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qimagescale.cpp

/****************************************************************************
**
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**
** This file is part of the QtGui module of the Qt Toolkit.
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#include <private/qimagescale_p.h>
#include <private/qdrawhelper_p.h>

#include "qimage.h"
#include "qcolor.h"

namespace QImageScale {
    struct QImageScaleInfo;
}

typedef void (*qt_qimageScaleFunc)(QImageScale::QImageScaleInfo *isi, unsigned int *dest,
                                   int dxx, int dyy, int dx, int dy, int dw,
                                   int dh, int dow, int sow);

static void qt_qimageScaleAARGB(QImageScale::QImageScaleInfo *isi, unsigned int *dest,
                         int dxx, int dyy, int dx, int dy, int dw,
                         int dh, int dow, int sow);

static void qt_qimageScaleAARGBA(QImageScale::QImageScaleInfo *isi, unsigned int *dest,
                          int dxx, int dyy, int dx, int dy, int dw,
                          int dh, int dow, int sow);

qt_qimageScaleFunc qt_qimageScaleArgb = qt_qimageScaleAARGBA;
qt_qimageScaleFunc qt_qimageScaleRgb  = qt_qimageScaleAARGB;


/*
 * Copyright (C) 2004, 2005 Daniel M. Duley
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

/* OTHER CREDITS:
 *
 * This is the normal smoothscale method, based on Imlib2's smoothscale.
 *
 * Originally I took the algorithm used in NetPBM and Qt and added MMX/3dnow
 * optimizations. It ran in about 1/2 the time as Qt. Then I ported Imlib's
 * C algorithm and it ran at about the same speed as my MMX optimized one...
 * Finally I ported Imlib's MMX version and it ran in less than half the
 * time as my MMX algorithm, (taking only a quarter of the time Qt does).
 * After further optimization it seems to run at around 1/6th.
 *
 * Changes include formatting, namespaces and other C++'ings, removal of old
 * #ifdef'ed code, and removal of unneeded border calculation code.
 *
 * Imlib2 is (C) Carsten Haitzler and various contributors. The MMX code
 * is by Willem Monsuwe <willem@stack.nl>. All other modifications are
 * (C) Daniel M. Duley.
 */


namespace QImageScale {
    struct QImageScaleInfo {
        int *xpoints;
        unsigned int **ypoints;
        int *xapoints, *yapoints;
        int xup_yup;
    };

    unsigned int** qimageCalcYPoints(unsigned int *src, int sw, int sh,
                                     int dh);
    int* qimageCalcXPoints(int sw, int dw);
    int* qimageCalcApoints(int s, int d, int up);
    QImageScaleInfo* qimageFreeScaleInfo(QImageScaleInfo *isi);
    QImageScaleInfo *qimageCalcScaleInfo(const QImage &img, int sw, int sh,
                                         int dw, int dh, char aa);
}

using namespace QImageScale;

//
// Code ported from Imlib...
//

// FIXME: replace with qRed, etc... These work on pointers to pixels, not
// pixel values
#define A_VAL(p) (qAlpha(*p))
#define R_VAL(p) (qRed(*p))
#define G_VAL(p) (qGreen(*p))
#define B_VAL(p) (qBlue(*p))

#define INV_XAP                   (256 - xapoints[x])
#define XAP                       (xapoints[x])
#define INV_YAP                   (256 - yapoints[dyy + y])
#define YAP                       (yapoints[dyy + y])

unsigned int** QImageScale::qimageCalcYPoints(unsigned int *src,
                                              int sw, int sh, int dh)
{
    unsigned int **p;
    int i, j = 0;
    int val, inc, rv = 0;

    if(dh < 0){
        dh = -dh;
        rv = 1;
    }
    p = new unsigned int* [dh+1];

    int up = abs(dh) >= sh;
    val = up ? 0x8000 * sh / dh - 0x8000 : 0;
    inc = (sh << 16) / dh;
    for(i = 0; i < dh; i++){
        p[j++] = src + qMax(0, val >> 16) * sw;
        val += inc;
    }
    if(rv){
        for(i = dh / 2; --i >= 0; ){
            unsigned int *tmp = p[i];
            p[i] = p[dh - i - 1];
            p[dh - i - 1] = tmp;
        }
    }
    return(p);
}

int* QImageScale::qimageCalcXPoints(int sw, int dw)
{
    int *p, i, j = 0;
    int val, inc, rv = 0;

    if(dw < 0){
        dw = -dw;
        rv = 1;
    }
    p = new int[dw+1];

    int up = abs(dw) >= sw;
    val = up ? 0x8000 * sw / dw - 0x8000 : 0;
    inc = (sw << 16) / dw;
    for(i = 0; i < dw; i++){
        p[j++] = qMax(0, val >> 16);
        val += inc;
    }

    if(rv){
        for(i = dw / 2; --i >= 0; ){
            int tmp = p[i];
            p[i] = p[dw - i - 1];
            p[dw - i - 1] = tmp;
        }
    }
   return(p);
}

int* QImageScale::qimageCalcApoints(int s, int d, int up)
{
    int *p, i, j = 0, rv = 0;

    if(d < 0){
        rv = 1;
        d = -d;
    }
    p = new int[d];

