source: trunk/src/gui/painting/qwindowsurface_raster.cpp

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**
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
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#include <qdebug.h>

#include <qglobal.h> // for Q_WS_WIN define (non-PCH)
#ifdef Q_WS_WIN
#include <qlibrary.h>
#include <qt_windows.h>
#endif

#include <QtGui/qpaintdevice.h>
#include <QtGui/qwidget.h>

#include "private/qwindowsurface_raster_p.h"
#include "private/qnativeimage_p.h"
#include "private/qwidget_p.h"

#ifdef Q_WS_X11
#include "private/qpixmap_x11_p.h"
#include "private/qt_x11_p.h"
#include "private/qwidget_p.h"
#include "qx11info_x11.h"
#endif
#include "private/qdrawhelper_p.h"

#ifdef Q_WS_MAC
#include <private/qt_cocoa_helpers_mac_p.h>
#endif

#if defined(Q_WS_PM) && defined(QT_LOG_BLITSPEED)
#include <InnotekLIBC/FastInfoBlocks.h>
#endif

#if defined(Q_WS_PM)
LONG APIENTRY GpiQueryYInversion(HPS hps);
BOOL APIENTRY GpiEnableYInversion(HPS hps, LONG lHeight);
#define QT_BITMAP_MIRROR 3  // 1 = QImage.mirrored()
                            // 2 = GpiEnableYInversion()
                            // 3 = GPI Matrix (seems to be the fastest)
#endif

QT_BEGIN_NAMESPACE

#if defined(Q_WS_PM) && defined(QT_LOG_BLITSPEED)
unsigned long long qt_total_blit_ms = 0;
unsigned long long qt_total_blit_pixels = 0;
#endif

class QRasterWindowSurfacePrivate
{
public:
    QNativeImage *image;

#ifdef Q_WS_X11
    GC gc;
#ifndef QT_NO_XRENDER
    uint translucentBackground : 1;
#endif
#endif
    uint inSetGeometry : 1;
};

QRasterWindowSurface::QRasterWindowSurface(QWidget *window)
    : QWindowSurface(window), d_ptr(new QRasterWindowSurfacePrivate)
{
#ifdef Q_WS_X11
    d_ptr->gc = XCreateGC(X11->display, window->handle(), 0, 0);
#ifndef QT_NO_XRENDER
    d_ptr->translucentBackground = X11->use_xrender
        && window->x11Info().depth() == 32;
#endif
#endif
    d_ptr->image = 0;
    d_ptr->inSetGeometry = false;
    setStaticContentsSupport(true);
}


QRasterWindowSurface::~QRasterWindowSurface()
{
#ifdef Q_WS_X11
    XFreeGC(X11->display, d_ptr->gc);
#endif
    if (d_ptr->image)
        delete d_ptr->image;
}


QPaintDevice *QRasterWindowSurface::paintDevice()
{
    return &d_ptr->image->image;
}

void QRasterWindowSurface::beginPaint(const QRegion &rgn)
{
#if (defined(Q_WS_X11) && !defined(QT_NO_XRENDER)) || (defined(Q_WS_WIN) && !defined(Q_WS_WINCE))
    if (!qt_widget_private(window())->isOpaque && window()->testAttribute(Qt::WA_TranslucentBackground)) {
#if defined(Q_WS_WIN) && !defined(Q_WS_WINCE)
        if (d_ptr->image->image.format() != QImage::Format_ARGB32_Premultiplied)
            prepareBuffer(QImage::Format_ARGB32_Premultiplied, window());
#endif
        QPainter p(&d_ptr->image->image);
        p.setCompositionMode(QPainter::CompositionMode_Source);
        const QVector<QRect> rects = rgn.rects();
        const QColor blank = Qt::transparent;
        for (QVector<QRect>::const_iterator it = rects.begin(); it != rects.end(); ++it) {
            p.fillRect(*it, blank);
        }
    }
#else
    Q_UNUSED(rgn);
#endif
}

void QRasterWindowSurface::flush(QWidget *widget, const QRegion &rgn, const QPoint &offset)
{
    Q_D(QRasterWindowSurface);

