[metapost] defaultcolormodel

Karel akk64 at quick.cz
Fri Jul 8 13:18:14 CEST 2011

luigi scarso napsal(a):
> 2011/7/8 Karel <akk64 at quick.cz>:
>> Taco Hoekwater napsal(a):
>>> On 07/08/2011 12:01 AM, Stephan Hennig wrote:
>>>> Hi,
>>>> I'm wondering what the meaning of variable defaultcolormodel is.  The
>>>> manual is rather terse (p.28):
>>>>   The ‘current default’ color model can be set up using the internal
>>>>   variable defaultcolormodel.  Table 2 lists the valid values.
>>>> Well, variable defaultcolormodel determines the colour space of the
>>>> black ink that is used for drawing and filling strokes, i.e., whether 0,
>>>> (0,0,0) or (0,0,0,1) is written into the output.
>>> Yes.
>> I think it is not the case. I tried
>> defaultcolormodel:=3;
>> beginfig(0);
>> defaultcolormodel:=3;
>> draw fullcircle scaled 10mm withcolor .5white;
>> endfig;
>> and the resulting color in the output is in rgb!
>> One has firstly redefine white and background as numeric... or write only
>> withcolor.5;
>> Karel Horak
>> --
>> http://tug.org/metapost/
> How is white defined ?
> if
> white = (1,1,1);
> then 0.5white is rgb
Of course, this is the way the white is predefined in plain.mp.
And one also has to keep in mind that white is there declared as 
color (=rgbcolor) as it was written down before wonderful times 
with cmykcolors:-)

Some time ago I have spent some time to overcome the default 
settings and found it to be not so easy. Finally I came to the 
following solution (I wanted to compile also the older files 
without rgb colours and without editing them to much):

def white= (1) enddef;
def background= (1) enddef;
def black= (0) enddef;

Karel Horak

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