Re: another MetaPost question (this time on ConTeXt->MetaPost color transfer)

["Rudd, Kevin" <kevin@lps.umd.edu>]

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... fixed minor typo that actually produced new information! invalid color => black, valid color => transparent black!---it seems like the color disappears in the transfer but not the transparency.

Hey---

There seems to be a change with color transfer from ConTeXt to MetaPost. Using string references to defined (spot?) colors seemed to work but now does not; all of my colorful figures are now rendered only in shades of gray when using defined (spot?) colors….

The figure drawn by the MWE should have a dark orange border and a transparent (thin) orange fill. However, all colors of this sort seem to end up being a single shade of gray (e.g. black), rendering a box perfect for Halloween use but not for my current purposes. Is there a change to how colors defined in ConTeXt are referenced in MetaPost that I've missed or is there an issue with transferring color (name or parameter) information to MetaPost? Defined (spot?) colors work fine in ConTeXt but not in MetaPost.

Many thanks,
 ---K

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

% system          > ConTeXt  ver: 2021.07.21 19:54 LMTX  fmt: 2021.7.22  int: english/english

\startMPdefinitions

    presetparameters "parameters_Test"
    [
    ]

    def Test =
        applyparameters "parameters_Test" "do_Test"
    enddef;

    def do_Test =
        pushparameters "parameters_Test";

        string p;  p = getparameter "prefix";  show p;
        string c;  c = getparameter "color";   show c;
        path   s;  s = unitsquare scaled 10cm; show s;
        path   t;  t = unitsquare scaled  5cm; show t;              % new

        fill s                               withcolor p&":"&c;     % tweaked
        fill t                               withcolor p    &c;     % new (and old)
        draw s  withpen pencircle scaled 5pt withcolor       c;
    enddef;

\stopMPdefinitions

\starttext

\definespotcolor[Thin:orange][orange][p=1,a=normal,t=0.5]

\color[orange]{hello}

\startalignment[center]
    \startplacefigure
        \startMPcode
            Test [ prefix = "Thin", color = "orange" ];
        \stopMPcode
    \stopplacefigure
\stopalignment

\color[Thin:orange]{goodbye}

\stoptext

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


Kevin W. Rudd, Ph.D.
CAPT, USN (Ret)

Computer Architecture & Computer Engineering
Advanced Computing Systems (ACS) Research Program
Laboratory for Physical Sciences (LPS)

443-654-7878
kevin@lps.umd.edu<mailto:kevin@lps.umd.edu>

Visiting Research Professor
United States Naval Academy

rudd@usna.edu<mailto:rudd@usna.edu>




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