drawcircle code in matlab explain

function varargout=drawcircle(center,radius,varargin)

global t DS DE

% This code is draw circle with different center,radius,type and positions

%The input

% center co-ordinated - [r c];

% radius - r

% Boundary - [LD UD] LD=Lower limit of Degree, UD upper limit of the degree

% 'quarter' - Draw the quater circle

% 'half' - Draw half circle

% 'full' - Draw full circle

% 'clk' - Draw circle clock wise

% 'aclk' - Draw circle Anti clock wise

% '1P' - 1st quardrant (+,+)

% '2P' - 2nd quardrant (-,+)

% '3P' - 3rd quardrant (-,-)

% '4P' - 4th quardrant (+,-)

% Example

% [row col]=drawcircle([1 1],2,'quarter','clk','1P');

% Draw the quarter circle with center(1,1), radius-2,

% 1st quardrant and circle draw clock wise position

% [row col]=drawcircle([1 1],2,[-90 90]);

% Draw circle with spefic Degree range

% drawcircle([1 1],2,[-90 90]);

% Draw only circle

% Created by Sundha R 28.02.2014

% Based on the basic formula circle with co-ordinates and radius

if length(varargin)== 1

D = varargin{1};

if D(1) >= D(2)

error('The Low limit must be smaller than the upper limit')

return

end

type = ' ';

CF = 'clk';

elseif length(varargin) == 2

D = varargin{1};

if D(1) >= D(2)

error('The Low limit of the Degree must smaller than the uper limit')

return

end

type = ' ';

CF = varargin{2};

elseif length(varargin) == 3

type = varargin{1};

CF = varargin{2};

PO = varargin{3};

else

error('Check the input Argument')

end

switch type

case 'quarter'

switch PO

case '1P'

t = pi:0.0067*pi:(3*pi/2);

case '2P'

t = (pi/2):0.0067*pi:pi;

case '3P'

t = 0:0.0067*pi:(pi/2);

case '4P'

t = (3*pi/2):0.0067*pi:2*pi;

end

case 'half'

switch PO

case '1P'

t = pi:0.0067*pi:2*pi;

case '2P'

t = (pi/2):0.0067*pi:(3*pi/2);

case '3P'

t = 0:0.0067*pi:pi;

case '4P'

t = (-pi/2):0.0067*pi:(pi/2);

end

case 'full'

switch PO

case '1P'

t = 0:0.0067*pi:2*pi;

case '2P'

t = 0:0.0067*pi:2*pi;

case '3P'

t = 0:0.0067*pi:2*pi;

case '4P'

t = 0:0.0067*pi:2*pi;

end

otherwise

type = D;

DS = (type(1)*pi)/180;

DE = (type(2)*pi)/180;

t = DS:0.0067*pi:DE;

end

switch CF

case 'clk'

t = t;

case 'aclk'

t = sort(t,'descend');

end

for i = 1 : length(t)

r(i) = center(1) - radius*sin(t(i));

c(i) = center(2) - radius*cos(t(i));

% figure(1),

% plot(r,c,'b-');

end

varargout{1} = r;

varargout{2} = c;

[Adam]

Well, I didn't write it and have no idea of its provenance so I would never waste my time trying to explain code that could be complete garbage for all I know (and the existence of global variables parachuted in from on-high in the 1st line doesn't bode well for the quality of the code!), especially if you don't appear to have made any effort to do so yourself. If literally every single line is a mystery to you you need to start with some basic Matlab learning, nevermind drawing circles!