Hi Pavneet,
I recommend avoiding the mod function. Just draw the two grids (major and
minor) each with their own spacing and pen.
I whole heatedly support converting TikZ to MetaPost!
- Gavin
\startreusableMPgraphic{graph}
minor=2mm; % Minor lines, each every 2mm
major=8mm; % Major lines, each every 4mm
z1 = (0,0); % lower left corner
% z2 = (2.75in,4.25in)-z1; % upper right corner
z2 = (2.75in,4.25in)-z1;% upper right corner
path v, h;
v := z1--(x1,y2); % vertical line
h := z1--(x2,y1); % horizontal line
% Use light gray
drawoptions(withcolor .4white);
% Draw the minor grid with the very thin pen
pickup pencircle scaled 0.1;
for i=minor step minor until (x2-x1):
draw v xshifted i;
endfor;
for i=minor step minor until (y2-y1):
draw h yshifted i;
endfor;
% Draw the major grid with the thicker pen
pickup pencircle scaled 0.3;
for i=major step major until (x2-x1):
draw v xshifted i;
endfor;
for i=major step major until (y2-y1):
draw h yshifted i;
endfor;
\stopreusableMPgraphic
> On Feb 18, 2025, at 3:28 PM, Pavneet Arora via ntg-context
> <ntg-context@ntg.nl> wrote:
>
> I am in the process of converting a bunch of old TikZ notepaper
> templates to native ConTeXt and MetaPost. This is a part of a project
> to generate notebooks with documentation data and then blank pages appended to
> fill out full sheets, and then collated in a particular order for trimming and
> binding.
>
> As such I rely on Imposition. I am having issues with the various
> techniques of trying to duplicate a MP graphic across the pages using
> \[start|stop]MPcode \[start|stop]useMPgraphic, etc. But that is a
> discussion for another time.
>
> The method that I found to work was to use
> \[start|stop]reusableMPgraphic along with overlays
>
> I am still struggling with some MetaPost code that works fine in
> standalone but not when included in a ConTeXt document.
>
> With standalone MP, we get thicker lines on major increments as
> expected. When the same code is included in a ConTeXt document the
> thicker lines are only drawn up a certain number and then stop ---
> presumably the mod function returning a non-zero result when it really
> shouldn't?
>
> Here are the MWEs:
>
>>>> ConTeXt
> % Paper size and layout {{{2
> \definepapersize
> | [PocketPage]
> | [width=2.75in,height=4.25in]
>
> \setuppapersize[PocketPage][letter,landscape]
> % }}}2
>
> % MetaPost template for graph paper for pocket sized notebook (2.75" W x
> % 4.25in H). {{{2
>
> \startreusableMPgraphic{graph}
> minor=2mm;| | % Minor lines, each every 2mm
> major=8mm;| | % Major lines, each every 4mm
> ┆ ┆ ┆ ┆ % major must be a multiple of minor
>
> z1 = (0,0);| % lower left corner
> % z2 = (2.75in,4.25in)-z1;| % upper right corner
> z2 = (2.75in,4.25in)-z1;|% upper right corner
>
> % Use the very thin pen
> pickup pencircle scaled 0.1;
>
> % Draw the vertical lines
> for i=minor step minor until (y2-y1):
> ┆ if (i mod major)=0:
> ┆ ┆ pickup pencircle scaled 0.3;
> ┆ fi;
> ┆ draw (z1 shifted (0,i))--((x2,y1) shifted (0,i)) withcolor .4white;
> ┆ if (i mod major)=0:
> ┆ ┆ pickup pencircle scaled 0.1;
> ┆ fi;
> endfor;
>
> % Draw the horizonal lines
> for i=minor step minor until (x2-x1):
> ┆ if (i mod major)=0:
> ┆ ┆ pickup pencircle scaled 0.3;
> ┆ fi;
> ┆ draw ( z1--(x1,y2) ) shifted (i,0) withcolor .4white;
> ┆ if (i mod major)=0:
> ┆ ┆ pickup pencircle scaled 0.1;
> ┆ fi;
> endfor;
>
> \stopreusableMPgraphic
>
> \defineoverlay[OLgraph][\useMPgraphic{graph}]
>
> \setupbackgrounds[page][background=OLgraph]
> % }}}2
>
> \starttext
>
> hello.
>
> \stoptext
>
> <<<
>
>>>> Standalone MP
> beginfig(1)
>
> margin=0mm; % Margin of the graph paper
> minor=2mm; % Minor lines, each every 1mm
> major=8mm; % Major lines, each every 10mm
> % major must be a multiple of minor
>
> z1 = (margin,margin); % lower left corner
> z2 = (2.75in,4.25in)-z1; % upper right corner
>
> % % Use the thick pen first
> % pickup pencircle scaled 0.5;
>
> % % Draw the frame
> % draw z1--(x1,y2)--z2--(x2,y1)--cycle withcolor .5white;
>
> % Use the very thin pen
> pickup pencircle scaled 0.1;
>
> % Draw the vertical lines
> for i=minor step minor until (y2-y1-minor):
> if (i mod major)=0:
> pickup pencircle scaled 0.3;
> fi;
> draw (z1 shifted (0,i))--((x2,y1) shifted (0,i)) withcolor .4white;
> if (i mod major)=0:
> pickup pencircle scaled 0.1;
> fi;
> endfor;
>
> % Draw the horizonal lines
> for i=minor step minor until (x2-x1-minor):
> if (i mod major)=0:
> pickup pencircle scaled 0.3;
> fi;
> draw ( z1--(x1,y2) ) shifted (i,0) withcolor .4white;
> if (i mod major)=0:
> pickup pencircle scaled 0.1;
> fi;
> endfor;
>
> endfig;
> end;
>
> <<<
>
> advTHANKance
>
> --
> Pavneet Arora m: +1 647-406-6843
> Waroc Informatik e: pavneet_ar...@waroc.com
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