Node:Point Drawing Functions, Next:, Previous:Point Intersections, Up:Point Reference


Drawing

There are two versions for each of the drawing functions. The second one has the Picture argument picture at the beginning of the argument list, rather than at the end. This is convenient when passing a picture argument. Where picture is optional, the default is always current_picture.

void drawdot ([const Color& ddrawdot_color = *Colors::default_color, [const string ppen = "", [Picture& picture = current_picture]]]) const function
void drawdot ([Picture& picture = current_picture, [const Color& ddrawdot_color = *Colors::default_color, [const string ppen = "", ]]]) const function
Draws a dot on picture. If ppen is specified, a "pen expression" is included in the drawdot command written to out_stream. Otherwise, MetaPost's currentpen is used. If ddrawdot_color is specified, the dot will be drawn using that Color. Otherwise, the Color currently pointed to by the pointer Colors::default_color will be used. This will normally be Colors::black. See Color Reference, for more information about Colors and the namespace Colors.

Please note that the "dot" will always be parallel to the plane of projection. Even where it appears to be a surface, as in [next figure] , it is never put into perspective, but will always have the same size and shape. 

          Point P(1, 1);
          P.drawdot(gray, "pensquare scaled 1cm");


[Figure 96. Not displayed.]

Fig. 96.

void undrawdot ([string pen = "", [Picture& picture = current_picture]]) Function
void undrawdot ([Picture& picture = current_picture, [string pen = ""]]) Function
Undraws a dot on picture. If ppen is specified, a "pen expression" is included in the undrawdot command written to out_stream. Otherwise, MetaPost's currentpen is used. 
          Point P(1, 1);
          P.drawdot(gray, "pensquare scaled 1cm");
          P.undrawdot("pencircle scaled .5cm");


[Figure 97. Not displayed.]

Fig. 97.

void draw (const Point& p, [const Color& ddraw_color = *Colors::default_color, [string ddashed = "", [string ppen = "", [Picture& picture = current_picture, [bool aarrow = false]]]]]) Function
void draw (Picture& picture = current_picture, const Point& p, [const Color& ddraw_color = *Colors::default_color, [string ddashed = "", [string ppen = "", [bool aarrow = false]]]]) Function
Draws a line from *this to p. Returns the Path *this -- p1. See Path Reference; Drawing and Filling, for more information. 
          Point P(-1, -1, -1);
          Point Q(2, 3, 5);
          P.draw(Q, Colors::gray, "", "pensquare scaled .5cm");


[Figure 98. Not displayed.]

Fig. 98.

void undraw (const Point& p, [string ddashed = "", [string ppen = "", [Picture& picture = current_picture]]]) Function
void undraw (Picture& picture, const Point& p, [string ddashed = "", [string ppen = ""]]) Function
Undraws a line from *this to p. Returns the Path *this -- p1. See Path Reference; Drawing and Filling, for more information. 
          Point P(-1, -1, -1);
          Point Q(2, 3, 5);
          P.draw(Q, Colors::gray, "", "pensquare scaled .5cm");
          P.undraw(Q, "evenly scaled 6", "pencircle scaled .3cm");


[Figure 99. Not displayed.]

Fig. 99.

Path draw_help (const Point& p, [const Color& ddraw_color = *Colors::help_color, [string ddashed = "", [string ppen = "", [Picture& picture = current_picture]]]]) Function
Path draw_help (Picture& picture, const Point& p, [const Color& ddraw_color = *Colors::help_color, [string ddashed = "", [string ppen = ""]]]) Function
Draws a "help line" from *this to p, but only if the static Path data member do_help_lines is true. See Path Reference; Data Members.

"Help lines" are lines that are used when constructing a drawing, but that should not be printed in the final version.

Path drawarrow (const Point& p, [const Color& ddraw_color = *Colors::default_color, [string ddashed = "", [string ppen = "", [Picture& picture = current_picture]]]]) Function
Path drawarrow (Picture& picture, const Point& p, [const Color& ddraw_color = *Colors::default_color, [string ddashed = "", [string ppen = ""]]]) Function
Draws an arrow from *this to p and returns the Path *this -- p. The second version is convenient for passing a Picture argument without having to specify all of the other arguments. 
          Point P(-3, -2, 1);
          Point Q(3, 3, 5);
          P.drawarrow(Q);


[Figure 100. Not displayed.]

Fig. 100.