# HG changeset patch # User Carnë Draug # Date 1385250231 0 # Node ID a40156e8b6a7096b0aa6840fbf91d0bcbd57b20f # Parent 4465699450c2e90eacd3b626c36e28f741227788 rgb2ind: backout 5d6243c2acbf removing all quantization (bug #40669) * rgb2ind.m: remove the options n, tol, map, and dither which were implemented by creating tif file, making a system call to gm convert, and reading back the new file. This removes all quantization options limiting rgb2ind to create indexed images equal to the input RGB image and a colormap with as many colors as the input image. diff -r 4465699450c2 -r a40156e8b6a7 scripts/image/rgb2ind.m --- a/scripts/image/rgb2ind.m Sat Nov 23 09:38:13 2013 -0800 +++ b/scripts/image/rgb2ind.m Sat Nov 23 23:43:51 2013 +0000 @@ -1,6 +1,5 @@ ## Copyright (C) 1994-2013 John W. Eaton ## Copyright (C) 2012 Carnë Draug -## Copyright (C) 2013 Adam H Aitkenhead ## ## This file is part of Octave. ## @@ -20,159 +19,51 @@ ## -*- texinfo -*- ## @deftypefn {Function File} {[@var{x}, @var{map}] =} rgb2ind (@var{rgb}) -## @deftypefnx {Function File} {[@var{x}, @var{map}] =} rgb2ind (@var{rgb}, @var{map}) -## @deftypefnx {Function File} {[@var{x}, @var{map}] =} rgb2ind (@var{rgb}, @var{n}) -## @deftypefnx {Function File} {[@var{x}, @var{map}] =} rgb2ind (@var{rgb}, @var{tol}) -## @deftypefnx {Function File} {[@var{x}, @var{map}] =} rgb2ind (@var{rgb}, @var{map}, @var{dither_option}) -## @deftypefnx {Function File} {[@var{x}, @var{map}] =} rgb2ind (@var{rgb}, @var{n}, @var{dither_option}) -## @deftypefnx {Function File} {[@var{x}, @var{map}] =} rgb2ind (@var{rgb}, @var{tol}, @var{dither_option}) ## @deftypefnx {Function File} {[@var{x}, @var{map}] =} rgb2ind (@var{R}, @var{G}, @var{B}) -## @deftypefnx {Function File} {[@var{x}, @var{map}] =} rgb2ind (@var{R}, @var{G}, @var{B}, @var{map}) -## @deftypefnx {Function File} {[@var{x}, @var{map}] =} rgb2ind (@var{R}, @var{G}, @var{B}, @var{n}) -## @deftypefnx {Function File} {[@var{x}, @var{map}] =} rgb2ind (@var{R}, @var{G}, @var{B}, @var{tol}) -## @deftypefnx {Function File} {[@var{x}, @var{map}] =} rgb2ind (@var{R}, @var{G}, @var{B}, @var{map}, @var{dither_option}) -## @deftypefnx {Function File} {[@var{x}, @var{map}] =} rgb2ind (@var{R}, @var{G}, @var{B}, @var{n}, @var{dither_option}) -## @deftypefnx {Function File} {[@var{x}, @var{map}] =} rgb2ind (@var{R}, @var{G}, @var{B}, @var{tol}, @var{dither_option}) ## Convert an image in red-green-blue (RGB) color space to an indexed image. ## -## The input image @var{rgb} must be an N-dimensional RGB image -## (@nospell{MxNxO}@dots{}x3 array) where M,N,O@dots{} are the image -## dimensions, and the final dimension contains the values in the red, green -## and blue channels. Alternatively, the red, green and blue color channels -## can be input as separate arrays @var{R}, @var{G}, and @var{B}. -## -## The input @var{map} defines the colormap to be used. Alternatively, @var{n} -## or @var{tol} may be used to define the maximum number of colors to use in an -## automatically generated colormap. @var{n} is related to @var{tol} by: -## @var{n} = (floor (1/@var{tol}) + 1)^3; where 0 < @var{tol} @leq{} 1. -## -## @var{dither_option} is a string which enables or disables dithering: -## @qcode{"dither"} (default) or @qcode{"nodither"}. -## ## @seealso{ind2rgb, rgb2hsv, rgb2ntsc} ## @end deftypefn +## FIXME: This function has a very different syntax than the Matlab +## one of the same name. +## Octave function does not support N, MAP, DITHER, or TOL arguments. + ## Author: Tony Richardson ## Created: July 1994 ## Adapted-By: jwe -function [x, map] = rgb2ind (varargin) - - ## Gather the inputs - if (nargin < 1 || nargin > 6) - print_usage (); - else - - ## Test for dither_option, by checking if the final input is a string - if (ischar (varargin{end})) - dither_option = varargin{end}; - dither_check = true; - else - dither_option = "dither"; - dither_check = false; - endif - - ## Read the rgb input - if (nargin-dither_check==1 || nargin-dither_check==2) - - rgb = varargin{1}; - if (size (rgb)(end) != 3) - error ("rgb2ind: The input image must be an RGB image (MxNxO...x3 array)."); - elseif (min (rgb(:)) < 0 || max (rgb(:)) > 1) - error ("rgb2ind: The input image must contain values between 0 and 1."); - endif - if (nargin-dither_check==2) - option = varargin{2}; - else - dither_option = "nodither"; - endif - - ## Read the R,G,B inputs - elseif (nargin - dither_check==3 || nargin - dither_check==4) - - R = varargin{1}; - G = varargin{2}; - B = varargin{3}; - if (! size_equal (R, G, B)) - error ("rgb2ind: R, G, and B must have the same size"); - endif - if (nargin-dither_check==4) - option = varargin{4}; - else - dither_option = "nodither"; - endif - - rgb = reshape ([R(:), G(:), B(:)], [size(R), 3]); +function [x, map] = rgb2ind (R, G, B) - endif - endif - - sz = size (rgb); - - ## Apply a limited colormap if required - if (exist ("option","var")) - - if (size (option, 1)==1) - - if (option>0 && option<=1) - ## option: tol - tol = option; - n = (floor (1/option) + 1)^3; - else - ## option: n - n = option; - endif - optionstr = sprintf ("-colors %d",n); - - else - - ## option: map - map = option; - if (isequal (map(:,1),map(:,2)) || isequal (map(:,1),map(:,3)) - || isequal (map(:,2),map(:,3))) - error ("rgb2ind: The colormap cannot contain matching R,G, or B channels.") - endif - fnmap = tmpnam; - map = reshape (map, size (map, 1), 1, 3); - imwrite (map, fnmap, "tiff"); - optionstr = sprintf ("-map %s", fnmap); - - endif - - ## If image is an ND array, convert it to a tiled 2D image - ## before processing it with Graphicsmagick - if (numel (sz) > 3) - rgb = reshape (rgb, [prod(sz(1:end-2)), sz(end-1), 3]); - endif - - ## Prepare the Graphicsmagick dithering option - if (strcmp (dither_option, "nodither")) - ditherstr = "+dither"; - elseif (strcmp (dither_option, "dither")) - ditherstr = "-dither"; - endif - - ## Perform the image processing using Graphicsmagick - fna = tmpnam; - fnb = tmpnam; - imwrite (rgb, fna, "tiff"); - gmstr = sprintf ("gm convert %s %s %s %s", fna, ditherstr, optionstr, fnb); - system (gmstr); - rgb = imread (fnb); - + if (nargin != 1 && nargin != 3) + print_usage (); endif - ## Conversion of rgb image to x,map - pr = prod (sz(1:end-1)); - x = zeros (sz(1:end-1)); - [map,~,x(:)] = unique (reshape (rgb, [pr, 3]), "rows"); + if (nargin == 1) + rgb = R; + if (ndims (rgb) != 3 || size (rgb, 3) != 3) + error ("rgb2ind: argument is not an RGB image"); + else + R = rgb(:,:,1); + G = rgb(:,:,2); + B = rgb(:,:,3); + endif + elseif (! size_equal (R, G, B)) + error ("rgb2ind: R, G, and B must have the same size"); + endif + + x = reshape (1:numel (R), size (R)); + + map = unique ([R(:) G(:) B(:)], "rows"); + [~, x] = ismember ([R(:) G(:) B(:)], map, "rows"); + x = reshape (x, size (R)); ## a colormap is of class double and values between 0 and 1 - switch (class (rgb)) + switch (class (R)) case {"single", "double", "logical"} ## do nothing, return the same case {"uint8", "uint16"} - map = double (map) / double (intmax (class (rgb))); + map = double (map) / double (intmax (class (R))); case "int16" map = (double (im) + 32768) / 65535; otherwise @@ -193,7 +84,6 @@ endfunction - %% FIXME: Need some functional tests or %!demo blocks %% Test input validation