# HG changeset patch
# User jwe
# Date 1200359046 0
# Node ID 4fbfce35012a2d2deedbd58465e32ae8a259bb35
# Parent  4ff9611147ba96cf976bcc63c203dc837f8bf5f8
[project @ 2008-01-15 01:04:06 by jwe]

diff --git a/scripts/ChangeLog b/scripts/ChangeLog
--- a/scripts/ChangeLog
+++ b/scripts/ChangeLog
@@ -1,3 +1,11 @@
+2008-01-14  Soren Hauberg  <hauberg@gmail.com>
+
+	* image/hsv2rgb.m, image/ntsc2rgb.m, image/rgb2hsv.m,
+	image/rgb2ntsc.m: Also accept images as input.
+
+	* image/gray2ind.m: Handle image type other than double.
+	Improve error checking and documentation.
+
 2008-01-14  John W. Eaton  <jwe@octave.org>
 
 	* plot/__go_draw_axes__.m (get_fontname_and_size): Use strcmpi
diff --git a/scripts/image/gray2ind.m b/scripts/image/gray2ind.m
--- a/scripts/image/gray2ind.m
+++ b/scripts/image/gray2ind.m
@@ -18,24 +18,45 @@
 ## <http://www.gnu.org/licenses/>.
 
 ## -*- texinfo -*-
-## @deftypefn {Function File} {[@var{img}, @var{map}] =} gray2ind (@var{})
+## @deftypefn {Function File} {[@var{img}, @var{map}] =} gray2ind (@var{I}, @var{n})
 ## Convert a gray scale intensity image to an Octave indexed image.
+## The indexed image will consist of @var{n} different intensity values. If not
+## given @var{n} will default to 64.
 ## @end deftypefn
 
 ## Author: Tony Richardson <arichard@stark.cc.oh.us>
 ## Created: July 1994
 ## Adapted-By: jwe
 
-function [X, map] = gray2ind (I, n)
-
+function [X, map] = gray2ind (I, n = 64)
+  ## Check input
   if (nargin < 1 || nargin > 2)
     print_usage ();
-  elseif (nargin == 1)
-    n = 64;
+  endif
+  C = class(I);
+  if (! ismatrix (I) || ndims (I) != 2)
+    error ("gray2ind: first input argument must be a gray scale image");
+  endif
+  if (! isscalar (n) || n < 0)
+    error ("gray2ind: second input argument must be a positive integer");
+  endif
+  ints = {"uint8", "uint16", "int8", "int16"};
+  floats = {"double", "single"};
+  if (! ismember (C, {ints{:}, floats{:}}))
+    error ("gray2ind: invalid data type '%s'", C);
+  endif
+  if (ismember (C, floats) && (min (I(:)) < 0 || max (I(:)) > 1))
+    error ("gray2ind: floating point images may only contain values between 0 and 1");
   endif
 
+  ## Convert data
   map = gray (n);
-
+  ## If @var{I} is an integer matrix convert it to a double matrix with values in [0, 1]
+  if (ismember (C, ints))
+    low = double (intmin (C));
+    high = double (intmax (C));
+    I = (double (I) - low) / (high - low);
+  endif
   X = round (I*(n-1)) + 1;
 
 endfunction
diff --git a/scripts/image/hsv2rgb.m b/scripts/image/hsv2rgb.m
--- a/scripts/image/hsv2rgb.m
+++ b/scripts/image/hsv2rgb.m
@@ -19,7 +19,7 @@
 
 ## -*- texinfo -*-
 ## @deftypefn {Function File} {@var{rgb_map} =} hsv2rgb (@var{hsv_map})
-## Transform a colormap from the hsv space to the rgb space. 
+## Transform a colormap or image from the hsv space to the rgb space. 
 ## @seealso{rgb2hsv}
 ## @end deftypefn
 
@@ -37,6 +37,22 @@
     print_usage ();
   endif
 
+  ## If we have an image convert it into a color map.
+  if (ismatrix (hsv_map) && ndims (hsv_map) == 3)
+    is_image = true;
+    Sz = size (hsv_map);
+    hsv_map = [hsv_map(:,:,1)(:), hsv_map(:,:,2)(:), hsv_map(:,:,3)(:)];
+    ## Convert to a double image.
+    if (isinteger (hsv_map))
+      C = class (hsv_map);
+      low = double (intmin (C));
+      high = double (intmax (C));
+      hsv_map = (double (hsv_map) - low) / (high - low);
+    endif
+  else
+    is_image = false;
+  endif
+
   if (! ismatrix (hsv_map) || columns (hsv_map) != 3)
     error ("hsv2rgb: argument must be a matrix of size nx3");
   endif
@@ -64,4 +80,9 @@
 			     + (hue >= 1/6 & hue < 1/2)
 			     + (hue >= 1/2 & hue < 2/3) .* (4 - 6 * hue));
 
+  ## If input was an image, convert it back into one.
+  if (is_image)
+    rgb_map = reshape (rgb_map, Sz);
+  endif
+
 endfunction
diff --git a/scripts/image/ntsc2rgb.m b/scripts/image/ntsc2rgb.m
--- a/scripts/image/ntsc2rgb.m
+++ b/scripts/image/ntsc2rgb.m
@@ -19,7 +19,8 @@
 
