No. It seems to be time dependent. So if you draw faster, the points will be spaced farther apart. If you want to interpolate so that it's spaced just one pixel apart, you can use interp1() on both x and y. Let me know if you don't
You could also fit a spline through them like my attached demo.
You might also use John D'Errico's interparc function http://www.mathworks.com/matlabcentral/fileexchange/34874-interparc to get points uniformly spaced along the curve you drew.
This might also be interesting: http://www.mathworks.com/matlabcentral/answers/44768-creating-masks-of-open-lines-with-imfreehand-and-impoly-roi-tools
