driver/testdither.c

   1 /*
   2  * "$Id$"
   3  *
   4  *   Dither test program for CUPS.
   5  *
   6  *   Try the following:
   7  *
   8  *       testdither 0 255 > filename.ppm
   9  *       testdither 0 127 255 > filename.ppm
  10  *       testdither 0 85 170 255 > filename.ppm
  11  *       testdither 0 63 127 170 198 227 255 > filename.ppm
  12  *       testdither 0 210 383 > filename.ppm
  13  *       testdither 0 82 255 > filename.ppm
  14  *
  15  *   Copyright 2007-2010 by Apple Inc.
  16  *   Copyright 1993-2005 by Easy Software Products.
  17  *
  18  *   These coded instructions, statements, and computer programs are the
  19  *   property of Apple Inc. and are protected by Federal copyright
  20  *   law.  Distribution and use rights are outlined in the file "LICENSE.txt"
  21  *   which should have been included with this file.  If this file is
  22  *   file is missing or damaged, see the license at "http://www.cups.org/".
  23  *
  24  * Contents:
  25  *
  26  *   main()  - Test dithering and output a PPM file.
  27  *   usage() - Show program usage...
  28  */
  29
  30 /*
  31  * Include necessary headers.
  32  */
  33
  34 #include "driver.h"
  35 #include <cups/string-private.h>
  36
  37
  38 /*
  39  * Local functions...
  40  */
  41
  42 void    usage(void);
  43
  44
  45 /*
  46  * 'main()' - Test dithering and output a PPM file.
  47  */
  48
  49 int                             /* O - Exit status */
  50 main(int  argc,                 /* I - Number of command-line arguments */
  51      char *argv[])              /* I - Command-line arguments */
  52 {
  53   int           x, y;           /* Current coordinate in image */
  54   short         line[512];      /* Line to dither */
  55   unsigned char pixels[512],    /* Dither pixels */
  56                 *pixptr;        /* Pointer in line */
  57   int           output;         /* Output pixel */
  58   cups_lut_t    *lut;           /* Dither lookup table */
  59   cups_dither_t *dither;        /* Dither state */
  60   int           nlutvals;       /* Number of lookup values */
  61   float         lutvals[16];    /* Lookup values */
  62   int           pixvals[16];    /* Pixel values */
  63
  64
  65  /*
  66   * See if we have lookup table values on the command-line...
  67   */
  68
  69   if (argc > 1)
  70   {
  71    /*
  72     * Yes, collect them...
  73     */
  74
  75     nlutvals = 0;
  76
  77     for (x = 1; x < argc; x ++)
  78       if (isdigit(argv[x][0]) && nlutvals < 16)
  79       {
  80         pixvals[nlutvals] = atoi(argv[x]);
  81         lutvals[nlutvals] = atof(argv[x]) / 255.0;
  82         nlutvals ++;
  83       }
  84       else
  85         usage();
  86
  87    /*
  88     * See if we have at least 2 values...
  89     */
  90
  91     if (nlutvals < 2)
  92       usage();
  93   }
  94   else
  95   {
  96    /*
  97     * Otherwise use the default 2-entry LUT with values of 0 and 255...
  98     */
  99
 100     nlutvals   = 2;
 101     lutvals[0] = 0.0;
 102     lutvals[1] = 1.0;
 103     pixvals[0] = 0;
 104     pixvals[1] = 255;
 105   }
 106
 107  /*
 108   * Create the lookup table and dither state...
 109   */
 110
 111   lut    = cupsLutNew(nlutvals, lutvals);
 112   dither = cupsDitherNew(512);
 113
 114  /*
 115   * Put out the PGM header for a raw 256x256x8-bit grayscale file...
 116   */
 117
 118   puts("P5\n512\n512\n255");
 119
 120  /*
 121   * Dither 512 lines, which are written out in 256 image lines...
 122   */
 123
 124   for (y = 0; y < 512; y ++)
 125   {
 126    /*
 127     * Create the grayscale data for the current line...
 128     */
 129
 130     for (x = 0; x < 512; x ++)
 131       line[x] = 4095 * ((y / 32) * 16 + x / 32) / 255;
 132
 133    /*
 134     * Dither the line...
 135     */
 136
 137     cupsDitherLine(dither, lut, line, 1, pixels);
 138
 139     if (y == 0)
 140     {
 141       fputs("DEBUG: pixels =", stderr);
 142       for (x = 0; x < 512; x ++)
 143         fprintf(stderr, " %d", pixels[x]);
 144       fputs("\n", stderr);
 145     }
 146
 147    /*
 148     * Add or set the output pixel values...
 149     */
 150
 151     for (x = 0, pixptr = pixels; x < 512; x ++, pixptr ++)
 152     {
 153       output = 255 - pixvals[*pixptr];
 154
 155       if (output < 0)
 156         putchar(0);
 157       else
 158         putchar(output);
 159     }
 160   }
 161
 162  /*
 163   * Free the dither state and lookup table...
 164   */
 165
 166   cupsDitherDelete(dither);
 167   cupsLutDelete(lut);
 168
 169  /*
 170   * Return with no errors...
 171   */
 172
 173   return (0);
 174 }
 175
 176
 177 /*
 178  * 'usage()' - Show program usage...
 179  */
 180
 181 void
 182 usage(void)
 183 {
 184   puts("Usage: testdither [val1 val2 [... val16]] >filename.ppm");
 185   exit(1);
 186 }
 187
 188
 189 /*
 190  * End of "$Id$".
 191  */