Q3ScrollView Class Reference

 #include <Q3ScrollView>

 Q3ScrollView* sv = new Q3ScrollView(...);
 QWidget *widget = new QWidget(sv->viewport());
 QVBoxLayout *layout = new QVBoxLayout(widget);
 addChild(widget);

 QLabel* child1 = new QLabel("CHILD", widget);
 QLabel* child2 = new QLabel("CHILD", widget);
 QLabel* child3 = new QLabel("CHILD", widget);
 layout->addWidget(child1);
 layout->addWidget(child2);
 layout->addWidget(child3);
 ...

 Q3ScrollView* sv = new Q3ScrollView(...);
 QLabel* child1 = new QLabel("CHILD", sv->viewport());
 sv->addChild(child1);
 QLabel* child2 = new QLabel("CHILD", sv->viewport());
 sv->addChild(child2);
 QLabel* child3 = new QLabel("CHILD", sv->viewport());
 sv->addChild(child3);

 Q3ScrollView* sv = new Q3ScrollView(...);
 sv->enableClipper(true);
 QLabel* child1 = new QLabel("CHILD", sv->viewport());
 sv->addChild(child1);
 QLabel* child2 = new QLabel("CHILD", sv->viewport());
 sv->addChild(child2);
 QLabel* child3 = new QLabel("CHILD", sv->viewport());
 sv->addChild(child3);

Member Function Documentation

Q3ScrollView::Q3ScrollView ( QWidget * parent = 0, const char * name = 0, Qt::WindowFlags f = 0 )

Constructs a Q3ScrollView called name with parent parent and widget flags f.

The widget flags WStaticContents, WNoAutoErase and WPaintClever are propagated to the viewport() widget. The other widget flags are propagated to the parent constructor as usual.

Q3ScrollView::~Q3ScrollView ()

Destroys the Q3ScrollView. Any children added with addChild() will be deleted.

void Q3ScrollView::addChild ( QWidget * child, int x = 0, int y = 0 ) [virtual]

Inserts the widget, child, into the scrolled area positioned at (x, y). The position defaults to (0, 0). If the child is already in the view, it is just moved.

You may want to call enableClipper(true) if you add a large number of widgets.

int Q3ScrollView::bottomMargin () const

Returns the bottom margin.

See also setMargins().

void Q3ScrollView::center ( int x, int y ) [slot]

Scrolls the content so that the point (x, y) is in the center of visible area.

void Q3ScrollView::center ( int x, int y, float xmargin, float ymargin ) [slot]

This is an overloaded function.

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

For example:

• Margin 0.0 allows (x, y) to be on the edge of the visible area.
• Margin 0.5 ensures that (x, y) is in middle 50% of the visible area.
• Margin 1.0 ensures that (x, y) is in the center of the visible area.

int Q3ScrollView::childX ( QWidget * child )

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

This function returns 0 if child has not been added to the view.

int Q3ScrollView::childY ( QWidget * child )

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

This function returns 0 if child has not been added to the view.

QWidget * Q3ScrollView::clipper () const

Returns the clipper widget. Contents in the scrollview are ultimately clipped to be inside the clipper widget.

You should not need to use this function.

See also visibleWidth() and visibleHeight().

void Q3ScrollView::contentsContextMenuEvent ( QContextMenuEvent * e ) [virtual protected]

This event handler is called whenever the Q3ScrollView receives a contextMenuEvent() in e: the mouse position is translated to be a point on the contents.

void Q3ScrollView::contentsDragEnterEvent ( QDragEnterEvent * event ) [virtual protected]

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 event parameter is ignored.

void Q3ScrollView::contentsDragLeaveEvent ( QDragLeaveEvent * event ) [virtual protected]

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 event parameter is ignored.

void Q3ScrollView::contentsDragMoveEvent ( QDragMoveEvent * event ) [virtual protected]

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 event parameter is ignored.

void Q3ScrollView::contentsDropEvent ( QDropEvent * event ) [virtual protected]

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 event parameter is ignored.

void Q3ScrollView::contentsMouseDoubleClickEvent ( QMouseEvent * e ) [virtual protected]

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

The default implementation generates a normal mouse press event.

void Q3ScrollView::contentsMouseMoveEvent ( QMouseEvent * e ) [virtual protected]

This event handler is called whenever the Q3ScrollView receives a mouseMoveEvent(): the mouse position in e is translated to be a point on the contents.

void Q3ScrollView::contentsMousePressEvent ( QMouseEvent * e ) [virtual protected]

This event handler is called whenever the Q3ScrollView receives a mousePressEvent(): the press position in e is translated to be a point on the contents.

void Q3ScrollView::contentsMouseReleaseEvent ( QMouseEvent * e ) [virtual protected]

This event handler is called whenever the Q3ScrollView receives a mouseReleaseEvent(): the release position in e is translated to be a point on the contents.

void Q3ScrollView::contentsMoving ( int x, int y ) [signal]

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

See also contentsX() and contentsY().

void Q3ScrollView::contentsToViewport ( int x, int y, int & vx, int & vy ) const

Translates a point (x, y) in the contents to a point (vx, vy) on the viewport() widget.