    // Not ready for painting yet, bail out. This can happen in
    // QWidget::create_sys()
    if (!d->image || rgn.rectCount() == 0)
        return;

#ifdef Q_WS_WIN
    QRect br = rgn.boundingRect();

#ifndef Q_WS_WINCE
    if (!qt_widget_private(window())->isOpaque
        && window()->testAttribute(Qt::WA_TranslucentBackground)
        && (qt_widget_private(window())->data.window_flags & Qt::FramelessWindowHint))
    {
        QRect r = window()->frameGeometry();
        QPoint frameOffset = qt_widget_private(window())->frameStrut().topLeft();
        QRect dirtyRect = br.translated(offset + frameOffset);

        SIZE size = {r.width(), r.height()};
        POINT ptDst = {r.x(), r.y()};
        POINT ptSrc = {0, 0};
        BLENDFUNCTION blend = {AC_SRC_OVER, 0, (int)(255.0 * window()->windowOpacity()), Q_AC_SRC_ALPHA};
        RECT dirty = {dirtyRect.x(), dirtyRect.y(),
            dirtyRect.x() + dirtyRect.width(), dirtyRect.y() + dirtyRect.height()};
        Q_UPDATELAYEREDWINDOWINFO info = {sizeof(info), NULL, &ptDst, &size, d->image->hdc, &ptSrc, 0, &blend, Q_ULW_ALPHA, &dirty};
        ptrUpdateLayeredWindowIndirect(window()->internalWinId(), &info);
    } else
#endif
    {
        QPoint wOffset = qt_qwidget_data(widget)->wrect.topLeft();

        HDC widget_dc = widget->getDC();

        QRect wbr = br.translated(-wOffset);
        BitBlt(widget_dc, wbr.x(), wbr.y(), wbr.width(), wbr.height(),
               d->image->hdc, br.x() + offset.x(), br.y() + offset.y(), SRCCOPY);
        widget->releaseDC(widget_dc);
    }

#ifndef QT_NO_DEBUG
    static bool flush = !qgetenv("QT_FLUSH_WINDOWSURFACE").isEmpty();
    if (flush) {
        SelectObject(qt_win_display_dc(), GetStockObject(BLACK_BRUSH));
        Rectangle(qt_win_display_dc(), 0, 0, d->image->width() + 2, d->image->height() + 2);
        BitBlt(qt_win_display_dc(), 1, 1, d->image->width(), d->image->height(),
               d->image->hdc, 0, 0, SRCCOPY);
    }
#endif

#endif

#ifdef Q_WS_PM
    QRect br = rgn.boundingRect();

    HPS wps = widget->getPS();

#if 0
    qDebug() << "QRasterWindowSurface::flush:" << widget
             << "wps" << qDebugFmtHex(wps) << "br" << br;
#endif

#ifdef QT_LOG_BLITSPEED
    unsigned long ticks = fibGetMsCount();
#endif

#if QT_BITMAP_MIRROR == 1

    // flip the image vertically for PM
    QImage img = d->image->image.mirrored();

    br.translate(offset);

    // make sure br doesn't exceed the backing storage size (it may happen
    // during resize & move due to the different event order)
    br = br.intersected(QRect(0, 0, img.width(), img.height()));

    QPoint wOffset = qt_qwidget_data(widget)->wrect.topLeft();
    // note that we remove offset from wbr because the widget's HPS has a proper
    // origin already that includes this offset (which is in fact a position of
    // the widget relative to its top-level parent)
    QRect wbr = br.translated(-offset - wOffset);

