qpixmapfilter.cpp

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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include <qglobal.h>
 
#include <QDebug>
 
#include "qpainter.h"
#include "qpixmap.h"
#include "qpixmapfilter_p.h"
#include "qvarlengtharray.h"
 
#include "private/qguiapplication_p.h"
#include "private/qpaintengineex_p.h"
#include "private/qpaintengine_raster_p.h"
#include "qmath.h"
#include "private/qmath_p.h"
#include "private/qmemrotate_p.h"
#include "private/qdrawhelper_p.h"
 
#include <memory>
 
QT_BEGIN_NAMESPACE
 
class QPixmapFilterPrivate : public QObjectPrivate
{
    Q_DECLARE_PUBLIC(QPixmapFilter)
public:
    QPixmapFilter::FilterType type;
};
 
QPixmapFilter::QPixmapFilter(FilterType type, QObject *parent)
    : QObject(*new QPixmapFilterPrivate, parent)
{
    d_func()->type = type;
}
 
 
 
QPixmapFilter::QPixmapFilter(QPixmapFilterPrivate&d, QPixmapFilter::FilterType type, QObject *parent)
    : QObject(d, parent)
{
    d_func()->type = type;
}
 
 
QPixmapFilter::~QPixmapFilter()
{
}
 
QPixmapFilter::FilterType QPixmapFilter::type() const
{
    Q_D(const QPixmapFilter);
    return d->type;
}
 
QRectF QPixmapFilter::boundingRectFor(const QRectF &rect) const
{
    return rect;
}
 
class QPixmapConvolutionFilterPrivate : public QPixmapFilterPrivate
{
public:
    QPixmapConvolutionFilterPrivate(): convolutionKernel(nullptr), kernelWidth(0), kernelHeight(0), convoluteAlpha(false) {}
    ~QPixmapConvolutionFilterPrivate() {
        delete[] convolutionKernel;
    }
 
    qreal *convolutionKernel;
    int kernelWidth;
    int kernelHeight;
    bool convoluteAlpha;
};
 
 
QPixmapConvolutionFilter::QPixmapConvolutionFilter(QObject *parent)
    : QPixmapFilter(*new QPixmapConvolutionFilterPrivate, ConvolutionFilter, parent)
{
    Q_D(QPixmapConvolutionFilter);
    d->convoluteAlpha = true;
}
 
QPixmapConvolutionFilter::~QPixmapConvolutionFilter()
{
}
 
void QPixmapConvolutionFilter::setConvolutionKernel(const qreal *kernel, int rows, int columns)
{
    Q_D(QPixmapConvolutionFilter);
    delete [] d->convolutionKernel;
    d->convolutionKernel = new qreal[rows * columns];
    memcpy(d->convolutionKernel, kernel, sizeof(qreal) * rows * columns);
    d->kernelWidth = columns;
    d->kernelHeight = rows;
}
 
const qreal *QPixmapConvolutionFilter::convolutionKernel() const
{
    Q_D(const QPixmapConvolutionFilter);
    return d->convolutionKernel;
}
 
int QPixmapConvolutionFilter::rows() const
{
    Q_D(const QPixmapConvolutionFilter);
    return d->kernelHeight;
}
 
int QPixmapConvolutionFilter::columns() const
{
    Q_D(const QPixmapConvolutionFilter);
    return d->kernelWidth;
}
 
 
QRectF QPixmapConvolutionFilter::boundingRectFor(const QRectF &rect) const
{
    Q_D(const QPixmapConvolutionFilter);
    return rect.adjusted(-d->kernelWidth / 2, -d->kernelHeight / 2, (d->kernelWidth - 1) / 2, (d->kernelHeight - 1) / 2);
}
 
// Convolutes the image
static void convolute(
        QImage *destImage,
        const QPointF &pos,
        const QImage &srcImage,
        const QRectF &srcRect,
        QPainter::CompositionMode mode,
        qreal *kernel,
        int kernelWidth,
        int kernelHeight )
{
    const QImage processImage = (srcImage.format() != QImage::Format_ARGB32_Premultiplied ) ?               srcImage.convertToFormat(QImage::Format_ARGB32_Premultiplied) : srcImage;
    // TODO: support also other formats directly without copying
 
    std::unique_ptr<int[]> fixedKernel(new int[kernelWidth * kernelHeight]);
    for(int i = 0; i < kernelWidth*kernelHeight; i++)
    {
        fixedKernel[i] = (int)(65536 * kernel[i]);
    }
    QRectF trect = srcRect.isNull() ? processImage.rect() : srcRect;
    trect.moveTo(pos);
    QRectF bounded = trect.adjusted(-kernelWidth / 2, -kernelHeight / 2, (kernelWidth - 1) / 2, (kernelHeight - 1) / 2);
    QRect rect = bounded.toAlignedRect();
    QRect targetRect = rect.intersected(destImage->rect());
 
