qsizegrip.cpp

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#include "qsizegrip.h"

#ifndef QT_NO_SIZEGRIP

#include "qapplication.h"
#include "qevent.h"
#include "qpainter.h"
#include "qstyle.h"
#include "qstyleoption.h"
#include "qlayout.h"
#include "qdebug.h"
#include <QDesktopWidget>

#if defined(Q_WS_X11)
#include <private/qt_x11_p.h>
#elif defined (Q_WS_WIN)
#include "qt_windows.h"
#endif
#ifdef Q_WS_MAC
#include <private/qt_mac_p.h>
#endif

#include <private/qwidget_p.h>
#include <QtGui/qabstractscrollarea.h>

#define SZ_SIZEBOTTOMRIGHT  0xf008
#define SZ_SIZEBOTTOMLEFT   0xf007
#define SZ_SIZETOPLEFT      0xf004
#define SZ_SIZETOPRIGHT     0xf005

QT_BEGIN_NAMESPACE

static QWidget *qt_sizegrip_topLevelWidget(QWidget* w)
{
    while (w && !w->isWindow() && w->windowType() != Qt::SubWindow)
        w = w->parentWidget();
    return w;
}

class QSizeGripPrivate : public QWidgetPrivate
{
    Q_DECLARE_PUBLIC(QSizeGrip)
public:
    void init();
    QPoint p;
    QRect r;
    int d;
    int dxMax;
    int dyMax;
    Qt::Corner m_corner;
    bool gotMousePress;
    QWidget *tlw;
#ifdef Q_WS_MAC
    void updateMacSizer(bool hide) const;
#endif
    Qt::Corner corner() const;
    inline bool atBottom() const
    {
        return m_corner == Qt::BottomRightCorner || m_corner == Qt::BottomLeftCorner;
    }

    inline bool atLeft() const
    {
        return m_corner == Qt::BottomLeftCorner || m_corner == Qt::TopLeftCorner;
    }

    void updateTopLevelWidget()
    {
        Q_Q(QSizeGrip);
        QWidget *w = qt_sizegrip_topLevelWidget(q);
        if (tlw == w)
            return;
        if (tlw)
            tlw->removeEventFilter(q);
        tlw = w;
        if (tlw)
            tlw->installEventFilter(q);
    }

    // This slot is invoked by QLayout when the size grip is added to
    // a layout or reparented after the tlw is shown. This re-implementation is basically
    // the same as QWidgetPrivate::_q_showIfNotHidden except that it checks
    // for Qt::WindowFullScreen and Qt::WindowMaximized as well.
    void _q_showIfNotHidden()
    {
        Q_Q(QSizeGrip);
        bool showSizeGrip = !(q->isHidden() && q->testAttribute(Qt::WA_WState_ExplicitShowHide));
        updateTopLevelWidget();
        if (tlw && showSizeGrip) {
            Qt::WindowStates sizeGripNotVisibleState = Qt::WindowFullScreen;
#ifndef Q_WS_MAC
            sizeGripNotVisibleState |= Qt::WindowMaximized;
#endif
            // Don't show the size grip if the tlw is maximized or in full screen mode.
            showSizeGrip = !(tlw->windowState() & sizeGripNotVisibleState);
        }
        if (showSizeGrip)
            q->setVisible(true);
    }
};

#ifdef Q_WS_MAC
void QSizeGripPrivate::updateMacSizer(bool hide) const
{
    Q_Q(const QSizeGrip);
    if (QApplication::closingDown() || !parent)
        return;
    QWidget *topLevelWindow = qt_sizegrip_topLevelWidget(const_cast<QSizeGrip *>(q));
    if(topLevelWindow && topLevelWindow->isWindow())
        QWidgetPrivate::qt_mac_update_sizer(topLevelWindow, hide ? -1 : 1);
}
#endif

Qt::Corner QSizeGripPrivate::corner() const
{
    Q_Q(const QSizeGrip);
    QWidget *tlw = qt_sizegrip_topLevelWidget(const_cast<QSizeGrip *>(q));
    const QPoint sizeGripPos = q->mapTo(tlw, QPoint(0, 0));
    bool isAtBottom = sizeGripPos.y() >= tlw->height() / 2;
    bool isAtLeft = sizeGripPos.x() <= tlw->width() / 2;
    if (isAtLeft)
        return isAtBottom ? Qt::BottomLeftCorner : Qt::TopLeftCorner;
    else
        return isAtBottom ? Qt::BottomRightCorner : Qt::TopRightCorner;
}

