qscreen_qws.cpp

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#include "qplatformdefs.h"
#include "qscreen_qws.h"

#include "qcolormap.h"
#include "qscreendriverfactory_qws.h"
#include "qwindowsystem_qws.h"
#include "qwidget.h"
#include "qcolor.h"
#include "qpixmap.h"
#include "qvarlengtharray.h"
#include "qwsdisplay_qws.h"
#include "qpainter.h"
#include <private/qdrawhelper_p.h>
#include <private/qpaintengine_raster_p.h>
#include <private/qpixmap_raster_p.h>
#include <private/qwindowsurface_qws_p.h>
#include <private/qpainter_p.h>
#include <private/qwidget_p.h>
#include <private/qgraphicssystem_qws_p.h>

QT_BEGIN_NAMESPACE

// #define QT_USE_MEMCPY_DUFF

#ifndef QT_NO_QWS_CURSOR
Q_GUI_EXPORT QScreenCursor * qt_screencursor = 0;
#endif
Q_GUI_EXPORT QScreen * qt_screen = 0;

ClearCacheFunc QScreen::clearCacheFunc = 0;

#ifndef QT_NO_QWS_CURSOR

QScreenCursor::QScreenCursor()
{
    pos = QPoint(qt_screen->deviceWidth()/2, qt_screen->deviceHeight()/2);
    size = QSize(0,0);
    enable = true;
    hwaccel = false;
    supportsAlpha = true;
}

QScreenCursor::~QScreenCursor()
{
}

void QScreenCursor::hide()
{
    if (enable) {
        enable = false;
        if (!hwaccel)
            qt_screen->exposeRegion(boundingRect(), 0);
    }
}

void QScreenCursor::show()
{
    if (!enable) {
        enable = true;
        if (!hwaccel)
            qt_screen->exposeRegion(boundingRect(), 0);
    }
}

void QScreenCursor::set(const QImage &image, int hotx, int hoty)
{
    const QRect r = boundingRect();

    hotspot = QPoint(hotx, hoty);
    // These are in almost all cases the fastest formats to blend
    QImage::Format f;
    switch (qt_screen->depth()) {
    case 12:
        f = QImage::Format_ARGB4444_Premultiplied;
        break;
    case 15:
        f =  QImage::Format_ARGB8555_Premultiplied;
        break;
    case 16:
        f = QImage::Format_ARGB8565_Premultiplied;
        break;
    case 18:
        f = QImage::Format_ARGB6666_Premultiplied;
        break;
    default:
        f =  QImage::Format_ARGB32_Premultiplied;
    }

    cursor = image.convertToFormat(f);

    size = image.size();

    if (enable && !hwaccel)
        qt_screen->exposeRegion(r | boundingRect(), 0);
}

void QScreenCursor::move(int x, int y)
{
    QRegion r = boundingRect();
    pos = QPoint(x,y);
    if (enable && !hwaccel) {
        r |= boundingRect();
        qt_screen->exposeRegion(r, 0);
    }
}


void QScreenCursor::initSoftwareCursor()
{
    qt_screencursor = new QScreenCursor;
}


#endif // QT_NO_QWS_CURSOR


/*
    \variable QScreenCursor::cursor

    \brief the cursor's image.

    \sa image()
*/

/*
    \variable QScreenCursor::size

    \brief the cursor's size
*/

/*
    \variable QScreenCursor::pos

    \brief the cursor's position, i.e., the position of the top-left
    corner of the crsor's image

    \sa set(), move()
*/

/*
    \variable QScreenCursor::hotspot

    \brief the cursor's hotspot, i.e., the point within the cursor's
    image that will be the position of the associated mouse events.

    \sa set(), move()
*/

/*
    \variable QScreenCursor::enable

    \brief whether the cursor is visible or not

    \sa isVisible()
*/

/*
    \variable QScreenCursor::hwaccel

    \brief holds whether the cursor is accelerated or not

    If the cursor is not accelerated, its image will be included by
    the screen when it composites the window surfaces.

    \sa isAccelerated()

*/

/*
    \variable QScreenCursor::supportsAlpha
*/

class QScreenPrivate
{
public:
    QScreenPrivate(QScreen *parent, QScreen::ClassId id = QScreen::CustomClass);
    ~QScreenPrivate();

    inline QImage::Format preferredImageFormat() const;

    typedef void (*SolidFillFunc)(QScreen*, const QColor&, const QRegion&);
    typedef void (*BlitFunc)(QScreen*, const QImage&, const QPoint&, const QRegion&);

    SolidFillFunc solidFill;
    BlitFunc blit;

    QPoint offset;
    QList<QScreen*> subScreens;
    QPixmapDataFactory* pixmapFactory;
    QGraphicsSystem* graphicsSystem;
    QWSGraphicsSystem defaultGraphicsSystem; //###
    QImage::Format pixelFormat;
#if Q_BYTE_ORDER == Q_BIG_ENDIAN
    bool fb_is_littleEndian;
#endif
#ifdef QT_QWS_CLIENTBLIT
    bool supportsBlitInClients;
#endif
    int classId;
    QScreen *q_ptr;
};

template <typename T>
static void solidFill_template(QScreen *screen, const QColor &color,
                               const QRegion &region)
{
    T *dest = reinterpret_cast<T*>(screen->base());
    const T c = qt_colorConvert<T, quint32>(color.rgba(), 0);
    const int stride = screen->linestep();
    const QVector<QRect> rects = region.rects();

    for (int i = 0; i < rects.size(); ++i) {
        const QRect r = rects.at(i);
        qt_rectfill(dest, c, r.x(), r.y(), r.width(), r.height(), stride);
    }
}

#ifdef QT_QWS_DEPTH_GENERIC
static void solidFill_rgb_32bpp(QScreen *screen, const QColor &color,
                                const QRegion &region)
{
    quint32 *dest = reinterpret_cast<quint32*>(screen->base());
    const quint32 c = qt_convertToRgb<quint32>(color.rgba());

    const int stride = screen->linestep();
    const QVector<QRect> rects = region.rects();

    for (int i = 0; i < rects.size(); ++i) {
        const QRect r = rects.at(i);
        qt_rectfill(dest, c, r.x(), r.y(), r.width(), r.height(), stride);
    }
}

static void solidFill_rgb_16bpp(QScreen *screen, const QColor &color,
                                const QRegion &region)
{
    quint16 *dest = reinterpret_cast<quint16*>(screen->base());
    const quint16 c = qt_convertToRgb<quint32>(color.rgba());

    const int stride = screen->linestep();
    const QVector<QRect> rects = region.rects();

    for (int i = 0; i < rects.size(); ++i) {
        const QRect r = rects.at(i);
        qt_rectfill(dest, c, r.x(), r.y(), r.width(), r.height(), stride);
    }
}
#endif // QT_QWS_DEPTH_GENERIC

#ifdef QT_QWS_DEPTH_4
static inline void qt_rectfill_gray4(quint8 *dest, quint8 value,
                                     int x, int y, int width, int height,
                                     int stride)
{
    const int pixelsPerByte = 2;
    dest += y * stride + x / pixelsPerByte;
    const int doAlign = x & 1;
    const int doTail = (width - doAlign) & 1;
    const int width8 = (width - doAlign) / pixelsPerByte;

    for (int j = 0; j < height; ++j) {
        if (doAlign)
            *dest = (*dest & 0xf0) | (value & 0x0f);
        if (width8)
            qt_memfill<quint8>(dest + doAlign, value, width8);
        if (doTail) {
            quint8 *d = dest + doAlign + width8;
            *d = (*d & 0x0f) | (value & 0xf0);
        }
        dest += stride;
    }
}

static void solidFill_gray4(QScreen *screen, const QColor &color,
                            const QRegion &region)
{
    quint8 *dest = reinterpret_cast<quint8*>(screen->base());
    const quint8 c = qGray(color.rgba()) >> 4;
    const quint8 c8 = (c << 4) | c;

    const int stride = screen->linestep();
    const QVector<QRect> rects = region.rects();

    for (int i = 0; i < rects.size(); ++i) {
        const QRect r = rects.at(i);
        qt_rectfill_gray4(dest, c8, r.x(), r.y(), r.width(), r.height(),
                          stride);
    }
}
#endif // QT_QWS_DEPTH_4

