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1 ## Copyright (C) 1996, 1997 John W. Eaton |
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2 ## |
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3 ## This file is part of Octave. |
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4 ## |
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5 ## Octave is free software; you can redistribute it and/or modify it |
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6 ## under the terms of the GNU General Public License as published by |
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7 ## the Free Software Foundation; either version 2, or (at your option) |
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8 ## any later version. |
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9 ## |
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10 ## Octave is distributed in the hope that it will be useful, but |
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11 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 ## General Public License for more details. |
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14 ## |
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15 ## You should have received a copy of the GNU General Public License |
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16 ## along with Octave; see the file COPYING. If not, write to the Free |
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17 ## Software Foundation, 59 Temple Place - Suite 330, Boston, MA |
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18 ## 02111-1307, USA. |
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19 |
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20 ## -*- texinfo -*- |
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21 ## @deftypefn {Function File} {} imshow (@var{i}) |
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22 ## @deftypefnx {Function File} {} imshow (@var{x}, @var{map}) |
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23 ## @deftypefnx {Function File} {} imshow (@var{x}, @var{n}) |
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24 ## @deftypefnx {Function File} {} imshow (@var{i}, @var{n}) |
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25 ## @deftypefnx {Function File} {} imshow (@var{r}, @var{g}, @var{b}) |
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26 ## Display an image. |
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27 ## |
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28 ## @code{imshow (@var{x})} displays an intensity image, estimating the |
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29 ## number of gray levels. |
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30 ## |
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31 ## @code{imshow (@var{x}, @var{map})} displays an indexed image using the |
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32 ## specified colormap. |
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33 ## |
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34 ## @code{imshow (@var{i}, @var{N})} displays a gray scale intensity image of |
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35 ## N levels. |
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36 ## |
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37 ## @code{imshow (@var{r}, @var{g}, @var{b})} displays an RGB image. |
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38 ## |
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39 ## The string @code{truesize} can always be used as an optional |
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40 ## final argument to prevent automatic zooming of the image. |
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41 ## @end deftypefn |
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42 ## |
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43 ## @seealso{image, imagesc, colormap, gray2ind, and rgb2ind} |
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44 |
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45 ## Author: Tony Richardson <arichard@stark.cc.oh.us> |
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46 ## Created: July 1994 |
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47 ## Adapted-By: jwe |
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48 |
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49 function imshow (varargin) |
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50 |
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51 usage_str = "imshow (x) or imshow (x, map) or imshow (i, N) or imshow (r, g, b)"; |
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52 |
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53 if (nargin == 0 || nargin > 4) |
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54 usage (usage_str); |
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55 endif |
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56 |
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57 ## Count nr of matrix arguments. |
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58 mvars = 0; |
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59 while (mvars < nargin && ismatrix (varargin{mvars+1})) |
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60 mvars++; |
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61 endwhile |
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62 |
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63 if (mvars < 1 || mvars > 3) |
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64 usage (usage_str); |
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65 endif |
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66 |
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67 ## All except imshow (r, g, b) |
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68 |
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69 if (mvars != 3) |
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70 I = varargin{1}; |
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71 if (iscomplex (I)) |
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72 warning ("imshow: displaying real part of complex image"); |
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73 I = real (I); |
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74 endif |
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75 if (max (I(:)) <= 1) |
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76 ## image in [0-1]; scale to [0-255] |
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77 I = I * 255; |
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78 M = gray (256); |
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79 endif |
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80 endif |
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81 |
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82 if (mvars == 1) |
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83 ## imshow (x) |
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84 ## Grayscale image [0-N] -- estimate gray levels. |
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85 N = 2 ^ ceil (log2 (max (I(:)))); |
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86 if (N <= 65536) |
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87 M = gray (N); |
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88 else |
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89 M = gray (256); |
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90 I = I / max (I(:)) * 255; |
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91 endif |
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92 elseif (mvars == 2) |
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93 ## imshow (x, map) or imshow (x, N) |
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94 M = varargin{2}; |
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95 if (isscalar (M)) |
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96 M = gray (M); |
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97 endif |
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98 elseif (mvars == 3) |
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99 ## imshow (r, g, b) |
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100 r = varargin{1}; |
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101 g = varargin{2}; |
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102 b = varargin{3}; |
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103 tmp = [r; g; b]; |
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104 if (iscomplex (tmp)) |
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105 warning ("imshow: displaying real part of complex rgb image"); |
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106 r = real (r); |
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107 g = real (g); |
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108 b = real (b); |
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109 endif |
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110 if (max (tmp(:)) > 1) |
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111 ## Normalise to [0-1]. |
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112 r = r / 255; |
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113 g = g / 255; |
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114 b = b / 255; |
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115 endif |
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116 [I, M] = rgb2ind (r, g, b); |
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117 endif |
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118 |
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119 ## Check for "truesize". |
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120 zoom = []; |
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121 for i = mvars+1:nargin |
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122 if (isstr (varargin{i}) && strcmp (varargin{i}, "truesize")) |
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123 zoom = 1; |
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124 endif |
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125 endfor |
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126 |
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127 colormap (M); |
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128 image (I, zoom); |
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129 |
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130 endfunction |
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131 |
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132 %!error imshow () # no arguments |
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133 %!error imshow (1, 2, 3, 4, 5) # too many arguments |
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134 %!error imshow ([1,2], [2,3], [3,4], [4,5]) # too many matrix arguments |
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135 %!error imshow ("image.png") # filename not accepted as argument |
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136 |
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137 %!demo |
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138 %! imshow (loadimage ("default.img")); |
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139 |
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140 %!demo |
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141 %! I = loadimage ("default.img"); |
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142 %! imshow (I, "truesize") |
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143 |
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144 %!demo |
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145 %! [I, M] = loadimage ("default.img"); |
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146 %! imshow(I, M); |
