/* Attention, aux fonctions point et truepoint !
   Elles ne font pas forcément ce que l'on pourrait croire.
*/

import geometry;

unitsize(25); // 25 bp = 25/72 pouce = (25*25,4)/72 mm

show("","","",defaultcoordsys);

pair pA=(4.5,-2.4), pC=(2,2);

draw(shift(-.5,-.5)*unitsquare,gray);
draw(unitsquare,gray);

draw(circle(pC,4));
dot(pC,red);

dot("pA",pA,S,blue);
draw(pA--(0,0)--rectify(pA)-(0.5,0.5),dashed);
draw(rectify(pA)-(0.5,0.5)--rectify(pA),green,Arrow);
draw((0,0)--rectify(pA),darkgreen,Arrow);
draw(truepoint(SW)--truepoint(SW)+rectify(pA),darkgreen,Arrow);
draw(truepoint(SW)--truepoint(pA),dashed+darkgreen);

draw(Label("rectify(pA)",W),(.2,2)--rectify(pA),Arrow(SimpleHead));
draw(Label("point(pA)",W),(3,3)--point(pA),Arrow(SimpleHead));
draw(Label("truepoint(pA)",W),(4,4)--truepoint(pA),Arrow(SimpleHead));
draw(Label("point(pA)",W),(5.5,2.5)--point(pA),red,Arrow(SimpleHead));
draw(Label("truepoint(pA)",W),(6.5,3.5)--truepoint(pA),red,Arrow(SimpleHead));