#ifdef QT_QWS_DEPTH_1
static inline void qt_rectfill_mono(quint8 *dest, quint8 value,
                                    int x, int y, int width, int height,
                                    int stride)
{
    const int pixelsPerByte = 8;
    const int alignWidth = qMin(width, (8 - (x & 7)) & 7);
    const int doAlign = (alignWidth > 0 ? 1 : 0);
    const int alignStart = pixelsPerByte - 1 - (x & 7);
    const int alignStop = alignStart - (alignWidth - 1);
    const quint8 alignMask = ((1 << alignWidth) - 1) << alignStop;
    const int tailWidth = (width - alignWidth) & 7;
    const int doTail = (tailWidth > 0 ? 1 : 0);
    const quint8 tailMask = (1 << (pixelsPerByte - tailWidth)) - 1;
    const int width8 = (width - alignWidth) / pixelsPerByte;

    dest += y * stride + x / pixelsPerByte;
    stride -= (doAlign + width8);

    for (int j = 0; j < height; ++j) {
        if (doAlign) {
            *dest = (*dest & ~alignMask) | (value & alignMask);
            ++dest;
        }
        if (width8) {
            qt_memfill<quint8>(dest, value, width8);
            dest += width8;
        }
        if (doTail)
            *dest = (*dest & tailMask) | (value & ~tailMask);
        dest += stride;
    }
}

static void solidFill_mono(QScreen *screen, const QColor &color,
                           const QRegion &region)
{
    quint8 *dest = reinterpret_cast<quint8*>(screen->base());
    const quint8 c8 = (qGray(color.rgba()) >> 7) * 0xff;

    const int stride = screen->linestep();
    const QVector<QRect> rects = region.rects();

    for (int i = 0; i < rects.size(); ++i) {
        const QRect r = rects.at(i);
        qt_rectfill_mono(dest, c8, r.x(), r.y(), r.width(), r.height(),
                         stride);
    }
}
#endif // QT_QWS_DEPTH_1

void qt_solidFill_setup(QScreen *screen, const QColor &color,
                        const QRegion &region)
{
    switch (screen->depth()) {
#ifdef QT_QWS_DEPTH_32
    case 32:
        if (screen->pixelType() == QScreen::NormalPixel)
            screen->d_ptr->solidFill = solidFill_template<quint32>;
        else
            screen->d_ptr->solidFill = solidFill_template<qabgr8888>;
        break;
#endif
#ifdef QT_QWS_DEPTH_24
    case 24:
        if (screen->pixelType() == QScreen::NormalPixel)
            screen->d_ptr->solidFill = solidFill_template<qrgb888>;
        else
            screen->d_ptr->solidFill = solidFill_template<quint24>;
        break;
#endif
#ifdef QT_QWS_DEPTH_18
    case 18:
        screen->d_ptr->solidFill = solidFill_template<quint18>;
        break;
#endif
#ifdef QT_QWS_DEPTH_16
    case 16:
        if (screen->pixelType() == QScreen::NormalPixel)
            screen->d_ptr->solidFill = solidFill_template<quint16>;
        else
            screen->d_ptr->solidFill = solidFill_template<qbgr565>;
        break;
#endif
#ifdef QT_QWS_DEPTH_15
    case 15:
        if (screen->pixelType() == QScreen::NormalPixel)
            screen->d_ptr->solidFill = solidFill_template<qrgb555>;
        else
            screen->d_ptr->solidFill = solidFill_template<qbgr555>;
        break;
#endif
#ifdef QT_QWS_DEPTH_12
    case 12:
        screen->d_ptr->solidFill = solidFill_template<qrgb444>;
        break;
#endif
#ifdef QT_QWS_DEPTH_8
    case 8:
        screen->d_ptr->solidFill = solidFill_template<quint8>;
        break;
#endif
#ifdef QT_QWS_DEPTH_4
    case 4:
        screen->d_ptr->solidFill = solidFill_gray4;
        break;
#endif
#ifdef QT_QWS_DEPTH_1
    case 1:
        screen->d_ptr->solidFill = solidFill_mono;
        break;
#endif
     default:
        qFatal("solidFill_setup(): Screen depth %d not supported!",
               screen->depth());
        screen->d_ptr->solidFill = 0;
        break;
    }
    screen->d_ptr->solidFill(screen, color, region);
}

template <typename DST, typename SRC>
static void blit_template(QScreen *screen, const QImage &image,
                          const QPoint &topLeft, const QRegion &region)
{
    DST *dest = reinterpret_cast<DST*>(screen->base());
    const int screenStride = screen->linestep();
    const int imageStride = image.bytesPerLine();

    if (region.rectCount() == 1) {
        const QRect r = region.boundingRect();
        const SRC *src = reinterpret_cast<const SRC*>(image.scanLine(r.y()))
                         + r.x();
        qt_rectconvert<DST, SRC>(dest, src,
                                 r.x() + topLeft.x(), r.y() + topLeft.y(),
                                 r.width(), r.height(),
                                 screenStride, imageStride);
    } else {
        const QVector<QRect> rects = region.rects();

        for (int i = 0; i < rects.size(); ++i) {
            const QRect r = rects.at(i);
            const SRC *src = reinterpret_cast<const SRC*>(image.scanLine(r.y()))
                             + r.x();
            qt_rectconvert<DST, SRC>(dest, src,
                                     r.x() + topLeft.x(), r.y() + topLeft.y(),
                                     r.width(), r.height(),
                                     screenStride, imageStride);
        }
    }
}

#ifdef QT_QWS_DEPTH_32
static void blit_32(QScreen *screen, const QImage &image,
                    const QPoint &topLeft, const QRegion &region)
{
    switch (image.format()) {
    case QImage::Format_RGB32:
    case QImage::Format_ARGB32:
    case QImage::Format_ARGB32_Premultiplied:
        blit_template<quint32, quint32>(screen, image, topLeft, region);
        return;
#ifdef QT_QWS_DEPTH_16
    case QImage::Format_RGB16:
        blit_template<quint32, quint16>(screen, image, topLeft, region);
        return;
#endif
    default:
        qCritical("blit_32(): Image format %d not supported!", image.format());
    }
}
#endif // QT_QWS_DEPTH_32

#ifdef QT_QWS_DEPTH_24
static void blit_24(QScreen *screen, const QImage &image,
                    const QPoint &topLeft, const QRegion &region)
{
    switch (image.format()) {
    case QImage::Format_RGB32:
    case QImage::Format_ARGB32:
    case QImage::Format_ARGB32_Premultiplied:
        blit_template<quint24, quint32>(screen, image, topLeft, region);
        return;
    case QImage::Format_RGB888:
        blit_template<quint24, qrgb888>(screen, image, topLeft, region);
        return;
#ifdef QT_QWS_DEPTH_16
    case QImage::Format_RGB16:
        blit_template<quint24, quint16>(screen, image, topLeft, region);
        return;
#endif
    default:
        qCritical("blit_24(): Image format %d not supported!", image.format());
    }
}

static void blit_qrgb888(QScreen *screen, const QImage &image,
                         const QPoint &topLeft, const QRegion &region)
{
    switch (image.format()) {
    case QImage::Format_RGB32:
    case QImage::Format_ARGB32:
    case QImage::Format_ARGB32_Premultiplied:
        blit_template<qrgb888, quint32>(screen, image, topLeft, region);
        return;
    case QImage::Format_RGB888:
        blit_template<qrgb888, qrgb888>(screen, image, topLeft, region);
        return;
#ifdef QT_QWS_DEPTH_16
    case QImage::Format_RGB16:
        blit_template<qrgb888, quint16>(screen, image, topLeft, region);
        return;
#endif
    default:
        qCritical("blit_24(): Image format %d not supported!", image.format());
        break;
    }
}
#endif // QT_QWS_DEPTH_24

