On Thu, 13 May 2021, Henning Hraban Ramm wrote: > > > Am 11.05.2021 um 18:02 schrieb Aditya Mahajan <[email protected]>: > > > > Look at this old code on how hide such code behind a macro to have a clean > > interface: > > > > https://github.com/adityam/mp-sketch/blob/master/mp-sketch.mp > > Hi Aditya, > I’m trying to include my additions into your code, but it doesn’t work. > > > numeric sketch_amount; sketch_amount := 3bp; > numeric sketch_passes; sketch_passes := 5; > > def sketchdraw expr p = > do_sketchdraw(p if (path p): randomized sketch_amount fi) > enddef; > > def do_sketchdraw(expr p) text t = > normaldraw p t ; > enddef; > > > Now I want to draw that path several times. > > If I understand it right, I can’t put that into "sketchdraw" because that > leaves the end open for path additions like "withcolor". > > But it also doesn’t work in "do_sketchdraw"; I thought it might like this:
A slightly different approach is needed. See attached. I also added a bit a error protection in case someone sets sketch_passes to be negative by mistake. It may be interesting to rewrite these macros using the new key-value interface for metapost, so that something like this works: \sketchdraw[amount=3bp, passes=5, transparency=yes] fullsquare scaled 1cm withcolor red;
test.pdf
Description: Adobe PDF document
test.tex
Description: TeX document
%D \module
%D [ file=mp-sketch.mp
%D version=2021.05.13
%D title=\CONTEXT\ \METAPOST\ graphics,
%D subtitle=Sketch drawing,
%D author=Aditya Mahajan,
%D date=\currentdate,
%D copyright={Aditya Mahajan}]
%D This metapost module is inspired by a TeX.SE question:
%D http://tex.stackexchange.com/q/39296/323
%D
%D I thought that it would be fun to implement a similar feature in MetaPost.
%D
%D To use this package in MetaPost:
%D
%D \starttyping
%D input mp-sketch;
%D
%D beginfig(1)
%D sketchypaths; % Make draw and fill sketchy
%D ...
%D naturalizepaths; % Restore the value of draw and fill
%D ...
%D endfig
%D \stoptyping
%D
%D The code is heavily inspired by Hans Hagen's Metafun macros.
%D
%D The macro \type{sketchypaths} is modeled after \type{visualizepaths} from
%D \filename{mp-tool}.
def sketchypaths =
let draw = sketchdraw ;
let fill = sketchfill ;
enddef ;
%D Check if \filename{mp-tool} is loaded
if not known context_tool :
let normaldraw = draw;
let normalfill = fill;
def naturalizepaths =
let fill = normalfill ;
let draw = normaldraw ;
enddef ;
fi
%D The variable \type{sketch_amount} determines the amount of randomness in the
%D drawing
numeric sketch_amount; sketch_amount := 3bp;
%D The variable \type{sketch_passes} determines the number of times the path
%D is drawn
numeric sketch_passes; sketch_passes := 1;
%D The macro \type{sketchdraw} draws the randomized path. The
%D \type{expr} ... \type{text} trick is copied from the definition of
%D \type{drawarrow}
def sketchdraw expr p =
do_sketchdraw(p)
enddef;
def do_sketchdraw(expr p) text t =
if (path p) :
for i = 1 upto max(1,sketch_passes) :
normaldraw p
randomized sketch_amount
withtransparency ("multiply", 1/max(1,sketch_passes))
t ;
endfor;
else :
normaldraw p t;
fi
enddef;
%D The macro \type{sketchfill} randomizes the path before filling it.
def sketchfill expr p =
do_sketchfill(p)
enddef ;
def do_sketchfill(expr p) text t =
if (path p) :
for i = 1 upto max(1,sketch_passes) :
normalfill p
randomized sketch_amount
withtransparency ("multiply", 1/max(1,sketch_passes))
t ;
endfor;
else :
normalfill p t;
fi
enddef;
endinput;
% Modified example from
% http://tex.loria.fr/prod-graph/zoonekynd/metapost/metapost.html
beginfig(1)
pair A,B,C,O;
A=(0,0); B=(3cm,0); C=(1cm,2cm);
O - 1/2[B,C] = whatever * (B-C) rotated 90;
O - 1/2[A,B] = whatever * (A-B) rotated 90;
sketchypaths;
sketch_amount := 5bp;
draw A--B--C--cycle;
draw O withpen pencircle scaled 4bp;
sketch_amount := 2bp;
draw fullcircle scaled 2abs(O-A) shifted O;
endfig
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