    /* scaling up */
    if(up){
        int val, inc;

        val = 0x8000 * s / d - 0x8000;
        inc = (s << 16) / d;
        for(i = 0; i < d; i++){
            int pos = val >> 16;
            if (pos < 0)
                p[j++] = 0;
            else if (pos >= (s - 1))
                p[j++] = 0;
            else
                p[j++] = (val >> 8) - ((val >> 8) & 0xffffff00);
            val += inc;
        }
    }
    /* scaling down */
    else{
        int val, inc, ap, Cp;
        val = 0;
        inc = (s << 16) / d;
        Cp = ((d << 14) / s) + 1;
        for(i = 0; i < d; i++){
            ap = ((0x100 - ((val >> 8) & 0xff)) * Cp) >> 8;
            p[j] = ap | (Cp << 16);
            j++;
            val += inc;
        }
    }
    if(rv){
        int tmp;
        for(i = d / 2; --i >= 0; ){
            tmp = p[i];
            p[i] = p[d - i - 1];
            p[d - i - 1] = tmp;
        }
    }
    return(p);
}

QImageScaleInfo* QImageScale::qimageFreeScaleInfo(QImageScaleInfo *isi)
{
    if(isi){
        delete[] isi->xpoints;
        delete[] isi->ypoints;
        delete[] isi->xapoints;
        delete[] isi->yapoints;
        delete isi;
    }
    return(NULL);
}

QImageScaleInfo* QImageScale::qimageCalcScaleInfo(const QImage &img,
                                                  int sw, int sh,
                                                  int dw, int dh, char aa)
{
    QImageScaleInfo *isi;
    int scw, sch;

    scw = dw * img.width() / sw;
    sch = dh * img.height() / sh;

    isi = new QImageScaleInfo;
    if(!isi)
        return(NULL);
    memset(isi, 0, sizeof(QImageScaleInfo));

    isi->xup_yup = (abs(dw) >= sw) + ((abs(dh) >= sh) << 1);

    isi->xpoints = qimageCalcXPoints(img.width(), scw);
    if(!isi->xpoints)
        return(qimageFreeScaleInfo(isi));
    isi->ypoints = qimageCalcYPoints((unsigned int *)img.scanLine(0),
                                     img.width(), img.height(), sch);
    if (!isi->ypoints)
        return(qimageFreeScaleInfo(isi));
    if(aa){
        isi->xapoints = qimageCalcApoints(img.width(), scw, isi->xup_yup & 1);
        if(!isi->xapoints)
            return(qimageFreeScaleInfo(isi));
        isi->yapoints = qimageCalcApoints(img.height(), sch, isi->xup_yup & 2);
        if(!isi->yapoints)
            return(qimageFreeScaleInfo(isi));
    }
    return(isi);
}

/* FIXME: NEED to optimise ScaleAARGBA - currently its "ok" but needs work*/

/* scale by area sampling */
static void qt_qimageScaleAARGBA(QImageScaleInfo *isi, unsigned int *dest,
                                 int dxx, int dyy, int dx, int dy, int dw,
                                 int dh, int dow, int sow)
{
    unsigned int *sptr, *dptr;
    int x, y, end;
    unsigned int **ypoints = isi->ypoints;
    int *xpoints = isi->xpoints;
    int *xapoints = isi->xapoints;
    int *yapoints = isi->yapoints;

    end = dxx + dw;
    /* scaling up both ways */
    if(isi->xup_yup == 3){
        /* go through every scanline in the output buffer */
        for(y = 0; y < dh; y++){
            /* calculate the source line we'll scan from */
            dptr = dest + dx + ((y + dy) * dow);
            sptr = ypoints[dyy + y];
            if(YAP > 0){
                for(x = dxx; x < end; x++){
                    int r, g, b, a;
                    int rr, gg, bb, aa;
                    unsigned int *pix;

