q3scrollview.cpp

奇趣公司比较新的qt/emd版本

    You may want to call enableClipper(true) if you add a large number
    of widgets.
*/
void Q3ScrollView::addChild(QWidget* child, int x, int y)
{
    if (!child) {
#if defined(QT_CHECK_NULL)
        qWarning("Q3ScrollView::addChild(): Cannot add null child");
#endif
        return;
    }
    child->polish();
    child->setBackgroundOrigin(WidgetOrigin);

    if (child->parentWidget() == viewport()) {
        // May already be there
        QSVChildRec *r = d->rec(child);
        if (r) {
            r->moveTo(this,x,y,d->clipped_viewport);
            if (d->policy > Manual) {
                d->autoResizeHint(this);
                d->autoResize(this); // #### better to just deal with this one widget!
            }
            return;
        }
    }

    if (d->children.isEmpty() && d->policy != Manual) {
        if (d->policy == Default)
            setResizePolicy(AutoOne);
        child->installEventFilter(this);
    } else if (d->policy == AutoOne) {
        child->removeEventFilter(this); //#### ?????
        setResizePolicy(Manual);
    }
    if (child->parentWidget() != viewport()) {
            child->reparent(viewport(), 0, QPoint(0,0), false);
    }
    d->addChildRec(child,x,y)->hideOrShow(this, d->clipped_viewport);

    if (d->policy > Manual) {
        d->autoResizeHint(this);
        d->autoResize(this); // #### better to just deal with this one widget!
    }
}

/*!
    Repositions the \a child widget to (\a x, \a y). This function is
    the same as addChild().
*/
void Q3ScrollView::moveChild(QWidget* child, int x, int y)
{
    addChild(child,x,y);
}

/*!
    Returns the X position of the given \a child widget. Use this
    rather than QWidget::x() for widgets added to the view.

    This function returns 0 if \a child has not been added to the view.
*/
int Q3ScrollView::childX(QWidget* child)
{
    QSVChildRec *r = d->rec(child);
    return r ? r->x : 0;
}

/*!
    Returns the Y position of the given \a child widget. Use this
    rather than QWidget::y() for widgets added to the view.

    This function returns 0 if \a child has not been added to the view.
*/
int Q3ScrollView::childY(QWidget* child)
{
    QSVChildRec *r = d->rec(child);
    return r ? r->y : 0;
}

/*! \fn bool Q3ScrollView::childIsVisible(QWidget*)
  \obsolete

  Returns true if \a child is visible. This is equivalent
  to child->isVisible().
*/

/*! \fn void Q3ScrollView::showChild(QWidget* child, bool y)
  \obsolete

  Sets the visibility of \a child. Equivalent to
  QWidget::show() or QWidget::hide().
*/

/*!
    This event filter ensures the scroll bars are updated when a
    single contents widget is resized, shown, hidden or destroyed; it
    passes mouse events to the Q3ScrollView. The event is in \a e and
    the object is in \a obj.
*/

