gimp/plug-ins/print/print-util.c
Manish Singh 0820b13c74 0.99.31 fun
updated print plugin

-Yosh
1998-05-17 07:16:50 +00:00

710 lines
17 KiB
C

/*
* "$Id$"
*
* Print plug-in driver utility functions for the GIMP.
*
* Copyright 1997-1998 Michael Sweet (mike@easysw.com)
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the Free
* Software Foundation; either version 2 of the License, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Contents:
*
* dither_black() - Dither grayscale pixels to black.
* dither_cmyk() - Dither RGB pixels to cyan, magenta, yellow, and
* black.
* gray_to_gray() - Convert grayscale image data to grayscale.
* indexed_to_gray() - Convert indexed image data to grayscale.
* indexed_to_rgb() - Convert indexed image data to RGB.
* rgb_to_gray() - Convert RGB image data to grayscale.
* rgb_to_rgb() - Convert RGB image data to RGB.
* default_media_size() - Return the size of a default page size.
*
* Revision History:
*
* $Log$
* Revision 1.10 1998/05/17 07:16:49 yosh
* 0.99.31 fun
*
* updated print plugin
*
* -Yosh
*
* Revision 1.14 1998/05/16 18:27:59 mike
* Cleaned up dithering functions - unnecessary extra data in dither buffer.
*
* Revision 1.13 1998/05/13 17:00:36 mike
* Minor change to CMYK generation code - now cube black difference value
* for better colors.
*
* Revision 1.12 1998/05/08 19:20:50 mike
* Updated CMYK generation code to use new method.
* Updated dithering algorithm (slightly more uniform now, less speckling)
* Added default media size function.
*
* Revision 1.11 1998/03/01 18:03:27 mike
* Whoops - need to add 255 - alpha to the output values (transparent to white
* and not transparent to black...)
*
* Revision 1.10 1998/03/01 17:20:48 mike
* Updated alpha code to do alpha computation before gamma/brightness lut.
*
* Revision 1.9 1998/03/01 17:13:46 mike
* Updated CMY/CMYK conversion code for dynamic BG and hue adjustment.
* Added alpha channel support to color conversion functions.
*
* Revision 1.8 1998/01/21 21:33:47 mike
* Replaced Burkes dither with stochastic (random) dither.
*
* Revision 1.7 1997/10/02 17:57:26 mike
* Replaced ordered dither with Burkes dither (error-diffusion).
* Now dither K separate from CMY.
*
* Revision 1.6 1997/07/30 20:33:05 mike
* Final changes for 1.1 release.
*
* Revision 1.5 1997/07/26 18:43:04 mike
* Fixed dither_black and dither_cmyk - wasn't clearing extra bits
* (caused problems with A3/A4 size output).
*
* Revision 1.5 1997/07/26 18:43:04 mike
* Fixed dither_black and dither_cmyk - wasn't clearing extra bits
* (caused problems with A3/A4 size output).
*
* Revision 1.4 1997/07/02 18:46:26 mike
* Fixed stupid bug in dither_black() - wasn't comparing against gray
* pixels (comparing against the first black byte - d'oh!)
* Changed 255 in dither matrix to 254 to shade correctly.
*
* Revision 1.4 1997/07/02 18:46:26 mike
* Fixed stupid bug in dither_black() - wasn't comparing against gray
* pixels (comparing against the first black byte - d'oh!)
* Changed 255 in dither matrix to 254 to shade correctly.
*
* Revision 1.3 1997/07/02 13:51:53 mike
* Added rgb_to_rgb and gray_to_gray conversion functions.
* Standardized calling args to conversion functions.
*
* Revision 1.2 1997/07/01 19:28:44 mike
* Updated dither matrix.
* Fixed scaling bugs in dither_*() functions.
*
* Revision 1.1 1997/06/19 02:18:15 mike
* Initial revision
*/
#include "print.h"
/*
* RGB to grayscale luminance constants...
*/
#define LUM_RED 31
#define LUM_GREEN 61
#define LUM_BLUE 8
/*
* Error buffer for dither functions. This needs to be at least 14xMAXDPI
* (currently 720) to avoid problems...
*/
int error[2][4][14*720+1] =
{
{ { 0 }, { 0 }, { 0 } , { 0 } },
{ { 0 }, { 0 }, { 0 } , { 0 } }
};
/*
* 'dither_black()' - Dither grayscale pixels to black.
