DesdeChaves mailto:desdechaves@gmail.com 25. Mai 2016 um 19:09 For educational purposes I try to simulate a ammeter for reading practice. I would like create six or more ammeter with different readings, but i'm not able to do that because metapost create the same random number every time I call the buffer that defines my ammeter.

How can I fix that? Is there a reason why you use \externalfigure because the width can be set with \scale, e.g.

\scale[width=8cm]{\getbuffer[ammeter]} Wolfgang

On 5/25/2016 7:09 PM, DesdeChaves wrote:

For educational purposes I try to simulate a ammeter for reading practice. I would like create six or more ammeter with different readings, but i'm not able to do that because metapost create the same random number every time I call the buffer that defines my ammeter.

How can I fix that?

Thanks

Jorge

My code:

\startbuffer[ammeter] \startMPcode r := 4cm; len := 10bp; min_thickness := 1.75bp; hour_thickness := 3bp; path cadran; cadran = fullcircle scaled (2r); numeric escala; escala := 0; for i = 50 upto 70: if i mod 5 = 0: j := i div 5; angl := 90-30j; freelabel("\tfb\bf" & decimal escala, (r+len)*dir angl, r*dir angl); draw ((r, 0) -- (r - len, 0)) rotated angl withpen pencircle scaled min_thickness; escala:= escala + 0.5; else: angl := 90 - 6i; draw ((r, 0) -- (r - .5len, 0)) rotated angl; fi endfor pickup pencircle scaled min_thickness; numeric minute; %randomseed := uniformdeviate infinity; minute:= 50 + uniformdeviate(20); pair A, B, C; A:=1.6r*right+.5r*up; C:=1.6r*right+.8r*up; B:=1.1r*left; drawarrow origin -- r*dir(90-minute*6) cutends (0, 1.5len); fill fullcircle scaled .75len; draw unitsquare xscaled 3.2r yscaled 1.5r shifted B; label("\tfb I (A)", 1.2r*up+1.6r*right) withcolor red; draw fullcircle scaled 2len shifted A; draw fullcircle scaled 2len shifted C; \stopMPcode \stopbuffer

\startbuffer[programa]

\placefigure[center,nonumber]{}{ \startcombination[2*1] {\externalfigure[ammeter][type=buffer,width=8cm]}{\_\_\_\_\_\_\_\_\_\_$\pm$\_\_\_\_\_\_\_\_} {\externalfigure[ammeter][type=buffer,width=8cm]}{\_\_\_\_\_\_\_\_\_\_$\pm$\_\_\_\_\_\_\_\_} } \stopcombination

\stopcombination in wrong spot

\stopbuffer

\starttext

\dorecurse{3} {\getbuffer[programa]}

\stoptext

disable object reuse \startplacefigure \startcombination[2*1] {\externalfigure[ammeter][type=buffer,object=no,width=8cm]}{\_\_\_\_\_\_\_\_\_\_$\pm$\_\_\_\_\_\_\_\_} {\externalfigure[ammeter][type=buffer,object=no,width=8cm]}{\_\_\_\_\_\_\_\_\_\_$\pm$\_\_\_\_\_\_\_\_} \stopcombination \stopplacefigure \stopbuffer ----------------------------------------------------------------- Hans Hagen | PRAGMA ADE Ridderstraat 27 | 8061 GH Hasselt | The Netherlands tel: 038 477 53 69 | www.pragma-ade.com | www.pragma-pod.nl -----------------------------------------------------------------