mmsfb_blit_blend_coloralpha_argb4444_to_argb4444.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_ARGB4444__

#include "mmstools/mmstools.h"

void mmsfb_blit_blend_coloralpha_argb4444_to_argb4444(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_blend_argb4444_to_argb4444(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 blend coloralpha ARGB4444 to ARGB4444.\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 short int *src = (unsigned short int *)src_planes->ptr;
    int src_pitch = src_planes->pitch;

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

    // prepare...
    int src_pitch_pix = src_pitch >> 1;
    int dst_pitch_pix = dst_pitch >> 1;
    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 short int OLDDST = (*dst) + 1;
    unsigned short int OLDSRC  = (*src) + 1;
    unsigned short 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 short int d;

    register unsigned int ALPHA = alpha;
    ALPHA++;

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

            // is the source alpha channel 0x00 or 0x0f?
            register unsigned int A = SRC >> 12;
            if (A) {
                // source alpha is > 0x00 and <= 0x0f
                register unsigned short 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 and multiply it with given ALPHA
                A = (ALPHA * A) >> 4;
                unsigned int sr = (ALPHA * (SRC & 0x0f00)) >> 12;
                unsigned int sg = (ALPHA * (SRC & 0x00f0)) >> 8;
                unsigned int sb = (ALPHA * (SRC & 0x000f)) >> 4;
                register unsigned int SA= 0x100 - A;

                unsigned int a = DST >> 12;
                unsigned int r = DST & 0x0f00;
                unsigned int g = DST & 0x00f0;
                unsigned int b = DST & 0x000f;

                // invert src alpha
                a = (SA * a) >> 4;
                r = (SA * r) >> 12;
                g = (SA * g) >> 8;
                b = (SA * b) >> 4;

                // add src to dst
                a += A;
                r += sr;
                g += sg;
                b += sb;
                d =   ((a >> 8) ? 0xf000 : ((a >> 4) << 12))
                    | ((r >> 8) ? 0x0f00 : ((r >> 4) << 8))
                    | ((g >> 8) ? 0xf0   : ((g >> 4) << 4))
                    | ((b >> 8) ? 0x0f   :  (b >> 4));
                *dst = d;
            }

            dst++;
            src++;
        }

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

#endif

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