bool Q3ScrollView::eventFilter(QObject *obj, QEvent *e)
{
    bool disabled = !(qobject_cast<QWidget*>(obj)->isEnabled());
    if (!d)
        return false; // we are destructing
    if (obj == d->viewport || obj == d->clipped_viewport) {
        switch (e->type()) {
            /* Forward many events to viewport...() functions */
        case QEvent::Paint:
            viewportPaintEvent((QPaintEvent*)e);
            break;
        case QEvent::Resize:
            if (!d->clipped_viewport)
                viewportResizeEvent((QResizeEvent *)e);
            break;
        case QEvent::MouseButtonPress:
            if (disabled)
                return false;
            viewportMousePressEvent((QMouseEvent*)e);
            if (((QMouseEvent*)e)->isAccepted())
                return true;
            break;
        case QEvent::MouseButtonRelease:
            if (disabled)
                return false;
            viewportMouseReleaseEvent((QMouseEvent*)e);
            if (((QMouseEvent*)e)->isAccepted())
                return true;
            break;
        case QEvent::MouseButtonDblClick:
            if (disabled)
                return false;
            viewportMouseDoubleClickEvent((QMouseEvent*)e);
            if (((QMouseEvent*)e)->isAccepted())
                return true;
            break;
        case QEvent::MouseMove:
            if (disabled)
                return false;
            viewportMouseMoveEvent((QMouseEvent*)e);
            if (((QMouseEvent*)e)->isAccepted())
                return true;
            break;
#ifndef QT_NO_DRAGANDDROP
        case QEvent::DragEnter:
            if (disabled)
                return false;
            viewportDragEnterEvent((QDragEnterEvent*)e);
            break;
        case QEvent::DragMove: {
            if (disabled)
                return false;
            if (d->drag_autoscroll) {
                QPoint vp = ((QDragMoveEvent*) e)->pos();
                QRect inside_margin(autoscroll_margin, autoscroll_margin,
                                     visibleWidth() - autoscroll_margin * 2,
                                     visibleHeight() - autoscroll_margin * 2);
                if (!inside_margin.contains(vp)) {
                    startDragAutoScroll();
                    // Keep sending move events
                    ((QDragMoveEvent*)e)->accept(QRect(0,0,0,0));
                }
            }
            viewportDragMoveEvent((QDragMoveEvent*)e);
        } break;
        case QEvent::DragLeave:
            if (disabled)
                return false;
            stopDragAutoScroll();
            viewportDragLeaveEvent((QDragLeaveEvent*)e);
            break;
        case QEvent::Drop:
            if (disabled)
                return false;
            stopDragAutoScroll();
            viewportDropEvent((QDropEvent*)e);
            break;
#endif // QT_NO_DRAGANDDROP
#ifndef QT_NO_WHEELEVENT
        case QEvent::Wheel:
            if (disabled)
                return false;
            break;
#endif
        case QEvent::ContextMenu:
            if (disabled)
                return false;
            viewportContextMenuEvent((QContextMenuEvent*)e);
            if (((QContextMenuEvent*)e)->isAccepted())
                return true;
            break;
        case QEvent::ChildRemoved:
            removeChild((QWidget*)((QChildEvent*)e)->child());
            break;
        case QEvent::LayoutHint:
            d->autoResizeHint(this);
            break;
        default:
            break;
        }
    } else if (d && d->rec((QWidget*)obj)) {  // must be a child
        if (e->type() == QEvent::Resize)
            d->autoResize(this);
        else if (e->type() == QEvent::Move)
            d->autoMove(this);
    }
    return Q3Frame::eventFilter(obj, e);  // always continue with standard event processing
}

/*!
    This event handler is called whenever the Q3ScrollView receives a
    mousePressEvent(): the press position in \a e is translated to be a point
    on the contents.
*/
void Q3ScrollView::contentsMousePressEvent(QMouseEvent* e)
{
    e->ignore();
}

/*!
    This event handler is called whenever the Q3ScrollView receives a
    mouseReleaseEvent(): the release position in \a e is translated to be a
    point on the contents.
*/
void Q3ScrollView::contentsMouseReleaseEvent(QMouseEvent* e)
{
    e->ignore();
}

/*!
    This event handler is called whenever the Q3ScrollView receives a
    mouseDoubleClickEvent(): the click position in \a e is translated to be a
    point on the contents.

    The default implementation generates a normal mouse press event.
*/
void Q3ScrollView::contentsMouseDoubleClickEvent(QMouseEvent* e)
{
    contentsMousePressEvent(e);             // try mouse press event
}

/*!
    This event handler is called whenever the Q3ScrollView receives a
    mouseMoveEvent(): the mouse position in \a e is translated to be a point
    on the contents.
*/
void Q3ScrollView::contentsMouseMoveEvent(QMouseEvent* e)
{
    e->ignore();
}

#ifndef QT_NO_DRAGANDDROP

/*!
    This event handler is called whenever the Q3ScrollView receives a
    dragEnterEvent(): the drag position is translated to be a point
    on the contents.

    The default implementation does nothing. The \a event parameter is
    ignored.
*/
void Q3ScrollView::contentsDragEnterEvent(QDragEnterEvent * /* event */)
{
}

/*!
    This event handler is called whenever the Q3ScrollView receives a
    dragMoveEvent(): the drag position is translated to be a point on
    the contents.

    The default implementation does nothing. The \a event parameter is
    ignored.
*/
void Q3ScrollView::contentsDragMoveEvent(QDragMoveEvent * /* event */)
{
}

/*!
    This event handler is called whenever the Q3ScrollView receives a
    dragLeaveEvent(): the drag position is translated to be a point
    on the contents.

    The default implementation does nothing. The \a event parameter is
    ignored.
*/
void Q3ScrollView::contentsDragLeaveEvent(QDragLeaveEvent * /* event */)
{
}

/*!
    This event handler is called whenever the Q3ScrollView receives a
    dropEvent(): the drop position is translated to be a point on the
    contents.

