QImageScale Namespace Reference

Classes
struct	QImageScaleInfo

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

Function Documentation

qimageCalcApoints()

int * QImageScale::qimageCalcApoints	(	int	s,
		int	d,
		int	up
	)

Definition at line 209 of file qimagescale.cpp.

Referenced by qimageCalcScaleInfo().

{
    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);
}

qimageCalcScaleInfo()

QImageScaleInfo * QImageScale::qimageCalcScaleInfo	(	const QImage &	img,
		int	sw,
		int	sh,
		int	dw,
		int	dh,
		char	aa
	)

Definition at line 272 of file qimagescale.cpp.

Referenced by qSmoothScaleImage().

{
    QImageScaleInfo *isi;
    int scw, sch;

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

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

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

    isi->xpoints = qimageCalcXPoints(img.width(), scw);
    if(!isi->xpoints)
        return(qimageFreeScaleInfo(isi));
    isi->ypoints = qimageCalcYPoints((unsigned int *)img.scanLine(0),
                                     img.bytesPerLine() / 4, 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);
}

qimageCalcXPoints()

int * QImageScale::qimageCalcXPoints	(	int	sw,
		int	dw
	)

Definition at line 180 of file qimagescale.cpp.

Referenced by qimageCalcScaleInfo().

{
    int *p, i, j = 0;
    int val, inc, rv = 0;

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

    int up = qAbs(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);
}

qimageCalcYPoints()

unsigned int ** QImageScale::qimageCalcYPoints	(	unsigned int *	src,
		int	sw,
		int	sh,
		int	dh
	)

Definition at line 150 of file qimagescale.cpp.

Referenced by qimageCalcScaleInfo().

{
    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 = qAbs(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);
}

qimageFreeScaleInfo()

QImageScaleInfo * QImageScale::qimageFreeScaleInfo

(

QImageScaleInfo *

isi

)

Definition at line 260 of file qimagescale.cpp.

Referenced by qimageCalcScaleInfo(), and qSmoothScaleImage().

{
    if(isi){
        delete[] isi->xpoints;
        delete[] isi->ypoints;
        delete[] isi->xapoints;
        delete[] isi->yapoints;
        delete isi;
    }
    return 0;
}