Re: bar graphs, m-graph, sarith

[John Kitzmiller <kitz@inradius.net>]

Thank you Alan. That was exactly the redirection needed.

John

On Jul 7, 2013, at 9:24 AM, Alan BRASLAU wrote:

> Metapost now has double precision arithmetic, so one no longer needs to
> use the string arithmetic macros. However, it may be necessary to use
> scantokens as in
> 
> clearxy;
> z = (scantokens v1, scantokens v2);
> augment.p(x,0);
> augment.p(x,y);
> x := x + 0.4 ;
> augment.p(x,y);
> augment.p(x,0);
> 
> 
> Alan
> 
> 
> On Sat, 6 Jul 2013 22:01:06 -0400
> John Kitzmiller <kitz@inradius.net> wrote:
> 
>> When trying to make a bar graph with m-graph.mkiv and sarith, the
>> command Ssub (string subtract) seems to augment.p(v1 Sadd
>> "0.4",v2);Sadd instead. An mwe of a bar graph:
>> 
>> (data1 is a separate file containing
>>  01 02
>>  02 03)
>> 
>> \usemodule[m-graph]
>> \startMPpage[instance=graph]
>> input sarith;
>> draw begingraph(5cm,5cm);
>> gdata("data1", v,
>>          path p;
>>          augment.p(v1,0);
>>          augment.p(v1,v2)
>>          augment.p(v1 Sadd "0.4",v2);
>>          augment.p(v1 Sadd "0.4",0);
>>          gfill p--cycle withcolor .8white;
>>          gdraw p--cycle;
>>          );
>> endgraph;
>> \stopMPpage
>> 
>> ...which gives bars of width 0.4 starting at abscissa 1 and 2 as
>> expected. To increase the width of the bars to 0.8 and have them
>> centered over 1 and 2, I expect to Ssub from the first two augments:
>> 
>> \usemodule[m-graph]
>> \startMPpage[instance=graph]
>> input sarith;
>> draw begingraph(5cm,5cm);
>> gdata("data1", v,
>>          path p;
>>          augment.p(v1 Ssub "0.4",0);
>>          augment.p(v1 Ssub "0.4",v2);
>>          augment.p(v1 Sadd "0.4",v2);
>>          augment.p(v1 Sadd "0.4",0);
>>          gfill p--cycle withcolor .8white;
>>          gdraw p--cycle;
>>          );
>> endgraph;
>> \stopMPpage
>> 
>> However, the Ssub adds instead and gives a line at 1.4 and 2.4.
>> 
>> Compiling the above with mpost or mptopdf gives the desired
>> result(s), but I am curious if this can be resolved so such bar
>> graphs could be made within ConTeXT/METAFUN.
>> 
>> Thanks! John

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