How can I generate an image with multiple lines?

I am generating a fibre system, so I need to create an image with multiple lines but the sad part is I only get one line. Can anybody body help me in this regard the part of the code which is used to generate the image is given below:

Inside the loop:

mat = zeros(250,250,'uint8');

x = prev(1):new(1);  %# x values at a higher resolution

m= (new(2)-prev(2))/(new(1)-prev(1));

y = m*x+prev(2);                   %# corresponding y values

index = sub2ind(size(mat),round(y),round(x));  %# Indices of the line

mat(index) = 255;  %# Set the values to the max value of 255 for uint8

Loop ends here

image(mat);                      %# Show original line image

colormap(gray);                  %# Change colormap

Answer 1

[Walter Roberson]

Move the

mat = zeros(250,250,'uint8');

to before the loop.

Answer 2

[Image Analyst]

Use imline() to burn lines into an image. See attached demo for full instructions/tutorial.