#ifdef QT_QWS_DEPTH_18
static void blit_18(QScreen *screen, const QImage &image,
                    const QPoint &topLeft, const QRegion &region)
{
    switch (image.format()) {
    case QImage::Format_RGB32:
    case QImage::Format_ARGB32:
    case QImage::Format_ARGB32_Premultiplied:
        blit_template<qrgb666, quint32>(screen, image, topLeft, region);
        return;
    case QImage::Format_RGB666:
        blit_template<qrgb666, qrgb666>(screen, image, topLeft, region);
        return;
#ifdef QT_QWS_DEPTH_16
    case QImage::Format_RGB16:
        blit_template<qrgb666, quint16>(screen, image, topLeft, region);
        return;
#endif
    default:
        qCritical("blit_18(): Image format %d not supported!", image.format());
    }
}
#endif // QT_QWS_DEPTH_18

#if (Q_BYTE_ORDER == Q_BIG_ENDIAN) && (defined(QT_QWS_DEPTH_16) || defined(QT_QWS_DEPTH_15))
class quint16LE
{
public:
    inline quint16LE(quint32 v) {
        data = ((v & 0xff00) >> 8) | ((v & 0x00ff) << 8);
    }

    inline quint16LE(int v) {
        data = ((v & 0xff00) >> 8) | ((v & 0x00ff) << 8);
    }

    inline quint16LE(quint16 v) {
        data = ((v & 0xff00) >> 8) | ((v & 0x00ff) << 8);
    }

    inline quint16LE(qrgb555 v) {
        data = (( (quint16)v & 0xff00) >> 8) |
               (( (quint16)v & 0x00ff) << 8);
    }

    inline bool operator==(const quint16LE &v) const
    {
        return data == v.data;
    }

private:
    quint16 data;
};
#endif

#ifdef QT_QWS_DEPTH_16
static void blit_16(QScreen *screen, const QImage &image,
                    const QPoint &topLeft, const QRegion &region)
{
    switch (image.format()) {
    case QImage::Format_RGB32:
    case QImage::Format_ARGB32:
    case QImage::Format_ARGB32_Premultiplied:
        // ### This probably doesn't work but it's a case which should never happen
        blit_template<quint16, quint32>(screen, image, topLeft, region);
        return;
    case QImage::Format_RGB16:
        blit_template<quint16, quint16>(screen, image, topLeft, region);
        return;
    default:
        qCritical("blit_16(): Image format %d not supported!", image.format());
    }
}

#if Q_BYTE_ORDER == Q_BIG_ENDIAN
static void blit_16_bigToLittleEndian(QScreen *screen, const QImage &image,
                                      const QPoint &topLeft,
                                      const QRegion &region)
{
    switch (image.format()) {
    case QImage::Format_RGB32:
    case QImage::Format_ARGB32:
    case QImage::Format_ARGB32_Premultiplied:
        blit_template<quint16LE, quint32>(screen, image, topLeft, region);
        return;
    case QImage::Format_RGB16:
        blit_template<quint16LE, quint16>(screen, image, topLeft, region);
        return;
    default:
        qCritical("blit_16_bigToLittleEndian(): Image format %d not supported!", image.format());
    }
}

#endif // Q_BIG_ENDIAN
#endif // QT_QWS_DEPTH_16

#ifdef QT_QWS_DEPTH_15
static void blit_15(QScreen *screen, const QImage &image,
                    const QPoint &topLeft, const QRegion &region)
{
    switch (image.format()) {
    case QImage::Format_RGB32:
    case QImage::Format_ARGB32:
    case QImage::Format_ARGB32_Premultiplied:
        blit_template<qrgb555, quint32>(screen, image, topLeft, region);
        return;
    case QImage::Format_RGB555:
        blit_template<qrgb555, qrgb555>(screen, image, topLeft, region);
        return;
    case QImage::Format_RGB16:
        blit_template<qrgb555, quint16>(screen, image, topLeft, region);
        return;
    default:
        qCritical("blit_15(): Image format %d not supported!", image.format());
    }
}

#if Q_BYTE_ORDER == Q_BIG_ENDIAN
static void blit_15_bigToLittleEndian(QScreen *screen, const QImage &image,
                                      const QPoint &topLeft,
                                      const QRegion &region)
{
    switch (image.format()) {
    case QImage::Format_RGB555:
        blit_template<quint16LE, qrgb555>(screen, image, topLeft, region);
        return;
    default:
        qCritical("blit_15_bigToLittleEndian(): Image format %d not supported!", image.format());
    }
}
#endif // Q_BIG_ENDIAN
#endif // QT_QWS_DEPTH_15


#ifdef QT_QWS_DEPTH_12
static void blit_12(QScreen *screen, const QImage &image,
                    const QPoint &topLeft, const QRegion &region)
{
    switch (image.format()) {
    case QImage::Format_ARGB4444_Premultiplied:
        blit_template<qrgb444, qargb4444>(screen, image, topLeft, region);
        return;
    case QImage::Format_RGB444:
        blit_template<qrgb444, qrgb444>(screen, image, topLeft, region);
        return;
    default:
        qCritical("blit_12(): Image format %d not supported!", image.format());
    }
}
#endif // QT_QWS_DEPTH_12

#ifdef QT_QWS_DEPTH_8
static void blit_8(QScreen *screen, const QImage &image,
                   const QPoint &topLeft, const QRegion &region)
{
    switch (image.format()) {
    case QImage::Format_RGB32:
    case QImage::Format_ARGB32:
    case QImage::Format_ARGB32_Premultiplied:
        blit_template<quint8, quint32>(screen, image, topLeft, region);
        return;
    case QImage::Format_RGB16:
        blit_template<quint8, quint16>(screen, image, topLeft, region);
        return;
    case QImage::Format_ARGB4444_Premultiplied:
        blit_template<quint8, qargb4444>(screen, image, topLeft, region);
        return;
    case QImage::Format_RGB444:
        blit_template<quint8, qrgb444>(screen, image, topLeft, region);
        return;
    default:
        qCritical("blit_8(): Image format %d not supported!", image.format());
    }
}
#endif // QT_QWS_DEPTH_8

#ifdef QT_QWS_DEPTH_4

struct qgray4 { quint8 dummy; } Q_PACKED;

template <typename SRC>
Q_STATIC_TEMPLATE_FUNCTION inline quint8 qt_convertToGray4(SRC color);

template <>
inline quint8 qt_convertToGray4(quint32 color)
{
    return qGray(color) >> 4;
}

template <>
inline quint8 qt_convertToGray4(quint16 color)
{
    const int r = (color & 0xf800) >> 11;
    const int g = (color & 0x07e0) >> 6; // only keep 5 bit
    const int b = (color & 0x001f);
    return (r * 11 + g * 16 + b * 5) >> 6;
}

template <>
inline quint8 qt_convertToGray4(qrgb444 color)
{
    return qt_convertToGray4(quint32(color));
}

template <>
inline quint8 qt_convertToGray4(qargb4444 color)
{
    return qt_convertToGray4(quint32(color));
}

template <typename SRC>
Q_STATIC_TEMPLATE_FUNCTION inline void qt_rectconvert_gray4(qgray4 *dest4, const SRC *src,
                                        int x, int y, int width, int height,
                                        int dstStride, int srcStride)
{
    const int pixelsPerByte = 2;
    quint8 *dest8 = reinterpret_cast<quint8*>(dest4)
                    + y * dstStride + x / pixelsPerByte;
    const int doAlign = x & 1;
    const int doTail = (width - doAlign) & 1;
    const int width8 = (width - doAlign) / pixelsPerByte;
    const int count8 = (width8 + 3) / 4;

