q3scrollview.cpp

奇趣公司比较新的qt/emd版本

void Q3ScrollView::viewportDragEnterEvent(QDragEnterEvent* e)
{
    e->setPoint(viewportToContents(e->pos()));
    contentsDragEnterEvent(e);
    e->setPoint(contentsToViewport(e->pos()));
}

/*!\internal

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

  \sa QWidget::dragMoveEvent()
*/
void Q3ScrollView::viewportDragMoveEvent(QDragMoveEvent* e)
{
    e->setPoint(viewportToContents(e->pos()));
    contentsDragMoveEvent(e);
    e->setPoint(contentsToViewport(e->pos()));
}

/*!\internal

  To provide simple processing of events on the contents, this function
  receives all drag leave events sent to the viewport and calls
  contentsDragLeaveEvent().

  \sa QWidget::dragLeaveEvent()
*/
void Q3ScrollView::viewportDragLeaveEvent(QDragLeaveEvent* e)
{
    contentsDragLeaveEvent(e);
}

/*!\internal

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

  \sa QWidget::dropEvent()
*/
void Q3ScrollView::viewportDropEvent(QDropEvent* e)
{
    e->setPoint(viewportToContents(e->pos()));
    contentsDropEvent(e);
    e->setPoint(contentsToViewport(e->pos()));
}

#endif // QT_NO_DRAGANDDROP

/*!\internal

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

  \sa QWidget::wheelEvent()
*/
#ifndef QT_NO_WHEELEVENT
void Q3ScrollView::viewportWheelEvent(QWheelEvent* e)
{
    /*
       Different than standard mouse events, because wheel events might
       be sent to the focus widget if the widget-under-mouse doesn't want
       the event itself.
    */
    QWheelEvent ce(viewportToContents(e->pos()),
        e->globalPos(), e->delta(), e->state());
    contentsWheelEvent(&ce);
    if (ce.isAccepted())
        e->accept();
    else
        e->ignore();
}
#endif

/*! \internal

  To provide simple processing of events on the contents, this function
  receives all context menu events sent to the viewport, translates the
  event and calls contentsContextMenuEvent().
*/
void Q3ScrollView::viewportContextMenuEvent(QContextMenuEvent *e)
{
    QContextMenuEvent ce(e->reason(), viewportToContents(e->pos()), e->globalPos(), e->state());
    contentsContextMenuEvent(&ce);
    if (ce.isAccepted())
        e->accept();
    else
        e->ignore();
}

/*!
    Returns the component horizontal scroll bar. It is made available
    to allow accelerators, autoscrolling, etc.

    It should not be used for other purposes.

    This function never returns 0.
*/
QScrollBar* Q3ScrollView::horizontalScrollBar() const
{
    return d->hbar;
}

/*!
    Returns the component vertical scroll bar. It is made available to
    allow accelerators, autoscrolling, etc.

    It should not be used for other purposes.

    This function never returns 0.
*/
QScrollBar* Q3ScrollView::verticalScrollBar() const {
    return d->vbar;
}


/*!
    Scrolls the content so that the point (\a x, \a y) is visible with at
    least 50-pixel margins (if possible, otherwise centered).
*/
void Q3ScrollView::ensureVisible(int x, int y)
{
    ensureVisible(x, y, 50, 50);
}

/*!
    \overload

    Scrolls the content so that the point (\a x, \a y) is visible with at
    least the \a xmargin and \a ymargin margins (if possible,
    otherwise centered).
*/
void Q3ScrollView::ensureVisible(int x, int y, int xmargin, int ymargin)
{
    int pw=visibleWidth();
    int ph=visibleHeight();

    int cx=-d->contentsX();
    int cy=-d->contentsY();
    int cw=d->contentsWidth();
    int ch=contentsHeight();

    if (pw < xmargin*2)
        xmargin=pw/2;
    if (ph < ymargin*2)
        ymargin=ph/2;