QSizeGrip::QSizeGrip(QWidget * parent)
    : QWidget(*new QSizeGripPrivate, parent, 0)
{
    Q_D(QSizeGrip);
    d->init();
}

#ifdef QT3_SUPPORT

QSizeGrip::QSizeGrip(QWidget * parent, const char* name)
    : QWidget(*new QSizeGripPrivate, parent, 0)
{
    Q_D(QSizeGrip);
    setObjectName(QString::fromAscii(name));
    d->init();
}
#endif

void QSizeGripPrivate::init()
{
    Q_Q(QSizeGrip);
    dxMax = 0;
    dyMax = 0;
    tlw = 0;
    m_corner = q->isLeftToRight() ? Qt::BottomRightCorner : Qt::BottomLeftCorner;
    gotMousePress = false;

#if !defined(QT_NO_CURSOR) && !defined(Q_WS_MAC)
    q->setCursor(m_corner == Qt::TopLeftCorner || m_corner == Qt::BottomRightCorner
                 ? Qt::SizeFDiagCursor : Qt::SizeBDiagCursor);
#endif
    q->setSizePolicy(QSizePolicy(QSizePolicy::Minimum, QSizePolicy::Fixed));
    updateTopLevelWidget();
}


QSizeGrip::~QSizeGrip()
{
}

QSize QSizeGrip::sizeHint() const
{
    QStyleOption opt(0);
    opt.init(this);
    return (style()->sizeFromContents(QStyle::CT_SizeGrip, &opt, QSize(13, 13), this).
            expandedTo(QApplication::globalStrut()));
}

void QSizeGrip::paintEvent(QPaintEvent *event)
{
    Q_UNUSED(event);
    Q_D(QSizeGrip);
    QPainter painter(this);
    QStyleOptionSizeGrip opt;
    opt.init(this);
    opt.corner = d->m_corner;
    style()->drawControl(QStyle::CE_SizeGrip, &opt, &painter, this);
}

void QSizeGrip::mousePressEvent(QMouseEvent * e)
{
    if (e->button() != Qt::LeftButton) {
        QWidget::mousePressEvent(e);
        return;
    }

    Q_D(QSizeGrip);
    QWidget *tlw = qt_sizegrip_topLevelWidget(this);
    d->p = e->globalPos();
    d->gotMousePress = true;
    d->r = tlw->geometry();

#ifdef Q_WS_X11
    // Use a native X11 sizegrip for "real" top-level windows if supported.
    if (tlw->isWindow() && X11->isSupportedByWM(ATOM(_NET_WM_MOVERESIZE))
        && !(tlw->windowFlags() & Qt::X11BypassWindowManagerHint)
        && !tlw->testAttribute(Qt::WA_DontShowOnScreen) && !qt_widget_private(tlw)->hasHeightForWidth()) {
        XEvent xev;
        xev.xclient.type = ClientMessage;
        xev.xclient.message_type = ATOM(_NET_WM_MOVERESIZE);
        xev.xclient.display = X11->display;
        xev.xclient.window = tlw->winId();
        xev.xclient.format = 32;
        xev.xclient.data.l[0] = e->globalPos().x();
        xev.xclient.data.l[1] = e->globalPos().y();
        if (d->atBottom())
            xev.xclient.data.l[2] = d->atLeft() ? 6 : 4; // bottomleft/bottomright
        else
            xev.xclient.data.l[2] = d->atLeft() ? 0 : 2; // topleft/topright
        xev.xclient.data.l[3] = Button1;
        xev.xclient.data.l[4] = 0;
        XUngrabPointer(X11->display, X11->time);
        XSendEvent(X11->display, QX11Info::appRootWindow(x11Info().screen()), False,
                   SubstructureRedirectMask | SubstructureNotifyMask, &xev);
        return;
    }
#endif // Q_WS_X11
#ifdef Q_WS_WIN
    if (tlw->isWindow() && !tlw->testAttribute(Qt::WA_DontShowOnScreen) && !qt_widget_private(tlw)->hasHeightForWidth()) {
        uint orientation = 0;
        if (d->atBottom())
            orientation = d->atLeft() ? SZ_SIZEBOTTOMLEFT : SZ_SIZEBOTTOMRIGHT;
        else
            orientation = d->atLeft() ? SZ_SIZETOPLEFT : SZ_SIZETOPRIGHT;

