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#include "qapplication.h"

#include "qdesktopwidget.h"

#include "qlibrary.h"

#include "qt_x11_p.h"

#include "qvariant.h"

#include "qwidget_p.h"

#include "qx11info_x11.h"

#include <limits.h>

QT_BEGIN_NAMESPACE

// defined in qwidget_x11.cpp

extern int qt_x11_create_desktop_on_screen;

// function to update the workarea of the screen

static bool qt_desktopwidget_workarea_dirty = true;

void qt_desktopwidget_update_workarea()

{

    qt_desktopwidget_workarea_dirty = true;

}

class QSingleDesktopWidget : public QWidget

{

public:

    QSingleDesktopWidget();

    ~QSingleDesktopWidget();

};

QSingleDesktopWidget::QSingleDesktopWidget()

    : QWidget(0, Qt::Desktop)

{

}

QSingleDesktopWidget::~QSingleDesktopWidget()

{

    const QObjectList &childList = children();

    for (int i = childList.size(); i > 0 ;) {

        --i;

        childList.at(i)->setParent(0);

    }

}

class QDesktopWidgetPrivate : public QWidgetPrivate

{

public:

    QDesktopWidgetPrivate();

    ~QDesktopWidgetPrivate();

    void init();

    bool use_xinerama;

    int defaultScreen;

    int screenCount;

    QWidget **screens;

    QRect *rects;

    QRect *workareas;

};

QDesktopWidgetPrivate::QDesktopWidgetPrivate()

    : use_xinerama(false), defaultScreen(0), screenCount(1),

      screens(0), rects(0), workareas(0)

{

}

QDesktopWidgetPrivate::~QDesktopWidgetPrivate()

{

    if (screens) {

        for (int i = 0; i < screenCount; ++i) {

            if (i == defaultScreen) continue;

            delete screens[i];

            screens[i] = 0;

        }

        free (screens);

    }

    if (rects)     delete [] rects;

    if (workareas) delete [] workareas;

}

void QDesktopWidgetPrivate::init()

{

    // get the screen count

    int newScreenCount = ScreenCount(X11->display);

#ifndef QT_NO_XINERAMA

    XineramaScreenInfo *xinerama_screeninfo = 0;

    // we ignore the Xinerama extension when using the display is

    // using traditional multi-screen (with multiple root windows)

    if (newScreenCount == 1

        && X11->ptrXineramaQueryExtension

        && X11->ptrXineramaIsActive

        && X11->ptrXineramaQueryScreens) {

        int unused;

        use_xinerama = (X11->ptrXineramaQueryExtension(X11->display, &unused, &unused)

                        && X11->ptrXineramaIsActive(X11->display));

    }

    if (use_xinerama) {

        xinerama_screeninfo =

            X11->ptrXineramaQueryScreens(X11->display, &newScreenCount);

    }

    if (xinerama_screeninfo) {

        defaultScreen = 0;

     } else

#endif // QT_NO_XINERAMA

    {

        defaultScreen = DefaultScreen(X11->display);

        newScreenCount = ScreenCount(X11->display);

        use_xinerama = false;

    }

    delete [] rects;

    rects     = new QRect[newScreenCount];

    delete [] workareas;

    workareas = new QRect[newScreenCount];

    // get the geometry of each screen

    int i, j, x, y, w, h;

    for (i = 0, j = 0; i < newScreenCount; i++, j++) {

#ifndef QT_NO_XINERAMA

        if (use_xinerama) {

            x = xinerama_screeninfo[i].x_org;

            y = xinerama_screeninfo[i].y_org;

            w = xinerama_screeninfo[i].width;

            h = xinerama_screeninfo[i].height;

        } else

#endif // QT_NO_XINERAMA

            {

                x = 0;

                y = 0;

                w = WidthOfScreen(ScreenOfDisplay(X11->display, i));

                h = HeightOfScreen(ScreenOfDisplay(X11->display, i));

            }

        rects[j].setRect(x, y, w, h);

        if (use_xinerama && j > 0 && rects[j-1].intersects(rects[j])) {

            // merge a "cloned" screen with the previous, hiding all crtcs

            // that are currently showing a sub-rect of the previous screen

            if ((rects[j].width()*rects[j].height()) >

                (rects[j-1].width()*rects[j-1].height()))

                rects[j-1] = rects[j];

            j--;

        }

        workareas[i] = QRect();

    }

    if (screens) {

        // leaks QWidget* pointers on purpose, can't delete them as pointer escapes

        screens = q_check_ptr((QWidget**) realloc(screens, j * sizeof(QWidget*)));

        if (j > screenCount)

            memset(&screens[screenCount], 0, (j-screenCount) * sizeof(QWidget*));

    }

    screenCount = j;

#ifndef QT_NO_XINERAMA

    if (use_xinerama && screenCount == 1)

        use_xinerama = false;

    if (xinerama_screeninfo)

        XFree(xinerama_screeninfo);

#endif // QT_NO_XINERAMA

}

// the QDesktopWidget itself will be created on the default screen

// as qt_x11_create_desktop_on_screen defaults to -1

QDesktopWidget::QDesktopWidget()

    : QWidget(*new QDesktopWidgetPrivate, 0, Qt::Desktop)

{

    Q_D(QDesktopWidget);

    d->init();

}

QDesktopWidget::~QDesktopWidget()

{

}

bool QDesktopWidget::isVirtualDesktop() const

{

    Q_D(const QDesktopWidget);

    return d->use_xinerama;

