changeset 52:a8a32e130893

(none)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Problems/private/thumbFromOp.m	Mon Mar 14 16:52:43 2011 +0000
@@ -0,0 +1,42 @@
+function P = thumbFromOp(op,m,n,sm,sn,grayscale)
+% Output matrix P, of size m x n, sampled at
+% sm x sn upper top
+
+%   Copyright 2008, Ewout van den Berg and Michael P. Friedlander
+%   http://www.cs.ubc.ca/labs/scl/sparco
+%   $Id: thumbFromOp.m 1040 2008-06-26 20:29:02Z ewout78 $
+
+if nargin < 6, grayscale = 0; end
+    
+info = op([],0);
+
+sm = min(info{1},sm);
+sn = min(info{2},sn);
+M  = zeros(sm,sn);
+
+for i=1:sn
+   v = zeros(info{2},1); v(i) = 1;
+   w = real(op(v,1));
+
+   M(:,i) = w(1:sm);
+end
+
+mn = min(min(M));
+mx = max(max(M));
+M  = (M - mn) / (mx-mn);
+
+idxm = floor(linspace(1,sm+1,m+1)); idxm = idxm(1:end-1);
+idxn = floor(linspace(1,sn+1,n+1)); idxn = idxn(1:end-1);
+
+if grayscale
+   P = 1-M(idxm,idxn);
+else
+   clrmap = hsv;
+   M = 1 + round(M * (length(clrmap)-1));
+   P = zeros(m,n,3);
+   for j1=1:m
+       for j2=1:n
+           P(j1,j2,:) = clrmap(M(idxm(j1),idxn(j2)),:);
+       end
+   end
+end