*/
void
dither_black(guchar *gray, /* I - Grayscale pixels */
int row, /* I - Current Y coordinate */
int src_width, /* I - Width of input row */
int dst_width, /* I - Width of output row */
unsigned char *black) /* O - Black bitmap pixels */
{
int x, /* Current X coordinate */
xerror, /* X error count */
xstep, /* X step */
xmod, /* X error modulus */
length; /* Length of output bitmap in bytes */
unsigned char bit, /* Current bit */
*kptr; /* Current black pixel */
int k, /* Current black error */
ditherk, /* Next error value in buffer */
*kerror0, /* Pointer to current error row */
*kerror1; /* Pointer to next error row */
int ditherbit; /* Random dithering bitmask */
xstep = src_width / dst_width;
xmod = src_width % dst_width;
length = (dst_width + 7) / 8;
kerror0 = error[row & 1][3];
kerror1 = error[1 - (row & 1)][3];
memset(black, 0, length);
for (x = 0, bit = 128, kptr = black, xerror = 0,
ditherbit = rand(), ditherk = *kerror0;
x < dst_width;
x ++, kerror0 ++, kerror1 ++)
{
k = 255 - *gray + ditherk / 8;
if (k > 127)
{
*kptr |= bit;
k -= 255;
};
if (ditherbit & bit)
{
kerror1[0] = 5 * k;
ditherk = kerror0[1] + 3 * k;
}
else
{
kerror1[0] = 3 * k;
ditherk = kerror0[1] + 5 * k;
};
if (bit == 1)
{
kptr ++;
bit = 128;
ditherbit = rand();
}
else
bit >>= 1;
gray += xstep;
xerror += xmod;
if (xerror >= dst_width)
{
xerror -= dst_width;
gray ++;
};
};
}
/*
* 'dither_cmyk()' - Dither RGB pixels to cyan, magenta, yellow, and black.
*/
void
dither_cmyk(guchar *rgb, /* I - RGB pixels */
int row, /* I - Current Y coordinate */
int src_width, /* I - Width of input row */
int dst_width, /* I - Width of output rows */
unsigned char *cyan, /* O - Cyan bitmap pixels */
unsigned char *magenta, /* O - Magenta bitmap pixels */
unsigned char *yellow, /* O - Yellow bitmap pixels */
unsigned char *black) /* O - Black bitmap pixels */
{
int x, /* Current X coordinate */
xerror, /* X error count */
xstep, /* X step */
xmod, /* X error modulus */
length; /* Length of output bitmap in bytes */
int c, m, y, k, /* CMYK values */
divk, /* Inverse of K */
diff; /* Average color difference */
unsigned char bit, /* Current bit */
*cptr, /* Current cyan pixel */
*mptr, /* Current magenta pixel */
*yptr, /* Current yellow pixel */
*kptr; /* Current black pixel */
int ditherc, /* Next error value in buffer */
*cerror0, /* Pointer to current error row */
*cerror1; /* Pointer to next error row */
int dithery, /* Next error value in buffer */
*yerror0, /* Pointer to current error row */
*yerror1; /* Pointer to next error row */
int ditherm, /* Next error value in buffer */
*merror0, /* Pointer to current error row */
*merror1; /* Pointer to next error row */
int ditherk, /* Next error value in buffer */
*kerror0, /* Pointer to current error row */
*kerror1; /* Pointer to next error row */
int ditherbit; /* Random dither bitmask */
xstep = 3 * (src_width / dst_width);
xmod = src_width % dst_width;
length = (dst_width + 7) / 8;
cerror0 = error[row & 1][0];
cerror1 = error[1 - (row & 1)][0];
merror0 = error[row & 1][1];
merror1 = error[1 - (row & 1)][1];
yerror0 = error[row & 1][2];
yerror1 = error[1 - (row & 1)][2];
kerror0 = error[row & 1][3];
kerror1 = error[1 - (row & 1)][3];
memset(cyan, 0, length);
memset(magenta, 0, length);
memset(yellow, 0, length);
if (black != NULL)
memset(black, 0, length);
for (x = 0, bit = 128, cptr = cyan, mptr = magenta, yptr = yellow,
kptr = black, xerror = 0, ditherbit = rand(), ditherc = cerror0[0],
ditherm = merror0[0], dithery = yerror0[0], ditherk = kerror0[0];
x < dst_width;
x ++, cerror0 ++, cerror1 ++, merror0 ++, merror1 ++, yerror0 ++,
yerror1 ++, kerror0 ++, kerror1 ++)
{
/*
* First compute the standard CMYK separation color values...
*/
c = 255 - rgb[0];
m = 255 - rgb[1];
y = 255 - rgb[2];
k = MIN(c, MIN(m, y));
if (black != NULL)
{
/*
* Since we're printing black, adjust the black level based upon
* the amount of color in the pixel (colorful pixels get less black)...
