jccolor.c

This is a resource based on j2me embedded,if you dont understand,you can connection with me .

/*
 *
 * @(#)jccolor.c	1.12 06/10/03
 *
 * Portions Copyright  2000-2008 Sun Microsystems, Inc. All Rights
 * Reserved.  Use is subject to license terms.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
 * 
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 only, as published by the Free Software Foundation.
 * 
 * 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 version 2 for more details (a copy is
 * included at /legal/license.txt).
 * 
 * You should have received a copy of the GNU General Public License
 * version 2 along with this work; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 * 
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
 * Clara, CA 95054 or visit www.sun.com if you need additional
 * information or have any questions.
 */

/*
 * jccolor.c
 *
 * Copyright (C) 1991-1996, Thomas G. Lane.
 * This file is part of the Independent JPEG Group's software.
 * For conditions of distribution and use, see the accompanying README file.
 *
 * This file contains input colorspace conversion routines.
 */

#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"


/* Private subobject */

typedef struct {
  struct jpeg_color_converter pub; /* public fields */

  /* Private state for RGB->YCC conversion */
  INT32 * rgb_ycc_tab;		/* => table for RGB to YCbCr conversion */
} my_color_converter;

typedef my_color_converter * my_cconvert_ptr;


/**************** RGB -> YCbCr conversion: most common case **************/

/*
 * YCbCr is defined per CCIR 601-1, except that Cb and Cr are
 * normalized to the range 0..MAXJSAMPLE rather than -0.5 .. 0.5.
 * The conversion equations to be implemented are therefore
 *	Y  =  0.29900 * R + 0.58700 * G + 0.11400 * B
 *	Cb = -0.16874 * R - 0.33126 * G + 0.50000 * B  + CENTERJSAMPLE
 *	Cr =  0.50000 * R - 0.41869 * G - 0.08131 * B  + CENTERJSAMPLE
 * (These numbers are derived from TIFF 6.0 section 21, dated 3-June-92.)
 * Note: older versions of the IJG code used a zero offset of MAXJSAMPLE/2,
 * rather than CENTERJSAMPLE, for Cb and Cr.  This gave equal positive and
 * negative swings for Cb/Cr, but meant that grayscale values (Cb=Cr=0)
 * were not represented exactly.  Now we sacrifice exact representation of
 * maximum red and maximum blue in order to get exact grayscales.
 *
 * To avoid floating-point arithmetic, we represent the fractional constants
 * as integers scaled up by 2^16 (about 4 digits precision); we have to divide
 * the products by 2^16, with appropriate rounding, to get the correct answer.
 *
 * For even more speed, we avoid doing any multiplications in the inner loop
 * by precalculating the constants times R,G,B for all possible values.
 * For 8-bit JSAMPLEs this is very reasonable (only 256 entries per table);
 * for 12-bit samples it is still acceptable.  It's not very reasonable for
 * 16-bit samples, but if you want lossless storage you shouldn't be changing
 * colorspace anyway.
 * The CENTERJSAMPLE offsets and the rounding fudge-factor of 0.5 are included
 * in the tables to save adding them separately in the inner loop.
 */

#define SCALEBITS	16	/* speediest right-shift on some machines */
#define CBCR_OFFSET	((INT32) CENTERJSAMPLE << SCALEBITS)
#define ONE_HALF	((INT32) 1 << (SCALEBITS-1))
#define FIX(x)		((INT32) ((x) * (1L<<SCALEBITS) + 0.5))

/* We allocate one big table and divide it up into eight parts, instead of
 * doing eight alloc_small requests.  This lets us use a single table base
 * address, which can be held in a register in the inner loops on many
 * machines (more than can hold all eight addresses, anyway).
 */

#define R_Y_OFF		0			/* offset to R => Y section */
#define G_Y_OFF		(1*(MAXJSAMPLE+1))	/* offset to G => Y section */
#define B_Y_OFF		(2*(MAXJSAMPLE+1))	/* etc. */
#define R_CB_OFF	(3*(MAXJSAMPLE+1))
#define G_CB_OFF	(4*(MAXJSAMPLE+1))
#define B_CB_OFF	(5*(MAXJSAMPLE+1))
#define R_CR_OFF	B_CB_OFF		/* B=>Cb, R=>Cr are the same */
#define G_CR_OFF	(6*(MAXJSAMPLE+1))
#define B_CR_OFF	(7*(MAXJSAMPLE+1))
#define TABLE_SIZE	(8*(MAXJSAMPLE+1))


