to draw a line by using Bresenham’s line drawing algorithm
// modified version checks slope sign and function realization
#include
#include
#include
#include
#include
void func(int, int, int, int);
void main()
{
int gd=DETECT, gm;
initgraph(&gd, &gm, “c:\\tc\\bgi”);
int x1, y1, x2, y2, dx, dy, p;
cout<
cin>>x2>>y2;
dx= abs(x2-x1);
dy= abs(y2-y1);
int slope= dy/dx;
p=(2*dy-dx);
int x=x1;
int y=y1;
if (slope<1)
func(x1,y1, x2, y2);
else
{
int tempx1=y1;
int tempy1=x1;
int tempx2=y2;
int tempy2=x2;
func(tempx1, tempy1, tempx2, tempy2);
}
getch();
closegraph();
}
void func(tempx1, tempy1, tempx2, tempy2)
{
int p, i, dx, dy, x, y, x1, y1;
putpixel(x1, y1,RED);
for(i=0; i
{
if(p<0)
{
p=(p+2*dy);
x=x+1;
putpixel(x,y,RED);
}
else
{
p=(p+2*dy-2*dx);
x=x++;
y=y++;
putpixel(x,y,RED);
}
}
closegraph();
}