Draw an angled line, with a slope relative to a reference point.

Draw a line at an angle in degrees which goes through a reference point inputted as an argument.

function [yline xline] = drawslope(I, alpha, refpoint)
%
% function to draw a line at a desired angle <alpha>,
% which goes through a reference point <refpoint>
% function inputs:
% <I>: Image for which the drawing is desired.
% Range:3Dim, grayscale, or logical
% <alpha>: Angle in degrees, where 0 is complete
% horizontal
% Range: -Inf - +Inf (cyclic after +
% (-) 180 degrees of course)
% <refpoint> : Reference interception point with the slope
% Range: A varaible of size 2x1, where
% refpoint(1) is horizontal and (2) is vertical
% function outputs:
% <yline> : Y axis coordinates of both line ends
% <xline>: X axis coordinates of both line ends
%
% outputs should be used with plot
% function as following:
% plot(yline,xline,...plot specifiers)
%
% Example usage:
% Image = imread('someImage');
% image_centroid = [100 240];
% [yline xline] = drawslope(Image, -60, image_centroid);
% imshow(Image);
% hold on;
% plot(yline, xline, 'blue','LineWidth',2);
%
%
% Written by Elad Boneh, 15.8.2009
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