gtCrop: vectorized it a little bit, to make it more easy to change and mantain

Signed-off-by: Nicola Vigano <nicola.vigano@esrf.fr>

git-svn-id: https://svn.code.sf.net/p/dct/code/trunk@316 4c865b51-4357-4376-afb4-474e03ccb993

zUtil_Imaging/gtCrop.m

-function im = gtCrop(im, gtbbox)
+function img = gtCrop(img, gtbbox)
 % GTCROP.M Crops an image given a bounding box
 % Usage:
 %       im=gtCrop(imorig,bbox)
@@ -13,7 +13,7 @@ function im = gtCrop(im, gtbbox)
 % Example:
 %   imorig=reshape(1:25,5,5)   % produce a 10x10 matrix
 %   bbox=[3 2 2 3];
-%   im=gtCrop(imorig,bbox)
+%   im=gtCrop(imorig, bbox)
 %
 %   imorig = 
 %     1     6    11    16    21
@@ -26,49 +26,30 @@ function im = gtCrop(im, gtbbox)
 %    13    18
 %    14    19
 
-
 % Greg Johnson, September 2006
 % Modified to work also with 3D volumes W. Ludwig,   March 2012
 
+    switch (length(gtbbox))
+        case 4  %  2D case
+            minLims = gtbbox(1:2);
+            maxLims = minLims + gtbbox(3:4) - 1;
+            % if bbox is too large, crop to image extent
+            minLims = max(minLims, 1);
+            maxLims = min(size(img), maxLims);
 
+            img = img(minLims(2):maxLims(2), minLims(1):maxLims(1));
+        case 6
+            % 3D case, uses different conventions from 2D case: x and y are not
+            % inverted
+            minLims = gtbbox(1:3);
+            maxLims = minLims + gtbbox(4:6) - 1;
+            % if bbox is too large, crop to image extent
+            minLims = max(minLims, 1);
+            maxLims = min(size(img), maxLims);
 
-if length(gtbbox) == 4  %  2D case
-     x1 = gtbbox(1);
-     y1 = gtbbox(2);
-     x2 = x1 + gtbbox(3) - 1;
-     y2 = y1 + gtbbox(4) - 1;
-  
-     % if bbox is too large, crop to image extent
-     if x1 < 1, x1 = 1; end
-     if y1 < 1, y1 = 1; end
-     
-     if x2 > size(im, 2), x2 = size(im, 2); end
-     if y2 > size(im, 1), y2 = size(im, 1); end
-
-     im=im(y1:y2, x1:x2);
-elseif length(gtbbox) == 6
-     x1 = gtbbox(1);
-     y1 = gtbbox(2);
-     z1 = gtbbox(3);
-     x2 = x1 + gtbbox(4) - 1;
-     y2 = y1 + gtbbox(5) - 1;
-     z2 = z1 + gtbbox(6) - 1; 
-     % if bbox is too large, crop to image extent
-     if x1 < 1, x1 = 1; end
-     if y1 < 1, y1 = 1; end
-     if z1 < 1 ,z1 = 1; end
-     
-     if x2 > size(im, 2), x2 = size(im, 2); end
-     if y2 > size(im, 1), y2 = size(im, 1); end
-     if z2 > size(im, 3), z2 = size(im, 3); end
-     
-     im=im(y1:y2, x1:x2, z1:z2);
-else 
-     error('gtCrop:wrongInput', 'Argument bbox needs either to be a 4 (2D) or 6 (3D) element vector');
-        
-end     
-    
-     
-     
-     
-     
+            img = img(minLims(1):maxLims(1), minLims(2):maxLims(2), minLims(3):maxLims(3));
+        otherwise
+            error('gtCrop:wrongInput', ...
+                  'Argument bbox needs either to be a 4 (2D) or 6 (3D) element vector');
+    end
+end