    srcStride = srcStride / sizeof(SRC) - width;
    dstStride -= (width8 + doAlign);

    for (int i = 0; i < height; ++i) {
        if (doAlign) {
            *dest8 = (*dest8 & 0xf0) | qt_convertToGray4<SRC>(*src++);
            ++dest8;
        }
        if (count8) {
            int n = count8;
            switch (width8 & 0x03) // duff's device
            {
            case 0: do { *dest8++ = qt_convertToGray4<SRC>(src[0]) << 4
                                    | qt_convertToGray4<SRC>(src[1]);
                         src += 2;
            case 3:      *dest8++ = qt_convertToGray4<SRC>(src[0]) << 4
                                    | qt_convertToGray4<SRC>(src[1]);
                         src += 2;
            case 2:      *dest8++ = qt_convertToGray4<SRC>(src[0]) << 4
                                    | qt_convertToGray4<SRC>(src[1]);
                         src += 2;
            case 1:      *dest8++ = qt_convertToGray4<SRC>(src[0]) << 4
                                    | qt_convertToGray4<SRC>(src[1]);
                         src += 2;
            } while (--n > 0);
            }
        }

        if (doTail)
            *dest8 = qt_convertToGray4<SRC>(*src++) << 4 | (*dest8 & 0x0f);

        dest8 += dstStride;
        src += srcStride;
    }
}

template <>
void qt_rectconvert(qgray4 *dest, const quint32 *src,
                    int x, int y, int width, int height,
                    int dstStride, int srcStride)
{
    qt_rectconvert_gray4<quint32>(dest, src, x, y, width, height,
                                  dstStride, srcStride);
}

template <>
void qt_rectconvert(qgray4 *dest, const quint16 *src,
                    int x, int y, int width, int height,
                    int dstStride, int srcStride)
{
    qt_rectconvert_gray4<quint16>(dest, src, x, y, width, height,
                                  dstStride, srcStride);
}

template <>
void qt_rectconvert(qgray4 *dest, const qrgb444 *src,
                    int x, int y, int width, int height,
                    int dstStride, int srcStride)
{
    qt_rectconvert_gray4<qrgb444>(dest, src, x, y, width, height,
                                  dstStride, srcStride);
}

template <>
void qt_rectconvert(qgray4 *dest, const qargb4444 *src,
                    int x, int y, int width, int height,
                    int dstStride, int srcStride)
{
    qt_rectconvert_gray4<qargb4444>(dest, src, x, y, width, height,
                                    dstStride, srcStride);
}

static void blit_4(QScreen *screen, const QImage &image,
                   const QPoint &topLeft, const QRegion &region)
{
    switch (image.format()) {
    case QImage::Format_ARGB32_Premultiplied:
        blit_template<qgray4, quint32>(screen, image, topLeft, region);
        return;
    case QImage::Format_RGB16:
        blit_template<qgray4, quint16>(screen, image, topLeft, region);
        return;
    case QImage::Format_RGB444:
        blit_template<qgray4, qrgb444>(screen, image, topLeft, region);
        return;
    case QImage::Format_ARGB4444_Premultiplied:
        blit_template<qgray4, qargb4444>(screen, image, topLeft, region);
        return;
    default:
        qCritical("blit_4(): Image format %d not supported!", image.format());
    }
}
#endif // QT_QWS_DEPTH_4

#ifdef QT_QWS_DEPTH_1

struct qmono { quint8 dummy; } Q_PACKED;

template <typename SRC>
Q_STATIC_TEMPLATE_FUNCTION inline quint8 qt_convertToMono(SRC color);

template <>
inline quint8 qt_convertToMono(quint32 color)
{
    return qGray(color) >> 7;
}

template <>
inline quint8 qt_convertToMono(quint16 color)
{
    return (qGray(qt_colorConvert<quint32, quint16>(color, 0)) >> 7);
}

template <>
inline quint8 qt_convertToMono(qargb4444 color)
{
    return (qGray(quint32(color)) >> 7);
}

template <>
inline quint8 qt_convertToMono(qrgb444 color)
{
    return (qGray(quint32(color)) >> 7);
}

template <typename SRC>
inline void qt_rectconvert_mono(qmono *dest, const SRC *src,
                                       int x, int y, int width, int height,
                                       int dstStride, int srcStride)
{
    const int pixelsPerByte = 8;
    quint8 *dest8 = reinterpret_cast<quint8*>(dest)
                    + y * dstStride + x / pixelsPerByte;
    const int alignWidth = qMin(width, (8 - (x & 7)) & 7);
    const int doAlign = (alignWidth > 0 ? 1 : 0);
    const int alignStart = pixelsPerByte - 1 - (x & 7);
    const int alignStop = alignStart - (alignWidth - 1);
    const quint8 alignMask = ((1 << alignWidth) - 1) << alignStop;
    const int tailWidth = (width - alignWidth) & 7;
    const int doTail = (tailWidth > 0 ? 1 : 0);
    const quint8 tailMask = (1 << (pixelsPerByte - tailWidth)) - 1;
    const int width8 = (width - alignWidth) / pixelsPerByte;

    srcStride = srcStride / sizeof(SRC) - (width8 * 8 + alignWidth);
    dstStride -= (width8 + doAlign);

    for (int j = 0;  j < height; ++j) {
        if (doAlign) {
            quint8 d = *dest8 & ~alignMask;
            for (int i = alignStart; i >= alignStop; --i)
                d |= qt_convertToMono<SRC>(*src++) << i;
            *dest8++ = d;
        }
        for (int i = 0; i < width8; ++i) {
            *dest8 = (qt_convertToMono<SRC>(src[0]) << 7)
                     | (qt_convertToMono<SRC>(src[1]) << 6)
                     | (qt_convertToMono<SRC>(src[2]) << 5)
                     | (qt_convertToMono<SRC>(src[3]) << 4)
                     | (qt_convertToMono<SRC>(src[4]) << 3)
                     | (qt_convertToMono<SRC>(src[5]) << 2)
                     | (qt_convertToMono<SRC>(src[6]) << 1)
                     | (qt_convertToMono<SRC>(src[7]));
            src += 8;
            ++dest8;
        }
        if (doTail) {
            quint8 d = *dest8 & tailMask;
            switch (tailWidth) {
            case 7: d |= qt_convertToMono<SRC>(src[6]) << 1;
            case 6: d |= qt_convertToMono<SRC>(src[5]) << 2;
            case 5: d |= qt_convertToMono<SRC>(src[4]) << 3;
            case 4: d |= qt_convertToMono<SRC>(src[3]) << 4;
            case 3: d |= qt_convertToMono<SRC>(src[2]) << 5;
            case 2: d |= qt_convertToMono<SRC>(src[1]) << 6;
            case 1: d |= qt_convertToMono<SRC>(src[0]) << 7;
            }
            *dest8 = d;
        }

        dest8 += dstStride;
        src += srcStride;
    }
}

template <>
void qt_rectconvert(qmono *dest, const quint32 *src,
                    int x, int y, int width, int height,
                    int dstStride, int srcStride)
{
    qt_rectconvert_mono<quint32>(dest, src, x, y, width, height,
                                 dstStride, srcStride);
}

template <>
void qt_rectconvert(qmono *dest, const quint16 *src,
                    int x, int y, int width, int height,
                    int dstStride, int srcStride)
{
    qt_rectconvert_mono<quint16>(dest, src, x, y, width, height,
                                 dstStride, srcStride);
}

template <>
void qt_rectconvert(qmono *dest, const qrgb444 *src,
                    int x, int y, int width, int height,
                    int dstStride, int srcStride)
{
    qt_rectconvert_mono<qrgb444>(dest, src, x, y, width, height,
                                 dstStride, srcStride);
}

template <>
void qt_rectconvert(qmono *dest, const qargb4444 *src,
                    int x, int y, int width, int height,
                    int dstStride, int srcStride)
{
    qt_rectconvert_mono<qargb4444>(dest, src, x, y, width, height,
                                   dstStride, srcStride);
}

static void blit_1(QScreen *screen, const QImage &image,
                   const QPoint &topLeft, const QRegion &region)
{
    switch (image.format()) {
    case QImage::Format_ARGB32_Premultiplied:
        blit_template<qmono, quint32>(screen, image, topLeft, region);
        return;
    case QImage::Format_RGB16:
        blit_template<qmono, quint16>(screen, image, topLeft, region);
        return;
    case QImage::Format_RGB444:
        blit_template<qmono, qrgb444>(screen, image, topLeft, region);
        return;
    case QImage::Format_ARGB4444_Premultiplied:
        blit_template<qmono, qargb4444>(screen, image, topLeft, region);
        return;
    default:
        qCritical("blit_1(): Image format %d not supported!", image.format());
    }
}
#endif // QT_QWS_DEPTH_1