                    if(XAP > 0){
                        pix = ypoints[dyy + y] + xpoints[x];
                        r = R_VAL(pix) * INV_XAP;
                        g = G_VAL(pix) * INV_XAP;
                        b = B_VAL(pix) * INV_XAP;
                        a = A_VAL(pix) * INV_XAP;
                        pix++;
                        r += R_VAL(pix) * XAP;
                        g += G_VAL(pix) * XAP;
                        b += B_VAL(pix) * XAP;
                        a += A_VAL(pix) * XAP;
                        pix += sow;
                        rr = R_VAL(pix) * XAP;
                        gg = G_VAL(pix) * XAP;
                        bb = B_VAL(pix) * XAP;
                        aa = A_VAL(pix) * XAP;
                        pix--;
                        rr += R_VAL(pix) * INV_XAP;
                        gg += G_VAL(pix) * INV_XAP;
                        bb += B_VAL(pix) * INV_XAP;
                        aa += A_VAL(pix) * INV_XAP;
                        r = ((rr * YAP) + (r * INV_YAP)) >> 16;
                        g = ((gg * YAP) + (g * INV_YAP)) >> 16;
                        b = ((bb * YAP) + (b * INV_YAP)) >> 16;
                        a = ((aa * YAP) + (a * INV_YAP)) >> 16;
                        *dptr++ = qRgba(r, g, b, a);
                    }
                    else{
                        pix = ypoints[dyy + y] + xpoints[x];
                        r = R_VAL(pix) * INV_YAP;
                        g = G_VAL(pix) * INV_YAP;
                        b = B_VAL(pix) * INV_YAP;
                        a = A_VAL(pix) * INV_YAP;
                        pix += sow;
                        r += R_VAL(pix) * YAP;
                        g += G_VAL(pix) * YAP;
                        b += B_VAL(pix) * YAP;
                        a += A_VAL(pix) * YAP;
                        r >>= 8;
                        g >>= 8;
                        b >>= 8;
                        a >>= 8;
                        *dptr++ = qRgba(r, g, b, a);
                    }
                }
            }
            else{
                for(x = dxx; x < end; x++){
                    int r, g, b, a;
                    unsigned int *pix;

                    if(XAP > 0){
                        pix = ypoints[dyy + y] + xpoints[x];
                        r = R_VAL(pix) * INV_XAP;
                        g = G_VAL(pix) * INV_XAP;
                        b = B_VAL(pix) * INV_XAP;
                        a = A_VAL(pix) * INV_XAP;
                        pix++;
                        r += R_VAL(pix) * XAP;
                        g += G_VAL(pix) * XAP;
                        b += B_VAL(pix) * XAP;
                        a += A_VAL(pix) * XAP;
                        r >>= 8;
                        g >>= 8;
                        b >>= 8;
                        a >>= 8;
                        *dptr++ = qRgba(r, g, b, a);
                    }
                    else
                        *dptr++ = sptr[xpoints[x] ];
                }
            }
        }
    }
    /* if we're scaling down vertically */
    else if(isi->xup_yup == 1){
        /*\ 'Correct' version, with math units prepared for MMXification \*/
        int Cy, j;
        unsigned int *pix;
        int r, g, b, a, rr, gg, bb, aa;
        int yap;

        /* go through every scanline in the output buffer */
        for(y = 0; y < dh; y++){
            Cy = YAP >> 16;
            yap = YAP & 0xffff;

            dptr = dest + dx + ((y + dy) * dow);
            for(x = dxx; x < end; x++){
                pix = ypoints[dyy + y] + xpoints[x];
                r = (R_VAL(pix) * yap) >> 10;
                g = (G_VAL(pix) * yap) >> 10;
                b = (B_VAL(pix) * yap) >> 10;
                a = (A_VAL(pix) * yap) >> 10;
                for(j = (1 << 14) - yap; j > Cy; j -= Cy){
                    pix += sow;
                    r += (R_VAL(pix) * Cy) >> 10;
                    g += (G_VAL(pix) * Cy) >> 10;
                    b += (B_VAL(pix) * Cy) >> 10;
                    a += (A_VAL(pix) * Cy) >> 10;
                }
                if(j > 0){
                    pix += sow;
                    r += (R_VAL(pix) * j) >> 10;
                    g += (G_VAL(pix) * j) >> 10;
                    b += (B_VAL(pix) * j) >> 10;
                    a += (A_VAL(pix) * j) >> 10;
                }
                if(XAP > 0){
                    pix = ypoints[dyy + y] + xpoints[x] + 1;
                    rr = (R_VAL(pix) * yap) >> 10;
                    gg = (G_VAL(pix) * yap) >> 10;
                    bb = (B_VAL(pix) * yap) >> 10;
                    aa = (A_VAL(pix) * yap) >> 10;
                    for(j = (1 << 14) - yap; j > Cy; j -= Cy){
                        pix += sow;
                        rr += (R_VAL(pix) * Cy) >> 10;
                        gg += (G_VAL(pix) * Cy) >> 10;
                        bb += (B_VAL(pix) * Cy) >> 10;
                        aa += (A_VAL(pix) * Cy) >> 10;
                    }
                    if(j > 0){
                        pix += sow;
                        rr += (R_VAL(pix) * j) >> 10;
                        gg += (G_VAL(pix) * j) >> 10;
                        bb += (B_VAL(pix) * j) >> 10;
                        aa += (A_VAL(pix) * j) >> 10;
                    }
                    r = r * INV_XAP;
                    g = g * INV_XAP;
                    b = b * INV_XAP;
                    a = a * INV_XAP;
                    r = (r + ((rr * XAP))) >> 12;
                    g = (g + ((gg * XAP))) >> 12;
                    b = (b + ((bb * XAP))) >> 12;
                    a = (a + ((aa * XAP))) >> 12;
                }
                else{
                    r >>= 4;
                    g >>= 4;
                    b >>= 4;
                    a >>= 4;
                }
                *dptr = qRgba(r, g, b, a);
                dptr++;
            }
        }
    }
    /* if we're scaling down horizontally */
    else if(isi->xup_yup == 2){
        /*\ 'Correct' version, with math units prepared for MMXification \*/
        int Cx, j;
        unsigned int *pix;
        int r, g, b, a, rr, gg, bb, aa;
        int xap;

