[metapost] background and non-rgbcolors

Stephan Hennig mailing_list at arcor.de
Fri May 18 23:55:40 CEST 2007


the internal variable background seems only to accept rgbcolor values
(which is not documented).  Would it be possible to make 'background'
accept cmykcolor or greyscale values as well?

Another option were to introduce a new macro 'setUnfillColor' that
accepts different colour types and is evaluated by 'unfill'.  For
compatibility 'background' should take precedence over 'setUnfillColor',
by default.  As soon as 'setUnfillColor' has been called with a valid
colour it should overrule 'background'.  Calling 'unfillcolor' with a
special value (e.g., any string value) should return 'unfill' to
compatibility behaviour, i.e., evaluate variable 'background' only.

Best regards,
Stephan Hennig

background := red;% RGB
% background := (1,0,0,0);% CMYK
% background := .5;% greyscale
% background := false;% withoutcolor
  unfill unitsquare scaled 100;

PS:  I'm especially interested in drawing the background without any
colour, i.e., ignoring 'unfill' operations performed by package MetaObj.

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