on the contents of strings.

#macro HTMLRGB(H)
 #local C=0;
 #while (strlen(H)>0) 
   #local A=substr(H,1,1);
   #local H=substr(H,2,strlen(H)-1);
   #if (strcmp(A,"0")=0) #local C=C*16; #end
   #if (strcmp(A,"1")=0) #local C=C*16+1; #end
   #if (strcmp(A,"2")=0) #local C=C*16+2; #end
   #if (strcmp(A,"3")=0) #local C=C*16+3; #end
   #if (strcmp(A,"4")=0) #local C=C*16+4; #end
   #if (strcmp(A,"5")=0) #local C=C*16+5; #end
   #if (strcmp(A,"6")=0) #local C=C*16+6; #end
   #if (strcmp(A,"7")=0) #local C=C*16+7; #end
   #if (strcmp(A,"8")=0) #local C=C*16+8; #end
   #if (strcmp(A,"9")=0) #local C=C*16+9; #end
   #if (strcmp(A,"A")=0 | strcmp(A,"a")=0) #local C=C*16+10; #end
   #if (strcmp(A,"B")=0 | strcmp(A,"b")=0) #local C=C*16+11; #end
   #if (strcmp(A,"C")=0 | strcmp(A,"c")=0) #local C=C*16+12; #end
   #if (strcmp(A,"D")=0 | strcmp(A,"d")=0) #local C=C*16+13; #end
   #if (strcmp(A,"E")=0 | strcmp(A,"e")=0) #local C=C*16+14; #end
   #if (strcmp(A,"F")=0 | strcmp(A,"f")=0) #local C=C*16+15; #end
 #end
 #local R=int(C/256/256);
 #local G=mod(int(C/256),256);
 #local B=mod(C,256);
 rgb <R,G,B>/255
#end                        


Use it like 

    pigment {HTMLRGB("FF0088")}


-- 
Mike Williams
Gentleman of Leisure


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From: Warp
Subject: Re: Colour conversion - HTML to RGB
Date: 1 Nov 2004 15:16:45
Message: <418699ac@news.povray.org>
Mike Williams <nos### [at] econymdemoncouk> wrote:
>  #local C=0;
>  #while (strlen(H)>0) 
>    #local A=substr(H,1,1);
>    #local H=substr(H,2,strlen(H)-1);
>    #if (strcmp(A,"0")=0) #local C=C*16; #end
>    #if (strcmp(A,"1")=0) #local C=C*16+1; #end
>    #if (strcmp(A,"2")=0) #local C=C*16+2; #end
>    #if (strcmp(A,"3")=0) #local C=C*16+3; #end
>    #if (strcmp(A,"4")=0) #local C=C*16+4; #end
>    #if (strcmp(A,"5")=0) #local C=C*16+5; #end
>    #if (strcmp(A,"6")=0) #local C=C*16+6; #end
>    #if (strcmp(A,"7")=0) #local C=C*16+7; #end
>    #if (strcmp(A,"8")=0) #local C=C*16+8; #end
>    #if (strcmp(A,"9")=0) #local C=C*16+9; #end
>    #if (strcmp(A,"A")=0 | strcmp(A,"a")=0) #local C=C*16+10; #end
>    #if (strcmp(A,"B")=0 | strcmp(A,"b")=0) #local C=C*16+11; #end
>    #if (strcmp(A,"C")=0 | strcmp(A,"c")=0) #local C=C*16+12; #end
>    #if (strcmp(A,"D")=0 | strcmp(A,"d")=0) #local C=C*16+13; #end
>    #if (strcmp(A,"E")=0 | strcmp(A,"e")=0) #local C=C*16+14; #end
>    #if (strcmp(A,"F")=0 | strcmp(A,"f")=0) #local C=C*16+15; #end
>  #end
>  #local R=int(C/256/256);
>  #local G=mod(int(C/256),256);
>  #local B=mod(C,256);
>  rgb <R,G,B>/255
> #end                        

  Code repetition is one of the biggest sins in programming.

