Plot a palette in Matlab

palette.m

function palette(cmap,varargin)
%% palette - Plot the color palette for a given map on x,y in [0,1]
%            in the current window/axis
% Inputs:
%   cmap    - N x 3 array of colors --OR-- a cell array of 1x3 colors
% Options/Flags (note the `-` on flags)
%   -no-label   - If specified, will *never* label. Otherwise, will label
%                 for N<=10
%   -vert       - Plot vertically
    
%%%%%%%%%%%%%%%%%%%%%%
%% Parse variables
vert = false;
no_label = false;

% Parse
iv = 1;
while iv <= length(varargin)
    param = varargin{iv};
    
    % Replace `-` with `_` for params
    param = strrep(param,'-','_');

    if strncmp(param,'_',1) % flag
        param = param(2:end); % remove -
        eval(sprintf('%s = ~%s;',param,param)); % flip the boolean
    else
        eval(sprintf('%s = varargin{iv+1} ;',param));    
        iv = iv + 1; % Extra increment
    end
    iv = iv + 1;
end 

%%%%%%%%%%%%%%%%%%

% Make it into a cell array if it isn't
if ~iscell(cmap)
    cmap = num2cell(cmap,2);
end

N = length(cmap);

Xs = linspace(0,1,N+1);

for ix = 1:N
    if ix == 1
        hold off
    else
        hold on
    end
    
    if ~vert
        x0 = Xs(ix);    x1 = Xs(ix+1);
        y0 = 0;         y1 = 1;
    else
        x0 = 0;         x1 = 1;
        y0 = Xs(ix);    y1 = Xs(ix+1);
    end
    
    fill([x0,x1,x1,x0,x0],[y0,y0,y1,y1,y0],cmap{ix},'linestyle', 'none')    
end % ix

% Add ticks
ticks = (Xs(2:end) + Xs(1:end-1))/2;

if N>10 || no_label
    set(gca,'xtick',[])
    set(gca,'ytick',[])
else
    if ~vert
        set(gca,'xtick',ticks)
        set(gca,'xticklabel',1:N)
        set(gca,'ytick',[])
    else
        set(gca,'ytick',ticks)
        set(gca,'yticklabel',1:N)
        set(gca,'xtick',[])
    end
end