nrbrect.m

强大的nurbs的工具箱 nurbs曲线

function curve = nrbrect(w,h)
% 
% Function Name:
% 
%   nrbrect - Construct NURBS representation of a rectangle.
% 
% Calling Sequence:
% 
%   crv = nrbrect()
%   crv = nrbrect(size)
%   crv = nrbrect(width, height)
% 
% Parameters:
% 
%   size		: Size of the square (width = height).
% 
%   width		: Width of the rectangle (along x-axis).
% 
%   height	: Height of the rectangle (along y-axis).
% 
%   crv		: NURBS curve, see nrbmak. 
%  
% 
% Description:
% 
%   Construct a rectangle or square in the x-y plane with the bottom
%   lhs corner at (0,0,0). If no rhs arguments provided the function
%   constructs a unit square.

%  D.M. Spink
%  Copyright (c) 2000.

if nargin < 1
   w = 1;
   h = 1;
end

if nargin < 2
   h = w;
end

coefs  = [0 w w w w 0 0 0;
          0 0 0 h h h h 0;
          0 0 0 0 0 0 0 0;
          1 1 1 1 1 1 1 1];

knots  = [0 0 0.25 0.25 0.5 0.5 0.75 0.75 1 1];

curve = nrbmak(coefs, knots);