[metapost] defaultcolormodel

Stephan Hennig mailing_list at arcor.de
Fri Jul 8 16:32:58 CEST 2011

schrieb luigi scarso:
> On Fri, Jul 8, 2011 at 12:31 PM, Stephan Hennig <mailing_list at arcor.de> wrote:
> yes, of course. Probably in the default format, or in metapost itself
> there is a default color (0,0,0)

In the engine, AFAIK.  And there are (0,0,0,1) for the CMYK model and 0
for the grey scale model, too.

>> Think about MetaFont that
>> has no notion of colours, yet it has to distinguish between pixels that
>> have been touched by a pen and those that haven't in the output.  This
>> 'implicit' black is what defaultcolormodel refers to (and what I meant
>> by 'black ink').
> Almost.
> In Metafont each pixel has 7 weights:  -3,-2,-1,0,1,2,3, hence
> it's a kind of gray color space.

Thanks for pointing this out.  I'm not a regular MetaFont user, but I do
know that MetaFont doesn't have a 'withcolor' primitive.  Do I figure
correctly, that the weights indicate to what extend the area of a pixel
has been covered by the pen?

Best regards,
Stephan Hennig

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