On 5/26/2017 12:53 PM, Fabrice Couvreur wrote:

Hello,
Hans suggested a macro to draw the vectors . It works well but I find that in some situations, the arrow is too big.
thank you,

             interim ahlength := 2;

Fabrice


https://mailman.ntg.nl/pipermail/ntg-context/2016/085828.html

\useMPlibrary[mat]

\startMPextensions
      vardef math_stacker_arrow_shape =
          image (
              drawarrow
                  (OverlayWidth,OverlayOffset) -- (0,OverlayOffset)
              withcolor
                  OverlayLineColor ;
              setbounds currentpicture to boundingbox currentpicture
bottomenlarged (OverlayOffset/2) topenlarged (OverlayOffset/2) ;
          )
      enddef ;
      vardef math_stacker_leftarrow_shape =
          math_stacker_arrow_shape
      enddef ;
      vardef math_stacker_rightarrow_shape =
          math_stacker_arrow_shape rotated 180
      enddef ;
\stopMPextensions

\startuniqueMPgraphic{math:stacker:\number"2190}
      math_stacker_draw(math_stacker_leftarrow_shape) ;
\stopuniqueMPgraphic

\startuniqueMPgraphic{math:stacker:\number"2192}
      math_stacker_draw(math_stacker_rightarrow_shape) ;
\stopuniqueMPgraphic

% so far

\setupmathstackers
    [both] % vfenced]
    [color=darkred,
     alternative=mp]

\setupmathstackers
    [top]
    [color=darkred,
     alternative=mp]

\setupmathstackers
    [bottom]
    [color=darkred,
     alternative=mp]

\starttext

$\overrightarrow  {i}$

\stoptext

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                                          Hans Hagen | PRAGMA ADE
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If your question is of interest to others as well, please add an entry to the Wiki!

maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context
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wiki     : http://contextgarden.net
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