Info Catalog asymptote: Labels asymptote: Tutorial

asymptote: Paths

 
 3.5 Paths
 =========
 
 This example draws a path that approximates a quarter circle, terminated
 with an arrowhead:
 size(100,0);
 draw((1,0){up}..{left}(0,1),Arrow);
 
                             [quartercircle]
 Here the directions 'up' and 'left' in braces specify the incoming and
 outgoing directions at the points '(1,0)' and '(0,1)', respectively.
 
    In general, a path is specified as a list of points (or other paths)
 interconnected with '--', which denotes a straight line segment, or
 '..', which denotes a cubic spline (Bezier curves).  Specifying
 a final '..cycle' creates a cyclic path that connects smoothly back to
 the initial node, as in this approximation (accurate to within 0.06%) of
 a unit circle:
 path unitcircle=E..N..W..S..cycle;
 
 An 'Asymptote' path, being connected, is equivalent to a 'Postscript
 subpath'.  The '^^' binary operator, which requests that the pen be
 moved (without drawing or affecting endpoint curvatures) from the final
 point of the left-hand path to the initial point of the right-hand path,
 may be used to group several 'Asymptote' paths into a 'path[]' array
 (equivalent to a 'PostScript' path):
 size(0,100);
 path unitcircle=E..N..W..S..cycle;
 path g=scale(2)*unitcircle;
 filldraw(unitcircle^^g,evenodd+yellow,black);
 
 
                               [superpath]
 
 The 'PostScript' even-odd fill rule here specifies that only the region
 bounded between the two unit circles is filled (fillrule).  In
 this example, the same effect can be achieved by using the default zero
 winding number fill rule, if one is careful to alternate the orientation
 of the paths:
 filldraw(unitcircle^^reverse(g),yellow,black);
 
    The '^^' operator is used by the 'box(triple, triple)' function in
 the module 'three.asy' to construct the edges of a cube 'unitbox'
 without retracing steps (three):
 import three;
 
 currentprojection=orthographic(5,4,2,center=true);
 
 size(5cm);
 size3(3cm,5cm,8cm);
 
 draw(unitbox);
 
 dot(unitbox,red);
 
 label("$O$",(0,0,0),NW);
 label("(1,0,0)",(1,0,0),S);
 label("(0,1,0)",(0,1,0),E);
 label("(0,0,1)",(0,0,1),Z);
 
                                 [cube]
 
    See section graph (or the online 'Asymptote' gallery and
 external links posted at <http://asymptote.sourceforge.net>) for further
 examples, including two-dimensional and interactive three-dimensional
 scientific graphs.  Additional examples have been posted by Philippe
 Ivaldi at <http://www.piprime.fr/asymptote>.
 

Info Catalog asymptote: Labels asymptote: Tutorial