autocrop 20 setxunit -18 13 setxrange -6 12 setyrange %quadrillage marks /q {6 4 0} def /r {6 -4 0} def /p {-5 0 0} def /s {0 0 8} def /vect_I {-10 cos -10 sin} def /vect_J {40 cos 40 sin .8 mulv} def /vect_K {0 1} def %% [O vect_I] (->) ligne %% [O vect_J] (->) ligne %% [O vect_K] (->) ligne /xyz2xy { 3 dict begin /z exch def /y exch def /x exch def vect_I x mulv vect_J y mulv vect_K z mulv addv addv end } def [/P /Q /R /S] [p q r s] {xyz2xy} capply mapnp /I {3 3} def %% le plan de base /P1 {2 -5} def /P2 {-7 -2} def /P3 {10 -2} def gsave 2 setlinewidth [P2 P1 P3] ligne grestore %% corrige S I R Q interdroite /A defpoint S P I paral A P interdroite /J defpoint I J P1 P2 interdroite /K defpoint gsave .6 setlinewidth pointilles orange [S A P] ligne .8 setlinewidth noir [I K] ligne 1.2 setlinewidth continu [I 8 I J ydpoint] ligne [K -5 I J ydpoint] ligne grestore J times2 %%%%%%%%%%% gsave .8 setlinewidth pointilles [P Q] ligne grestore /dotscale {2 dup} def [I] {times} plot 1.2 setlinewidth [S P R] ligne [S Q R] ligne [S R] ligne 12 setfontsize setTimesItalic (I) I ultext (J) J drtext (P) P dltext (Q) Q drtext (R) R drtext (S) S urtext (d) 7 I J ydpoint ultext