    BITMAPINFOHEADER2 bmh;
    memset(&bmh, 0, sizeof(BITMAPINFOHEADER2));
    bmh.cbFix = sizeof(BITMAPINFOHEADER2);
    bmh.cPlanes = 1;
    bmh.cBitCount = 32; // @todo support 8-bit indexed colors?
    bmh.cx = img.width();
    bmh.cy = img.height();

    int wh = widget->height();
    int ih = img.height();

#ifdef QT_PM_NATIVEWIDGETMASK
    // produce a clip region that excludes all descending obstacles
    // (like child widgets with real HWNDs which are not excluded by Qt)
    HWND wwnd = widget->winId();
    RECTL wrcl = { wbr.left(), wh - wbr.bottom() - 1,
                   wbr.right() + 1, wh - wbr.top() };
    HRGN wrgn = GpiCreateRegion(wps, 1L, &wrcl);
    ULONG rc = qt_WinProcessWindowObstacles(wwnd, NULL, wrgn, CRGN_DIFF,
                                            PWO_Children);
    if (rc == RGN_RECT || rc == RGN_COMPLEX) {
        // set the clip region
        HRGN oldRgn;
        GpiSetClipRegion(wps, wrgn, &oldRgn);
        wrgn = oldRgn;
#endif
        // Note: target is inclusive-inclusive, source is inclusive-exclusive
        POINTL ptls[] = { { wbr.left(), wh - wbr.bottom() - 1 },
                          { wbr.right(), wh - wbr.top() - 1 },
                          { br.left(), ih - br.bottom() - 1 },
                          { br.right() + 1, ih - br.top() } };
#if 0
        qDebug() << "QRasterWindowSurface::flush:" << widget << "ptls"
                 << ptls[0].x << ptls[0].y << ptls[1].x << ptls[1].y
                 << ptls[2].x << ptls[2].y << ptls[3].x << ptls[3].y
                 << "img.size" << img.size() << "img.bits" << img.bits();
#endif
        GpiDrawBits(wps, (PVOID) img.bits(), (PBITMAPINFO2) &bmh, 4, ptls,
                    ROP_SRCCOPY, BBO_IGNORE);

#ifdef QT_PM_NATIVEWIDGETMASK
    }

    if (wrgn != NULLHANDLE)
        GpiDestroyRegion(wps, wrgn);
#endif

#elif QT_BITMAP_MIRROR == 2

    // Use GpiEnableYInversion to flip the y axis. This is almost as fast as
    // QT_BITMAP_MIRROR == 3. "Almost" is probably due to some extra overhead
    // on the method call compared to the direct matrix manipulation.

    br.translate(offset);

    // make sure br doesn't exceed the backing storage size (it may happen
    // during resize & move due to the different event order)
    br = br.intersected(QRect(0, 0, d->image->width(), d->image->height()));

    QPoint wOffset = qt_qwidget_data(widget)->wrect.topLeft();
    // note that we remove offset from wbr because the widget's HPS has a proper
    // origin already that includes this offset (which is in fact a position of
    // the widget relative to its top-level parent)
    QRect wbr = br.translated(-offset - wOffset);

    BITMAPINFOHEADER2 bmh;
    memset(&bmh, 0, sizeof(BITMAPINFOHEADER2));
    bmh.cbFix = sizeof(BITMAPINFOHEADER2);
    bmh.cPlanes = 1;
    bmh.cBitCount = 32; // @todo support 8-bit indexed colors?
    bmh.cx = d->image->width();
    bmh.cy = d->image->height();

#ifdef QT_PM_NATIVEWIDGETMASK
    int wh = widget->height();