#ifdef QT_QWS_DEPTH_GENERIC

static void blit_rgb(QScreen *screen, const QImage &image,
                     const QPoint &topLeft, const QRegion &region)
{
    switch (image.format()) {
    case QImage::Format_ARGB32_Premultiplied:
        blit_template<qrgb, quint32>(screen, image, topLeft, region);
        return;
    case QImage::Format_RGB16:
        blit_template<qrgb, quint16>(screen, image, topLeft, region);
        return;
    default:
        qCritical("blit_rgb(): Image format %d not supported!", image.format());
    }
}

void qt_set_generic_blit(QScreen *screen, int bpp,
                         int len_red, int len_green, int len_blue, int len_alpha,
                         int off_red, int off_green, int off_blue, int off_alpha)
{
    qrgb::bpp = bpp / 8;
    qrgb::len_red = len_red;
    qrgb::len_green = len_green;
    qrgb::len_blue = len_blue;
    qrgb::len_alpha = len_alpha;
    qrgb::off_red = off_red;
    qrgb::off_green = off_green;
    qrgb::off_blue = off_blue;
    qrgb::off_alpha = off_alpha;
    screen->d_ptr->blit = blit_rgb;
    if (bpp == 16)
        screen->d_ptr->solidFill = solidFill_rgb_16bpp;
    else if (bpp == 32)
        screen->d_ptr->solidFill = solidFill_rgb_32bpp;
}

#endif // QT_QWS_DEPTH_GENERIC

void qt_blit_setup(QScreen *screen, const QImage &image,
                   const QPoint &topLeft, const QRegion &region)
{
    switch (screen->depth()) {
#ifdef QT_QWS_DEPTH_32
    case 32:
        if (screen->pixelType() == QScreen::NormalPixel)
            screen->d_ptr->blit = blit_32;
        else
            screen->d_ptr->blit = blit_template<qabgr8888, quint32>;
        break;
#endif
#ifdef QT_QWS_DEPTH_24
    case 24:
        if (screen->pixelType() == QScreen::NormalPixel)
            screen->d_ptr->blit = blit_qrgb888;
        else
            screen->d_ptr->blit = blit_24;
        break;
#endif
#ifdef QT_QWS_DEPTH_18
    case 18:
        screen->d_ptr->blit = blit_18;
        break;
#endif
#ifdef QT_QWS_DEPTH_16
    case 16:
#if Q_BYTE_ORDER == Q_BIG_ENDIAN
        if (screen->d_ptr->fb_is_littleEndian)
            screen->d_ptr->blit = blit_16_bigToLittleEndian;
        else
#endif
        if (screen->pixelType() == QScreen::NormalPixel)
            screen->d_ptr->blit = blit_16;
        else
            screen->d_ptr->blit = blit_template<qbgr565, quint16>;
        break;
#endif
#ifdef QT_QWS_DEPTH_15
    case 15:
#if Q_BYTE_ORDER == Q_BIG_ENDIAN
        if (screen->d_ptr->fb_is_littleEndian)
            screen->d_ptr->blit = blit_15_bigToLittleEndian;
        else
#endif // Q_BIG_ENDIAN
        if (screen->pixelType() == QScreen::NormalPixel)
            screen->d_ptr->blit = blit_15;
        else
            screen->d_ptr->blit = blit_template<qbgr555, qrgb555>;
        break;
#endif
#ifdef QT_QWS_DEPTH_12
    case 12:
        screen->d_ptr->blit = blit_12;
        break;
#endif
#ifdef QT_QWS_DEPTH_8
    case 8:
        screen->d_ptr->blit = blit_8;
        break;
#endif
#ifdef QT_QWS_DEPTH_4
    case 4:
        screen->d_ptr->blit = blit_4;
        break;
#endif
#ifdef QT_QWS_DEPTH_1
    case 1:
        screen->d_ptr->blit = blit_1;
        break;
#endif
    default:
        qFatal("blit_setup(): Screen depth %d not supported!",
               screen->depth());
        screen->d_ptr->blit = 0;
        break;
    }
    screen->d_ptr->blit(screen, image, topLeft, region);
}

QScreenPrivate::QScreenPrivate(QScreen *parent, QScreen::ClassId id)
    : defaultGraphicsSystem(QWSGraphicsSystem(parent)),
      pixelFormat(QImage::Format_Invalid),
#ifdef QT_QWS_CLIENTBLIT
      supportsBlitInClients(false),
#endif
      classId(id), q_ptr(parent)
{
    solidFill = qt_solidFill_setup;
    blit = qt_blit_setup;
#if Q_BYTE_ORDER == Q_BIG_ENDIAN
    fb_is_littleEndian = false;
#endif
    pixmapFactory = 0;
    graphicsSystem = &defaultGraphicsSystem;
}

QScreenPrivate::~QScreenPrivate()
{
}

QImage::Format QScreenPrivate::preferredImageFormat() const
{
    if (pixelFormat > QImage::Format_Indexed8)
        return pixelFormat;

    if (q_ptr->depth() <= 16)
        return QImage::Format_RGB16;
    else
        return QImage::Format_ARGB32_Premultiplied;
}

// Unaccelerated screen/driver setup. Can be overridden by accelerated
// drivers

QScreen::QScreen(int display_id, ClassId classId)
    : screencols(0), data(0), entries(0), entryp(0), lowest(0),
      w(0), lstep(0), h(0), d(1), pixeltype(NormalPixel), grayscale(false),
      dw(0), dh(0), size(0), mapsize(0), displayId(display_id),
      physWidth(0), physHeight(0), d_ptr(new QScreenPrivate(this, classId))
{
    clearCacheFunc = 0;
}

QScreen::QScreen(int display_id)
    : screencols(0), data(0), entries(0), entryp(0), lowest(0),
      w(0), lstep(0), h(0), d(1), pixeltype(NormalPixel), grayscale(false),
      dw(0), dh(0), size(0), mapsize(0), displayId(display_id),
      physWidth(0), physHeight(0), d_ptr(new QScreenPrivate(this))
{
    clearCacheFunc = 0;
}

QScreen::~QScreen()
{
    delete d_ptr;
}

void QScreen::shutdownDevice()
{
#ifndef QT_NO_QWS_CURSOR
    if (qt_screencursor)
        qt_screencursor->hide();
#endif
}

extern bool qws_accel; //in qapplication_qws.cpp

QImage::Format QScreen::pixelFormat() const
{
    return d_ptr->pixelFormat;
}

void QScreen::setPixelFormat(QImage::Format format)
{
    d_ptr->pixelFormat = format;
}


int QScreen::alloc(unsigned int r,unsigned int g,unsigned int b)
{
    int ret = 0;
    if (d == 8) {
        if (grayscale)
            return qGray(r, g, b);

        // First we look to see if we match a default color
        const int pos = (r + 25) / 51 * 36 + (g + 25) / 51 * 6 + (b + 25) / 51;
        if (pos < screencols && screenclut[pos] == qRgb(r, g, b)) {
            return pos;
        }

