Hello, This code:
\startMPcode u = 2cm; % unit length; xmax = 1.5 ; ymax = 1.5 ; % axes parameters path circle; circle = fullcircle scaled 2u; draw circle withcolor blue; x = -1.0 ; % any value between -1 and 1 len = 3u; % tangent length t = (acos x)/45 ; % point-node of fullcircle corresponding to x pair I; I = point t of circle ; if (x <> 0.0) and (abs(x) <> 1.0): draw origin -- I ; fi ; % tangent on the upper part of circle pair v ; v = unitvector I rotated 90 ; draw I - 0.5len*v -- I + 0.5len*v withcolor red ; draw I withpen pencircle scaled 3bp; drawarrow (-xmax*u, 0) -- (xmax*u, 0) ; % horizontal axis drawarrow (0, -ymax*u) -- (0, ymax*u) ; % vertical axis label.bot(btex $x$ etex, (xmax*u, 0)) ; \stopMPcode Should draw a circle with a tangent at x = -1 parallel to y. However, the point of tangency is shown at approximately x = 1, y = 0.01 or so. I got the code from a metapost example: u = 2cm; % unit length; xmax = 1.5 ; ymax = 1.5 ; % axes parameters beginfig(1); path circle; circle = fullcircle scaled 2u; draw circle withcolor blue ; x = -1.0 ; % any value between -1 and 1 len = 3u; % tangent length t = (acos x)/45 ; % point-node of fullcircle corresponding to x pair I; I = point t of circle ; if (x <> 0) and (abs(x) <> 1): draw origin -- I ; fi ; % tangent on the upper part of circle pair v ; v = unitvector I rotated 90 ; draw I - 0.5len*v -- I + 0.5len*v withcolor red ; draw I withpen pencircle scaled 3bp; drawarrow (-xmax*u, 0) -- (xmax*u, 0) ; % horizontal axis drawarrow (0, -ymax*u) -- (0, ymax*u) ; % vertical axis label.bot(btex $x$ etex, (xmax*u, 0)) ; endfig; end; The original code generates the expected output when run using: mpost --mem=metafun --numbersystem="double" tangent.mp What do I need to get ConTeXt to compile this code corretly? Thanks, Roger mtx-context | ConTeXt Process Management 1.06 mtx-context | mtx-context | main context file: /usr/home/rmason/tex/texmf-context/tex/context/base/mkiv/context.mkiv mtx-context | current version: 2025.02.28 18:12 mtx-context | main context file: /usr/home/rmason/tex/texmf-context/tex/context/base/mkxl/context.mkxl mtx-context | current version: 2025.02.28 18:12
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