DDA算法

DDA算法原理：直线的一阶导是连续的，Δx和Δy是成比例的，有xi+1=xi+ε·Δx,yi+1=yi+ε·Δy.   ε=1/max(|Δx|,|Δy|);

|k|<=1时，x_i+1＝x_i+/-1;y_i+1=y_i+/-k;

|k|>=1时，max(|Δx|,|Δy|)=|Δy|,x_i+1=x_i+ε·Δx=x_i+Δx/|Δy|=x_i+/- 1/k;

y_i+1=yi+/- 1;

对求出的xi+1和yi+1进行四舍五入。

round(xi+1) = (int)(x_i+1+0.5),round(y_i+1)=(int)(y_i+1+0.5).

DDA算法程序：

 1 void DDALine(int x1,int y1,int x2,int y2,int color){
 2 int dx,dy,epsl,k;
 3 float x,y,xIncre,yIncre;
 4 dx=x2-x1;  dy=y2-y1;
 5 x=x1;  y=y1;
 6 if(abs(dx)>abs(dy)) epsl = abs(dx);
 7 else eps = abs(dy);
 8 xIncre = (float)dx/(float)epsl;
 9 yIncre = (float)dy/(float)epsl;
10 for(k=0;k<=epsl;k++){
11 putpixel(int(x+0.5),(int)(y+0.5));
12 x+=xIncre;
13 y+=yIncre;
14 }
15 }

 

来源：https://www.cnblogs.com/benbencoding798/p/4875317.html