        ReleaseCapture();
        PostMessage(tlw->winId(), WM_SYSCOMMAND, orientation, 0);
        return;
    }
#endif // Q_WS_WIN

    // Find available desktop/workspace geometry.
    QRect availableGeometry;
    bool hasVerticalSizeConstraint = true;
    bool hasHorizontalSizeConstraint = true;
    if (tlw->isWindow())
        availableGeometry = QApplication::desktop()->availableGeometry(tlw);
    else {
        const QWidget *tlwParent = tlw->parentWidget();
        // Check if tlw is inside QAbstractScrollArea/QScrollArea.
        // If that's the case tlw->parentWidget() will return the viewport
        // and tlw->parentWidget()->parentWidget() will return the scroll area.
#ifndef QT_NO_SCROLLAREA
        QAbstractScrollArea *scrollArea = qobject_cast<QAbstractScrollArea *>(tlwParent->parentWidget());
        if (scrollArea) {
            hasHorizontalSizeConstraint = scrollArea->horizontalScrollBarPolicy() == Qt::ScrollBarAlwaysOff;
            hasVerticalSizeConstraint = scrollArea->verticalScrollBarPolicy() == Qt::ScrollBarAlwaysOff;
        }
#endif // QT_NO_SCROLLAREA
        availableGeometry = tlwParent->contentsRect();
    }

    // Find frame geometries, title bar height, and decoration sizes.
    const QRect frameGeometry = tlw->frameGeometry();
    const int titleBarHeight = qMax(tlw->geometry().y() - frameGeometry.y(), 0);
    const int bottomDecoration = qMax(frameGeometry.height() - tlw->height() - titleBarHeight, 0);
    const int leftRightDecoration = qMax((frameGeometry.width() - tlw->width()) / 2, 0);

    // Determine dyMax depending on whether the sizegrip is at the bottom
    // of the widget or not.
    if (d->atBottom()) {
        if (hasVerticalSizeConstraint)
            d->dyMax = availableGeometry.bottom() - d->r.bottom() - bottomDecoration;
        else
            d->dyMax = INT_MAX;
    } else {
        if (hasVerticalSizeConstraint)
            d->dyMax = availableGeometry.y() - d->r.y() + titleBarHeight;
        else
            d->dyMax = -INT_MAX;
    }

    // In RTL mode, the size grip is to the left; find dxMax from the desktop/workspace
    // geometry, the size grip geometry and the width of the decoration.
    if (d->atLeft()) {
        if (hasHorizontalSizeConstraint)
            d->dxMax = availableGeometry.x() - d->r.x() + leftRightDecoration;
        else
            d->dxMax = -INT_MAX;
    } else {
        if (hasHorizontalSizeConstraint)
            d->dxMax = availableGeometry.right() - d->r.right() - leftRightDecoration;
        else
            d->dxMax = INT_MAX;
    }
}


void QSizeGrip::mouseMoveEvent(QMouseEvent * e)
{
    if (e->buttons() != Qt::LeftButton) {
        QWidget::mouseMoveEvent(e);
        return;
    }

    Q_D(QSizeGrip);
    QWidget* tlw = qt_sizegrip_topLevelWidget(this);
    if (!d->gotMousePress || tlw->testAttribute(Qt::WA_WState_ConfigPending))
        return;

#ifdef Q_WS_X11
    if (tlw->isWindow() && X11->isSupportedByWM(ATOM(_NET_WM_MOVERESIZE))
        && tlw->isTopLevel() && !(tlw->windowFlags() & Qt::X11BypassWindowManagerHint)
        && !tlw->testAttribute(Qt::WA_DontShowOnScreen) && !qt_widget_private(tlw)->hasHeightForWidth())
        return;
#endif
#ifdef Q_WS_WIN
    if (tlw->isWindow() && GetSystemMenu(tlw->winId(), FALSE) != 0 && internalWinId()
        && !tlw->testAttribute(Qt::WA_DontShowOnScreen) && !qt_widget_private(tlw)->hasHeightForWidth()) {
        MSG msg;
        while(PeekMessage(&msg, winId(), WM_MOUSEMOVE, WM_MOUSEMOVE, PM_REMOVE));
        return;
    }
#endif

