/************************************************************************/
/* Brute force arc generation                                           */
/************************************************************************/

brute_arc(xc,yc,xp,yp,a0,a1,color)
int     xc,yc;                  /* Center of the arc                    */
int     xp,yp;                  /* Any point on full circle             */
int     a0,a1;                  /* Starting and ending angle in degrees */
int     color;                  /* Color of the arc                     */
        {
        #include <math.h>
        #define PI 3.1415926
        float   a,b,f,dx,dy;
        int     xa,ya,xb,yb,alpha,delta;

        if (xp - xc == 0 && yp - yc == 0)/* Process degenerate case     */
                {
                pixel_write(xc,yc,color);
                return;
                }
                                        /* Compute major & minor axis   */
        if (get_scanlines() > 200)      f = 480./350.;
        else                            f = 480./200.;
        dx= xp - xc;
        dy=(yp - yc)*f;
        a = sqrt(dx * dx + dy * dy);
        b  = a/f;
                                        /* Compute first point          */
        xa = xc + a * cos((double)(a0 * PI/180.));
        ya = yc + b * sin((double)(a0 * PI/180.));
        delta = 6 * 180./(PI * a);      /* Force 6 pixels per segment   */
                                        /* Loop over segment on ellipse */
        for (alpha = a0; alpha <= a1; alpha = alpha + delta)
                {                       /* Compute next point on ellipse*/
                xb = xc + a * cos(alpha * PI/180.);
                yb = yc + b * sin(alpha * PI/180.);
                line (xa, ya, xb, yb, color);   /* Draw to previous pt  */
                xa = xb;
                ya = yb;
                }
                                        /* Do the last segment          */
        xb = xc + a * cos(a1 * PI/180.);
        yb = yc + b * sin(a1 * PI/180.);
        line (xa, ya, xb, yb, color);
        }