    QRectF srect = srcRect.isNull() ? processImage.rect() : srcRect;
    QRectF sbounded = srect.adjusted(-kernelWidth / 2, -kernelHeight / 2, (kernelWidth - 1) / 2, (kernelHeight - 1) / 2);
    QPoint srcStartPoint = sbounded.toAlignedRect().topLeft()+(targetRect.topLeft()-rect.topLeft());
 
    const uint *sourceStart = (const uint*)processImage.scanLine(0);
    uint *outputStart = (uint*)destImage->scanLine(0);
 
    int yk = srcStartPoint.y();
    for (int y = targetRect.top(); y <= targetRect.bottom(); y++) {
        uint* output = outputStart + (destImage->bytesPerLine()/sizeof(uint))*y+targetRect.left();
        int xk = srcStartPoint.x();
        for(int x = targetRect.left(); x <= targetRect.right(); x++) {
            int r = 0;
            int g = 0;
            int b = 0;
            int a = 0;
 
            // some out of bounds pre-checking to avoid inner-loop ifs
            int kernely = -kernelHeight/2;
            int starty = 0;
            int endy = kernelHeight;
            if (yk+kernely+endy >= srcImage.height())
                endy = kernelHeight-((yk+kernely+endy)-srcImage.height())-1;
            if (yk+kernely < 0)
                starty = -(yk+kernely);
 
            int kernelx = -kernelWidth/2;
            int startx = 0;
            int endx = kernelWidth;
            if (xk+kernelx+endx >= srcImage.width())
                endx = kernelWidth-((xk+kernelx+endx)-srcImage.width())-1;
            if (xk+kernelx < 0)
                startx = -(xk+kernelx);
 
            for (int ys = starty; ys < endy; ys ++) {
                const uint *pix = sourceStart + (processImage.bytesPerLine()/sizeof(uint))*(yk+kernely+ys) + ((xk+kernelx+startx));
                const uint *endPix = pix+endx-startx;
                int kernelPos = ys*kernelWidth+startx;
                while (pix < endPix) {
                    int factor = fixedKernel[kernelPos++];
                    a += (((*pix) & 0xff000000)>>24) * factor;
                    r += (((*pix) & 0x00ff0000)>>16) * factor;
                    g += (((*pix) & 0x0000ff00)>>8 ) * factor;
                    b += (((*pix) & 0x000000ff)    ) * factor;
                    pix++;
                }
            }
 
            r = qBound((int)0, r >> 16, (int)255);
            g = qBound((int)0, g >> 16, (int)255);
            b = qBound((int)0, b >> 16, (int)255);
            a = qBound((int)0, a >> 16, (int)255);
            // composition mode checking could be moved outside of loop
            if (mode == QPainter::CompositionMode_Source) {
                uint color = (a<<24)+(r<<16)+(g<<8)+b;
                *output++ = color;
            } else {
                uint current = *output;
                uchar ca = (current&0xff000000)>>24;
                uchar cr = (current&0x00ff0000)>>16;
                uchar cg = (current&0x0000ff00)>>8;
                uchar cb = (current&0x000000ff);
                uint color =
                        (((ca*(255-a) >> 8)+a) << 24)+
                        (((cr*(255-a) >> 8)+r) << 16)+
                        (((cg*(255-a) >> 8)+g) << 8)+
                        (((cb*(255-a) >> 8)+b));
                *output++ = color;;
            }
            xk++;
        }
        yk++;
    }
}
 
void QPixmapConvolutionFilter::draw(QPainter *painter, const QPointF &p, const QPixmap &src, const QRectF& srcRect) const
{
    Q_D(const QPixmapConvolutionFilter);
    if (!painter->isActive())
        return;
 
    if (d->kernelWidth<=0 || d->kernelHeight <= 0)
        return;
 
    if (src.isNull())
        return;
 
