function [x, y] = symbsafe(symb, x0, y0, theSize, theColor, varargin)

% symbsafe -- Plot symbols.
%  symbsafe('demo') demonstrates itself with stars
%   or polygons.
%  symbsafe(N) demonstrates itself with N stars.
%  symbsafe (no argument) updates the existing symbols in all
%   the axes of the current figure.  The axes are left in
%   in "manual" mode.
%  symbsafe(symb, x0, y0, theSize, theColor, ...) draws symbols
%   as patchs, centered on (x0, y0), with theSize and theColor.
%   Additional name/value pairs are passed directly to the "patch"
%   routine.  The symb sizes are given in the units of the y-axis.
%   The symb can be given as a two-column [x(:) y(:)] array of
%   values, or as a function statement (with or without arguments) 
%   will be called with "[x, y] = eval(symb)".  The (x, y) data
%   are expected to be suitable for input to the Matlab "patch"
%   routine.
%  [xx, yy] = symbsafe(...) returns the (x, y) coordinates of
%   the symbols, one per row, but does not plot them.
%  h = symbsafe(...) draws the stars and returns their handles.
%
% Also see: arrowsafe, star (internal), polygon (internal).
 
% Copyright (C) 2000 Dr. Charles R. Denham, ZYDECO.
%  All Rights Reserved.
%   Disclosure without explicit written consent from the
%    copyright owner does not constitute publication.
 
% Version of 13-Jan-2000 16:21:37.
% Updated    15-Jan-2000 16:04:58.

if nargin < 3, y0 = 0; end
if nargin < 4, theSize = 1; end
if nargin < 5, theColor = [0 0 0]; end

% Update.

if nargin < 1
	oldGCA = gca;
	h = findobj(gcf, 'Type', 'patch', 'Tag', mfilename);
	if any(h)
		for i = 1:length(h)
			u = get(h(i), 'UserData');
			[xx, yy] = feval(mfilename, u{:});
			set(h(i), 'XData', xx, 'YData', yy)
		end
	end
	axes(oldGCA)
	return
end

% Demonstration.

if nargin == 1
	if isequal(symb, 'demo')
		symb = ceil(rand(1, 1)*20 + 5);
	end
	n = symb;
	if ischar(n), n = eval(n); end
	f = findobj('Type', 'figure', 'Name', [mfilename ' demo']);
	if any(f), figure(f(1)), else, figure, end
	delete(findobj(gcf, 'Type', 'patch', 'Tag', mfilename))
	axis auto
	x0 = (rand(1, n) - 0.5) * n;
	y0 = rand(1, n) - 0.5;
	s = rand(1, n)/10;
	cmap = colormap;
	index = floor(rand(prod(size(x0)), 1) * size(cmap, 1)) + 1;
	c = cmap(index, :);
	fcn = 'star';
	if rand(1, 1) > 0.5, fcn = 'polygon'; end
	k = ceil(rand(1, 1)*8) + 2;
	if rem(k, 4) == 0, k = k+1; end
	fcn = [fcn '(' int2str(k) ')'];
	feval(mfilename, fcn, x0, y0, s, c)
	set(gca, 'XLim', [-n n], 'Ylim', [-1 1])
	set(gcf, 'Name', [mfilename ' demo'])
	if exist('zoomsafe', 'file') == 2
		set(gcf, 'WindowButtonDownFcn', ...
			['if zoomsafe(''down''), ' mfilename ', end'])
	end
	feval(mfilename)
	return
end

if ischar(symb)
	[xs, ys] = eval(symb);   % "symb" may have arguments.
else
	xs = symb(:, 1);
	ys = symb(:, 2);
end

if length(x0) == 1
	x0 = x0 * ones(size(y0));
elseif length(y0) == 1
	y0 = y0 * ones(size(x0));
end

if length(theSize) == 1
	theSize = theSize * ones(size(x0));
end

if size(theColor, 1) == 1
	theColor = ones(prod(size(x0)), 1) * theColor;
end

oldUnits = get(gca, 'Units');
set(gca, 'Units', 'pixels')
thePosition = get(gca, 'Position');
set(gca, 'Units', oldUnits)
theWidth = thePosition(3);
theHeight = thePosition(4);

axis('manual')
dx = diff(get(gca, 'XLim'));
dy = diff(get(gca, 'YLim'));
dydx = dy / dx;   % Not used.
dxdp = dx / theWidth;   % sci/pixel.
dydp = dy / theHeight;   % sci/pixel.