/*
 * Initialize for RGB->YCC colorspace conversion.
 */

METHODDEF(void)
rgb_ycc_start (j_compress_ptr cinfo)
{
  my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
  INT32 * rgb_ycc_tab;
  INT32 i;

  /* Allocate and fill in the conversion tables. */
  cconvert->rgb_ycc_tab = rgb_ycc_tab = (INT32 *)
    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
				(TABLE_SIZE * SIZEOF(INT32)));

  for (i = 0; i <= MAXJSAMPLE; i++) {
    rgb_ycc_tab[i+R_Y_OFF] = FIX(0.29900) * i;
    rgb_ycc_tab[i+G_Y_OFF] = FIX(0.58700) * i;
    rgb_ycc_tab[i+B_Y_OFF] = FIX(0.11400) * i     + ONE_HALF;
    rgb_ycc_tab[i+R_CB_OFF] = (-FIX(0.16874)) * i;
    rgb_ycc_tab[i+G_CB_OFF] = (-FIX(0.33126)) * i;
    /* We use a rounding fudge-factor of 0.5-epsilon for Cb and Cr.
     * This ensures that the maximum output will round to MAXJSAMPLE
     * not MAXJSAMPLE+1, and thus that we don't have to range-limit.
     */
    rgb_ycc_tab[i+B_CB_OFF] = FIX(0.50000) * i    + CBCR_OFFSET + ONE_HALF-1;
/*  B=>Cb and R=>Cr tables are the same
    rgb_ycc_tab[i+R_CR_OFF] = FIX(0.50000) * i    + CBCR_OFFSET + ONE_HALF-1;
*/
    rgb_ycc_tab[i+G_CR_OFF] = (-FIX(0.41869)) * i;
    rgb_ycc_tab[i+B_CR_OFF] = (-FIX(0.08131)) * i;
  }
}


/*
 * Convert some rows of samples to the JPEG colorspace.
 *
 * Note that we change from the application's interleaved-pixel format
 * to our internal noninterleaved, one-plane-per-component format.
 * The input buffer is therefore three times as wide as the output buffer.
 *
 * A starting row offset is provided only for the output buffer.  The caller
 * can easily adjust the passed input_buf value to accommodate any row
 * offset required on that side.
 */

METHODDEF(void)
rgb_ycc_convert (j_compress_ptr cinfo,
		 JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
		 JDIMENSION output_row, int num_rows)
{
  my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
  register int r, g, b;
  register INT32 * ctab = cconvert->rgb_ycc_tab;
  register JSAMPROW inptr;
  register JSAMPROW outptr0, outptr1, outptr2;
  register JDIMENSION col;
  JDIMENSION num_cols = cinfo->image_width;

  while (--num_rows >= 0) {
    inptr = *input_buf++;
    outptr0 = output_buf[0][output_row];
    outptr1 = output_buf[1][output_row];
    outptr2 = output_buf[2][output_row];
    output_row++;
    for (col = 0; col < num_cols; col++) {
      r = GETJSAMPLE(inptr[RGB_RED]);
      g = GETJSAMPLE(inptr[RGB_GREEN]);
      b = GETJSAMPLE(inptr[RGB_BLUE]);
      inptr += RGB_PIXELSIZE;
      /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
       * must be too; we do not need an explicit range-limiting operation.
       * Hence the value being shifted is never negative, and we don't
       * need the general RIGHT_SHIFT macro.
       */
      /* Y */
      outptr0[col] = (JSAMPLE)
		((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
		 >> SCALEBITS);
      /* Cb */
      outptr1[col] = (JSAMPLE)
		((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF])
		 >> SCALEBITS);
      /* Cr */
      outptr2[col] = (JSAMPLE)
		((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF])
		 >> SCALEBITS);
    }
  }
}


/**************** Cases other than RGB -> YCbCr **************/


/*
 * Convert some rows of samples to the JPEG colorspace.
 * This version handles RGB->grayscale conversion, which is the same
 * as the RGB->Y portion of RGB->YCbCr.
 * We assume rgb_ycc_start has been called (we only use the Y tables).
 */

