void render_partial_circle_pts(double xc,double yc,double radius,
double theta0,double theta1,int nsteps)
{
int i;
if (theta0==0. && theta1==0.)
theta1=2.*PI;
if (nsteps<1)
{
int n1,n2;
n1=lbmp->width*1.33*radius/width_pts;
n2=lbmp->height*1.33*radius/height_pts;
nsteps = n1<n2 ? n2 : n1;
if (nsteps<8)
nsteps=8;
nsteps *= fabs(theta1-theta0)/(2.*PI);
if (nsteps<1)
nsteps=1;
}
for (i=0;i<nsteps;i++)
{
double th1,th2;
th1=theta0+i*(theta1-theta0)/nsteps;
th2=(i==nsteps-1)?theta1:theta0+(i+1)*(theta1-theta0)/nsteps;
render_tri_pts(xc,yc,xc+radius*cos(th1),yc+radius*sin(th1),
xc+radius*cos(th2),yc+radius*sin(th2));
}
}
/*
** x0,y0,x1,y1 in points
*/
static void render_solid_line_pts(double x0,double y0,double x1,double y1)
{
double theta;
double dx,dy,r;
dx=x1-x0;
dy=y1-y0;
r=linewidth/2.;
if (fabs(dx)>1e-8 || fabs(dy)>1e-8)
theta=atan2(dy,dx);
else
theta=0.;
switch (linecap)
{
case 0: /* butt */
case 1: /* round */
{
double xa,ya,xb,yb,xc,yc,xd,yd;
xa=x0+r*cos(theta-PI/2.);
ya=y0+r*sin(theta-PI/2.);
xb=x0+r*cos(theta+PI/2.);
yb=y0+r*sin(theta+PI/2.);
xc=x1+r*cos(theta+PI/2.);
yc=y1+r*sin(theta+PI/2.);
xd=x1+r*cos(theta-PI/2.);
yd=y1+r*sin(theta-PI/2.);
render_rect_pts(xa,ya,xb,yb,xc,yc,xd,yd);
if (linecap==0)
break;
render_partial_circle_pts(x0,y0,r,theta+PI/2.,theta+3.*PI/2.,-1);
render_partial_circle_pts(x1,y1,r,theta-PI/2.,theta+PI/2.,-1);
break;
}
case 2: /* project */
{
double xa,ya,xb,yb,xc,yc,xd,yd;
double r2;
r2=r*SQRT2;
xa=x0+r2*cos(theta-1.5*PI/2.);
ya=y0+r2*sin(theta-1.5*PI/2.);
xb=x0+r2*cos(theta+1.5*PI/2.);
yb=y0+r2*sin(theta+1.5*PI/2.);
xc=x1+r2*cos(theta+PI/4.);
yc=y1+r2*sin(theta+PI/4.);
xd=x1+r2*cos(theta-PI/4.);
yd=y1+r2*sin(theta-PI/4.);
render_rect_pts(xa,ya,xb,yb,xc,yc,xd,yd);
break;
}
case 3: /* arrow */
{
double xa,ya,xb,yb,xc,yc,xd,yd;
double xe,ye,xf,yf,xg,yg,xh,yh;
/* Back up (x1,y1) along line to give room for arrow head */
xg=x1-r*7.00*cos(theta);
yg=y1-r*7.00*sin(theta);
xa=x0+r*cos(theta-PI/2.);
ya=y0+r*sin(theta-PI/2.);
xb=x0+r*cos(theta+PI/2.);
yb=y0+r*sin(theta+PI/2.);
xc=xg+r*cos(theta+PI/2.);
yc=yg+r*sin(theta+PI/2.);
xd=xg+r*cos(theta-PI/2.);
yd=yg+r*sin(theta-PI/2.);
/* Draw butt-ended line */
render_rect_pts(xa,ya,xb,yb,xc,yc,xd,yd);
/* Arrowhead points */
xe=x1-r*6.25*cos(theta);
ye=y1-r*6.25*sin(theta);
xf=x1-r*10.0*cos(theta);
yf=y1-r*10.0*sin(theta);
xg=xf+5*r*cos(theta+PI/2.);
yg=yf+5*r*sin(theta+PI/2.);
xh=xf+5*r*cos(theta-PI/2.);
yh=yf+5*r*sin(theta-PI/2.);
render_tri_pts(xc,yc,xe,ye,xd,yd);
render_tri_pts(xe,ye,xg,yg,x1,y1);
render_tri_pts(xe,ye,x1,y1,xh,yh);
break;
}
}
}
