1 | #! /usr/bin/env python |
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2 | # -*- coding: ISO-8859-15 -*- |
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3 | # |
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4 | # pkpgcounter : a generic Page Description Language parser |
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5 | # |
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6 | # (c) 2003, 2004, 2005, 2006, 2007 Jerome Alet <alet@librelogiciel.com> |
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7 | # This program is free software: you can redistribute it and/or modify |
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8 | # it under the terms of the GNU General Public License as published by |
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9 | # the Free Software Foundation, either version 3 of the License, or |
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10 | # (at your option) any later version. |
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11 | # |
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12 | # This program is distributed in the hope that it will be useful, |
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13 | # but WITHOUT ANY WARRANTY; without even the implied warranty of |
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14 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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15 | # GNU General Public License for more details. |
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16 | # |
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17 | # You should have received a copy of the GNU General Public License |
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18 | # along with this program. If not, see <http://www.gnu.org/licenses/>. |
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19 | # |
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20 | # $Id$ |
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21 | # |
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22 | |
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23 | """This modules implements the computation of ink coverage in different colorspaces.""" |
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24 | |
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25 | import sys |
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26 | |
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27 | from PIL import Image |
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28 | |
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29 | import pdlparser |
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30 | |
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31 | def getPercent(img, nbpix) : |
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32 | """Extracts the percents per color component from a picture. |
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33 | |
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34 | Faster without Psyco on my own machine. |
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35 | """ |
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36 | result = {} |
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37 | bands = img.split() |
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38 | for (i, bandname) in enumerate(img.getbands()) : |
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39 | result[bandname] = 100.0 * (reduce(lambda current, next: current + (next[1] * next[0]), enumerate(bands[i].histogram()), 0) / 255.0) / nbpix |
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40 | return result |
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41 | |
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42 | def getPercentCMYK(img, nbpix) : |
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43 | """Extracts the percents of Cyan, Magenta, Yellow, and Black from a picture. |
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44 | |
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45 | PIL doesn't produce useable CMYK for our algorithm, so we use the algorithm from PrintBill. |
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46 | Psyco speeds this function up by around 2.5 times on my computer. |
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47 | """ |
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48 | if img.mode != "RGB" : |
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49 | img = img.convert("RGB") |
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50 | cyan = magenta = yellow = black = 0 |
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51 | for (r, g, b) in img.getdata() : |
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52 | if r == g == b : |
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53 | black += 255 - r |
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54 | else : |
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55 | cyan += 255 - r |
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56 | magenta += 255 - g |
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57 | yellow += 255 - b |
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58 | return { "C" : 100.0 * (cyan / 255.0) / nbpix, |
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59 | "M" : 100.0 * (magenta / 255.0) / nbpix, |
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60 | "Y" : 100.0 * (yellow / 255.0) / nbpix, |
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61 | "K" : 100.0 * (black / 255.0) / nbpix, |
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62 | } |
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63 | |
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64 | def getPercentGC(img, nbpix) : |
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65 | """Determines if a page is in grayscale or colour mode.""" |
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66 | if img.mode != "RGB" : |
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67 | img = img.convert("RGB") |
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68 | gray = 0 |
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69 | for (r, g, b) in img.getdata() : |
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70 | if not (r == g == b) : |
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71 | # optimize : if a single pixel is no gray the whole page is colored. |
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72 | return { "G" : 0.0, "C" : 100.0 } |
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73 | return { "G" : 100.0, "C" : 0.0 } |
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74 | |
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75 | def getPercentBW(img, nbpix) : |
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76 | """Extracts the percents of Black from a picture, once converted to gray levels.""" |
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77 | if img.mode != "L" : |
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78 | img = img.convert("L") |
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79 | return { "B" : 100.0 - getPercent(img, nbpix)["L"] } |
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80 | |
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81 | def getPercentRGB(img, nbpix) : |
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82 | """Extracts the percents of Red, Green, Blue from a picture, once converted to RGB.""" |
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83 | if img.mode != "RGB" : |
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84 | img = img.convert("RGB") |
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85 | return getPercent(img, nbpix) |
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86 | |
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87 | def getPercentCMY(img, nbpix) : |
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88 | """Extracts the percents of Cyan, Magenta, and Yellow from a picture once converted to RGB.""" |
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89 | result = getPercentRGB(img, nbpix) |
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90 | return { "C" : 100.0 - result["R"], |
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91 | "M" : 100.0 - result["G"], |
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92 | "Y" : 100.0 - result["B"], |
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93 | } |
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94 | |
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95 | def getInkCoverage(fname, colorspace) : |
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96 | """Returns a list of dictionnaries containing for each page, |
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97 | for each color component, the percent of ink coverage on |
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98 | that particular page. |
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99 | """ |
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100 | result = [] |
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101 | colorspace = colorspace.upper() |
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102 | computation = globals()["getPercent%s" % colorspace] |
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103 | if colorspace in ("CMYK", "GC") : # faster with psyco on my machine |
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104 | try : |
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105 | import psyco |
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106 | except ImportError : |
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107 | pass |
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108 | else : |
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109 | psyco.bind(getPercentCMYK) |
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110 | |
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111 | index = 0 |
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112 | try : |
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113 | image = Image.open(fname) |
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114 | except IOError, msg : |
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115 | raise pdlparser.PDLParserError, "%s (%s)" % (msg, fname) |
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116 | else : |
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117 | try : |
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118 | while True : |
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119 | nbpixels = image.size[0] * image.size[1] |
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120 | result.append(computation(image, nbpixels)) |
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121 | index += 1 |
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122 | image.seek(index) |
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123 | except EOFError : |
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124 | pass |
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125 | return (colorspace, result) |
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126 | |
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127 | if __name__ == "__main__" : |
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128 | # NB : length of result gives number of pages ! |
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129 | print getInkCoverage(sys.argv[1], "CMYK") |
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