    // raster implementation
 
    QImage *target = nullptr;
    if (painter->paintEngine()->paintDevice()->devType() == QInternal::Image) {
        target = static_cast<QImage *>(painter->paintEngine()->paintDevice());
 
        QTransform mat = painter->combinedTransform();
 
        if (mat.type() > QTransform::TxTranslate) {
            // Disabled because of transformation...
            target = nullptr;
        } else {
            QRasterPaintEngine *pe = static_cast<QRasterPaintEngine *>(painter->paintEngine());
            if (pe->clipType() == QRasterPaintEngine::ComplexClip)
                // disabled because of complex clipping...
                target = nullptr;
            else {
                QRectF clip = pe->clipBoundingRect();
                QRectF rect = boundingRectFor(srcRect.isEmpty() ? src.rect() : srcRect);
                QTransform x = painter->deviceTransform();
                if (!clip.contains(rect.translated(x.dx() + p.x(), x.dy() + p.y()))) {
                    target = nullptr;
                }
 
            }
        }
    }
 
    if (target) {
        QTransform x = painter->deviceTransform();
        QPointF offset(x.dx(), x.dy());
 
        convolute(target, p+offset, src.toImage(), srcRect, QPainter::CompositionMode_SourceOver, d->convolutionKernel, d->kernelWidth, d->kernelHeight);
    } else {
        QRect srect = srcRect.isNull() ? src.rect() : srcRect.toRect();
        QRect rect = boundingRectFor(srect).toRect();
        QImage result = QImage(rect.size(), QImage::Format_ARGB32_Premultiplied);
        QPoint offset = srect.topLeft() - rect.topLeft();
        convolute(&result,
                  offset,
                  src.toImage(),
                  srect,
                  QPainter::CompositionMode_Source,
                  d->convolutionKernel,
                  d->kernelWidth,
                  d->kernelHeight);
        painter->drawImage(p - offset, result);
    }
}
 
class QPixmapBlurFilterPrivate : public QPixmapFilterPrivate
{
public:
    QPixmapBlurFilterPrivate() : radius(5), hints(QGraphicsBlurEffect::PerformanceHint) {}
 
    qreal radius;
    QGraphicsBlurEffect::BlurHints hints;
};
 
 
QPixmapBlurFilter::QPixmapBlurFilter(QObject *parent)
    : QPixmapFilter(*new QPixmapBlurFilterPrivate, BlurFilter, parent)
{
}
 
QPixmapBlurFilter::~QPixmapBlurFilter()
{
}
 
void QPixmapBlurFilter::setRadius(qreal radius)
{
    Q_D(QPixmapBlurFilter);
    d->radius = radius;
}
 
qreal QPixmapBlurFilter::radius() const
{
    Q_D(const QPixmapBlurFilter);
    return d->radius;
}
 
void QPixmapBlurFilter::setBlurHints(QGraphicsBlurEffect::BlurHints hints)
{
    Q_D(QPixmapBlurFilter);
    d->hints = hints;
}
 
QGraphicsBlurEffect::BlurHints QPixmapBlurFilter::blurHints() const
{
    Q_D(const QPixmapBlurFilter);
    return d->hints;
}
 
const qreal radiusScale = qreal(2.5);
 
QRectF QPixmapBlurFilter::boundingRectFor(const QRectF &rect) const
{
    Q_D(const QPixmapBlurFilter);
    const qreal delta = radiusScale * d->radius + 1;
    return rect.adjusted(-delta, -delta, delta, delta);
}
 
template <int shift>
inline int qt_static_shift(int value)
{
    if (shift == 0)
        return value;
    else if (shift > 0)
        return value << (uint(shift) & 0x1f);
    else
        return value >> (uint(-shift) & 0x1f);
}
 
template<int aprec, int zprec>
inline void qt_blurinner(uchar *bptr, int &zR, int &zG, int &zB, int &zA, int alpha)
{
    QRgb *pixel = (QRgb *)bptr;
 
#define Z_MASK (0xff << zprec)
    const int A_zprec = qt_static_shift<zprec - 24>(*pixel) & Z_MASK;
    const int R_zprec = qt_static_shift<zprec - 16>(*pixel) & Z_MASK;
    const int G_zprec = qt_static_shift<zprec - 8>(*pixel)  & Z_MASK;
    const int B_zprec = qt_static_shift<zprec>(*pixel)      & Z_MASK;
#undef Z_MASK
 
    const int zR_zprec = zR >> aprec;
    const int zG_zprec = zG >> aprec;
    const int zB_zprec = zB >> aprec;
    const int zA_zprec = zA >> aprec;
 
    zR += alpha * (R_zprec - zR_zprec);
    zG += alpha * (G_zprec - zG_zprec);
    zB += alpha * (B_zprec - zB_zprec);
    zA += alpha * (A_zprec - zA_zprec);
 
