Re: How does MPinclusions work in mkiv?

["Wolfgang Schuster" <schuster.wolfgang@googlemail.com>]

On Tue, Sep 2, 2008 at 1:13 PM, Mojca Miklavec
<mojca.miklavec.lists@gmail.com> wrote:
> Hello (Hans),
>
> this "minimal" example worked OK in mkiv back in May (most of settings
> in the code below are just unimportant cosmetics, but otherwise it's
> difficult to explain the idea behind); now it still works in mkii, but
> not in mkiv.
>
> \def\mynextmpgraphic{\startMPinclusions erase_picture := 1; \stopMPinclusions}
>
> \startusableMPgraphic{bubble}
> if erase_picture = 0:
>        draw last_picture;
> else:
>        % draw a new picture; in mkiv this code is only reached once,
>        % \mynextgraphic does not reset erase_picture
> fi;
> \stopusableMPgraphic
>
> The code is ugly anyway, I know, but how should I reset variables to
> redraw the picture once more?
>
> Thanks a lot,
>    Mojca
>
> -------------------
>
> \setupcolors[state=start]
> \definecolor[color 1][r=.7,g=.0,b=.0]
> \definecolor[color 2][r=.7,g=.35,b=.0]
> \definecolor[color 3][r=.67,g=.7,b=.0]
> \definecolor[color 4][r=.3,g=.7,b=.0]
> \definecolor[color 5][r=.0,g=.7,b=.0]
> \definecolor[color 6][r=.0,g=.7,b=.4]
> \definecolor[color 7][r=.0,g=.6,b=.7]
> \definecolor[color 8][r=.0,g=.3,b=.7]
> \definecolor[color 9][r=.1,g=.0,b=.7]
> \definecolor[color 10][r=.4,g=.0,b=.7]
> \definecolor[pagecolor][color 1]
>
> \setuphead
>  [section]
>  [number=no,
>   page=yes,
>   style=\bfd,
>   color=pagecolor]
> \setuppapersize
>  [S6][S6]
> \setuppagenumbering
>  [location=]

> \definelayer
>  [page]
>  [width=\paperwidth,
>   height=\paperheight]

?

> \setupbackgrounds
>  [page]
>  [background=bubble]
> \defineoverlay
>  [bubble]
>  [\useMPgraphic{bubble}]
>
> \startMPinclusions
> picture last_picture;
> last_picture := nullpicture;
> erase_picture := 1;
> \stopMPinclusions
>
> \startusableMPgraphic{bubble}
> if erase_picture = 0:
>  draw last_picture;
> else:
>  for i=1 upto 20:
>    path p; p := fullcircle
>      scaled (2cm+uniformdeviate(3cm))
>      shifted (uniformdeviate(\overlaywidth),uniformdeviate(\overlayheight));
>    fill p withcolor .2[white,\MPcolor{pagecolor}];
>    draw p withcolor .5[white,\MPcolor{pagecolor}];
>  endfor;
>
>  setbounds currentpicture to unitsquare xyscaled
> (\overlaywidth,\overlayheight);
>
>  last_picture := currentpicture;
>  erase_picture := 0;
> fi;
> \stopusableMPgraphic
>
> \def\mynextmpgraphic{\startMPinclusions erase_picture := 1; \stopMPinclusions}
>
> \starttext
>
> \section{abc first time}
> \section{abc second time}
> \section{abc third time}
>
> \page\definecolor[pagecolor][color 2]\mynextmpgraphic\page
>
> \section{def first time}
> \section{def second time}
> \section{def third time}
>
> \page\definecolor[pagecolor][color 3]\mynextmpgraphic\page
>
> \section{ghi first time}
> \section{ghi second time}
>
> \page\definecolor[pagecolor][color 4]\mynextmpgraphic\page
>
> \section{jkl first time}
> \section{jkl second time}
> \section{jkl third time}
> \section{jkl fourth time}
>
> \stoptext

Write the test in TeX, the information will not be lost in this way.

Wolfgang
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