        /* go through every scanline in the output buffer */
        for(y = 0; y < dh; y++){
            dptr = dest + dx + ((y + dy) * dow);
            for(x = dxx; x < end; x++){
                Cx = XAP >> 16;
                xap = XAP & 0xffff;

                pix = ypoints[dyy + y] + xpoints[x];
                r = (R_VAL(pix) * xap) >> 10;
                g = (G_VAL(pix) * xap) >> 10;
                b = (B_VAL(pix) * xap) >> 10;
                a = (A_VAL(pix) * xap) >> 10;
                for(j = (1 << 14) - xap; j > Cx; j -= Cx){
                    pix++;
                    r += (R_VAL(pix) * Cx) >> 10;
                    g += (G_VAL(pix) * Cx) >> 10;
                    b += (B_VAL(pix) * Cx) >> 10;
                    a += (A_VAL(pix) * Cx) >> 10;
                }
                if(j > 0){
                    pix++;
                    r += (R_VAL(pix) * j) >> 10;
                    g += (G_VAL(pix) * j) >> 10;
                    b += (B_VAL(pix) * j) >> 10;
                    a += (A_VAL(pix) * j) >> 10;
                }
                if(YAP > 0){
                    pix = ypoints[dyy + y] + xpoints[x] + sow;
                    rr = (R_VAL(pix) * xap) >> 10;
                    gg = (G_VAL(pix) * xap) >> 10;
                    bb = (B_VAL(pix) * xap) >> 10;
                    aa = (A_VAL(pix) * xap) >> 10;
                    for(j = (1 << 14) - xap; j > Cx; j -= Cx){
                        pix++;
                        rr += (R_VAL(pix) * Cx) >> 10;
                        gg += (G_VAL(pix) * Cx) >> 10;
                        bb += (B_VAL(pix) * Cx) >> 10;
                        aa += (A_VAL(pix) * Cx) >> 10;
                    }
                    if(j > 0){
                        pix++;
                        rr += (R_VAL(pix) * j) >> 10;
                        gg += (G_VAL(pix) * j) >> 10;
                        bb += (B_VAL(pix) * j) >> 10;
                        aa += (A_VAL(pix) * j) >> 10;
                    }
                    r = r * INV_YAP;
                    g = g * INV_YAP;
                    b = b * INV_YAP;
                    a = a * INV_YAP;
                    r = (r + ((rr * YAP))) >> 12;
                    g = (g + ((gg * YAP))) >> 12;
                    b = (b + ((bb * YAP))) >> 12;
                    a = (a + ((aa * YAP))) >> 12;
                }
                else{
                    r >>= 4;
                    g >>= 4;
                    b >>= 4;
                    a >>= 4;
                }
                *dptr = qRgba(r, g, b, a);
                dptr++;
            }
        }
    }
    /* if we're scaling down horizontally & vertically */
    else{
        /*\ 'Correct' version, with math units prepared for MMXification:
         |*|  The operation 'b = (b * c) >> 16' translates to pmulhw,
         |*|  so the operation 'b = (b * c) >> d' would translate to
         |*|  psllw (16 - d), %mmb; pmulh %mmc, %mmb
         \*/
        int Cx, Cy, i, j;
        unsigned int *pix;
        int a, r, g, b, ax, rx, gx, bx;
        int xap, yap;

