C++ (Cpp) point_and_slope_to_line示例

示例#1

文件： c_geometric.cpp 项目： frandibar/acm-valladolid

void closest_point(point2d p, line l, point2d *cp)
{
	if (fabs(l.b) <= EPSILON) {		// vertical line
		cp->x = -l.c;
		cp->y = p.y;
		return;
	}

	if (fabs(l.a) <= EPSILON) {		// horizontal line
		cp->x = p.x;
		cp->y = -l.c;
		return;
	}
	// line with slope
	line perp;	// perpendicular to l through (x,y)
	point_and_slope_to_line(p, 1/l.a, &perp);
	intersection_point(l, perp, cp);
}	

示例#2

文件： geometry.c 项目： armenr/algorist

void closest_point(const point p_in, line l, point p_c) {
	line perp;		/* perpendicular to l through (x,y) */

	if(fabs(l.b) <= EPSILON) {	/* vertical line */
		p_c[X] = -(l.c);
		p_c[Y] = p_in[Y];
		return;
	}

	if(fabs(l.a) <= EPSILON) {	/* horizontal line */
		p_c[X] = p_in[X];
		p_c[Y] = -(l.c);
		return;
	}

	point_and_slope_to_line(p_in, 1/l.a, &perp); /* non-degenerate line */
/*printf("perpendicular bisector "); print_line(perp);*/
	intersection_point(l, perp, p_c);
/*printf("closest point "); print_point(p_c);*/
}