    // produce a clip region that excludes all descending obstacles
    // (like child widgets with real HWNDs which are not excluded by Qt)
    HWND wwnd = widget->winId();
    RECTL wrcl = { wbr.left(), wh - wbr.bottom() - 1,
                   wbr.right() + 1, wh - wbr.top() };
    HRGN wrgn = GpiCreateRegion(wps, 1L, &wrcl);
    ULONG rc = qt_WinProcessWindowObstacles(wwnd, NULL, wrgn, CRGN_DIFF,
                                            PWO_Children);
    if (rc == RGN_RECT || rc == RGN_COMPLEX) {
        // set the clip region
        HRGN oldRgn;
        GpiSetClipRegion(wps, wrgn, &oldRgn);
        wrgn = oldRgn;
#endif
        // Note: target is inclusive-inclusive, source is inclusive-exclusive
        POINTL ptls[] = { { wbr.left(), wbr.top() },
                          { wbr.right(), wbr.bottom() },
                          { br.left(), br.top() },
                          { br.right() + 1, br.bottom() + 1 } };
#if 0
        qDebug() << "QRasterWindowSurface::flush:" << widget << "ptls"
                 << ptls[0].x << ptls[0].y << ptls[1].x << ptls[1].y
                 << ptls[2].x << ptls[2].y << ptls[3].x << ptls[3].y
                 << "img.size" << d->image->size() << "img.bits" << d->image->bits();
#endif

        // setup the Y coordinate inversion (this seems to use the same GPI matrix
        // transformation internally as we do in method 3 below)
        LONG oldInversion = GpiQueryYInversion(wps);
        GpiEnableYInversion(wps, widget->height() - 1);

        GpiDrawBits(wps, (PVOID) const_cast<const QImage &>(d->image->image).bits(),
                    (PBITMAPINFO2) &bmh, 4, ptls, ROP_SRCCOPY, BBO_IGNORE);

        GpiEnableYInversion(wps, oldInversion);

#ifdef QT_PM_NATIVEWIDGETMASK
    }

    if (wrgn != NULLHANDLE)
        GpiDestroyRegion(wps, wrgn);
#endif

#ifndef QT_NO_DEBUG
    // for debug flushing
    const QImage img = d->image->image;
#endif

#elif QT_BITMAP_MIRROR == 3

    // Use the reflection + transformation matrix to flip the y axis.
    // This is proven to be much faster than manual image flipping on the real
    // video hardware as it probably involves some hardware acceleration in
    // the video driver.

    MATRIXLF m;
    m.fxM11 = MAKEFIXED(1, 0);
    m.fxM12 = 0;
    m.lM13 = 0;
    m.fxM21 = 0;
    m.fxM22 = MAKEFIXED(-1, 0);
    m.lM23 = 0;
    m.lM31 = 0;
    m.lM32 = widget->height() - 1;
    GpiSetDefaultViewMatrix(wps, 8, &m, TRANSFORM_REPLACE);

    br.translate(offset);

    // make sure br doesn't exceed the backing storage size (it may happen
    // during resize & move due to the different event order)
    br = br.intersected(QRect(0, 0, d->image->width(), d->image->height()));

    QPoint wOffset = qt_qwidget_data(widget)->wrect.topLeft();
    // note that we remove offset from wbr because the widget's HPS has a proper
    // origin already that includes this offset (which is in fact a position of
    // the widget relative to its top-level parent)
    QRect wbr = br.translated(-offset - wOffset);

    BITMAPINFOHEADER2 bmh;
    memset(&bmh, 0, sizeof(BITMAPINFOHEADER2));
    bmh.cbFix = sizeof(BITMAPINFOHEADER2);
    bmh.cPlanes = 1;
    bmh.cBitCount = 32; // @todo support 8-bit indexed colors?
    bmh.cx = d->image->width();
    bmh.cy = d->image->height();

#ifdef QT_PM_NATIVEWIDGETMASK
    int wh = widget->height();