    QPoint np(e->globalPos());

    // Don't extend beyond the available geometry; bound to dyMax and dxMax.
    QSize ns;
    if (d->atBottom())
        ns.rheight() = d->r.height() + qMin(np.y() - d->p.y(), d->dyMax);
    else
        ns.rheight() = d->r.height() - qMax(np.y() - d->p.y(), d->dyMax);

    if (d->atLeft())
        ns.rwidth() = d->r.width() - qMax(np.x() - d->p.x(), d->dxMax);
    else
        ns.rwidth() = d->r.width() + qMin(np.x() - d->p.x(), d->dxMax);

    ns = QLayout::closestAcceptableSize(tlw, ns);

    QPoint p;
    QRect nr(p, ns);
    if (d->atBottom()) {
        if (d->atLeft())
            nr.moveTopRight(d->r.topRight());
        else
            nr.moveTopLeft(d->r.topLeft());
    } else {
        if (d->atLeft())
            nr.moveBottomRight(d->r.bottomRight());
        else
            nr.moveBottomLeft(d->r.bottomLeft());
    }

    tlw->setGeometry(nr);
}

void QSizeGrip::mouseReleaseEvent(QMouseEvent *mouseEvent)
{
    if (mouseEvent->button() == Qt::LeftButton) {
        Q_D(QSizeGrip);
        d->gotMousePress = false;
        d->p = QPoint();
    } else {
        QWidget::mouseReleaseEvent(mouseEvent);
    }
}

void QSizeGrip::moveEvent(QMoveEvent * /*moveEvent*/)
{
    Q_D(QSizeGrip);
    // We're inside a resize operation; no update necessary.
    if (!d->p.isNull())
        return;

    d->m_corner = d->corner();
#if !defined(QT_NO_CURSOR) && !defined(Q_WS_MAC)
    setCursor(d->m_corner == Qt::TopLeftCorner || d->m_corner == Qt::BottomRightCorner
              ? Qt::SizeFDiagCursor : Qt::SizeBDiagCursor);
#endif
}

void QSizeGrip::showEvent(QShowEvent *showEvent)
{
#ifdef Q_WS_MAC
    d_func()->updateMacSizer(false);
#endif
    QWidget::showEvent(showEvent);
}

void QSizeGrip::hideEvent(QHideEvent *hideEvent)
{
#ifdef Q_WS_MAC
    d_func()->updateMacSizer(true);
#endif
    QWidget::hideEvent(hideEvent);
}

void QSizeGrip::setVisible(bool visible)
{
    QWidget::setVisible(visible);
}

bool QSizeGrip::eventFilter(QObject *o, QEvent *e)
{
    Q_D(QSizeGrip);
    if ((isHidden() && testAttribute(Qt::WA_WState_ExplicitShowHide))
        || e->type() != QEvent::WindowStateChange
        || o != d->tlw) {
        return QWidget::eventFilter(o, e);
    }
    Qt::WindowStates sizeGripNotVisibleState = Qt::WindowFullScreen;
#ifndef Q_WS_MAC
    sizeGripNotVisibleState |= Qt::WindowMaximized;
#endif
    // Don't show the size grip if the tlw is maximized or in full screen mode.
    setVisible(!(d->tlw->windowState() & sizeGripNotVisibleState));
    setAttribute(Qt::WA_WState_ExplicitShowHide, false);
    return QWidget::eventFilter(o, e);
}

bool QSizeGrip::event(QEvent *event)
{
    return QWidget::event(event);
}

#ifdef Q_WS_WIN

bool QSizeGrip::winEvent( MSG *m, long *result )
{
    return QWidget::winEvent(m, result);
}
#endif

QT_END_NAMESPACE

#include "moc_qsizegrip.cpp"

#endif //QT_NO_SIZEGRIP