diff options
Diffstat (limited to 'driver/dither.c')
| -rw-r--r-- | driver/dither.c | 306 |
1 files changed, 0 insertions, 306 deletions
diff --git a/driver/dither.c b/driver/dither.c deleted file mode 100644 index bebaaece..00000000 --- a/driver/dither.c +++ /dev/null @@ -1,306 +0,0 @@ -/* - * "$Id: dither.c 8937 2009-12-18 23:50:23Z mike $" - * - * Dithering routines for CUPS. - * - * Copyright 2007 by Apple Inc. - * Copyright 1993-2005 by Easy Software Products. - * - * These coded instructions, statements, and computer programs are the - * property of Apple Inc. and are protected by Federal copyright - * law. Distribution and use rights are outlined in the file "LICENSE.txt" - * which should have been included with this file. If this file is - * file is missing or damaged, see the license at "http://www.cups.org/". - * - * Contents: - * - * cupsDitherDelete() - Free a dithering buffer. - * cupsDitherLine() - Dither a line of pixels... - * cupsDitherNew() - Create a dithering buffer. - */ - -/* - * Include necessary headers. - */ - -#include "driver.h" -#include <config.h> - - -/* - * 'cupsDitherDelete()' - Free a dithering buffer. - * - * Returns 0 on success, -1 on failure. - */ - -void -cupsDitherDelete(cups_dither_t *d) /* I - Dithering buffer */ -{ - if (d != NULL) - free(d); -} - - -/* - * 'cupsDitherLine()' - Dither a line of pixels... - */ - -void -cupsDitherLine(cups_dither_t *d, /* I - Dither data */ - const cups_lut_t *lut, /* I - Lookup table */ - const short *data, /* I - Separation data */ - int num_channels, - /* I - Number of components */ - unsigned char *p) /* O - Pixels */ -{ - register int x, /* Horizontal position in line... */ - pixel, /* Current adjusted pixel... */ - e, /* Current error */ - e0,e1,e2; /* Error values */ - register int errval0, /* First half of error value */ - errval1, /* Second half of error value */ - errbase, /* Base multiplier */ - errbase0, /* Base multiplier for large values */ - errbase1, /* Base multiplier for small values */ - errrange; /* Range of random multiplier */ - register int *p0, /* Error buffer pointers... */ - *p1; - static char logtable[16384]; /* Error magnitude for randomness */ - static char loginit = 0; /* Has the table been initialized? */ - - - if (!loginit) - { - /* - * Initialize a logarithmic table for the magnitude of randomness - * that is introduced. - */ - - loginit = 1; - - logtable[0] = 0; - for (x = 1; x < 2049; x ++) - logtable[x] = (int)(log(x / 16.0) / log(2.0) + 1.0); - for (; x < 16384; x ++) - logtable[x] = logtable[2049]; - } - - if (d->row == 0) - { - /* - * Dither from left to right: - * - * e0 == p0[0] - * e1 e2 == p1[-1] p1[0] - */ - - p0 = d->errors + 2; - p1 = d->errors + 2 + d->width + 4; - e0 = p0[0]; - e1 = 0; - e2 = 0; - - /* - * Error diffuse each output pixel... - */ - - for (x = d->width; - x > 0; - x --, p0 ++, p1 ++, p ++, data += num_channels) - { - /* - * Skip blank pixels... - */ - - if (*data == 0) - { - *p = 0; - e0 = p0[1]; - p1[-1] = e1; - e1 = e2; - e2 = 0; - continue; - } - - /* - * Compute the net pixel brightness and brightness error. Set a dot - * if necessary... - */ - - pixel = lut[*data].intensity + e0 / 128; - - if (pixel > CUPS_MAX_LUT) - pixel = CUPS_MAX_LUT; - else if (pixel < 0) - pixel = 0; - - *p = lut[pixel].pixel; - e = lut[pixel].error; - - /* - * Set the randomness factor... - */ - - if (e > 0) - errrange = logtable[e]; - else - errrange = logtable[-e]; - - errbase = 8 - errrange; - errrange = errrange * 2 + 1; - - /* - * Randomize the error value. - */ - - if (errrange > 1) - { - errbase0 = errbase + (CUPS_RAND() % errrange); - errbase1 = errbase + (CUPS_RAND() % errrange); - } - else - errbase0 = errbase1 = errbase; - - /* - * X 7/16 = X e0 - * 3/16 5/16 1/16 = e1 e2 - */ - - errval0 = errbase0 * e; - errval1 = (16 - errbase0) * e; - e0 = p0[1] + 7 * errval0; - e1 = e2 + 5 * errval1; - - errval0 = errbase1 * e; - errval1 = (16 - errbase1) * e; - e2 = errval0; - p1[-1] = e1 + 3 * errval1; - } - } - else - { - /* - * Dither from right to left: - * - * e0 == p0[0] - * e2 e1 == p1[0] p1[1] - */ - - p0 = d->errors + d->width + 1 + d->width + 4; - p1 = d->errors + d->width + 1; - p += d->width - 1; - data += num_channels * (d->width - 1); - e0 = p0[0]; - e1 = 0; - e2 = 0; - - /* - * Error diffuse each output pixel... - */ - - for (x = d->width; - x > 0; - x --, p0 --, p1 --, p --, data -= num_channels) - { - /* - * Skip blank pixels... - */ - - if (*data == 0) - { - *p = 0; - e0 = p0[-1]; - p1[1] = e1; - e1 = e2; - e2 = 0; - continue; - } - - /* - * Compute the net pixel brightness and brightness error. Set a dot - * if necessary... - */ - - pixel = lut[*data].intensity + e0 / 128; - - if (pixel > CUPS_MAX_LUT) - pixel = CUPS_MAX_LUT; - else if (pixel < 0) - pixel = 0; - - *p = lut[pixel].pixel; - e = lut[pixel].error; - - /* - * Set the randomness factor... - */ - - if (e > 0) - errrange = logtable[e]; - else - errrange = logtable[-e]; - - errbase = 8 - errrange; - errrange = errrange * 2 + 1; - - /* - * Randomize the error value. - */ - - if (errrange > 1) - { - errbase0 = errbase + (CUPS_RAND() % errrange); - errbase1 = errbase + (CUPS_RAND() % errrange); - } - else - errbase0 = errbase1 = errbase; - - /* - * X 7/16 = X e0 - * 3/16 5/16 1/16 = e1 e2 - */ - - errval0 = errbase0 * e; - errval1 = (16 - errbase0) * e; - e0 = p0[-1] + 7 * errval0; - e1 = e2 + 5 * errval1; - - errval0 = errbase1 * e; - errval1 = (16 - errbase1) * e; - e2 = errval0; - p1[1] = e1 + 3 * errval1; - } - } - - /* - * Update to the next row... - */ - - d->row = 1 - d->row; -} - - -/* - * 'cupsDitherNew()' - Create an error-diffusion dithering buffer. - */ - -cups_dither_t * /* O - New state array */ -cupsDitherNew(int width) /* I - Width of output in pixels */ -{ - cups_dither_t *d; /* New dithering buffer */ - - - if ((d = (cups_dither_t *)calloc(1, sizeof(cups_dither_t) + - 2 * (width + 4) * - sizeof(int))) == NULL) - return (NULL); - - d->width = width; - - return (d); -} - - -/* - * End of "$Id: dither.c 8937 2009-12-18 23:50:23Z mike $". - */ |