pPxlGrd.m

function pPxlGrd(X,XLbl,YLbl,Ttl,IsBW,Dmn,Grd);
%function pPxlGrd(X,XLbl,YLbl,Ttl,IsBW,Dmn,Grd);
%
%Shell Projects & Technology, Statistics & Chemometrics
%Philip Jonathan
%June 2010
%
%Overview: General-purpose "pixel" checker-board pseudo-colour plotting for rectangular array X
%1 Works with 0 (test), 1 (basic plot) or 5 (full spec) arguments
%2 No interpolation performed. Simply plots colour level corresponding to the values in X
%
%Input
% X    Rectangular array (n x p) to visualise
% XLbl X LaBeL (n x 1); one value for each level of X
% YLbl Y LaBeL (p x 1); one value for each level of Y
% Ttl  Title (text string)
% IsBW IS Black and White (=0 == plot in colour, =1 == plot in greyscale)
% Dmn  DoMaiN for values to plot (defines limits of colours / greyscale if present)
% Grd  GRaDation increment for "white-out" of colour (produces "non-parametric" contours)
%
%Output
% No data output

if nargin==0;
	n=100;	p=100;	X=(1:n)'*(1:p)+5;	XLbl=(1:n)';	YLbl=(1:p)';	Ttl='TestPixelPlot'; IsBW=0; Dmn=[-2000;12000]; Grd=1000; 
elseif nargin==1;
	[n,p]=size(X); XLbl=(1:n)';	YLbl=(1:p)';	Ttl='TestPixelPlot'; IsBW=0;  Dmn=NaN; Grd=NaN;
elseif nargin==5;
	Dmn=NaN; Grd=NaN;
elseif nargin==6;
	Grd=NaN;
elseif nargin<7;
	return;
end;

[n,p]=size(X);

if isnan(Dmn)==1;
	MnmX=min(min(X));
	MxmX=max(max(X));
else;
	MnmX=Dmn(1);
	MxmX=Dmn(2);
end;

if isnan(Grd)==1;
	Grd=(MxmX-MnmX)/9;
end;

X=[X MnmX*zeros(n,1)];
X=[X;MnmX*zeros(1,p+1)];

h=pcolor(X');set(h,'EdgeColor','none');

nTck=10;
LblSpcX=max(floor(n/nTck),1);
LblSpcY=max(floor(p/nTck),1);

t=(LblSpcX:LblSpcX:n)'; XLbl=[t XLbl(t)];
t=(LblSpcY:LblSpcY:p)'; YLbl=[t YLbl(t)];

set(gca,'XTick',XLbl(:,1)+1,'XTickLabel',XLbl(:,2));
set(gca,'YTick',YLbl(:,1)+1,'YTickLabel',YLbl(:,2));

if IsBW==1;
	colormap(gray);
else;
	colormap('default');
end;

ClrMap=colormap(jet(128));
WhtLvl=round(127*((MnmX+Grd:Grd:MxmX)'-MnmX)/(MxmX-MnmX)+1);
ClrMap(WhtLvl,:)=1;
colormap(ClrMap);
pClrBar([MnmX MxmX],10);

set(gca,'FontSize',20,'FontName','Garamond');grid off;
set(gca,'TickDir','out')
title(Ttl);

set(gcf,'Renderer','painters'); %required for printing using pGI

return;