#define ZA_MASK (0xff << (zprec + aprec))
    *pixel =
        qt_static_shift<24 - zprec - aprec>(zA & ZA_MASK)
        | qt_static_shift<16 - zprec - aprec>(zR & ZA_MASK)
        | qt_static_shift<8 - zprec - aprec>(zG & ZA_MASK)
        | qt_static_shift<-zprec - aprec>(zB & ZA_MASK);
#undef ZA_MASK
}
 
const int alphaIndex = (QSysInfo::ByteOrder == QSysInfo::BigEndian ? 0 : 3);
 
template<int aprec, int zprec>
inline void qt_blurinner_alphaOnly(uchar *bptr, int &z, int alpha)
{
    const int A_zprec = int(*(bptr)) << zprec;
    const int z_zprec = z >> aprec;
    z += alpha * (A_zprec - z_zprec);
    *(bptr) = z >> (zprec + aprec);
}
 
template<int aprec, int zprec, bool alphaOnly>
inline void qt_blurrow(QImage & im, int line, int alpha)
{
    uchar *bptr = im.scanLine(line);
 
    int zR = 0, zG = 0, zB = 0, zA = 0;
 
    if (alphaOnly && im.format() != QImage::Format_Indexed8)
        bptr += alphaIndex;
 
    const int stride = im.depth() >> 3;
    const int im_width = im.width();
    for (int index = 0; index < im_width; ++index) {
        if (alphaOnly)
            qt_blurinner_alphaOnly<aprec, zprec>(bptr, zA, alpha);
        else
            qt_blurinner<aprec, zprec>(bptr, zR, zG, zB, zA, alpha);
        bptr += stride;
    }
 
    bptr -= stride;
 
    for (int index = im_width - 2; index >= 0; --index) {
        bptr -= stride;
        if (alphaOnly)
            qt_blurinner_alphaOnly<aprec, zprec>(bptr, zA, alpha);
        else
            qt_blurinner<aprec, zprec>(bptr, zR, zG, zB, zA, alpha);
    }
}
 
/*
*  expblur(QImage &img, int radius)
*
*  Based on exponential blur algorithm by Jani Huhtanen
*
*  In-place blur of image 'img' with kernel
*  of approximate radius 'radius'.
*
*  Blurs with two sided exponential impulse
*  response.
*
*  aprec = precision of alpha parameter
*  in fixed-point format 0.aprec
*
*  zprec = precision of state parameters
*  zR,zG,zB and zA in fp format 8.zprec
*/
template <int aprec, int zprec, bool alphaOnly>
void expblur(QImage &img, qreal radius, bool improvedQuality = false, int transposed = 0)
{
    // halve the radius if we're using two passes
    if (improvedQuality)
        radius *= qreal(0.5);
 
    Q_ASSERT(img.format() == QImage::Format_ARGB32_Premultiplied
             || img.format() == QImage::Format_RGB32
             || img.format() == QImage::Format_Indexed8
             || img.format() == QImage::Format_Grayscale8);
 
    // choose the alpha such that pixels at radius distance from a fully
    // saturated pixel will have an alpha component of no greater than
    // the cutOffIntensity
    const qreal cutOffIntensity = 2;
    int alpha = radius <= qreal(1e-5)
        ? ((1 << aprec)-1)
        : qRound((1<<aprec)*(1 - qPow(cutOffIntensity * (1 / qreal(255)), 1 / radius)));
 
    int img_height = img.height();
    for (int row = 0; row < img_height; ++row) {
        for (int i = 0; i <= int(improvedQuality); ++i)
            qt_blurrow<aprec, zprec, alphaOnly>(img, row, alpha);
    }
 