        // search for nearest color
        unsigned int mindiff = 0xffffffff;
        unsigned int diff;
        int dr,dg,db;

        for (int loopc = 0; loopc < screencols; ++loopc) {
            dr = qRed(screenclut[loopc]) - r;
            dg = qGreen(screenclut[loopc]) - g;
            db = qBlue(screenclut[loopc]) - b;
            diff = dr*dr + dg*dg + db*db;

            if (diff < mindiff) {
                ret = loopc;
                if (!diff)
                    break;
                mindiff = diff;
            }
        }
    } else if (d == 4) {
        ret = qGray(r, g, b) >> 4;
    } else if (d == 1) {
        ret = qGray(r, g, b) >= 128;
    } else {
        qFatal("cannot alloc %dbpp color", d);
    }

    return ret;
}

void QScreen::save()
{
}

void QScreen::restore()
{
}

void QScreen::blank(bool)
{
}

void QScreen::set(unsigned int, unsigned int, unsigned int, unsigned int)
{
}

bool QScreen::supportsDepth(int d) const
{
    if (false) {
        //Just to simplify the ifdeffery
#ifdef QT_QWS_DEPTH_1
    } else if(d==1) {
        return true;
#endif
#ifdef QT_QWS_DEPTH_4
    } else if(d==4) {
        return true;
#endif
#ifdef QT_QWS_DEPTH_8
    } else if(d==8) {
        return true;
#endif
#ifdef QT_QWS_DEPTH_16
    } else if(d==16) {
        return true;
#endif
#ifdef QT_QWS_DEPTH_15
    } else if (d == 15) {
        return true;
#endif
#ifdef QT_QWS_DEPTH_18
    } else if(d==18 || d==19) {
        return true;
#endif
#ifdef QT_QWS_DEPTH_24
    } else if(d==24) {
        return true;
#endif
#ifdef QT_QWS_DEPTH_32
    } else if(d==32) {
        return true;
#endif
    }
    return false;
}

bool QScreen::onCard(const unsigned char * p) const
{
    long t=(unsigned long)p;
    long bmin=(unsigned long)data;
    if (t < bmin)
        return false;
    if(t >= bmin+mapsize)
        return false;
    return true;
}

bool QScreen::onCard(const unsigned char * p, ulong& offset) const
{
    long t=(unsigned long)p;
    long bmin=(unsigned long)data;
    if (t < bmin)
        return false;
    long o = t - bmin;
    if (o >= mapsize)
        return false;
    offset = o;
    return true;
}

/*
#if !defined(QT_NO_QWS_REPEATER)
    { "Repeater", qt_get_screen_repeater, 0 },
#endif
#if defined(QT_QWS_EE)
    { "EE", qt_get_screen_ee, 0 },
#endif

*/

/*
Given a display_id (number of the \l{Qt for Embedded Linux} server to connect to)
and a spec (e.g. Mach64:/dev/fb0) return a QScreen-descendant.
The QScreenDriverFactory is queried for a suitable driver and, if found,
asked to create a driver.
People writing new graphics drivers should either hook their own
QScreen-descendant into QScreenDriverFactory or use the QScreenDriverPlugin
to make a dynamically loadable driver.
*/

Q_GUI_EXPORT QScreen* qt_get_screen(int display_id, const char *spec)
{
    QString displaySpec = QString::fromAscii(spec);
    QString driver = displaySpec;
    int colon = displaySpec.indexOf(QLatin1Char(':'));
    if (colon >= 0)
        driver.truncate(colon);
    driver = driver.trimmed();

    bool foundDriver = false;
    QString driverName = driver;

    QStringList driverList;
    if (!driver.isEmpty())
        driverList << driver;
    else
        driverList = QScreenDriverFactory::keys();

    for (int i = 0; i < driverList.size(); ++i) {
        const QString driverName = driverList.at(i);
        qt_screen = QScreenDriverFactory::create(driverName, display_id);
        if (qt_screen) {
            foundDriver = true;
            if (qt_screen->connect(displaySpec)) {
                return qt_screen;
            } else {
                delete qt_screen;
                qt_screen = 0;
            }
        }
    }

    if (driver.isNull())
        qFatal("No suitable driver found");
    else if (foundDriver)
        qFatal("%s: driver cannot connect", driver.toLatin1().constData());
    else
        qFatal("%s: driver not found", driver.toLatin1().constData());

    return 0;
}

#ifndef QT_NO_QWS_CURSOR
static void blendCursor(QImage *dest, const QImage &cursor, const QPoint &offset)
{
    QRasterBuffer rb;
    rb.prepare(dest);

    QSpanData spanData;
    spanData.init(&rb, 0);
    spanData.type = QSpanData::Texture;
    spanData.initTexture(&cursor, 256);
    spanData.dx = -offset.x();
    spanData.dy = -offset.y();
    if (!spanData.blend)
        return;

    const QRect rect = QRect(offset, cursor.size())
                       & QRect(QPoint(0, 0), dest->size());
    const int w = rect.width();
    const int h = rect.height();

    QVarLengthArray<QT_FT_Span, 32> spans(h);
    for (int i = 0; i < h; ++i) {
        spans[i].x = rect.x();
        spans[i].len = w;
        spans[i].y = rect.y() + i;
        spans[i].coverage = 255;
    }
    spanData.blend(h, spans.constData(), &spanData);
}
#endif // QT_NO_QWS_CURSOR

void QScreen::exposeRegion(QRegion r, int windowIndex)
{
    r &= region();
    if (r.isEmpty())
        return;

    int changing = windowIndex;
    // when we have just lowered a window, we have to expose all the windows below where the
    // window used to be.
    if (changing && qwsServer->clientWindows().at(changing)->state() == QWSWindow::Lowering)
        changing = 0;
#ifdef QTOPIA_PERFTEST
    static enum { PerfTestUnknown, PerfTestOn, PerfTestOff } perfTestState = PerfTestUnknown;
    if(PerfTestUnknown == perfTestState) {
        if(::getenv("QTOPIA_PERFTEST"))
            perfTestState = PerfTestOn;
        else
            perfTestState = PerfTestOff;
    }
    if(PerfTestOn == perfTestState) {
        QWSWindow *changed = qwsServer->clientWindows().at(changing);
        if(!changed->client()->identity().isEmpty())
            qDebug() << "Performance  :  expose_region  :"
                     << changed->client()->identity()
                     << r.boundingRect() << ": "
                     << qPrintable( QTime::currentTime().toString( "h:mm:ss.zzz" ) );
    }
#endif

    const QRect bounds = r.boundingRect();
    QRegion blendRegion;
    QImage *blendBuffer = 0;

#ifndef QT_NO_QWS_CURSOR
    if (qt_screencursor && !qt_screencursor->isAccelerated()) {
        blendRegion = r & qt_screencursor->boundingRect();
    }
#endif
    compose(0, r, blendRegion, &blendBuffer, changing);

    if (blendBuffer && !blendBuffer->isNull()) {
        const QPoint offset = blendRegion.boundingRect().topLeft();
#ifndef QT_NO_QWS_CURSOR
        if (qt_screencursor && !qt_screencursor->isAccelerated()) {
            const QRect cursorRect = qt_screencursor->boundingRect();
            if (blendRegion.intersects(cursorRect)) {
                blendCursor(blendBuffer, qt_screencursor->image(),
                            cursorRect.topLeft() - offset);
            }
        }
#endif // QT_NO_QWS_CURSOR
        blit(*blendBuffer, offset, blendRegion);
        delete blendBuffer;
    }

    if (r.rectCount() == 1) {
        setDirty(r.boundingRect());
    } else {
        const QVector<QRect> rects = r.rects();
        for (int i = 0; i < rects.size(); ++i)
            setDirty(rects.at(i));
    }
}

void QScreen::blit(const QImage &img, const QPoint &topLeft, const QRegion &reg)
{
    const QRect bound = (region() & QRect(topLeft, img.size())).boundingRect();
    QWSDisplay::grab();
    d_ptr->blit(this, img, topLeft - offset(),
            (reg & bound).translated(-topLeft));
    QWSDisplay::ungrab();
}