  How about this (it has the advantage to support both uppercase and
lowercase hexadecimal numbers, ie. "c2Ab0F" is ok):

#macro HTMLRGB(H)
  #local value = 0;
  #local len = strlen(H);
  #local index = 1;
  #while(index <= len)
    #local char = asc(substr(H, index, 1)) - 48;
    #if(char > 9) #local char = char - 7; #end
    #if(char > 15) #local char = char - 32; #end
    #local value = value*16 + char;
    #local index = index + 1;
  #end
  <int(value/65536), mod(int(value/256), 256), mod(value,256)>
#end


-- 
plane{-x+y,-1pigment{bozo color_map{[0rgb x][1rgb x+y]}turbulence 1}}
sphere{0,2pigment{rgbt 1}interior{media{emission 1density{spherical
density_map{[0rgb 0][.5rgb<1,.5>][1rgb 1]}turbulence.9}}}scale
<1,1,3>hollow}text{ttf"timrom""Warp".1,0translate<-1,-.1,2>}//  - Warp -


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From: Mike Williams
Subject: Re: Colour conversion - HTML to RGB
Date: 1 Nov 2004 16:02:31
Message: <90mHBAAdRqhBFwzj@econym.demon.co.uk>
Wasn't it Warp who wrote:
>
>  Code repetition is one of the biggest sins in programming.
>
>  How about this (it has the advantage to support both uppercase and
>lowercase hexadecimal numbers, ie. "c2Ab0F" is ok):

Looks good, and only needs a couple of tiny fixes for it to give the
correct results.

-- 
Mike Williams
Gentleman of Leisure


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From: Warp
Subject: Re: Colour conversion - HTML to RGB
Date: 1 Nov 2004 17:32:21
Message: <4186b975@news.povray.org>
Mike Williams <nos### [at] econymdemoncouk> wrote:
> Looks good, and only needs a couple of tiny fixes for it to give the
> correct results.

  Like what?

  I know it gives garbage if you give it something else than a hex number,
but I assumed the input is always ok.

-- 
#macro M(A,N,D,L)plane{-z,-9pigment{mandel L*9translate N color_map{[0rgb x]
[1rgb 9]}scale<D,D*3D>*1e3}rotate y*A*8}#end M(-3<1.206434.28623>70,7)M(
-1<.7438.1795>1,20)M(1<.77595.13699>30,20)M(3<.75923.07145>80,99)// - Warp -


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From: David Robinson
Subject: Re: Colour conversion - HTML to RGB
Date: 2 Nov 2004 11:30:44
Message: <4187b634$1@news.povray.org>
"Warp" <war### [at] tagpovrayorg> wrote in message
news:4186b975@news.povray.org...
> Mike Williams <nos### [at] econymdemoncouk> wrote:
> > Looks good, and only needs a couple of tiny fixes for it to give the
> > correct results.
>
>   Like what?
>
>   I know it gives garbage if you give it something else than a hex number,
> but I assumed the input is always ok.
>
Just this:

rgbf<int(value/65536), mod(int(value/256), 256), mod(value,256)>

Thanks a lot though, great script, works beautifully :)

David
[learning something new every day]


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From: David Robinson
Subject: Re: Colour conversion - HTML to RGB
Date: 3 Nov 2004 09:51:05
Message: <4188f059$1@news.povray.org>
"David Robinson" <tdf### [at] ezrscom> wrote in message
news:4187b634$1@news.povray.org...
> "Warp" <war### [at] tagpovrayorg> wrote in message
> news:4186b975@news.povray.org...
> > Mike Williams <nos### [at] econymdemoncouk> wrote:
> > > Looks good, and only needs a couple of tiny fixes for it to give the
> > > correct results.
> >
> >   Like what?
> >
> >   I know it gives garbage if you give it something else than a hex
number,
> > but I assumed the input is always ok.
> >
> Just this:
>
> rgbf<int(value/65536), mod(int(value/256), 256), mod(value,256)>
>
> Thanks a lot though, great script, works beautifully :)
>
No wait, I got that wrong. After running a few values through, a lot of
colours seem to come out as white, so it must be a maths thing...?

David


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From: Warp
Subject: Re: Colour conversion - HTML to RGB
Date: 3 Nov 2004 13:52:52
Message: <41892904@news.povray.org>
David Robinson <tdf### [at] ezrscom> wrote:
> No wait, I got that wrong. After running a few values through, a lot of
> colours seem to come out as white, so it must be a maths thing...?

  That's because there really was a bug in my code. I forgot a /255.
The last line should be:

<int(value/65536), mod(int(value/256), 256), mod(value,256)>/255

-- 
#macro N(D)#if(D>99)cylinder{M()#local D=div(D,104);M().5,2pigment{rgb M()}}
N(D)#end#end#macro M()<mod(D,13)-6mod(div(D,13)8)-3,10>#end blob{
N(11117333955)N(4254934330)N(3900569407)N(7382340)N(3358)N(970)}//  - Warp -


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