}

int QDesktopWidget::primaryScreen() const

{

    Q_D(const QDesktopWidget);

    return d->defaultScreen;

}

int QDesktopWidget::numScreens() const

{

    Q_D(const QDesktopWidget);

    return d->screenCount;

}

QWidget *QDesktopWidget::screen(int screen)

{

    Q_D(QDesktopWidget);

    if (d->use_xinerama)

        return this;

    if (screen < 0 || screen >= d->screenCount)

        screen = d->defaultScreen;

    if (! d->screens) {

        d->screens = (QWidget**) calloc( d->screenCount, sizeof(QWidget*));

        d->screens[d->defaultScreen] = this;

    }

    if (! d->screens[screen] ||               // not created yet

        ! (d->screens[screen]->windowType() == Qt::Desktop)) { // reparented away

        qt_x11_create_desktop_on_screen = screen;

        d->screens[screen] = new QSingleDesktopWidget;

        qt_x11_create_desktop_on_screen = -1;

    }

    return d->screens[screen];

}

const QRect QDesktopWidget::availableGeometry(int screen) const

{

    Q_D(const QDesktopWidget);

    if (qt_desktopwidget_workarea_dirty) {

        // the workareas are dirty, invalidate them

        for (int i = 0; i < d->screenCount; ++i)

            d->workareas[i] = QRect();

        qt_desktopwidget_workarea_dirty = false;

    }

    if (screen < 0 || screen >= d->screenCount)

        screen = d->defaultScreen;

    if (d->workareas[screen].isValid())

        return d->workareas[screen];

    if (X11->isSupportedByWM(ATOM(_NET_WORKAREA))) {

        int x11Screen = isVirtualDesktop() ? DefaultScreen(X11->display) : screen;

        Atom ret;

        int format, e;

        unsigned char *data = 0;

        unsigned long nitems, after;

        e = XGetWindowProperty(X11->display,

                               QX11Info::appRootWindow(x11Screen),

                               ATOM(_NET_WORKAREA), 0, 4, False, XA_CARDINAL,

                               &ret, &format, &nitems, &after, &data);

        QRect workArea;

        if (e == Success && ret == XA_CARDINAL &&

            format == 32 && nitems == 4) {

            long *workarea = (long *) data;

            workArea = QRect(workarea[0], workarea[1], workarea[2], workarea[3]);

        } else {

            workArea = screenGeometry(screen);

        }

        if (isVirtualDesktop()) {

            // intersect the workarea (which spawns all Xinerama screens) with the rect for the

            // requested screen

            workArea &= screenGeometry(screen);

        }

        d->workareas[screen] = workArea;

        if (data)

            XFree(data);

    } else {

        d->workareas[screen] = screenGeometry(screen);

    }

    return d->workareas[screen];

}

const QRect QDesktopWidget::screenGeometry(int screen) const

{

    Q_D(const QDesktopWidget);

    if (screen < 0 || screen >= d->screenCount)

        screen = d->defaultScreen;

    return d->rects[screen];

}

int QDesktopWidget::screenNumber(const QWidget *widget) const

{

    Q_D(const QDesktopWidget);

    if (!widget)

        return d->defaultScreen;

#ifndef QT_NO_XINERAMA

    if (d->use_xinerama) {

        // this is how we do it for xinerama

        QRect frame = widget->frameGeometry();

        if (!widget->isWindow())

            frame.moveTopLeft(widget->mapToGlobal(QPoint(0, 0)));

        int maxSize = -1;

        int maxScreen = -1;

        for (int i = 0; i < d->screenCount; ++i) {

            QRect sect = d->rects[i].intersected(frame);

            int size = sect.width() * sect.height();

            if (size > maxSize && sect.width() > 0 && sect.height() > 0) {

                maxSize = size;

                maxScreen = i;

            }

        }

        return maxScreen;

    }

#endif // QT_NO_XINERAMA

    return widget->x11Info().screen();

}

int QDesktopWidget::screenNumber(const QPoint &point) const

{

    Q_D(const QDesktopWidget);

    int closestScreen = -1;

    int shortestDistance = INT_MAX;

    for (int i = 0; i < d->screenCount; ++i) {

        int thisDistance = d->pointToRect(point, d->rects[i]);

        if (thisDistance < shortestDistance) {

            shortestDistance = thisDistance;

            closestScreen = i;

        }

    }

    return closestScreen;

}

void QDesktopWidget::resizeEvent(QResizeEvent *event)

{

    Q_D(QDesktopWidget);

    int oldScreenCount = d->screenCount;

    QVector<QRect> oldRects(oldScreenCount);

    QVector<QRect> oldWorks(oldScreenCount);

    for (int i = 0; i < oldScreenCount; ++i) {

        oldRects[i] = d->rects[i];

        oldWorks[i] = d->workareas[i];

    }

    d->init();

    for (int i = 0; i < qMin(oldScreenCount, d->screenCount); ++i) {

        if (oldRects.at(i) != d->rects[i])

            emit resized(i);

    }

    // ### workareas are just reset by init, not filled with new values

    // ### so this will not work correctly

    for (int j = 0; j < qMin(oldScreenCount, d->screenCount); ++j) {

        if (oldWorks.at(j) != d->workareas[j])

            emit workAreaResized(j);

    }

    if (oldScreenCount != d->screenCount) {

        emit screenCountChanged(d->screenCount);

    }

    qt_desktopwidget_workarea_dirty = true;

    QWidget::resizeEvent(event);

}

QT_END_NAMESPACE