Programming and Graphics

7.4 Plotting a line 217

/*-------------------------------------------

void drawline2d

Draw a polygonal line defined by a set of points

and put symbols at the points

If a segment crosses the boundaries of the plotting

window, interpolate for the crossing point

SYMBOLS

--------

n: number of points to be plotted

x,y: coordinates of the points

xmin,xmax: x plotting window

ymin,ymax: y plotting window

tol: tolerance for window crossing

Icheck: 1 to perform crossing checks

------------------------------------------ */

#include "VOGLE/voglec++.h"

using namespace std;

void drawline2d (int n, float x[], float y[]

,float xmin, float xmax

,float ymin, float ymax, int Icheck)

{

float xrange = xmax-xmin;

float yrange = ymax-ymin;

float xp, yp, xpp, ypp; // temporary positions

float xint, yint; // interpolation variables

float tol=0.000001; // tolerance

//--- Move to the first point:

xp=x[0]; yp=y[0];

move2 (xp,yp);

/*------------------------------------------

If both the current and the previous point

lie outside the window, do not draw the line

If a segment crosses the borders, draw up to

the interpolated crossing points

------------------------------------------ */

for (int i=1; i<n; i++) // closes at sousami

{

xpp=x[i-1];

ypp=y[i-1];