Making a Line Visible Over an Image in MATLAB

(Originally posted on Doug's MATLAB Video Tutorials blog.)

It can be difficult to see a line that is drawn over an image. The line is often lost in the background colors. That is why cursors are colored as they are, so that they are visible on any background. I demonstrate some code that makes a line more visible with the same technique.

function h = cursorLine(x,y,innerThickness, outerThickness)

if nargin == 2
    innerThickness = 2;
    outerThickness = 4;
end

h.thick = line(x,y);
h.thin  = line(x,y);

set(h.thick, 'color', [1 1 1]);
set(h.thin , 'color', [0 0 0]);

set(h.thick, 'linewidth', outerThickness);
set(h.thin , 'linewidth', innerThickness);