Simple function to plot a straight dashed line with custom dash width. Gap width = dash width.

% DASHEDLINE(X,Y) plots a dashed line on the current axis along X and
% Y, with dash and gaps equal to 2 points. X and Y should each have
% exactly two elements defining the start and end of the line
%
% DASHEDLINE(X,Y, WIDTH) plots a dashed line with dash and gaps equal to
% WIDTH points
%
% H = DASHEDLINE(X,Y,...) returns a handle to the dashed line
%
%
% Example:
% x = get(gca,'XLim');
% y = [0 0];
% dashedline(x, y, 4)
%
% Note 1: the dash width is adjusted slightly to ensure a dash is present
% at the beginning and end of the line
%
% Note 2: point measurement assumes the dashed line is plotted along the
% whole width or height of the axis, otherwise it will be slightly off.
% 1 pt = 1/72 in = .3528 mm
%
% Includes plotboxpos, copyright 2010 Kelly Kearney