 ## -*- texinfo -*-
 ## @deftypefn {Function File} {} ntsc2rgb (@var{yiq})
-## Image format conversion.
+## Transform a colormap or image from NTSC to RGB.
+## @seealso{rgb2ntsc}
 ## @end deftypefn
 
 ## Author: Tony Richardson <arichard@stark.cc.oh.us>
@@ -32,10 +33,36 @@
     print_usage ();
   endif
 
+  ## If we have an image convert it into a color map.
+  if (ismatrix (yiq) && ndims (yiq) == 3)
+    is_image = true;
+    Sz = size (yiq);
+    yiq = [yiq(:,:,1)(:), yiq(:,:,2)(:), yiq(:,:,3)(:)];
+    ## Convert to a double image.
+    if (isinteger (yiq))
+      C = class (yiq);
+      low = double (intmin (C));
+      high = double (intmax (C));
+      yiq = (double (yiq) - low) / (high - low);
+    endif
+  else
+    is_image = false;
+  endif
+
+  if (! ismatrix (yiq) || columns (yiq) != 3)
+    error ("ntsc2rgb: argument must be a matrix of size Nx3 or NxMx3");
+  endif
+  
+  ## Convert data
   trans = [ 1.0,      1.0,      1.0;
             0.95617, -0.27269, -1.10374;
             0.62143, -0.64681, 1.70062 ];
 
   rgb = yiq * trans;
 
+  ## If input was an image, convert it back into one.
+  if (is_image)
+    rgb = reshape (rgb, Sz);
+  endif
+
 endfunction
diff --git a/scripts/image/rgb2hsv.m b/scripts/image/rgb2hsv.m
--- a/scripts/image/rgb2hsv.m
+++ b/scripts/image/rgb2hsv.m
@@ -19,7 +19,7 @@
 
 ## -*- texinfo -*-
 ## @deftypefn {Function File} {@var{hsv_map} =} rgb2hsv (@var{rgb_map})
-## Transform a colormap from the rgb space to the hsv space.
+## Transform a colormap or image from the rgb space to the hsv space.
 ##
 ## A color n the RGB space consists of the red, green and blue intensities.
 ##
@@ -39,6 +39,22 @@
     print_usage ();
   endif
 
+  ## If we have an image convert it into a color map.
+  if (ismatrix (rgb) && ndims (rgb) == 3)
+    is_image = true;
+    Sz = size (rgb);
+    rgb = [rgb(:,:,1)(:), rgb(:,:,2)(:), rgb(:,:,3)(:)];
+    ## Convert to a double image.
+    if (isinteger (rgb))
+      C = class (rgb);
+      low = double (intmin (C));
+      high = double (intmax (C));
+      rgb = (double (rgb) - low) / (high - low);
+    endif
+  else
+    is_image = false;
+  endif
+
   if (! ismatrix (rgb) || columns (rgb) != 3)
     error ("rgb2hsv: argument must be a matrix of size n x 3");
   endif
@@ -78,5 +94,10 @@
   s(notgray) = 1 - s(notgray) ./ v(notgray);
 
   hsval = [h, s, v];
+  
+  ## If input was an image, convert it back into one.
+  if (is_image)
+    hsval = reshape (hsval, Sz);
+  endif
 
 endfunction
diff --git a/scripts/image/rgb2ntsc.m b/scripts/image/rgb2ntsc.m
--- a/scripts/image/rgb2ntsc.m
+++ b/scripts/image/rgb2ntsc.m
@@ -19,7 +19,8 @@
 
 ## -*- texinfo -*-
 ## @deftypefn {Function File} {} rgb2ntsc (@var{rgb})
-## Image format conversion.
+## Transform a colormap or image from RGB to NTSC.
+## @seealso{ntsc2rgb}
 ## @end deftypefn
 
 ## Author: Tony Richardson <arichard@stark.cc.oh.us>
@@ -32,10 +33,36 @@
     print_usage ();
   endif
 
+  ## If we have an image convert it into a color map.
+  if (ismatrix (rgb) && ndims (rgb) == 3)
+    is_image = true;
+    Sz = size (rgb);
+    rgb = [rgb(:,:,1)(:), rgb(:,:,2)(:), rgb(:,:,3)(:)];
+    ## Convert to a double image.
+    if (isinteger (rgb))
+      C = class (rgb);
+      low = double (intmin (C));
+      high = double (intmax (C));
+      rgb = (double (rgb) - low) / (high - low);
+    endif
+  else
+    is_image = false;
+  endif
+
+  if (! ismatrix (rgb) || columns (rgb) != 3)
+    error ("rgb2ntsc: argument must be a matrix of size Nx3 or NxMx3");
+  endif
+  
+  ## Convert data
   trans = [ 0.299,  0.596,  0.211;
             0.587, -0.274, -0.523;
             0.114, -0.322,  0.312 ];
 
   yiq = rgb * trans;
 
+  ## If input was an image, convert it back into one.
+  if (is_image)
+    yiq = reshape (yiq, Sz);
+  endif
+
 endfunction