    // produce a clip region that excludes all descending obstacles
    // (like child widgets with real HWNDs which are not excluded by Qt)
    HWND wwnd = widget->winId();
    RECTL wrcl = { wbr.left(), wh - wbr.bottom() - 1,
                   wbr.right() + 1, wh - wbr.top() };
    HRGN wrgn = GpiCreateRegion(wps, 1L, &wrcl);
    ULONG rc = qt_WinProcessWindowObstacles(wwnd, NULL, wrgn, CRGN_DIFF,
                                            PWO_Children);
    if (rc == RGN_RECT || rc == RGN_COMPLEX) {
        // set the clip region
        HRGN oldRgn;
        GpiSetClipRegion(wps, wrgn, &oldRgn);
        wrgn = oldRgn;
#endif
        // Note: target is inclusive-inclusive, source is inclusive-exclusive
        POINTL ptls[] = { { wbr.left(), wbr.top() },
                          { wbr.right(), wbr.bottom() },
                          { br.left(), br.top() },
                          { br.right() + 1, br.bottom() + 1 } };
        GpiDrawBits(wps, (PVOID) const_cast<const QImage &>(d->image->image).bits(),
                    (PBITMAPINFO2) &bmh, 4, ptls, ROP_SRCCOPY, BBO_IGNORE);

#ifdef QT_PM_NATIVEWIDGETMASK
    }

    if (wrgn != NULLHANDLE)
        GpiDestroyRegion(wps, wrgn);
#endif

#ifndef QT_NO_DEBUG
        // for debug flushing
        const QImage img = d->image->image;
#endif

#else // if QT_BITMAP_MIRROR == 3
# error "QT_BITMAP_MIRROR must be 1, 2 or 3"
#endif

    widget->releasePS(wps);

#ifdef QT_LOG_BLITSPEED
    ticks = fibGetMsCount() - ticks;
    qt_total_blit_ms += ticks;
    qt_total_blit_pixels += br.width() * br.height();
#endif

#ifndef QT_NO_DEBUG
    static bool flush = !qgetenv("QT_FLUSH_WINDOWSURFACE").isEmpty();
    if (flush) {
        HPS dps = qt_display_ps();
        RECTL rcl = { 10, 50, 10 + img.width() + 2, 50 + img.height() + 2 };
        WinDrawBorder(dps, &rcl, 1, 1, CLR_BLACK, CLR_BLACK, 0);
        POINTL ptls[] = { { 11, 51, },
                          { 11 + img.width() - 1, 51 + img.height() - 1 },
                          { 0, 0 },
                          { img.width(), img.height() } };
        GpiDrawBits(dps, (PVOID) img.bits(), (PBITMAPINFO2) &bmh, 4, ptls,
                    ROP_SRCCOPY, BBO_IGNORE);
    }
#endif

#endif // Q_WS_PM

#ifdef Q_WS_X11
    extern void *qt_getClipRects(const QRegion &r, int &num); // in qpaintengine_x11.cpp
    extern QWidgetData* qt_widget_data(QWidget *);
    QPoint wOffset = qt_qwidget_data(widget)->wrect.topLeft();

    if (widget->window() != window()) {
        XFreeGC(X11->display, d_ptr->gc);
        d_ptr->gc = XCreateGC(X11->display, widget->handle(), 0, 0);
    }

    QRegion wrgn(rgn);
    if (!wOffset.isNull())
        wrgn.translate(-wOffset);
    QRect wbr = wrgn.boundingRect();

    if (wrgn.rectCount() != 1) {
        int num;
        XRectangle *rects = (XRectangle *)qt_getClipRects(wrgn, num);
        XSetClipRectangles(X11->display, d_ptr->gc, 0, 0, rects, num, YXBanded);
    }