        for(y = 0; y < dh; y++){
            Cy = YAP >> 16;
            yap = YAP & 0xffff;

            dptr = dest + dx + ((y + dy) * dow);
            for(x = dxx; x < end; x++){
                Cx = XAP >> 16;
                xap = XAP & 0xffff;

                sptr = ypoints[dyy + y] + xpoints[x];
                pix = sptr;
                sptr += sow;
                rx = (R_VAL(pix) * xap) >> 9;
                gx = (G_VAL(pix) * xap) >> 9;
                bx = (B_VAL(pix) * xap) >> 9;
                ax = (A_VAL(pix) * xap) >> 9;
                pix++;
                for(i = (1 << 14) - xap; i > Cx; i -= Cx){
                    rx += (R_VAL(pix) * Cx) >> 9;
                    gx += (G_VAL(pix) * Cx) >> 9;
                    bx += (B_VAL(pix) * Cx) >> 9;
                    ax += (A_VAL(pix) * Cx) >> 9;
                    pix++;
                }
                if(i > 0){
                    rx += (R_VAL(pix) * i) >> 9;
                    gx += (G_VAL(pix) * i) >> 9;
                    bx += (B_VAL(pix) * i) >> 9;
                    ax += (A_VAL(pix) * i) >> 9;
                }

                r = (rx * yap) >> 14;
                g = (gx * yap) >> 14;
                b = (bx * yap) >> 14;
                a = (ax * yap) >> 14;

                for(j = (1 << 14) - yap; j > Cy; j -= Cy){
                    pix = sptr;
                    sptr += sow;
                    rx = (R_VAL(pix) * xap) >> 9;
                    gx = (G_VAL(pix) * xap) >> 9;
                    bx = (B_VAL(pix) * xap) >> 9;
                    ax = (A_VAL(pix) * xap) >> 9;
                    pix++;
                    for(i = (1 << 14) - xap; i > Cx; i -= Cx){
                        rx += (R_VAL(pix) * Cx) >> 9;
                        gx += (G_VAL(pix) * Cx) >> 9;
                        bx += (B_VAL(pix) * Cx) >> 9;
                        ax += (A_VAL(pix) * Cx) >> 9;
                        pix++;
                    }
                    if(i > 0){
                        rx += (R_VAL(pix) * i) >> 9;
                        gx += (G_VAL(pix) * i) >> 9;
                        bx += (B_VAL(pix) * i) >> 9;
                        ax += (A_VAL(pix) * i) >> 9;
                    }

                    r += (rx * Cy) >> 14;
                    g += (gx * Cy) >> 14;
                    b += (bx * Cy) >> 14;
                    a += (ax * Cy) >> 14;
                }
                if(j > 0){
                    pix = sptr;
                    sptr += sow;
                    rx = (R_VAL(pix) * xap) >> 9;
                    gx = (G_VAL(pix) * xap) >> 9;
                    bx = (B_VAL(pix) * xap) >> 9;
                    ax = (A_VAL(pix) * xap) >> 9;
                    pix++;
                    for(i = (1 << 14) - xap; i > Cx; i -= Cx){
                        rx += (R_VAL(pix) * Cx) >> 9;
                        gx += (G_VAL(pix) * Cx) >> 9;
                        bx += (B_VAL(pix) * Cx) >> 9;
                        ax += (A_VAL(pix) * Cx) >> 9;
                        pix++;
                    }
                    if(i > 0){
                        rx += (R_VAL(pix) * i) >> 9;
                        gx += (G_VAL(pix) * i) >> 9;
                        bx += (B_VAL(pix) * i) >> 9;
                        ax += (A_VAL(pix) * i) >> 9;
                    }

                    r += (rx * j) >> 14;
                    g += (gx * j) >> 14;
                    b += (bx * j) >> 14;
                    a += (ax * j) >> 14;
                }

                *dptr = qRgba(r >> 5, g >> 5, b >> 5, a >> 5);
                dptr++;
            }
        }
    }
}