*/
diff = 255 - (abs(c - m) + abs(c - y) + abs(m - y)) / 3;
diff = diff * diff * diff / 65025; /* diff = diff^3 */
k = diff * k / 255;
divk = 255 - k;
if (divk == 0)
c = m = y = 0; /* Grayscale */
else
{
/*
* Full color; update the CMY values for the black value and reduce
* CMY as necessary to give better blues, greens, and reds... :)
*/
c = (255 - rgb[1] / 4) * (c - k) / divk;
m = (255 - rgb[2] / 4) * (m - k) / divk;
y = (255 - rgb[0] / 4) * (y - k) / divk;
};
k += ditherk / 8;
if (k > 127)
{
*kptr |= bit;
k -= 255;
};
if (ditherbit & bit)
{
kerror1[0] = 5 * k;
ditherk = kerror0[1] + 3 * k;
}
else
{
kerror1[0] = 3 * k;
ditherk = kerror0[1] + 5 * k;
};
if (bit == 1)
kptr ++;
}
else
{
/*
* We're not printing black, but let's adjust the CMY levels to produce
* better reds, greens, and blues...
*/
c = (255 - rgb[1] / 4) * (c - k) / 255 + k;
m = (255 - rgb[2] / 4) * (m - k) / 255 + k;
y = (255 - rgb[0] / 4) * (y - k) / 255 + k;
};
c += ditherc / 8;
if (c > 127)
{
*cptr |= bit;
c -= 255;
};
if (ditherbit & bit)
{
cerror1[0] = 5 * c;
ditherc = cerror0[1] + 3 * c;
}
else
{
cerror1[0] = 3 * c;
ditherc = cerror0[1] + 5 * c;
};
m += ditherm / 8;
if (m > 127)
{
*mptr |= bit;
m -= 255;
};
if (ditherbit & bit)
{
merror1[0] = 5 * m;
ditherm = merror0[1] + 3 * m;
}
else
{
merror1[0] = 3 * m;
ditherm = merror0[1] + 5 * m;
};
y += dithery / 8;
if (y > 127)
{
*yptr |= bit;
y -= 255;
};
if (ditherbit & bit)
{
yerror1[0] = 5 * y;
dithery = yerror0[1] + 3 * y;
}
else
{
yerror1[0] = 3 * y;
dithery = yerror0[1] + 5 * y;
};
if (bit == 1)
{
cptr ++;
mptr ++;
yptr ++;
bit = 128;
ditherbit = rand();
}
else
bit >>= 1;
rgb += xstep;
xerror += xmod;
if (xerror >= dst_width)
{
xerror -= dst_width;
rgb += 3;
};
};
}
/*
* 'gray_to_gray()' - Convert grayscale image data to grayscale (brightness
* adjusted).
*/
void
gray_to_gray(guchar *grayin, /* I - RGB pixels */
guchar *grayout, /* O - RGB pixels */
int width, /* I - Width of row */
int bpp, /* I - Bytes-per-pixel in grayin */
guchar *lut, /* I - Brightness lookup table */
guchar *cmap) /* I - Colormap (unused) */
{
if (bpp == 1)
{
/*
* No alpha in image...
*/
while (width > 0)
{
*grayout = lut[*grayin];
grayin ++;
grayout ++;
width --;
};
}
else
{
/*
* Handle alpha in image...
*/
while (width > 0)
{
*grayout = lut[grayin[0] * grayin[1] / 255] + 255 - grayin[1];
grayin += bpp;
grayout ++;
width --;
};
};
}
/*
* 'indexed_to_gray()' - Convert indexed image data to grayscale.
*/
void
indexed_to_gray(guchar *indexed, /* I - Indexed pixels */
guchar *gray, /* O - Grayscale pixels */
int width, /* I - Width of row */
int bpp, /* I - Bytes-per-pixel in indexed */
guchar *lut, /* I - Brightness lookup table */
guchar *cmap) /* I - Colormap */
{
int i; /* Looping var */
unsigned char gray_cmap[256]; /* Grayscale colormap */
for (i = 0; i < 256; i ++, cmap += 3)
gray_cmap[i] = (cmap[0] * LUM_RED + cmap[1] * LUM_GREEN + cmap[2] * LUM_BLUE) / 100;
if (bpp == 1)
{
/*
* No alpha in image...
*/
while (width > 0)
{
*gray = lut[gray_cmap[*indexed]];
indexed ++;
gray ++;
width --;
};
}
else
{
/*
* Handle alpha in image...
*/
while (width > 0)
{
*gray = lut[gray_cmap[indexed[0] * indexed[1] / 255] + 255 - indexed[1]];
indexed += bpp;
gray ++;
width --;
};
};
}
/*
* 'indexed_to_rgb()' - Convert indexed image data to RGB.