QPoint Q3ScrollView::contentsToViewport ( const QPoint & p ) const

This is an overloaded function.

Returns the point p translated to a point on the viewport() widget.

void Q3ScrollView::contentsWheelEvent ( QWheelEvent * e ) [virtual protected]

This event handler is called whenever the Q3ScrollView receives a wheelEvent() in e: the mouse position is translated to be a point on the contents.

void Q3ScrollView::contextMenuEvent ( QContextMenuEvent * e ) [virtual protected]

Reimplemented from QWidget::contextMenuEvent().

QWidget * Q3ScrollView::cornerWidget () const

Returns the widget in the corner between the two scroll bars.

By default, no corner widget is present.

See also setCornerWidget().

void Q3ScrollView::drawContents ( QPainter * p, int clipx, int clipy, int clipw, int cliph ) [virtual protected]

Reimplement this function if you are viewing a drawing area rather than a widget.

The function should draw the rectangle (clipx, clipy, clipw, cliph) of the contents using painter p. The clip rectangle is in the scrollview's coordinates.

For example:

 {
     // Fill a 40000 by 50000 rectangle at (100000,150000)

     // Calculate the coordinates...
     int x1 = 100000, y1 = 150000;
     int x2 = x1+40000-1, y2 = y1+50000-1;

     // Clip the coordinates so X/Windows will not have problems...
     if (x1 < clipx) x1=clipx;
     if (y1 < clipy) y1=clipy;
     if (x2 > clipx+clipw-1) x2=clipx+clipw-1;
     if (y2 > clipy+cliph-1) y2=clipy+cliph-1;

     // Paint using the small coordinates...
     if (x2 >= x1 && y2 >= y1)
         p->fillRect(x1, y1, x2-x1+1, y2-y1+1, red);
 }

The clip rectangle and translation of the painter p is already set appropriately.

void Q3ScrollView::drawContentsOffset ( QPainter * p, int offsetx, int offsety, int clipx, int clipy, int clipw, int cliph ) [virtual protected]

For backward-compatibility only. It is easier to use drawContents(QPainter*,int,int,int,int).

The default implementation translates the painter appropriately and calls drawContents(QPainter*,int,int,int,int). See drawContents() for an explanation of the parameters p, offsetx, offsety, clipx, clipy, clipw and cliph.

void Q3ScrollView::enableClipper ( bool y )

When a large numbers of child widgets are in a scrollview, especially if they are close together, the scrolling performance can suffer greatly. If y is true the scrollview will use an extra widget to group child widgets.

Note that you may only call enableClipper() prior to adding widgets.

void Q3ScrollView::ensureVisible ( int x, int y ) [slot]

Scrolls the content so that the point (x, y) is visible with at least 50-pixel margins (if possible, otherwise centered).

void Q3ScrollView::ensureVisible ( int x, int y, int xmargin, int ymargin ) [slot]

This is an overloaded function.

Scrolls the content so that the point (x, y) is visible with at least the xmargin and ymargin margins (if possible, otherwise centered).

bool Q3ScrollView::eventFilter ( QObject * obj, QEvent * e ) [virtual protected]

Reimplemented from QObject::eventFilter().

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 e and the object is in obj.

bool Q3ScrollView::focusNextPrevChild ( bool next ) [virtual protected]

Reimplemented from QWidget::focusNextPrevChild().

void Q3ScrollView::frameChanged () [virtual protected]

Reimplemented from Q3Frame::frameChanged().

bool Q3ScrollView::hasStaticBackground () const

Returns true if Q3ScrollView uses a static background; otherwise returns false.

See also setStaticBackground().

QScrollBar * Q3ScrollView::horizontalScrollBar () const

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.

void Q3ScrollView::horizontalSliderPressed () [signal]

This signal is emitted whenever the user presses the horizontal slider.

void Q3ScrollView::horizontalSliderReleased () [signal]

This signal is emitted whenever the user releases the horizontal slider.

bool Q3ScrollView::isHorizontalSliderPressed ()

Returns true if horizontal slider is pressed by user; otherwise returns false.

bool Q3ScrollView::isVerticalSliderPressed ()

Returns true if vertical slider is pressed by user; otherwise returns false.

int Q3ScrollView::leftMargin () const

Returns the left margin.