    QImage temp(img.height(), img.width(), img.format());
    temp.setDevicePixelRatio(img.devicePixelRatio());
    if (transposed >= 0) {
        if (img.depth() == 8) {
            qt_memrotate270(reinterpret_cast<const quint8*>(img.bits()),
                            img.width(), img.height(), img.bytesPerLine(),
                            reinterpret_cast<quint8*>(temp.bits()),
                            temp.bytesPerLine());
        } else {
            qt_memrotate270(reinterpret_cast<const quint32*>(img.bits()),
                            img.width(), img.height(), img.bytesPerLine(),
                            reinterpret_cast<quint32*>(temp.bits()),
                            temp.bytesPerLine());
        }
    } else {
        if (img.depth() == 8) {
            qt_memrotate90(reinterpret_cast<const quint8*>(img.bits()),
                           img.width(), img.height(), img.bytesPerLine(),
                           reinterpret_cast<quint8*>(temp.bits()),
                           temp.bytesPerLine());
        } else {
            qt_memrotate90(reinterpret_cast<const quint32*>(img.bits()),
                           img.width(), img.height(), img.bytesPerLine(),
                           reinterpret_cast<quint32*>(temp.bits()),
                           temp.bytesPerLine());
        }
    }
 
    img_height = temp.height();
    for (int row = 0; row < img_height; ++row) {
        for (int i = 0; i <= int(improvedQuality); ++i)
            qt_blurrow<aprec, zprec, alphaOnly>(temp, row, alpha);
    }
 
    if (transposed == 0) {
        if (img.depth() == 8) {
            qt_memrotate90(reinterpret_cast<const quint8*>(temp.bits()),
                           temp.width(), temp.height(), temp.bytesPerLine(),
                           reinterpret_cast<quint8*>(img.bits()),
                           img.bytesPerLine());
        } else {
            qt_memrotate90(reinterpret_cast<const quint32*>(temp.bits()),
                           temp.width(), temp.height(), temp.bytesPerLine(),
                           reinterpret_cast<quint32*>(img.bits()),
                           img.bytesPerLine());
        }
    } else {
        img = temp;
    }
}
#define AVG(a,b)  ( ((((a)^(b)) & 0xfefefefeUL) >> 1) + ((a)&(b)) )
#define AVG16(a,b)  ( ((((a)^(b)) & 0xf7deUL) >> 1) + ((a)&(b)) )
 
Q_WIDGETS_EXPORT QImage qt_halfScaled(const QImage &source)
{
    if (source.width() < 2 || source.height() < 2)
        return QImage();
 
    QImage srcImage = source;
 
    if (source.format() == QImage::Format_Indexed8 || source.format() == QImage::Format_Grayscale8) {
        // assumes grayscale
        QImage dest(source.width() / 2, source.height() / 2, srcImage.format());
        dest.setDevicePixelRatio(source.devicePixelRatio());
 
        const uchar *src = reinterpret_cast<const uchar*>(const_cast<const QImage &>(srcImage).bits());
        qsizetype sx = srcImage.bytesPerLine();
        qsizetype sx2 = sx << 1;
 
        uchar *dst = reinterpret_cast<uchar*>(dest.bits());
        qsizetype dx = dest.bytesPerLine();
        int ww = dest.width();
        int hh = dest.height();
 
        for (int y = hh; y; --y, dst += dx, src += sx2) {
            const uchar *p1 = src;
            const uchar *p2 = src + sx;
            uchar *q = dst;
            for (int x = ww; x; --x, ++q, p1 += 2, p2 += 2)
                *q = ((int(p1[0]) + int(p1[1]) + int(p2[0]) + int(p2[1])) + 2) >> 2;
        }
 
        return dest;
    } else if (source.format() == QImage::Format_ARGB8565_Premultiplied) {
        QImage dest(source.width() / 2, source.height() / 2, srcImage.format());
        dest.setDevicePixelRatio(source.devicePixelRatio());
 
        const uchar *src = reinterpret_cast<const uchar*>(const_cast<const QImage &>(srcImage).bits());
        qsizetype sx = srcImage.bytesPerLine();
        qsizetype sx2 = sx << 1;
 
        uchar *dst = reinterpret_cast<uchar*>(dest.bits());
        qsizetype dx = dest.bytesPerLine();
        int ww = dest.width();
        int hh = dest.height();
 
        for (int y = hh; y; --y, dst += dx, src += sx2) {
            const uchar *p1 = src;
            const uchar *p2 = src + sx;
            uchar *q = dst;
            for (int x = ww; x; --x, q += 3, p1 += 6, p2 += 6) {
                // alpha
                q[0] = AVG(AVG(p1[0], p1[3]), AVG(p2[0], p2[3]));
                // rgb
                const quint16 p16_1 = (p1[2] << 8) | p1[1];
                const quint16 p16_2 = (p1[5] << 8) | p1[4];
                const quint16 p16_3 = (p2[2] << 8) | p2[1];
                const quint16 p16_4 = (p2[5] << 8) | p2[4];
                const quint16 result = AVG16(AVG16(p16_1, p16_2), AVG16(p16_3, p16_4));
                q[1] = result & 0xff;
                q[2] = result >> 8;
            }
        }
 
        return dest;
    } else if (source.format() != QImage::Format_ARGB32_Premultiplied
               && source.format() != QImage::Format_RGB32)
    {
        srcImage = source.convertToFormat(QImage::Format_ARGB32_Premultiplied);
    }
 