*/
void
indexed_to_rgb(guchar *indexed, /* I - Indexed pixels */
guchar *rgb, /* O - RGB pixels */
int width, /* I - Width of row */
int bpp, /* I - Bytes-per-pixel in indexed */
guchar *lut, /* I - Brightness lookup table */
guchar *cmap) /* I - Colormap */
{
if (bpp == 1)
{
/*
* No alpha in image...
*/
while (width > 0)
{
rgb[0] = lut[cmap[*indexed * 3 + 0]];
rgb[1] = lut[cmap[*indexed * 3 + 1]];
rgb[2] = lut[cmap[*indexed * 3 + 2]];
rgb += 3;
indexed ++;
width --;
};
}
else
{
/*
* RGBA image...
*/
while (width > 0)
{
rgb[0] = lut[cmap[indexed[0] * 3 + 0] * indexed[1] / 255 + 255 - indexed[1]];
rgb[1] = lut[cmap[indexed[0] * 3 + 1] * indexed[1] / 255 + 255 - indexed[1]];
rgb[2] = lut[cmap[indexed[0] * 3 + 2] * indexed[1] / 255 + 255 - indexed[1]];
rgb += 3;
indexed += bpp;
width --;
};
};
}
/*
* 'rgb_to_gray()' - Convert RGB image data to grayscale.
*/
void
rgb_to_gray(guchar *rgb, /* I - RGB pixels */
guchar *gray, /* O - Grayscale pixels */
int width, /* I - Width of row */
int bpp, /* I - Bytes-per-pixel in RGB */
guchar *lut, /* I - Brightness lookup table */
guchar *cmap) /* I - Colormap (unused) */
{
if (bpp == 3)
{
/*
* No alpha in image...
*/
while (width > 0)
{
*gray = lut[(rgb[0] * LUM_RED + rgb[1] * LUM_GREEN + rgb[2] * LUM_BLUE) / 100];
gray ++;
rgb += 3;
width --;
};
}
else
{
/*
* Image has alpha channel...
*/
while (width > 0)
{
*gray = lut[(rgb[0] * LUM_RED + rgb[1] * LUM_GREEN + rgb[2] * LUM_BLUE) *
rgb[3] / 25500 + 255 - rgb[3]];
gray ++;
rgb += bpp;
width --;
};
};
}
/*
* 'rgb_to_rgb()' - Convert rgb image data to RGB.
*/
void
rgb_to_rgb(guchar *rgbin, /* I - RGB pixels */
guchar *rgbout, /* O - RGB pixels */
int width, /* I - Width of row */
int bpp, /* I - Bytes-per-pixel in indexed */
guchar *lut, /* I - Brightness lookup table */
guchar *cmap) /* I - Colormap */
{
if (bpp == 3)
{
/*
* No alpha in image...
*/
while (width > 0)
{
rgbout[0] = lut[rgbin[0]];
rgbout[1] = lut[rgbin[1]];
rgbout[2] = lut[rgbin[2]];
rgbin += 3;
rgbout += 3;
width --;
};
}
else
{
/*
* RGBA image...
*/
while (width > 0)
{
rgbout[0] = lut[rgbin[0] * rgbin[3] / 255 + 255 - rgbin[3]];
rgbout[1] = lut[rgbin[1] * rgbin[3] / 255 + 255 - rgbin[3]];
rgbout[2] = lut[rgbin[2] * rgbin[3] / 255 + 255 - rgbin[3]];
rgbin += bpp;
rgbout += 3;
width --;
};
};
}
/*
* 'default_media_size()' - Return the size of a default page size.
*/
void
default_media_size(int model, /* I - Printer model */
char *ppd_file, /* I - PPD file (not used) */
char *media_size, /* I - Media size */
int *width, /* O - Width in points */
int *length) /* O - Length in points */
{
if (strcmp(media_size, "Letter") == 0)
{
*width = 612;
*length = 792;
}
else if (strcmp(media_size, "Legal") == 0)
{
*width = 612;
*length = 1008;
}
else if (strcmp(media_size, "Tabloid") == 0)
{
*width = 792;
*length = 1214;
}
else if (strcmp(media_size, "12x18") == 0)
{
*width = 864;
*length = 1296;
}
else if (strcmp(media_size, "A4") == 0)
{
*width = 595;
*length = 842;
}
else if (strcmp(media_size, "A3") == 0)
{
*width = 842;
*length = 1191;
}
else
{
*width = 0;
*length = 0;
};
}
/*
* End of "$Id$".
*/