8.5 Primitives drawing

These commands draw some simple objects like line, point, sphere, drop, cone and so on.

MGL command: clf

Clear the picture by removes all drawing from it. Does not change transformation matrix.

MGL command: ball x y ['col'='r']

MGL command: ball x y z ['col'='r']

Draws a point (ball) at position {x, y, z} with color defined by string col.

MGL command: line x1 y1 x2 y2 ['stl'='']

MGL command: line x1 y1 z1 x2 y2 z2 ['stl'='']

Draws a geodesic line (straight line in Cartesian coordinates) from point {x1,y1,z1} to {x2,y2,z2} using line style stl.

MGL command: curve x1 y1 dx1 dy1 x2 y2 dx2 dy2 ['stl'='']

MGL command: curve x1 y1 z1 dx1 dy1 dz1 x2 y2 z2 dx2 dy2 dz2 ['stl'='']

Draws Bezier-like curve from point {x1,y1,z1} to {x2,y2,z2} using line style stl. At this tangent is co-directed with {dx1,dy1,dz1}, {dx2,dy2,dz2} and proportional to its amplitude.

MGL command: facex x0 y0 z0 wy wz ['stl'='' d1=0 d2=0]

MGL command: facey x0 y0 z0 wx wz ['stl'='' d1=0 d2=0]

MGL command: facez x0 y0 z0 wx wy ['stl'='' d1=0 d2=0]

Draws the solid rectangle (face) perpendicular to [x,y,z]-axis correspondingly at position {x0, y0, z0} with color stl and with widths wx, wy, wz along corresponding directions. At this colors can be the same for all vertexes or different if all 4 colors are specified for each vertex. Parameters d1!=0, d2!=0 set additional shift of the last vertex (i.e. to draw quadrangle).

MGL command: sphere x0 y0 r ['col'='r']

MGL command: sphere x0 y0 z0 r ['col'='r']

Draw the sphere with radius r and center at point {x0, y0, z0} and color stl.

MGL command: drop x0 y0 dx dy r ['col'='b' sh=1 asp=1]

MGL command: drop x0 y0 z0 dx dy dz r ['col'='b' sh=1 asp=1]

Draw the drop with radius r at point {x0,y0,z0} elongated in direction {dx,dy,dz} and with color col. Parameter sh set the degree of drop oblongness: ‘0’ is sphere, ‘1’ is maximally oblongness drop. Parameter asp set relative width of the drop (this is analogue of “ellipticity” for the sphere). See section Drops sample, for sample code and picture.

MGL command: cone x1 y1 z1 x2 y2 z2 r1 [r2=-1 'stl'='' edge=off]

Draw tube (or truncated cone if edge=off) between points {x1,y1,z1}, {x2,y2,z2} with radiuses at the edges r1, r2. If r2<0 then it is supposed that r2=r1. The cone color is defined by string stl.

MGL command: rect x1 y1 x2 y2 ['st'='']

MGL command: rect x1 y1 z1 x2 y2 z2 ['st'='']

Draw rectangle from point {x1,y1,z1} to point {x2,y2,z2} using colors stl. If stl have 4 or more colors then it defines colors for each rectangle vertex (useful for making gradients, like ‘wwrr’) else first color is used for whole rectangle.