ccvt_c.c

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/*  CCVT: ColourConVerT: simple library for converting colourspaces
    Copyright (C) 2002 Nemosoft Unv.

    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

    For questions, remarks, patches, etc. for this program, the author can be
    reached at nemosoft@smcc.demon.nl.
*/

#include "ccvt.h"

#define PUSH_RGB24      1
#define PUSH_BGR24      2
#define PUSH_RGB32      3
#define PUSH_BGR32      4


/* This is a simplistic approach. */
static void ccvt_420p(int width, int height, const unsigned char *src, unsigned char *dst, int push)
{
        int line, col, linewidth;
        int y, u, v, yy, vr, ug, vg, ub;
        int r, g, b;
        const unsigned char *py, *pu, *pv;

        linewidth = width >> 1;
        py = src;
        pu = py + (width * height);
        pv = pu + (width * height) / 4;

        y = *py++;
        yy = y << 8;
        u = *pu - 128;
        ug =   88 * u;
        ub =  454 * u;
        v = *pv - 128;
        vg =  183 * v;
        vr =  359 * v;

        for (line = 0; line < height; line++) {
                for (col = 0; col < width; col++) {
                        r = (yy +      vr) >> 8;
                        g = (yy - ug - vg) >> 8;
                        b = (yy + ub     ) >> 8;

                        if (r < 0)   r = 0;
                        if (r > 255) r = 255;
                        if (g < 0)   g = 0;
                        if (g > 255) g = 255;
                        if (b < 0)   b = 0;
                        if (b > 255) b = 255;

                        switch(push) {
                        case PUSH_RGB24:
                                *dst++ = r;
                                *dst++ = g;
                                *dst++ = b;
                                break;

                        case PUSH_BGR24:
                                *dst++ = b;
                                *dst++ = g;
                                *dst++ = r;
                                break;

                        case PUSH_RGB32:
                                *dst++ = r;
                                *dst++ = g;
                                *dst++ = b;
                                *dst++ = 0;
                                break;

                        case PUSH_BGR32:
                                *dst++ = b;
                                *dst++ = g;
                                *dst++ = r;
                                *dst++ = 0;
                                break;
                        }

                        y = *py++;
                        yy = y << 8;
                        if (col & 1) {
                                pu++;
                                pv++;

                                u = *pu - 128;
                                ug =   88 * u;
                                ub =  454 * u;
                                v = *pv - 128;
                                vg =  183 * v;
                                vr =  359 * v;
                        }
                } /* ..for col */
                if ((line & 1) == 0) { // even line: rewind
                        pu -= linewidth;
                        pv -= linewidth;
                }
        } /* ..for line */
}

void ccvt_420p_rgb24(int width, int height, const void *src, void *dst)
{
        ccvt_420p(width, height, (const unsigned char *)src, (unsigned char *)dst, PUSH_RGB24);
}

void ccvt_420p_bgr24(int width, int height, const void *src, void *dst)
{
        ccvt_420p(width, height, (const unsigned char *)src, (unsigned char *)dst, PUSH_BGR24);
}

void ccvt_420p_rgb32(int width, int height, const void *src, void *dst)
{
        ccvt_420p(width, height, (const unsigned char *)src, (unsigned char *)dst, PUSH_RGB32);
}

void ccvt_420p_bgr32(int width, int height, const void *src, void *dst)
{
        ccvt_420p(width, height, (const unsigned char *)src, (unsigned char *)dst, PUSH_BGR32);
}