METHODDEF(void)
rgb_gray_convert (j_compress_ptr cinfo,
		  JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
		  JDIMENSION output_row, int num_rows)
{
  my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
  register int r, g, b;
  register INT32 * ctab = cconvert->rgb_ycc_tab;
  register JSAMPROW inptr;
  register JSAMPROW outptr;
  register JDIMENSION col;
  JDIMENSION num_cols = cinfo->image_width;

  while (--num_rows >= 0) {
    inptr = *input_buf++;
    outptr = output_buf[0][output_row];
    output_row++;
    for (col = 0; col < num_cols; col++) {
      r = GETJSAMPLE(inptr[RGB_RED]);
      g = GETJSAMPLE(inptr[RGB_GREEN]);
      b = GETJSAMPLE(inptr[RGB_BLUE]);
      inptr += RGB_PIXELSIZE;
      /* Y */
      outptr[col] = (JSAMPLE)
		((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
		 >> SCALEBITS);
    }
  }
}

#ifdef NIFTY

METHODDEF(void)
rgba_ycbcra_convert (j_compress_ptr cinfo,
		   JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
		   JDIMENSION output_row, int num_rows)
{
  my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
  register int r, g, b;
  register INT32 * ctab = cconvert->rgb_ycc_tab;
  register JSAMPROW inptr;
  register JSAMPROW outptr0, outptr1, outptr2, outptr3;
  register JDIMENSION col;
  JDIMENSION num_cols = cinfo->image_width;
 
  while (--num_rows >= 0) {
    inptr = *input_buf++;
    outptr0 = output_buf[0][output_row];
    outptr1 = output_buf[1][output_row];
    outptr2 = output_buf[2][output_row];
    outptr3 = output_buf[3][output_row];
    output_row++;
    for (col = 0; col < num_cols; col++) {
      r = GETJSAMPLE(inptr[0]);
      g = GETJSAMPLE(inptr[1]);
      b = GETJSAMPLE(inptr[2]);
      /* Alpha passes through as-is */
      outptr3[col] = inptr[3];  /* don't need GETJSAMPLE here */
      inptr += 4;
      /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
       * must be too; we do not need an explicit range-limiting operation.
       * Hence the value being shifted is never negative, and we don't
       * need the general RIGHT_SHIFT macro.
       */
      /* Y */
      outptr0[col] = (JSAMPLE)
                ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
                 >> SCALEBITS);
      /* Cb */
      outptr1[col] = (JSAMPLE)
                ((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF])
                 >> SCALEBITS);
      /* Cr */
      outptr2[col] = (JSAMPLE)
                ((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF])
                 >> SCALEBITS);
    }
  }
}


/* the following version contains a bug which has been
   given an eternal life via the FlashPix spec.
*/
METHODDEF(void)
rgba_ycbcra_legacy_convert (j_compress_ptr cinfo,
		   JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
		   JDIMENSION output_row, int num_rows)
{
  my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
  register int r, g, b;
  register INT32 * ctab = cconvert->rgb_ycc_tab;
  register JSAMPROW inptr;
  register JSAMPROW outptr0, outptr1, outptr2, outptr3;
  register JDIMENSION col;
  JDIMENSION num_cols = cinfo->image_width;
 
  while (--num_rows >= 0) {
    inptr = *input_buf++;
    outptr0 = output_buf[0][output_row];
    outptr1 = output_buf[1][output_row];
    outptr2 = output_buf[2][output_row];
    outptr3 = output_buf[3][output_row];
    output_row++;
    for (col = 0; col < num_cols; col++) {
      r = MAXJSAMPLE - GETJSAMPLE(inptr[0]);
      g = MAXJSAMPLE - GETJSAMPLE(inptr[1]);
      b = MAXJSAMPLE - GETJSAMPLE(inptr[2]);
      /* Alpha passes through as-is */
      outptr3[col] = inptr[3];  /* don't need GETJSAMPLE here */
      inptr += 4;
      /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
       * must be too; we do not need an explicit range-limiting operation.
       * Hence the value being shifted is never negative, and we don't
       * need the general RIGHT_SHIFT macro.
       */
      /* Y */
      outptr0[col] = (JSAMPLE)
                ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
                 >> SCALEBITS);
      /* Cb */
      outptr1[col] = (JSAMPLE)
                ((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF])
                 >> SCALEBITS);
      /* Cr */
      outptr2[col] = (JSAMPLE)
                ((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF])
                 >> SCALEBITS);
    }
  }
}


#endif

/*
 * Convert some rows of samples to the JPEG colorspace.
 * This version handles Adobe-style CMYK->YCCK conversion,