MATLAB: Drawing a line over a black and white image

Question

What is the best way to draw a line over a black and white (binary) image in MATLAB, provided the start and end coordinates are known?

Please note, I am not trying to add an annotation line, I would like the line to become part of the image.

Answer 1

This algorithm offers one approach.

Answer 2

And here is an implementation of Bresenham's line from the file exchange.

Answer 3

You may want to look at my answer to an SO question about adding a line to an image matrix. Here's a simpler example than the one I have in that answer, which will make a white line running from row and column index (10,10) to (240,240):

img = imread('cameraman.tif');  %# Load a sample black and white image
[r,c] = size(img);              %# Get the image size
rpts = linspace(10,240,1000);   %# A set of row points for the line
cpts = linspace(10,240,1000);   %# A set of column points for the line
index = sub2ind([r c],round(rpts),round(cpts));  %# Compute a linear index
img(index) = 255;               %# Set the line points to white
imshow(img);                    %# Display the image

And here's the resulting image: