ivan@77: function P = thumbFromOp(op,m,n,sm,sn,grayscale)
ivan@77: % Output matrix P, of size m x n, sampled at
ivan@77: % sm x sn upper top
ivan@77: 
ivan@77: %   Copyright 2008, Ewout van den Berg and Michael P. Friedlander
ivan@77: %   http://www.cs.ubc.ca/labs/scl/sparco
ivan@77: %   $Id: thumbFromOp.m 1040 2008-06-26 20:29:02Z ewout78 $
ivan@77: 
ivan@77: if nargin < 6, grayscale = 0; end
ivan@77:     
ivan@77: info = op([],0);
ivan@77: 
ivan@77: sm = min(info{1},sm);
ivan@77: sn = min(info{2},sn);
ivan@77: M  = zeros(sm,sn);
ivan@77: 
ivan@77: for i=1:sn
ivan@77:    v = zeros(info{2},1); v(i) = 1;
ivan@77:    w = real(op(v,1));
ivan@77: 
ivan@77:    M(:,i) = w(1:sm);
ivan@77: end
ivan@77: 
ivan@77: mn = min(min(M));
ivan@77: mx = max(max(M));
ivan@77: M  = (M - mn) / (mx-mn);
ivan@77: 
ivan@77: idxm = floor(linspace(1,sm+1,m+1)); idxm = idxm(1:end-1);
ivan@77: idxn = floor(linspace(1,sn+1,n+1)); idxn = idxn(1:end-1);
ivan@77: 
ivan@77: if grayscale
ivan@77:    P = 1-M(idxm,idxn);
ivan@77: else
ivan@77:    clrmap = hsv;
ivan@77:    M = 1 + round(M * (length(clrmap)-1));
ivan@77:    P = zeros(m,n,3);
ivan@77:    for j1=1:m
ivan@77:        for j2=1:n
ivan@77:            P(j1,j2,:) = clrmap(M(idxm(j1),idxn(j2)),:);
ivan@77:        end
ivan@77:    end
ivan@77: end