    The default implementation does nothing. The \a event parameter is
    ignored.
*/

void Q3ScrollView::contentsDropEvent(QDropEvent * /* event */)
{
}

#endif // QT_NO_DRAGANDDROP

/*!
    This event handler is called whenever the Q3ScrollView receives a
    wheelEvent() in \a{e}: the mouse position is translated to be a
    point on the contents.
*/
#ifndef QT_NO_WHEELEVENT
void Q3ScrollView::contentsWheelEvent(QWheelEvent * e)
{
    e->ignore();
}
#endif
/*!
    This event handler is called whenever the Q3ScrollView receives a
    contextMenuEvent() in \a{e}: the mouse position is translated to
    be a point on the contents.
*/
void Q3ScrollView::contentsContextMenuEvent(QContextMenuEvent *e)
{
    e->ignore();
}

/*!
    This is a low-level painting routine that draws the viewport
    contents. Reimplement this if drawContents() is too high-level
    (for example, if you don't want to open a QPainter on the
    viewport). The paint event is passed in \a pe.
*/
void Q3ScrollView::viewportPaintEvent(QPaintEvent* pe)
{
    QWidget* vp = viewport();

    QPainter p(vp);
    QRect r = pe->rect();

    if (d->clipped_viewport) {
        QRect rr(
            -d->clipped_viewport->x(), -d->clipped_viewport->y(),
            d->viewport->width(), d->viewport->height()
           );
        r &= rr;
        if (r.isValid()) {
            int ex = r.x() + d->clipped_viewport->x() + d->contentsX();
            int ey = r.y() + d->clipped_viewport->y() + d->contentsY();
            int ew = r.width();
            int eh = r.height();
            drawContentsOffset(&p,
                d->contentsX()+d->clipped_viewport->x(),
                d->contentsY()+d->clipped_viewport->y(),
                ex, ey, ew, eh);
        }
    } else {
        r &= d->viewport->rect();
        int ex = r.x() + d->contentsX();
        int ey = r.y() + d->contentsY();
        int ew = r.width();
        int eh = r.height();
        drawContentsOffset(&p, d->contentsX(), d->contentsY(), ex, ey, ew, eh);
    }
}


/*!
    To provide simple processing of events on the contents, this
    function receives all resize events sent to the viewport.

    The default implementation does nothing. The \a event parameter is
    ignored.

    \sa QWidget::resizeEvent()
*/
void Q3ScrollView::viewportResizeEvent(QResizeEvent * /* event */)
{
}

/*! \internal

  To provide simple processing of events on the contents, this
  function receives all mouse press events sent to the viewport,
  translates the event and calls contentsMousePressEvent().

  \sa contentsMousePressEvent(), QWidget::mousePressEvent()
*/
void Q3ScrollView::viewportMousePressEvent(QMouseEvent* e)
{
    QMouseEvent ce(e->type(), viewportToContents(e->pos()),
        e->globalPos(), e->button(), e->state());
    contentsMousePressEvent(&ce);
    if (!ce.isAccepted())
        e->ignore();
}

/*!\internal

  To provide simple processing of events on the contents, this function
  receives all mouse release events sent to the viewport, translates
  the event and calls contentsMouseReleaseEvent().

  \sa QWidget::mouseReleaseEvent()
*/
void Q3ScrollView::viewportMouseReleaseEvent(QMouseEvent* e)
{
    QMouseEvent ce(e->type(), viewportToContents(e->pos()),
        e->globalPos(), e->button(), e->state());
    contentsMouseReleaseEvent(&ce);
    if (!ce.isAccepted())
        e->ignore();
}

/*!\internal

  To provide simple processing of events on the contents, this function
  receives all mouse double click events sent to the viewport,
  translates the event and calls contentsMouseDoubleClickEvent().

  \sa QWidget::mouseDoubleClickEvent()
*/
void Q3ScrollView::viewportMouseDoubleClickEvent(QMouseEvent* e)
{
    QMouseEvent ce(e->type(), viewportToContents(e->pos()),
        e->globalPos(), e->button(), e->state());
    contentsMouseDoubleClickEvent(&ce);
    if (!ce.isAccepted())
        e->ignore();
}

/*!\internal

  To provide simple processing of events on the contents, this function
  receives all mouse move events sent to the viewport, translates the
  event and calls contentsMouseMoveEvent().

  \sa QWidget::mouseMoveEvent()
*/
void Q3ScrollView::viewportMouseMoveEvent(QMouseEvent* e)
{
    QMouseEvent ce(e->type(), viewportToContents(e->pos()),
        e->globalPos(), e->button(), e->state());
    contentsMouseMoveEvent(&ce);
    if (!ce.isAccepted())
        e->ignore();
}

#ifndef QT_NO_DRAGANDDROP

/*!\internal

  To provide simple processing of events on the contents, this function
  receives all drag enter events sent to the viewport, translates the
  event and calls contentsDragEnterEvent().

  \sa QWidget::dragEnterEvent()
*/