    if (cw <= pw) {
        xmargin=0;
        cx=0;
    }
    if (ch <= ph) {
        ymargin=0;
        cy=0;
    }

    if (x < -cx+xmargin)
        cx = -x+xmargin;
    else if (x >= -cx+pw-xmargin)
        cx = -x+pw-xmargin;

    if (y < -cy+ymargin)
        cy = -y+ymargin;
    else if (y >= -cy+ph-ymargin)
        cy = -y+ph-ymargin;

    if (cx > 0)
        cx=0;
    else if (cx < pw-cw && cw>pw)
        cx=pw-cw;

    if (cy > 0)
        cy=0;
    else if (cy < ph-ch && ch>ph)
        cy=ph-ch;

    setContentsPos(-cx, -cy);
}

/*!
    Scrolls the content so that the point (\a x, \a y) is in the top-left
    corner.
*/
void Q3ScrollView::setContentsPos(int x, int y)
{
#if 0
    // bounds checking...
    if (QApplication::reverseLayout())
        if (x > d->contentsWidth() - visibleWidth()) x = d->contentsWidth() - visibleWidth();
    else
#endif
        if (x < 0) x = 0;
    if (y < 0) y = 0;
    // Choke signal handling while we update BOTH sliders.
    d->signal_choke=true;
    moveContents(-x, -y);
    d->vbar->setValue(y);
    d->hbar->setValue(x);
    d->signal_choke=false;
}

/*!
    Scrolls the content by \a dx to the left and \a dy upwards.
*/
void Q3ScrollView::scrollBy(int dx, int dy)
{
    setContentsPos(QMAX(d->contentsX()+dx, 0), QMAX(d->contentsY()+dy, 0));
}

/*!
    Scrolls the content so that the point (\a x, \a y) is in the center
    of visible area.
*/
void Q3ScrollView::center(int x, int y)
{
    ensureVisible(x, y, 32000, 32000);
}

/*!
    \overload

    Scrolls the content so that the point (\a x, \a y) is visible with
    the \a xmargin and \a ymargin margins (as fractions of visible
    the area).

    For example:
    \list
    \i Margin 0.0 allows (x, y) to be on the edge of the visible area.
    \i Margin 0.5 ensures that (x, y) is in middle 50% of the visible area.
    \i Margin 1.0 ensures that (x, y) is in the center of the the visible area.
    \endlist
*/
void Q3ScrollView::center(int x, int y, float xmargin, float ymargin)
{
    int pw=visibleWidth();
    int ph=visibleHeight();
    ensureVisible(x, y, int(xmargin/2.0*pw+0.5), int(ymargin/2.0*ph+0.5));
}


/*!
    \fn void Q3ScrollView::contentsMoving(int x, int y)

    This signal is emitted just before the contents are moved to
    position (\a x, \a y).

    \sa contentsX(), contentsY()
*/

/*!
    Moves the contents by (\a x, \a y).
*/
void Q3ScrollView::moveContents(int x, int y)
{
    if (-x+visibleWidth() > d->contentsWidth())
#if 0
        if(QApplication::reverseLayout())
            x=QMAX(0,-d->contentsWidth()+visibleWidth());
        else
#endif
            x=QMIN(0,-d->contentsWidth()+visibleWidth());
    if (-y+visibleHeight() > contentsHeight())
        y=QMIN(0,-contentsHeight()+visibleHeight());

    int dx = x - d->vx;
    int dy = y - d->vy;

    if (!dx && !dy)
        return; // Nothing to do

    emit contentsMoving(-x, -y);

    d->vx = x;
    d->vy = y;

    if (d->clipped_viewport || d->static_bg) {
        // Cheap move (usually)
        d->moveAllBy(dx,dy);
    } else if (/*dx && dy ||*/
         (QABS(dy) * 5 > visibleHeight() * 4) ||
         (QABS(dx) * 5 > visibleWidth() * 4)
       )
    {
        // Big move
        if (viewport()->updatesEnabled())
            viewport()->update();
        d->moveAllBy(dx,dy);
    } else if (!d->fake_scroll || d->contentsWidth() > visibleWidth()) {
        // Small move
        clipper()->scroll(dx,dy);
    }
    d->hideOrShowAll(this, true);
}