    QImage dest(source.width() / 2, source.height() / 2, srcImage.format());
    dest.setDevicePixelRatio(source.devicePixelRatio());
 
    const quint32 *src = reinterpret_cast<const quint32*>(const_cast<const QImage &>(srcImage).bits());
    qsizetype sx = srcImage.bytesPerLine() >> 2;
    qsizetype sx2 = sx << 1;
 
    quint32 *dst = reinterpret_cast<quint32*>(dest.bits());
    qsizetype dx = dest.bytesPerLine() >> 2;
    int ww = dest.width();
    int hh = dest.height();
 
    for (int y = hh; y; --y, dst += dx, src += sx2) {
        const quint32 *p1 = src;
        const quint32 *p2 = src + sx;
        quint32 *q = dst;
        for (int x = ww; x; --x, q++, p1 += 2, p2 += 2)
            *q = AVG(AVG(p1[0], p1[1]), AVG(p2[0], p2[1]));
    }
 
    return dest;
}
 
Q_WIDGETS_EXPORT void qt_blurImage(QPainter *p, QImage &blurImage, qreal radius, bool quality, bool alphaOnly, int transposed = 0)
{
    if (blurImage.format() != QImage::Format_ARGB32_Premultiplied
        && blurImage.format() != QImage::Format_RGB32)
    {
        blurImage = blurImage.convertToFormat(QImage::Format_ARGB32_Premultiplied);
    }
 
    qreal scale = 1;
    if (radius >= 4 && blurImage.width() >= 2 && blurImage.height() >= 2) {
        blurImage = qt_halfScaled(blurImage);
        scale = 2;
        radius *= qreal(0.5);
    }
 
    if (alphaOnly)
        expblur<12, 10, true>(blurImage, radius, quality, transposed);
    else
        expblur<12, 10, false>(blurImage, radius, quality, transposed);
 
    if (p) {
        p->scale(scale, scale);
        p->setRenderHint(QPainter::SmoothPixmapTransform);
        p->drawImage(QRect(QPoint(0, 0), blurImage.deviceIndependentSize().toSize()), blurImage);
    }
}
 
Q_WIDGETS_EXPORT void qt_blurImage(QImage &blurImage, qreal radius, bool quality, int transposed = 0)
{
    if (blurImage.format() == QImage::Format_Indexed8 || blurImage.format() == QImage::Format_Grayscale8)
        expblur<12, 10, true>(blurImage, radius, quality, transposed);
    else
        expblur<12, 10, false>(blurImage, radius, quality, transposed);
}
 
Q_GUI_EXPORT extern bool qt_scaleForTransform(const QTransform &transform, qreal *scale);
 
void QPixmapBlurFilter::draw(QPainter *painter, const QPointF &p, const QPixmap &src, const QRectF &rect) const
{
    Q_D(const QPixmapBlurFilter);
    if (!painter->isActive())
        return;
 
    if (src.isNull())
        return;
 
    QRectF srcRect = rect;
    if (srcRect.isNull())
        srcRect = src.rect();
 
    if (d->radius <= 1) {
        painter->drawPixmap(srcRect.translated(p), src, srcRect);
        return;
    }
 
    qreal scaledRadius = radiusScale * d->radius;
    qreal scale;
    if (qt_scaleForTransform(painter->transform(), &scale))
        scaledRadius /= scale;
 
    QImage srcImage;
 
    if (srcRect == src.rect()) {
        srcImage = src.toImage();
    } else {
        QRect rect = srcRect.toAlignedRect().intersected(src.rect());
        srcImage = src.copy(rect).toImage();
    }
 
    QTransform transform = painter->worldTransform();
    painter->translate(p);
    qt_blurImage(painter, srcImage, scaledRadius, (d->hints & QGraphicsBlurEffect::QualityHint), false);
    painter->setWorldTransform(transform);
}
 