#ifdef QT_QWS_CLIENTBLIT

bool QScreen::supportsBlitInClients() const
{
    return d_ptr->supportsBlitInClients;
}

void QScreen::setSupportsBlitInClients(bool supported)
{
    d_ptr->supportsBlitInClients = supported;
}
#endif

void QScreen::blit(QWSWindow *win, const QRegion &clip)
{
    QWSWindowSurface *surface = win->windowSurface();
    if (!surface)
        return;

    const QImage &img = surface->image();
    if (img.isNull())
        return;

    const QRegion rgn = clip & win->paintedRegion();
    if (rgn.isEmpty())
        return;

    surface->lock();
    blit(img, win->requestedRegion().boundingRect().topLeft(), rgn);
    surface->unlock();
}

struct fill_data {
    quint32 color;
    uchar *data;
    int lineStep;
    int x;
    int y;
    int w;
    int h;
};

// the base class implementation works in device coordinates, so that transformed drivers can use it
void QScreen::solidFill(const QColor &color, const QRegion &region)
{
    QWSDisplay::grab();
    d_ptr->solidFill(this, color,
                     region.translated(-offset()) & QRect(0, 0, dw, dh));
    QWSDisplay::ungrab();
}

QWSWindowSurface* QScreen::createSurface(const QString &key) const
{
#ifndef QT_NO_PAINTONSCREEN
    if (key == QLatin1String("OnScreen"))
        return new QWSOnScreenSurface;
    else
#endif
    if (key == QLatin1String("mem"))
        return new QWSLocalMemSurface;
#ifndef QT_NO_QWS_MULTIPROCESS
    else if (key == QLatin1String("shm"))
        return new QWSSharedMemSurface;
#endif
#ifndef QT_NO_PAINT_DEBUG
    else if (key == QLatin1String("Yellow"))
        return new QWSYellowSurface;
#endif
#ifndef QT_NO_DIRECTPAINTER
    else if (key == QLatin1String("DirectPainter"))
        return new QWSDirectPainterSurface;
#endif

    return 0;
}

#ifndef QT_NO_PAINTONSCREEN
bool QScreen::isWidgetPaintOnScreen(const QWidget *w)
{
    static int doOnScreen = -1;
    if (doOnScreen == -1) {
        const QByteArray env = qgetenv("QT_ONSCREEN_PAINT");
        if (env == "force")
            doOnScreen = 2;
        else
            doOnScreen = (env.toInt() > 0 ? 1 : 0);
    }

    if (doOnScreen == 2) // force
        return true;

    if (doOnScreen == 0 && !w->testAttribute(Qt::WA_PaintOnScreen))
        return false;

    return w->d_func()->isOpaque;
}
#endif

QWSWindowSurface* QScreen::createSurface(QWidget *widget) const
{
#ifndef QT_NO_PAINTONSCREEN
    if (isWidgetPaintOnScreen(widget) && base())
        return new QWSOnScreenSurface(widget);
    else
#endif
    if (QApplication::type() == QApplication::GuiServer)
        return new QWSLocalMemSurface(widget);
#ifndef QT_NO_QWS_MULTIPROCESS
    else
        return new QWSSharedMemSurface(widget);
#endif

    return 0;
}

void QScreen::compose(int level, const QRegion &exposed, QRegion &blend,
                      QImage **blendbuffer, int changing_level)
{
    QRect exposed_bounds = exposed.boundingRect();
    QWSWindow *win = 0;
    do {
        win = qwsServer->clientWindows().value(level); // null is background
        ++level;
    } while (win && !win->paintedRegion().boundingRect().intersects(exposed_bounds));

    QWSWindowSurface *surface = (win ? win->windowSurface() : 0);
    bool above_changing = level <= changing_level; // 0 is topmost

    QRegion exposedBelow = exposed;
    bool opaque = true;

    if (win) {
        opaque = win->isOpaque() || !surface->isBuffered();
        if (opaque) {
            exposedBelow -= win->paintedRegion();
            if (above_changing || !surface->isBuffered())
                blend -= exposed & win->paintedRegion();
        } else {
            blend += exposed & win->paintedRegion();
        }
    }
    if (win && !exposedBelow.isEmpty()) {
        compose(level, exposedBelow, blend, blendbuffer, changing_level);
    } else {
        QSize blendSize = blend.boundingRect().size();
        if (!blendSize.isNull()) {
            *blendbuffer = new QImage(blendSize, d_ptr->preferredImageFormat());
        }
    }

    const QRegion blitRegion = exposed - blend;
    if (!win)
        paintBackground(blitRegion);
    else if (!above_changing && surface->isBuffered())
        blit(win, blitRegion);

    QRegion blendRegion = exposed & blend;

    if (win)
        blendRegion &= win->paintedRegion();
    if (!blendRegion.isEmpty()) {

        QPoint off = blend.boundingRect().topLeft();

        QRasterBuffer rb;
        rb.prepare(*blendbuffer);
        QSpanData spanData;
        spanData.init(&rb, 0);
        if (!win) {
            const QImage::Format format = (*blendbuffer)->format();
            switch (format) {
            case QImage::Format_ARGB32_Premultiplied:
            case QImage::Format_ARGB32:
            case QImage::Format_ARGB8565_Premultiplied:
            case QImage::Format_ARGB8555_Premultiplied:
            case QImage::Format_ARGB6666_Premultiplied:
            case QImage::Format_ARGB4444_Premultiplied:
                spanData.rasterBuffer->compositionMode = QPainter::CompositionMode_Source;
                break;
            default:
                break;
            }
            spanData.setup(qwsServer->backgroundBrush(), 256, QPainter::CompositionMode_Source);
            spanData.dx = off.x();
            spanData.dy = off.y();
        } else if (!surface->isBuffered()) {
                return;
        } else {
            const QImage &img = surface->image();
            QPoint winoff = off - win->requestedRegion().boundingRect().topLeft();
            // convert win->opacity() from scale [0..255] to [0..256]
            int const_alpha = win->opacity();
            const_alpha += (const_alpha >> 7);
            spanData.type = QSpanData::Texture;
            spanData.initTexture(&img, const_alpha);
            spanData.dx = winoff.x();
            spanData.dy = winoff.y();
        }
        if (!spanData.blend)
            return;

        if (surface)
            surface->lock();
        const QVector<QRect> rects = blendRegion.rects();
        const int nspans = 256;
        QT_FT_Span spans[nspans];
        for (int i = 0; i < rects.size(); ++i) {
            int y = rects.at(i).y() - off.y();
            int ye = y + rects.at(i).height();
            int x = rects.at(i).x() - off.x();
            int len = rects.at(i).width();
            while (y < ye) {
                int n = qMin(nspans, ye - y);
                int i = 0;
                while (i < n) {
                    spans[i].x = x;
                    spans[i].len = len;
                    spans[i].y = y + i;
                    spans[i].coverage = 255;
                    ++i;
                }
                spanData.blend(n, spans, &spanData);
                y += n;
            }
        }
        if (surface)
            surface->unlock();
    }
}

void QScreen::paintBackground(const QRegion &r)
{
    const QBrush &bg = qwsServer->backgroundBrush();
    Qt::BrushStyle bs = bg.style();
    if (bs == Qt::NoBrush || r.isEmpty())
        return;

    if (bs == Qt::SolidPattern) {
        solidFill(bg.color(), r);
    } else {
        const QRect br = r.boundingRect();
        QImage img(br.size(), d_ptr->preferredImageFormat());
        QPoint off = br.topLeft();
        QRasterBuffer rb;
        rb.prepare(&img);
        QSpanData spanData;
        spanData.init(&rb, 0);
        spanData.setup(bg, 256, QPainter::CompositionMode_Source);
        spanData.dx = off.x();
        spanData.dy = off.y();
        Q_ASSERT(spanData.blend);

        const QVector<QRect> rects = r.rects();
        const int nspans = 256;
        QT_FT_Span spans[nspans];
        for (int i = 0; i < rects.size(); ++i) {
            int y = rects.at(i).y() - off.y();
            int ye = y + rects.at(i).height();
            int x = rects.at(i).x() - off.x();
            int len = rects.at(i).width();
            while (y < ye) {
                int n = qMin(nspans, ye - y);
                int i = 0;
                while (i < n) {
                    spans[i].x = x;
                    spans[i].len = len;
                    spans[i].y = y + i;
                    spans[i].coverage = 255;
                    ++i;
                }
                spanData.blend(n, spans, &spanData);
                y += n;
            }
        }
        blit(img, br.topLeft(), r);
    }
}

void QScreen::setDirty(const QRect&)
{
}

bool QScreen::isTransformed() const
{
    return false;
}

bool QScreen::isInterlaced() const
{
    return false;//qws_screen_is_interlaced;;
}