/*!
    \property Q3ScrollView::contentsX
    \brief the X coordinate of the contents that are at the left edge of
    the viewport.
*/
int Q3ScrollView::contentsX() const
{
    return d->contentsX();
}

/*!
    \property Q3ScrollView::contentsY
    \brief the Y coordinate of the contents that are at the top edge of
    the viewport.
*/
int Q3ScrollView::contentsY() const
{
    return d->contentsY();
}

/*!
    \property Q3ScrollView::contentsWidth
    \brief the width of the contents area
*/
int Q3ScrollView::contentsWidth() const
{
    return d->contentsWidth();
}

/*!
    \property Q3ScrollView::contentsHeight
    \brief the height of the contents area
*/
int Q3ScrollView::contentsHeight() const
{
    return d->vheight;
}

/*!
    Sets the size of the contents area to \a w pixels wide and \a h
    pixels high and updates the viewport accordingly.
*/
void Q3ScrollView::resizeContents(int w, int h)
{
    int ow = d->vwidth;
    int oh = d->vheight;
    d->vwidth = w;
    d->vheight = h;

    d->scrollbar_timer.start(0, true);

    if (d->children.isEmpty() && d->policy == Default)
        setResizePolicy(Manual);

    if (ow > w) {
        // Swap
        int t=w;
        w=ow;
        ow=t;
    }
    // Refresh area ow..w
    if (ow < visibleWidth() && w >= 0) {
        if (ow < 0)
            ow = 0;
        if (w > visibleWidth())
            w = visibleWidth();
        clipper()->update(d->contentsX()+ow, 0, w-ow, visibleHeight());
    }

    if (oh > h) {
        // Swap
        int t=h;
        h=oh;
        oh=t;
    }
    // Refresh area oh..h
    if (oh < visibleHeight() && h >= 0) {
        if (oh < 0)
            oh = 0;
        if (h > visibleHeight())
            h = visibleHeight();
        clipper()->update(0, d->contentsY()+oh, visibleWidth(), h-oh);
    }
}

/*!
    Calls update() on a rectangle defined by \a x, \a y, \a w, \a h,
    translated appropriately. If the rectangle is not visible, nothing
    is repainted.

    \sa repaintContents()
*/
void Q3ScrollView::updateContents(int x, int y, int w, int h)
{
    if (!isVisible() || !updatesEnabled())
        return;

    QWidget* vp = viewport();

    // Translate
    x -= d->contentsX();
    y -= d->contentsY();

    if (x < 0) {
        w += x;
        x = 0;
    }
    if (y < 0) {
        h += y;
        y = 0;
    }

    if (w < 0 || h < 0)
        return;
    if (x > visibleWidth() || y > visibleHeight())
        return;

    if (w > visibleWidth())
        w = visibleWidth();
    if (h > visibleHeight())
        h = visibleHeight();

    if (d->clipped_viewport) {
        // Translate clipper() to viewport()
        x -= d->clipped_viewport->x();
        y -= d->clipped_viewport->y();
    }

    vp->update(x, y, w, h);
}

/*!
    \overload

    Updates the contents in rectangle \a r
*/
void Q3ScrollView::updateContents(const QRect& r)
{
    updateContents(r.x(), r.y(), r.width(), r.height());
}

/*!
    \overload
*/
void Q3ScrollView::updateContents()
{
    updateContents(d->contentsX(), d->contentsY(), visibleWidth(), visibleHeight());
}

/*!
    \overload

    Repaints the contents of rectangle \a r. If \a erase is true the
    background is cleared using the background color.
*/
void Q3ScrollView::repaintContents(const QRect& r, bool erase)
{