// grayscales the image to dest (could be same). If rect isn't defined
// destination image size is used to determine the dimension of grayscaling
// process.
static void grayscale(const QImage &image, QImage &dest, const QRect& rect = QRect())
{
    QRect destRect = rect;
    QRect srcRect = rect;
    if (rect.isNull()) {
        srcRect = dest.rect();
        destRect = dest.rect();
    }
    if (&image != &dest) {
        destRect.moveTo(QPoint(0, 0));
    }
 
    const unsigned int *data = (const unsigned int *)image.bits();
    unsigned int *outData = (unsigned int *)dest.bits();
 
    if (dest.size() == image.size() && image.rect() == srcRect) {
        // a bit faster loop for grayscaling everything
        int pixels = dest.width() * dest.height();
        for (int i = 0; i < pixels; ++i) {
            int val = qGray(data[i]);
            outData[i] = qRgba(val, val, val, qAlpha(data[i]));
        }
    } else {
        int yd = destRect.top();
        for (int y = srcRect.top(); y <= srcRect.bottom() && y < image.height(); y++) {
            data = (const unsigned int*)image.scanLine(y);
            outData = (unsigned int*)dest.scanLine(yd++);
            int xd = destRect.left();
            for (int x = srcRect.left(); x <= srcRect.right() && x < image.width(); x++) {
                int val = qGray(data[x]);
                outData[xd++] = qRgba(val, val, val, qAlpha(data[x]));
            }
        }
    }
}
 
class QPixmapColorizeFilterPrivate : public QPixmapFilterPrivate
{
    Q_DECLARE_PUBLIC(QPixmapColorizeFilter)
public:
    QColor color;
    qreal strength;
    quint32 opaque : 1;
    quint32 alphaBlend : 1;
    quint32 padding : 30;
};
 
QPixmapColorizeFilter::QPixmapColorizeFilter(QObject *parent)
    : QPixmapFilter(*new QPixmapColorizeFilterPrivate, ColorizeFilter, parent)
{
    Q_D(QPixmapColorizeFilter);
    d->color = QColor(0, 0, 192);
    d->strength = qreal(1);
    d->opaque = true;
    d->alphaBlend = false;
}
 
QPixmapColorizeFilter::~QPixmapColorizeFilter()
{
}
 
QColor QPixmapColorizeFilter::color() const
{
    Q_D(const QPixmapColorizeFilter);
    return d->color;
}
 
void QPixmapColorizeFilter::setColor(const QColor &color)
{
    Q_D(QPixmapColorizeFilter);
    d->color = color;
}
 
qreal QPixmapColorizeFilter::strength() const
{
    Q_D(const QPixmapColorizeFilter);
    return d->strength;
}
 
void QPixmapColorizeFilter::setStrength(qreal strength)
{
    Q_D(QPixmapColorizeFilter);
    d->strength = qBound(qreal(0), strength, qreal(1));
    d->opaque = !qFuzzyIsNull(d->strength);
    d->alphaBlend = !qFuzzyIsNull(d->strength - 1);
}
 
void QPixmapColorizeFilter::draw(QPainter *painter, const QPointF &dest, const QPixmap &src, const QRectF &srcRect) const
{
    Q_D(const QPixmapColorizeFilter);
 
    if (src.isNull())
        return;
 
    // raster implementation
 
    if (!d->opaque) {
        painter->drawPixmap(dest, src, srcRect);
        return;
    }
 
    QImage srcImage;
    QImage destImage;
 
    if (srcRect.isNull()) {
        srcImage = src.toImage();
        const auto format = srcImage.hasAlphaChannel() ? QImage::Format_ARGB32_Premultiplied : QImage::Format_RGB32;
        srcImage = std::move(srcImage).convertToFormat(format);
        destImage = QImage(srcImage.size(), srcImage.format());
    } else {
        QRect rect = srcRect.toAlignedRect().intersected(src.rect());
 
        srcImage = src.copy(rect).toImage();
        const auto format = srcImage.hasAlphaChannel() ? QImage::Format_ARGB32_Premultiplied : QImage::Format_RGB32;
        srcImage = std::move(srcImage).convertToFormat(format);
        destImage = QImage(rect.size(), srcImage.format());
    }
    destImage.setDevicePixelRatio(src.devicePixelRatio());
 
