# Computer Graphics – 14. DDA Line Drawing Algorithm

[wpdm_package id=’1237′]

**Sample Input –** Draw a line using DDA Line Drawing Algorithm. End points of the line should be accepted using mouse clicks. Use ‘+’ and ‘-‘ to increase and decrease the width of the line. Clear screen using right click.

**Sample Ouput –**

[sourcecode lang=”cpp”]

void dda_draw_line(GLintPoint p1, GLintPoint p2){

GLdouble x=0, y=0;

int dx=(p2.x-p1.x);

int dy=(p2.y-p1.y);

int steps=(abs(dx)>abs(dy)?abs(dx):abs(dy));

GLdouble x_inc=(dx*1.0/steps);

GLdouble y_inc=(dy*1.0/steps);

x=p1.x, y=p1.y;

for(int i=0; i<=steps; i++){

draw_dot(x,y);

y+=y_inc;

x+=x_inc;

}

}

[/sourcecode]

To compile the above program in ubuntu terminal –

# g++ -lGL -lGLU -lglut DDA_Line_Drawing.cpp

# ./a.out