    QRect br = rgn.boundingRect().translated(offset);
#ifndef QT_NO_MITSHM
    if (d_ptr->image->xshmpm) {
        XCopyArea(X11->display, d_ptr->image->xshmpm, widget->handle(), d_ptr->gc,
                  br.x(), br.y(), br.width(), br.height(), wbr.x(), wbr.y());
        XSync(X11->display, False);
    } else if (d_ptr->image->xshmimg) {
        const QImage &src = d->image->image;
        br = br.intersected(src.rect());
        XShmPutImage(X11->display, widget->handle(), d_ptr->gc, d_ptr->image->xshmimg,
                     br.x(), br.y(), wbr.x(), wbr.y(), br.width(), br.height(), False);
        XSync(X11->display, False);
    } else
#endif
    {
        const QImage &src = d->image->image;
        br = br.intersected(src.rect());
        if (src.format() != QImage::Format_RGB32 || widget->x11Info().depth() < 24) {
            Q_ASSERT(src.depth() >= 16);
            const QImage sub_src(src.scanLine(br.y()) + br.x() * (uint(src.depth()) / 8),
                                 br.width(), br.height(), src.bytesPerLine(), src.format());
            QX11PixmapData *data = new QX11PixmapData(QPixmapData::PixmapType);
            data->xinfo = widget->x11Info();
            data->fromImage(sub_src, Qt::NoOpaqueDetection);
            QPixmap pm = QPixmap(data);
            XCopyArea(X11->display, pm.handle(), widget->handle(), d_ptr->gc, 0 , 0 , br.width(), br.height(), wbr.x(), wbr.y());
        } else {
            // qpaintengine_x11.cpp
            extern void qt_x11_drawImage(const QRect &rect, const QPoint &pos, const QImage &image, Drawable hd, GC gc, Display *dpy, Visual *visual, int depth);
            qt_x11_drawImage(br, wbr.topLeft(), src, widget->handle(), d_ptr->gc, X11->display, (Visual *)widget->x11Info().visual(), widget->x11Info().depth());
        }
    }

    if (wrgn.rectCount() != 1)
        XSetClipMask(X11->display, d_ptr->gc, XNone);
#endif // FALCON

#ifdef Q_WS_MAC

//     qDebug() << "Flushing" << widget << rgn << offset;

//     d->image->image.save("flush.png");

    Q_UNUSED(offset);
    // Get a context for the widget.
#ifndef QT_MAC_USE_COCOA
    CGContextRef context;
    CGrafPtr port = GetWindowPort(qt_mac_window_for(widget));
    QDBeginCGContext(port, &context);
#else
    extern CGContextRef qt_mac_graphicsContextFor(QWidget *);
    CGContextRef context = qt_mac_graphicsContextFor(widget);
#endif
    CGContextSaveGState(context);

    // Flip context.
    CGContextTranslateCTM(context, 0, widget->height());
    CGContextScaleCTM(context, 1, -1);

    // Clip to region.
    const QVector<QRect> &rects = rgn.rects();
    for (int i = 0; i < rects.size(); ++i) {
        const QRect &rect = rects.at(i);
        CGContextAddRect(context, CGRectMake(rect.x(), rect.y(), rect.width(), rect.height()));
    }
    CGContextClip(context);

    QRect r = rgn.boundingRect();
    const CGRect area = CGRectMake(r.x(), r.y(), r.width(), r.height());
    CGImageRef image = CGBitmapContextCreateImage(d->image->cg);
    CGImageRef subImage = CGImageCreateWithImageInRect(image, area);

    qt_mac_drawCGImage(context, &area, subImage);
    CGImageRelease(subImage);
    CGImageRelease(image);

//     CGSize size = { d->image->image.width(), d->image->image.height() };
//     CGLayerRef layer = CGLayerCreateWithContext(d->image->cg, size, 0);
//     CGPoint pt = { 0, 0 };
//     CGContextDrawLayerAtPoint(context, pt, layer);
//     CGLayerRelease(layer);

    // Restore context.
    CGContextRestoreGState(context);
#ifndef QT_MAC_USE_COCOA
    QDEndCGContext(port, &context);
#endif
#endif // Q_WS_MAC

