mmsfb_blit_coloralpha_rgb32_to_rgb32.cpp

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/***************************************************************************
 *   Copyright (C) 2005-2007 Stefan Schwarzer, Jens Schneider,             *
 *                           Matthias Hardt, Guido Madaus                  *
 *                                                                         *
 *   Copyright (C) 2007-2008 BerLinux Solutions GbR                        *
 *                           Stefan Schwarzer & Guido Madaus               *
 *                                                                         *
 *   Copyright (C) 2009-2012 BerLinux Solutions GmbH                       *
 *                                                                         *
 *   Authors:                                                              *
 *      Stefan Schwarzer   <stefan.schwarzer@diskohq.org>,                 *
 *      Matthias Hardt     <matthias.hardt@diskohq.org>,                   *
 *      Jens Schneider     <jens.schneider@diskohq.org>,                   *
 *      Guido Madaus       <guido.madaus@diskohq.org>,                     *
 *      Patrick Helterhoff <patrick.helterhoff@diskohq.org>,               *
 *      René Bählkow       <rene.baehlkow@diskohq.org>                     *
 *                                                                         *
 *   This library is free software; you can redistribute it and/or         *
 *   modify it under the terms of the GNU Lesser General Public            *
 *   License version 2.1 as published by the Free Software Foundation.     *
 *                                                                         *
 *   This library 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     *
 *   Lesser General Public License for more details.                       *
 *                                                                         *
 *   You should have received a copy of the GNU Lesser General Public      *
 *   License along with this library; if not, write to the                 *
 *   Free Software Foundation, Inc.,                                       *
 *   51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA            *
 **************************************************************************/

#include "mmsgui/fb/mmsfbconv.h"

#ifdef __HAVE_PF_RGB32__

#include "mmstools/mmstools.h"

void mmsfb_blit_coloralpha_rgb32_to_rgb32(MMSFBSurfacePlanes *src_planes, int src_height, int sx, int sy, int sw, int sh,
                                          MMSFBSurfacePlanes *dst_planes, int dst_height, int dx, int dy,
                                          unsigned char alpha) {
    // check for full alpha value
    if (alpha == 0xff) {
        // max alpha is specified, so i can ignore it and use faster routine
        mmsfb_blit_rgb32_to_rgb32(src_planes, src_height, sx, sy, sw, sh,
                                  dst_planes, dst_height, dx, dy);
        return;
    }

    // first time?
    static bool firsttime = true;
    if (firsttime) {
        printf("DISKO: Using accelerated blit coloralpha RGB32 to RGB32.\n");
        firsttime = false;
    }

    // something to do?
    if (!alpha)
        // source should blitted full transparent, so leave destination as is
        return;

    // get the first source ptr/pitch
    unsigned int *src = (unsigned int *)src_planes->ptr;
    int src_pitch = src_planes->pitch;

    // get the first destination ptr/pitch
    unsigned int *dst = (unsigned int *)dst_planes->ptr;
    int dst_pitch = dst_planes->pitch;

    // prepare...
    int src_pitch_pix = src_pitch >> 2;
    int dst_pitch_pix = dst_pitch >> 2;
    src+= sx + sy * src_pitch_pix;
    dst+= dx + dy * dst_pitch_pix;

    // check the surface range
    if (dst_pitch_pix - dx < sw - sx)
        sw = dst_pitch_pix - dx - sx;
    if (dst_height - dy < sh - sy)
        sh = dst_height - dy - sy;
    if ((sw <= 0)||(sh <= 0))
        return;

    unsigned int OLDDST = (*dst) + 1;
    unsigned int OLDSRC  = (*src) + 1;
    unsigned int *src_end = src + src_pitch_pix * sh;
    int src_pitch_diff = src_pitch_pix - sw;
    int dst_pitch_diff = dst_pitch_pix - sw;
    register unsigned int d;

    register unsigned int A = alpha;
    register unsigned int SA= 0x100 - A;

    // for all lines
    while (src < src_end) {
        // for all pixels in the line
        unsigned int *line_end = src + sw;
        while (src < line_end) {
            // load pixel from memory and check if the previous pixel is the same
            register unsigned int SRC = *src;
            register unsigned int DST = *dst;

            if ((DST==OLDDST)&&(SRC==OLDSRC)) {
                // same pixel, use the previous value
                *dst = d;
                dst++;
                src++;
                continue;
            }
            OLDDST = DST;
            OLDSRC = SRC;

            // load source pixel
            unsigned int sr = (SRC << 8) >> 24;
            unsigned int sg = (SRC << 16) >> 24;
            unsigned int sb = SRC & 0xff;

            // load destination pixel
            unsigned int r = (DST << 8) >> 24;
            unsigned int g = (DST << 16) >> 24;
            unsigned int b = DST & 0xff;

            // invert src alpha
            r = (SA * r) >> 8;
            g = (SA * g) >> 8;
            b = (SA * b) >> 8;

            // add src to dst
            r += (A * sr) >> 8;
            g += (A * sg) >> 8;
            b += (A * sb) >> 8;
            d =   0xff000000
                | ((r >> 8) ? 0xff0000   : (r << 16))
                | ((g >> 8) ? 0xff00     : (g << 8))
                | ((b >> 8) ? 0xff       :  b);
            *dst = d;

            dst++;
            src++;
        }

        // go to the next line
        src+= src_pitch_diff;
        dst+= dst_pitch_diff;
    }
}

#endif

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