/* scale by area sampling - IGNORE the ALPHA byte*/
static void qt_qimageScaleAARGB(QImageScaleInfo *isi, unsigned int *dest,
                                int dxx, int dyy, int dx, int dy, int dw,
                                int dh, int dow, int sow)
{
    unsigned int *sptr, *dptr;
    int x, y, end;
    unsigned int **ypoints = isi->ypoints;
    int *xpoints = isi->xpoints;
    int *xapoints = isi->xapoints;
    int *yapoints = isi->yapoints;

    end = dxx + dw;
    /* scaling up both ways */
    if(isi->xup_yup == 3){
        /* go through every scanline in the output buffer */
        for(y = 0; y < dh; y++){
            /* calculate the source line we'll scan from */
            dptr = dest + dx + ((y + dy) * dow);
            sptr = ypoints[dyy + y];
            if(YAP > 0){
                for(x = dxx; x < end; x++){
                    int r = 0, g = 0, b = 0;
                    int rr = 0, gg = 0, bb = 0;
                    unsigned int *pix;

                    if(XAP > 0){
                        pix = ypoints[dyy + y] + xpoints[x];
                        r = R_VAL(pix) * INV_XAP;
                        g = G_VAL(pix) * INV_XAP;
                        b = B_VAL(pix) * INV_XAP;
                        pix++;
                        r += R_VAL(pix) * XAP;
                        g += G_VAL(pix) * XAP;
                        b += B_VAL(pix) * XAP;
                        pix += sow;
                        rr = R_VAL(pix) * XAP;
                        gg = G_VAL(pix) * XAP;
                        bb = B_VAL(pix) * XAP;
                        pix --;
                        rr += R_VAL(pix) * INV_XAP;
                        gg += G_VAL(pix) * INV_XAP;
                        bb += B_VAL(pix) * INV_XAP;
                        r = ((rr * YAP) + (r * INV_YAP)) >> 16;
                        g = ((gg * YAP) + (g * INV_YAP)) >> 16;
                        b = ((bb * YAP) + (b * INV_YAP)) >> 16;
                        *dptr++ = qRgba(r, g, b, 0xff);
                    }
                    else{
                        pix = ypoints[dyy + y] + xpoints[x];
                        r = R_VAL(pix) * INV_YAP;
                        g = G_VAL(pix) * INV_YAP;
                        b = B_VAL(pix) * INV_YAP;
                        pix += sow;
                        r += R_VAL(pix) * YAP;
                        g += G_VAL(pix) * YAP;
                        b += B_VAL(pix) * YAP;
                        r >>= 8;
                        g >>= 8;
                        b >>= 8;
                        *dptr++ = qRgba(r, g, b, 0xff);
                    }
                }
            }
            else{
                for(x = dxx; x < end; x++){
                    int r = 0, g = 0, b = 0;
                    unsigned int *pix;

                    if(XAP > 0){
                        pix = ypoints[dyy + y] + xpoints[x];
                        r = R_VAL(pix) * INV_XAP;
                        g = G_VAL(pix) * INV_XAP;
                        b = B_VAL(pix) * INV_XAP;
                        pix++;
                        r += R_VAL(pix) * XAP;
                        g += G_VAL(pix) * XAP;
                        b += B_VAL(pix) * XAP;
                        r >>= 8;
                        g >>= 8;
                        b >>= 8;
                        *dptr++ = qRgba(r, g, b, 0xff);
                    }
                    else
                        *dptr++ = sptr[xpoints[x] ];
                }
            }
        }
    }
    /* if we're scaling down vertically */
    else if(isi->xup_yup == 1){
        /*\ 'Correct' version, with math units prepared for MMXification \*/
        int Cy, j;
        unsigned int *pix;
        int r, g, b, rr, gg, bb;
        int yap;

        /* go through every scanline in the output buffer */
        for(y = 0; y < dh; y++){
            Cy = YAP >> 16;
            yap = YAP & 0xffff;

            dptr = dest + dx + ((y + dy) * dow);
            for(x = dxx; x < end; x++){
                pix = ypoints[dyy + y] + xpoints[x];
                r = (R_VAL(pix) * yap) >> 10;
                g = (G_VAL(pix) * yap) >> 10;
                b = (B_VAL(pix) * yap) >> 10;
                pix += sow;
                for(j = (1 << 14) - yap; j > Cy; j -= Cy){
                    r += (R_VAL(pix) * Cy) >> 10;
                    g += (G_VAL(pix) * Cy) >> 10;
                    b += (B_VAL(pix) * Cy) >> 10;
                    pix += sow;
                }
                if(j > 0){
                    r += (R_VAL(pix) * j) >> 10;
                    g += (G_VAL(pix) * j) >> 10;
                    b += (B_VAL(pix) * j) >> 10;
                }
                if(XAP > 0){
                    pix = ypoints[dyy + y] + xpoints[x] + 1;
                    rr = (R_VAL(pix) * yap) >> 10;
                    gg = (G_VAL(pix) * yap) >> 10;
                    bb = (B_VAL(pix) * yap) >> 10;
                    pix += sow;
                    for(j = (1 << 14) - yap; j > Cy; j -= Cy){
                        rr += (R_VAL(pix) * Cy) >> 10;
                        gg += (G_VAL(pix) * Cy) >> 10;
                        bb += (B_VAL(pix) * Cy) >> 10;
                        pix += sow;
                    }
                    if(j > 0){
                        rr += (R_VAL(pix) * j) >> 10;
                        gg += (G_VAL(pix) * j) >> 10;
                        bb += (B_VAL(pix) * j) >> 10;
                    }
                    r = r * INV_XAP;
                    g = g * INV_XAP;
                    b = b * INV_XAP;
                    r = (r + ((rr * XAP))) >> 12;
                    g = (g + ((gg * XAP))) >> 12;
                    b = (b + ((bb * XAP))) >> 12;
                }
                else{
                    r >>= 4;
                    g >>= 4;
                    b >>= 4;
                }
                *dptr = qRgba(r, g, b, 0xff);
                dptr++;
            }
        }
    }
    /* if we're scaling down horizontally */
    else if(isi->xup_yup == 2){
        /*\ 'Correct' version, with math units prepared for MMXification \*/
        int Cx, j;
        unsigned int *pix;
        int r, g, b, rr, gg, bb;
        int xap;

