dda_line.m

dda画线算法（数值微分法）

function DDA_Line
% 这是一个适用于所有象限的通用DDA画线算法的Matlab程序
%
% Copyright (c) 2005.  Smart.  All rights reserved.
% Department of Computer Science & Technology
% Northern China Electric Power University(Beijing)(NCEPU)
%

x0 = -50; y0 = 20; x1 = 10; y1 = -5; % 要扫描转换的线段
     	
hold on; axis equal;
grid on;
% 画出要扫描转换的线段
plot([x0 x1],[y0 y1],'b-','LineWidth',1.3);
text(x0,y0,'\leftarrow P0','FontSize',16,'Color',[0,0,1]);
text(x1,y1,'\leftarrow P1','FontSize',16,'Color',[0,0,1]);
title('适用于所有象限的通用DDA画线算法');

n_time = 2;
if abs(x1-x0) >= abs(y1-y0)  % 计算步长 
    length = abs(x1-x0);
else  
    length = abs(y1-y0); 
end
dx = (x1-x0)/length; dy = (y1-y0)/length;
x = x0; y = y0;
i = 1;	
while i <= length % 主循环		   
 	plot(round(x),round(y),'ro','MarkerSize',8,'MarkerFaceColor','g');	
	x = x + dx; y = y + dy; 
    i = i + 1;
    pause(n_time); % 延时n_time秒
end
plot(round(x1),round(y1),'ro','MarkerSize',8,'MarkerFaceColor','g');
hold off;