#ifdef Q_OS_SYMBIAN
    Q_UNUSED(widget);
    Q_UNUSED(rgn);
    Q_UNUSED(offset);
#endif
}

void QRasterWindowSurface::setGeometry(const QRect &rect)
{
    QWindowSurface::setGeometry(rect);
    Q_D(QRasterWindowSurface);
    d->inSetGeometry = true;
    if (d->image == 0 || d->image->width() < rect.width() || d->image->height() < rect.height()) {
#if (defined(Q_WS_X11) && !defined(QT_NO_XRENDER)) || (defined(Q_WS_WIN) && !defined(Q_WS_WINCE))
#ifndef Q_WS_WIN
        if (d_ptr->translucentBackground)
#else
        if (!qt_widget_private(window())->isOpaque)
#endif
            prepareBuffer(QImage::Format_ARGB32_Premultiplied, window());
        else
#endif
            prepareBuffer(QNativeImage::systemFormat(), window());
    }
    d->inSetGeometry = false;
}

// from qwindowsurface.cpp
extern void qt_scrollRectInImage(QImage &img, const QRect &rect, const QPoint &offset);

bool QRasterWindowSurface::scroll(const QRegion &area, int dx, int dy)
{
#ifdef Q_WS_WIN
    Q_D(QRasterWindowSurface);

    if (!d->image || !d->image->hdc)
        return false;

    QRect rect = area.boundingRect();
    BitBlt(d->image->hdc, rect.x()+dx, rect.y()+dy, rect.width(), rect.height(),
           d->image->hdc, rect.x(), rect.y(), SRCCOPY);

    return true;
#else
    Q_D(QRasterWindowSurface);

    if (!d->image || d->image->image.isNull())
        return false;

    const QVector<QRect> rects = area.rects();
    for (int i = 0; i < rects.size(); ++i)
        qt_scrollRectInImage(d->image->image, rects.at(i), QPoint(dx, dy));

    return true;
#endif
}


void QRasterWindowSurface::prepareBuffer(QImage::Format format, QWidget *widget)
{
    Q_D(QRasterWindowSurface);

    int width = window()->width();
    int height = window()->height();
    if (d->image) {
        width = qMax(d->image->width(), width);
        height = qMax(d->image->height(), height);
    }

    if (width == 0 || height == 0) {
        delete d->image;
        d->image = 0;
        return;
    }

    QNativeImage *oldImage = d->image;

    d->image = new QNativeImage(width, height, format, false, widget);

    if (oldImage && d->inSetGeometry && hasStaticContents()) {
        // Make sure we use the const version of bits() (no detach).
        const uchar *src = const_cast<const QImage &>(oldImage->image).bits();
        uchar *dst = d->image->image.bits();

        const int srcBytesPerLine = oldImage->image.bytesPerLine();
        const int dstBytesPerLine = d->image->image.bytesPerLine();
        const int bytesPerPixel = oldImage->image.depth() >> 3;

        QRegion staticRegion(staticContents());
        // Make sure we're inside the boundaries of the old image.
        staticRegion &= QRect(0, 0, oldImage->image.width(), oldImage->image.height());
        const QVector<QRect> &rects = staticRegion.rects();
        const QRect *srcRect = rects.constData();

        // Copy the static content of the old image into the new one.
        int numRectsLeft = rects.size();
        do {
            const int bytesOffset = srcRect->x() * bytesPerPixel;
            const int dy = srcRect->y();

            // Adjust src and dst to point to the right offset.
            const uchar *s = src + dy * srcBytesPerLine + bytesOffset;
            uchar *d = dst + dy * dstBytesPerLine + bytesOffset;
            const int numBytes = srcRect->width() * bytesPerPixel;

            int numScanLinesLeft = srcRect->height();
            do {
                ::memcpy(d, s, numBytes);
                d += dstBytesPerLine;
                s += srcBytesPerLine;
            } while (--numScanLinesLeft);

            ++srcRect;
        } while (--numRectsLeft);
    }

    delete oldImage;
}

QT_END_NAMESPACE