    // do colorizing
    QPainter destPainter(&destImage);
    grayscale(srcImage, destImage, srcImage.rect());
    destPainter.setCompositionMode(QPainter::CompositionMode_Screen);
    destPainter.fillRect(srcImage.rect(), d->color);
    destPainter.end();
 
    if (d->alphaBlend) {
        // alpha blending srcImage and destImage
        QImage buffer = srcImage;
        QPainter bufPainter(&buffer);
        bufPainter.setOpacity(d->strength);
        bufPainter.drawImage(0, 0, destImage);
        bufPainter.end();
        destImage = std::move(buffer);
    }
 
    if (srcImage.hasAlphaChannel()) {
        Q_ASSERT(destImage.format() == QImage::Format_ARGB32_Premultiplied);
        QPainter maskPainter(&destImage);
        maskPainter.setCompositionMode(QPainter::CompositionMode_DestinationIn);
        maskPainter.drawImage(0, 0, srcImage);
    }
 
    painter->drawImage(dest, destImage);
}
 
class QPixmapDropShadowFilterPrivate : public QPixmapFilterPrivate
{
public:
    QPixmapDropShadowFilterPrivate()
        : offset(8, 8), color(63, 63, 63, 180), radius(1) {}
 
    QPointF offset;
    QColor color;
    qreal radius;
};
 
QPixmapDropShadowFilter::QPixmapDropShadowFilter(QObject *parent)
    : QPixmapFilter(*new QPixmapDropShadowFilterPrivate, DropShadowFilter, parent)
{
}
 
QPixmapDropShadowFilter::~QPixmapDropShadowFilter()
{
}
 
qreal QPixmapDropShadowFilter::blurRadius() const
{
    Q_D(const QPixmapDropShadowFilter);
    return d->radius;
}
 
void QPixmapDropShadowFilter::setBlurRadius(qreal radius)
{
    Q_D(QPixmapDropShadowFilter);
    d->radius = radius;
}
 
QColor QPixmapDropShadowFilter::color() const
{
    Q_D(const QPixmapDropShadowFilter);
    return d->color;
}
 
void QPixmapDropShadowFilter::setColor(const QColor &color)
{
    Q_D(QPixmapDropShadowFilter);
    d->color = color;
}
 
QPointF QPixmapDropShadowFilter::offset() const
{
    Q_D(const QPixmapDropShadowFilter);
    return d->offset;
}
 
void QPixmapDropShadowFilter::setOffset(const QPointF &offset)
{
    Q_D(QPixmapDropShadowFilter);
    d->offset = offset;
}
 
QRectF QPixmapDropShadowFilter::boundingRectFor(const QRectF &rect) const
{
    Q_D(const QPixmapDropShadowFilter);
    return rect.united(rect.translated(d->offset).adjusted(-d->radius, -d->radius, d->radius, d->radius));
}
 
void QPixmapDropShadowFilter::draw(QPainter *p,
                                   const QPointF &pos,
                                   const QPixmap &px,
                                   const QRectF &src) const
{
    Q_D(const QPixmapDropShadowFilter);
 
    if (px.isNull())
        return;
 
    QImage tmp(px.size(), QImage::Format_ARGB32_Premultiplied);
    tmp.setDevicePixelRatio(px.devicePixelRatio());
    tmp.fill(0);
    QPainter tmpPainter(&tmp);
    tmpPainter.setCompositionMode(QPainter::CompositionMode_Source);
    tmpPainter.drawPixmap(d->offset, px);
    tmpPainter.end();
 
    // blur the alpha channel
    QImage blurred(tmp.size(), QImage::Format_ARGB32_Premultiplied);
    blurred.setDevicePixelRatio(px.devicePixelRatio());
    blurred.fill(0);
    QPainter blurPainter(&blurred);
    qt_blurImage(&blurPainter, tmp, d->radius, false, true);
    blurPainter.end();
 
    tmp = std::move(blurred);
 
    // blacken the image...
    tmpPainter.begin(&tmp);
    tmpPainter.setCompositionMode(QPainter::CompositionMode_SourceIn);
    tmpPainter.fillRect(tmp.rect(), d->color);
    tmpPainter.end();
 
    // draw the blurred drop shadow...
    p->drawImage(pos, tmp);
 
    // Draw the actual pixmap...
    p->drawPixmap(pos, px, src);
}
 
QT_END_NAMESPACE
 
#include "moc_qpixmapfilter_p.cpp"