        /* go through every scanline in the output buffer */
        for(y = 0; y < dh; y++){
            dptr = dest + dx + ((y + dy) * dow);
            for(x = dxx; x < end; x++){
                Cx = XAP >> 16;
                xap = XAP & 0xffff;

                pix = ypoints[dyy + y] + xpoints[x];
                r = (R_VAL(pix) * xap) >> 10;
                g = (G_VAL(pix) * xap) >> 10;
                b = (B_VAL(pix) * xap) >> 10;
                pix++;
                for(j = (1 << 14) - xap; j > Cx; j -= Cx){
                    r += (R_VAL(pix) * Cx) >> 10;
                    g += (G_VAL(pix) * Cx) >> 10;
                    b += (B_VAL(pix) * Cx) >> 10;
                    pix++;
                }
                if(j > 0){
                    r += (R_VAL(pix) * j) >> 10;
                    g += (G_VAL(pix) * j) >> 10;
                    b += (B_VAL(pix) * j) >> 10;
                }
                if(YAP > 0){
                    pix = ypoints[dyy + y] + xpoints[x] + sow;
                    rr = (R_VAL(pix) * xap) >> 10;
                    gg = (G_VAL(pix) * xap) >> 10;
                    bb = (B_VAL(pix) * xap) >> 10;
                    pix++;
                    for(j = (1 << 14) - xap; j > Cx; j -= Cx){
                        rr += (R_VAL(pix) * Cx) >> 10;
                        gg += (G_VAL(pix) * Cx) >> 10;
                        bb += (B_VAL(pix) * Cx) >> 10;
                        pix++;
                    }
                    if(j > 0){
                        rr += (R_VAL(pix) * j) >> 10;
                        gg += (G_VAL(pix) * j) >> 10;
                        bb += (B_VAL(pix) * j) >> 10;
                    }
                    r = r * INV_YAP;
                    g = g * INV_YAP;
                    b = b * INV_YAP;
                    r = (r + ((rr * YAP))) >> 12;
                    g = (g + ((gg * YAP))) >> 12;
                    b = (b + ((bb * YAP))) >> 12;
                }
                else{
                    r >>= 4;
                    g >>= 4;
                    b >>= 4;
                }
                *dptr = qRgba(r, g, b, 0xff);
                dptr++;
            }
        }
    }
    /* fully optimized (i think) - onyl change of algorithm can help */
    /* if we're scaling down horizontally & vertically */
    else{
        /*\ 'Correct' version, with math units prepared for MMXification \*/
        int Cx, Cy, i, j;
        unsigned int *pix;
        int r, g, b, rx, gx, bx;
        int xap, yap;

        for(y = 0; y < dh; y++){
            Cy = YAP >> 16;
            yap = YAP & 0xffff;

            dptr = dest + dx + ((y + dy) * dow);
            for(x = dxx; x < end; x++){
                Cx = XAP >> 16;
                xap = XAP & 0xffff;

                sptr = ypoints[dyy + y] + xpoints[x];
                pix = sptr;
                sptr += sow;
                rx = (R_VAL(pix) * xap) >> 9;
                gx = (G_VAL(pix) * xap) >> 9;
                bx = (B_VAL(pix) * xap) >> 9;
                pix++;
                for(i = (1 << 14) - xap; i > Cx; i -= Cx){
                    rx += (R_VAL(pix) * Cx) >> 9;
                    gx += (G_VAL(pix) * Cx) >> 9;
                    bx += (B_VAL(pix) * Cx) >> 9;
                    pix++;
                }
                if(i > 0){
                    rx += (R_VAL(pix) * i) >> 9;
                    gx += (G_VAL(pix) * i) >> 9;
                    bx += (B_VAL(pix) * i) >> 9;
                }