QSize QScreen::mapToDevice(const QSize &s) const
{
    return s;
}

QSize QScreen::mapFromDevice(const QSize &s) const
{
    return s;
}

QPoint QScreen::mapToDevice(const QPoint &p, const QSize &) const
{
    return p;
}

QPoint QScreen::mapFromDevice(const QPoint &p, const QSize &) const
{
    return p;
}

QRect QScreen::mapToDevice(const QRect &r, const QSize &) const
{
    return r;
}

QRect QScreen::mapFromDevice(const QRect &r, const QSize &) const
{
    return r;
}

QImage QScreen::mapToDevice(const QImage &i) const
{
    return i;
}

QImage QScreen::mapFromDevice(const QImage &i) const
{
    return i;
}

QRegion QScreen::mapToDevice(const QRegion &r, const QSize &) const
{
    return r;
}

QRegion QScreen::mapFromDevice(const QRegion &r, const QSize &) const
{
    return r;
}

int QScreen::transformOrientation() const
{
    return 0;
}

int QScreen::pixmapDepth() const
{
    return depth();
}

int QScreen::memoryNeeded(const QString&)
{
    return 0;
}

void QScreen::haltUpdates()
{
}

void QScreen::resumeUpdates()
{
}

void QScreen::setOffset(const QPoint &p)
{
    d_ptr->offset = p;
}

QPoint QScreen::offset() const
{
    return d_ptr->offset;
}

#if Q_BYTE_ORDER == Q_BIG_ENDIAN
void QScreen::setFrameBufferLittleEndian(bool littleEndian)
{
    d_ptr->fb_is_littleEndian = littleEndian;
}

bool QScreen::frameBufferLittleEndian() const
{
    return d_ptr->fb_is_littleEndian;
}
#endif

int QScreen::subScreenIndexAt(const QPoint &p) const
{
    const QList<QScreen*> screens = subScreens();
    const int n = screens.count();
    for (int i = 0; i < n; ++i) {
        if (screens.at(i)->region().contains(p))
            return i;
    }

    return -1;
}

#if 0
#ifdef QT_LOADABLE_MODULES
#include <dlfcn.h>

// ### needs update after driver init changes

static QScreen * qt_dodriver(char * driver,char * a,unsigned char * b)

{
    char buf[200];
    strcpy(buf,"/etc/qws/drivers/");
    qstrcpy(buf+17,driver);
    qDebug("Attempting driver %s",driver);

    void * handle;
    handle=dlopen(buf,RTLD_LAZY);
    if(handle==0) {
        qFatal("Module load error");
    }
    QScreen *(*qt_get_screen_func)(char *,unsigned char *);
    qt_get_screen_func=dlsym(handle,"qt_get_screen");
    if(qt_get_screen_func==0) {
        qFatal("Couldn't get symbol");
    }
    QScreen * ret=qt_get_screen_func(a,b);
    return ret;
}

static QScreen * qt_do_entry(char * entry)
{
    unsigned char config[256];

    FILE * f=fopen(entry,"r");
    if(!f) {
        return 0;
    }

    int r=fread(config,256,1,f);
    if(r<1)
        return 0;

    fclose(f);

    unsigned short vendorid=*((unsigned short int *)config);
    unsigned short deviceid=*(((unsigned short int *)config)+1);
    if(config[0xb]!=3)
        return 0;

    if(vendorid==0x1002) {
        if(deviceid==0x4c4d) {
            qDebug("Compaq Armada/IBM Thinkpad's Mach64 card");
            return qt_dodriver("mach64.so",entry,config);
        } else if(deviceid==0x4742) {
            qDebug("Desktop Rage Pro Mach64 card");
            return qt_dodriver("mach64.so",entry,config);
        } else {
            qDebug("Unrecognised ATI card id %x",deviceid);
            return 0;
        }
    } else {
        qDebug("Unrecognised vendor");
    }
    return 0;
}

extern bool qws_accel;


QScreen * qt_probe_bus()
{
    if(!qws_accel) {
        return qt_dodriver("unaccel.so",0,0);
    }

    QT_DIR *dirptr = QT_OPENDIR("/proc/bus/pci");
    if(!dirptr)
        return qt_dodriver("unaccel.so",0,0);
    QT_DIR * dirptr2;
    QT_DIRENT *cards;

    QT_DIRENT *busses = QT_READDIR(dirptr);

    while(busses) {
        if(busses->d_name[0]!='.') {
            char buf[100];
            strcpy(buf,"/proc/bus/pci/");
            qstrcpy(buf+14,busses->d_name);
            int p=strlen(buf);
            dirptr2 = QT_OPENDIR(buf);
            if(dirptr2) {
                cards = QT_READDIR(dirptr2);
                while(cards) {
                    if(cards->d_name[0]!='.') {
                        buf[p]='/';
                        qstrcpy(buf+p+1,cards->d_name);
                        QScreen * ret=qt_do_entry(buf);
                        if(ret)
                            return ret;
                    }
                    cards = QT_READDIR(dirptr2);
                }
                QT_CLOSEDIR(dirptr2);
            }
        }
        busses = QT_READDIR(dirptr);
    }
    QT_CLOSEDIR(dirptr);

    return qt_dodriver("unaccel.so",0,0);
}

#else

char *qt_qws_hardcoded_slot = "/proc/bus/pci/01/00.0";

const unsigned char* qt_probe_bus()
{
    const char * slot;
    slot=::getenv("QWS_CARD_SLOT");
    if(!slot)
        slot=qt_qws_hardcoded_slot;
    if (slot) {
        static unsigned char config[256];
        FILE * f=fopen(slot,"r");
        if(!f) {
            qDebug("Open failure for %s",slot);
            slot=0;
        } else {
            int r=fread((char*)config,256,1,f);
            fclose(f);
            if(r<1) {
                qDebug("Read failure");
                return 0;
            } else {
                return config;
            }
        }
    }
    return 0;
}

#endif

#endif // 0

void QScreen::setPixmapDataFactory(QPixmapDataFactory *factory)
{
    static bool shownWarning = false;
    if (!shownWarning) {
        qWarning("QScreen::setPixmapDataFactory() is deprecated - use setGraphicsSystem() instead");
        shownWarning = true;
    }

    d_ptr->pixmapFactory = factory;
}

QPixmapDataFactory* QScreen::pixmapDataFactory() const
{
    return d_ptr->pixmapFactory;
}

void QScreen::setGraphicsSystem(QGraphicsSystem* system)
{
    d_ptr->graphicsSystem = system;
}

QGraphicsSystem* QScreen::graphicsSystem() const
{
    return d_ptr->graphicsSystem;
}

QScreen::ClassId QScreen::classId() const
{
    return static_cast<ClassId>(d_ptr->classId);
}

QT_END_NAMESPACE