scale = dxdp / dydp;

f = zeros(1, 10);
f(2) = 1;
f = ifft(f)*length(f);
f(2:2:end) = f(2:2:end) * 0.38;
f(end+1) = f(1);
xs = -imag(f);
ys = real(f);

if ischar(symb)
	[xs, ys] = eval(symb);
else
	xs = symb(:, 1);
	ys = symb(:, 2);
end

h = zeros(size(x0));

for i = 1:prod(size(x0))
	xsymb = xs * theSize(i) * scale + x0(i);
	ysymb = ys * theSize(i) + y0(i);
	csymb = theColor(i, :);
	usymb = {symb, x0(i), y0(i), theSize(i)};
	if nargout == 2
		x(i, 1:length(xsymb)) = xsymb;
		y(i, 1:length(ysymb)) = ysymb;
	else
		if length(varargin) > 1
			h(i) = patch(xsymb, ysymb, csymb, ...
				'Tag', mfilename, ...
				'UserData', usymb);
		else
			h(i) = patch(xsymb, ysymb, csymb, ...
				'Tag', mfilename, ...
				'UserData', usymb);
		end
	end
end

set(gcf, 'ResizeFcn', mfilename)

% ---------- star ---------- %

function [x, y] = star(nPoints, theInnerRadius)

% star -- Coordinates of a unit-star.
%  [x, y] = star(nPoints) returns the (x, y) coordinates
%   of a closed unit-star of nPoints (default = 5). If
%   only one output argument is provided, the result
%   is complex x+i*y.  If none, a plot is made.  The
%   points go counterclockwise, starting at (x = 0, y = 1).
%  [x, y] = star(nPoints, theInnerRadius) sets the radius
%   of the valley points to theInnerRadius [0 .. 1].
 
% Copyright (C) 2000 Dr. Charles R. Denham, ZYDECO.
%  All Rights Reserved.
%   Disclosure without explicit written consent from the
%    copyright owner does not constitute publication.
 
% Version of 14-Jan-2000 12:48:41.
% Updated    15-Jan-2000 15:43:44.

if nargin < 1 & nargout < 1
	nPoints = 'demo';
elseif nargin < 1
	nPoints = 5;
end

if isequal(nPoints, 'demo')
	nPoints = 5;
	plot(star(nPoints))
	set(gca, 'XLim', [-1 1], 'YLim', [-1 1])
	axis equal
	set(gcf, 'Name', [mfilename ' demo'])
	figure(gcf)
	return
end

if nargin < 1, nPoints = 5; end
if nargin < 2, theInnerRadius = 1; end

if ischar(nPoints), nPoints = eval(nPoints); end

zs = exp(sqrt(-1) * linspace(0, 2*pi, 2*nPoints+1));
zs(end) = zs(1);
xs = -imag(zs);
ys = real(zs);

if nargin > 1
	if ischar(theInnerRadius), theInnerRadius = eval(theInnerRadius); end
	theScale = theInnerRadius;
else   % Make valleys similar to Star of David.
	k = [1 5];
	p = polyfit(xs(k), ys(k), 1);
	q = polyfit(xs(k+2), ys(k+2), 1);
	x0 = (q(2) - p(2)) / (p(1) - q(1));
	y0 = polyval(p, x0);
	theScale = norm([x0 y0]);
end

xs(2:2:end) = xs(2:2:end) * theScale;
ys(2:2:end) = ys(2:2:end) * theScale;

if nargout > 1
	x = xs; y = ys;
elseif nargout > 0
	x = xs + sqrt(-1)*ys;
else
	plot(xs, ys)
end

% ---------- polygon ---------- %

function [x, y] = polygon(nVertices)

% polygon -- Unit-polygon coordinates.
%  polygon('demo') demonstrates itself.
%  [x, y] = polygon(nSides) returns the (x, y)
%   coordinates for a closed unit-polygon of
%  nVertices (default = 3).  If only one output
%   argument is provided, the result is complex
%   x+i*y.  If none, a plot is made.  The points
%   go counterclockwise, starting at (x = 0, y = 1).
 
% Copyright (C) 2000 Dr. Charles R. Denham, ZYDECO.
%  All Rights Reserved.
%   Disclosure without explicit written consent from the
%    copyright owner does not constitute publication.
 
% Version of 15-Jan-2000 14:05:25.
% Updated    15-Jan-2000 15:43:44.

if nargin < 1 & nargout < 1
	help(mfilename)
	nVertices = 'demo';
elseif nargin < 1
	nVertices = 5;
end

if isequal(nVertices, 'demo')
	nVertices = 5;
	plot(polygon(nVertices))
	set(gca, 'XLim', [-1 1], 'YLim', [-1 1])
	axis equal
	set(gcf, 'Name', [mfilename ' demo'])
	figure(gcf)
	return
end

if ischar(nVertices), nVertices = eval(nVertices); end

z = exp(sqrt(-1)*linspace(0, 2*pi, nVertices+1));
z(end) = z(1);

xx = -imag(z);
yy = real(z);

if nargout > 1
	x = xx;
	y = yy;
elseif nargout > 0
	x = xx + sqrt(-1)*yy;
else
	plot(xx, yy)
end