                r = (rx * yap) >> 14;
                g = (gx * yap) >> 14;
                b = (bx * yap) >> 14;

                for(j = (1 << 14) - yap; j > Cy; j -= Cy){
                    pix = sptr;
                    sptr += sow;
                    rx = (R_VAL(pix) * xap) >> 9;
                    gx = (G_VAL(pix) * xap) >> 9;
                    bx = (B_VAL(pix) * xap) >> 9;
                    pix++;
                    for(i = (1 << 14) - xap; i > Cx; i -= Cx){
                        rx += (R_VAL(pix) * Cx) >> 9;
                        gx += (G_VAL(pix) * Cx) >> 9;
                        bx += (B_VAL(pix) * Cx) >> 9;
                        pix++;
                    }
                    if(i > 0){
                        rx += (R_VAL(pix) * i) >> 9;
                        gx += (G_VAL(pix) * i) >> 9;
                        bx += (B_VAL(pix) * i) >> 9;
                    }

                    r += (rx * Cy) >> 14;
                    g += (gx * Cy) >> 14;
                    b += (bx * Cy) >> 14;
                }
                if(j > 0){
                    pix = sptr;
                    sptr += sow;
                    rx = (R_VAL(pix) * xap) >> 9;
                    gx = (G_VAL(pix) * xap) >> 9;
                    bx = (B_VAL(pix) * xap) >> 9;
                    pix++;
                    for(i = (1 << 14) - xap; i > Cx; i -= Cx){
                        rx += (R_VAL(pix) * Cx) >> 9;
                        gx += (G_VAL(pix) * Cx) >> 9;
                        bx += (B_VAL(pix) * Cx) >> 9;
                        pix++;
                    }
                    if(i > 0){
                        rx += (R_VAL(pix) * i) >> 9;
                        gx += (G_VAL(pix) * i) >> 9;
                        bx += (B_VAL(pix) * i) >> 9;
                    }

                    r += (rx * j) >> 14;
                    g += (gx * j) >> 14;
                    b += (bx * j) >> 14;
                }

                *dptr = qRgb(r >> 5, g >> 5, b >> 5);
                dptr++;
            }
        }
    }
}

#if 0
static void qt_qimageScaleAARGBASetup(QImageScaleInfo *isi, unsigned int *dest,
                                      int dxx, int dyy, int dx, int dy, int dw,
                                      int dh, int dow, int sow)
{
    qInitDrawhelperAsm();
    qt_qimageScaleAARGBA(isi, dest, dxx, dyy, dx, dy, dw, dh, dow, sow);
}

static void qt_qimageScaleAARGBSetup(QImageScaleInfo *isi, unsigned int *dest,
                                 int dxx, int dyy, int dx, int dy, int dw,
                                 int dh, int dow, int sow)
{
    qInitDrawhelperAsm();
    qt_qimageScaleAARGB(isi, dest, dxx, dyy, dx, dy, dw, dh, dow, sow);
}
#endif

QImage qSmoothScaleImageAutoConvert(QImage &src, int dw, int dh)
{
    QImage buffer;
    if (src.isNull())
        return buffer;

    if (src.format() == QImage::Format_ARGB32_Premultiplied)
        src = src.convertToFormat(QImage::Format_ARGB32);
    else if (src.depth() < 32) {
        if (src.hasAlphaChannel())
            src = src.convertToFormat(QImage::Format_ARGB32);
        else
            src = src.convertToFormat(QImage::Format_RGB32);
    }

    return qSmoothScaleImage(src, dw, dh);
}


QImage qSmoothScaleImage(const QImage &src, int dw, int dh)
{
    QImage buffer;
    if (src.isNull() || dw <= 0 || dh <= 0)
        return buffer;

    int w = src.width();
    int h = src.height();
    QImageScaleInfo *scaleinfo =
        qimageCalcScaleInfo(src, w, h, dw, dh, true);
    if (!scaleinfo)
        return buffer;

    buffer = QImage(dw, dh, src.format());
    if (buffer.isNull()) {
        qWarning("QImage: out of memory, returning null");
        return QImage();
    }

    if (src.format() == QImage::Format_ARGB32)
        qt_qimageScaleArgb(scaleinfo, (unsigned int *)buffer.scanLine(0),
                           0, 0, 0, 0, dw, dh, dw, w);
    else
        qt_qimageScaleRgb(scaleinfo, (unsigned int *)buffer.scanLine(0),
                          0, 0, 0, 0, dw, dh, dw, w);

    qimageFreeScaleInfo(scaleinfo);

    return buffer;
}

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