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comparison scripts/image/private/ind2x.m @ 18578:875f4510d6dc

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Accept indexed images with color values below the first colormap entry (bug #41851). Change made for Matlab compatibility. * ind2gray.m: Change %!tests to accept an indexed image with colors below the first entry in the colormap. * ind2rgb.m: Change %!tests to accept an indexed image with colors below the first entry in the colormap. * ind2x.m: Change input validation to accept all floating point images with integer indices. Issue a warning if any of the indices are below the first entry in the colormap. Map all color indices below the first entry to the first color in the colormap.
author Rik <rik@octave.org>
date Mon, 17 Mar 2014 09:10:32 -0700
parents d63878346099
children 4197fc428c7d
comparison
equal deleted inserted replaced
18577:3a1a4d587c4e 18578:875f4510d6dc
20 ## private function for the ind2XXX functions which have a lot of code in common 20 ## private function for the ind2XXX functions which have a lot of code in common
21 21
22 function [x, map] = ind2x (caller, x, map) 22 function [x, map] = ind2x (caller, x, map)
23 23
24 ## Check if X is an indexed image. 24 ## Check if X is an indexed image.
25 ## an indexed image is defined has having only 2D, and that's how Matlab 25 ## An indexed image is defined has having only 2D, and that's how Matlab
26 ## behaves. But we want to support ND images, so we will allow up to 4D 26 ## behaves. But we want to support ND images, so we will allow up to 4D
27 ## and check that the 3rd is a singleton 27 ## and check that the 3rd dimension is a singleton.
28 if (all (ndims (x) != [2 4]) || size (x, 3) != 1 || issparse (x) || 28 if (all (ndims (x) != [2 4]) || size (x, 3) != 1
29 (isfloat (x) && ! isindex (x)) || 29 || iscomplex (x) || issparse (x)
30 ! any (strcmp (class (x), {"uint8", "uint16", "single", "double"}))) 30 || (isfloat (x) && x != fix (x))
31 || ! any (strcmp (class (x), {"uint8", "uint16", "single", "double"})))
31 error ("%s: X must be an indexed image", caller); 32 error ("%s: X must be an indexed image", caller);
32 endif 33 endif
33 34
34 ## Check if map is a valid colormap. 35 ## Check if map is a valid colormap.
35 if (! iscolormap (map)) 36 if (! iscolormap (map))
36 error ("%s: MAP must be a valid colormap", caller); 37 error ("%s: MAP must be a valid colormap", caller);
37 endif 38 endif
38 39
39 ## Do we have enough colors in the color map? 40 ## Any color indices below the lower bound of the color map are modified
40 ## there's an offset of 1 when the indexed image is an integer class so we fix 41 ## to point to the first color in the map (see bug #41851).
41 ## it now and convert it to float only if really necessary and even then only 42 if (isfloat (x))
42 ## to single precision since that is enough for both uint8 and uint16. 43 invalid_idx = x < 1;
44 if (any (invalid_idx(:)))
45 warning (["Octave:" caller ":invalid-idx-img"],
46 [caller ": indexed image contains colors outside of colormap"]);
47 x(invalid_idx) = 1;
48 endif
49 endif
50
51 ## Switch to using 1-based indexing.
52 ## It is possible that an integer storage class may not have enough room
53 ## to make the switch, in which case we convert the data to single.
43 maxidx = max (x(:)); 54 maxidx = max (x(:));
44 if (isinteger (x)) 55 if (isinteger (x))
45 if (maxidx == intmax (class (x))) 56 if (maxidx == intmax (class (x)))
46 x = single (x); 57 x = single (x);
47 endif 58 endif
48 x += 1; 59 x += 1;
49 maxidx += 1; 60 maxidx += 1;
50 endif 61 endif
51 62
63 ## When there are more colors in the image, than there are in the map,
64 ## pad the colormap with the last color in the map for Matlab compatibility.
52 num_colors = rows (map); 65 num_colors = rows (map);
53 if (num_colors < maxidx) 66 if (num_colors < maxidx)
54 ## Pad with the last color in the map for Matlab compatibility 67 warning (["Octave:" caller ":invalid-idx-img"],
68 [caller ": indexed image contains colors outside of colormap"]);
55 pad = repmat (map(end,:), maxidx - num_colors, 1); 69 pad = repmat (map(end,:), maxidx - num_colors, 1);
56 map(end+1:maxidx, :) = pad; 70 map(end+1:maxidx, :) = pad;
57 endif 71 endif
58 72
59 endfunction 73 endfunction