See also setMargins().

QSize Q3ScrollView::minimumSizeHint () const [virtual]

Reimplemented from QWidget::minimumSizeHint().

void Q3ScrollView::mouseDoubleClickEvent ( QMouseEvent * e ) [virtual protected]

Reimplemented from QWidget::mouseDoubleClickEvent().

void Q3ScrollView::mouseMoveEvent ( QMouseEvent * e ) [virtual protected]

Reimplemented from QWidget::mouseMoveEvent().

void Q3ScrollView::mousePressEvent ( QMouseEvent * e ) [virtual protected]

Reimplemented from QWidget::mousePressEvent().

void Q3ScrollView::mouseReleaseEvent ( QMouseEvent * e ) [virtual protected]

Reimplemented from QWidget::mouseReleaseEvent().

void Q3ScrollView::moveChild ( QWidget * child, int x, int y ) [virtual]

Repositions the child widget to (x, y). This function is the same as addChild().

void Q3ScrollView::removeChild ( QWidget * child )

Removes the child widget from the scrolled area. Note that this happens automatically if the child is deleted.

void Q3ScrollView::repaintContents ( int x, int y, int w, int h, bool erase = true )

Calls repaint() on a rectangle defined by x, y, w, h, translated appropriately. If the rectangle is not visible, nothing is repainted. If erase is true the background is cleared using the background color.

See also updateContents().

void Q3ScrollView::repaintContents ( const QRect & r, bool erase = true )

This is an overloaded function.

Repaints the contents of rectangle r. If erase is true the background is cleared using the background color.

void Q3ScrollView::repaintContents ( bool erase = true )

This is an overloaded function.

Repaints the contents. If erase is true the background is cleared using the background color.

void Q3ScrollView::resizeContents ( int w, int h ) [virtual slot]

Sets the size of the contents area to w pixels wide and h pixels high and updates the viewport accordingly.

void Q3ScrollView::resizeEvent ( QResizeEvent * event ) [virtual protected]

Reimplemented from QWidget::resizeEvent().

int Q3ScrollView::rightMargin () const

Returns the right margin.

See also setMargins().

void Q3ScrollView::scrollBy ( int dx, int dy ) [slot]

Scrolls the content by dx to the left and dy upwards.

void Q3ScrollView::setContentsPos ( int x, int y ) [virtual slot]

Scrolls the content so that the point (x, y) is in the top-left corner.

void Q3ScrollView::setCornerWidget ( QWidget * corner ) [virtual]

Sets the widget in the corner between the two scroll bars.

You will probably also want to set at least one of the scroll bar modes to AlwaysOn.

Passing 0 shows no widget in the corner.

Any previous corner widget is hidden.

You may call setCornerWidget() with the same widget at different times.

All widgets set here will be deleted by the Q3ScrollView when it is destroyed unless you separately reparent the widget after setting some other corner widget (or 0).

Any newly set widget should have no current parent.

By default, no corner widget is present.

See also cornerWidget(), setVScrollBarMode(), and setHScrollBarMode().

void Q3ScrollView::setHBarGeometry ( QScrollBar & hbar, int x, int y, int w, int h ) [virtual protected]

Called when the horizontal scroll bar geometry changes. This is provided as a protected function so that subclasses can do interesting things such as providing extra buttons in some of the space normally used by the scroll bars.

The default implementation simply gives all the space to hbar. The new geometry is given by x, y, w and h.

See also setVBarGeometry().

void Q3ScrollView::setMargins ( int left, int top, int right, int bottom ) [virtual]

Sets the margins around the scrolling area to left, top, right and bottom. This is useful for applications such as spreadsheets with "locked" rows and columns. The marginal space is inside the frameRect() and is left blank; reimplement drawFrame() or put widgets in the unused area.

By default all margins are zero.

See also frameChanged().

void Q3ScrollView::setStaticBackground ( bool y )

Sets the scrollview to have a static background if y is true, or a scrolling background if y is false. By default, the background is scrolling.

Be aware that this mode is quite slow, as a full repaint of the visible area has to be triggered on every contents move.

See also hasStaticBackground().

void Q3ScrollView::setVBarGeometry ( QScrollBar & vbar, int x, int y, int w, int h ) [virtual protected]

Called when the vertical scroll bar geometry changes. This is provided as a protected function so that subclasses can do interesting things such as providing extra buttons in some of the space normally used by the scroll bars.

The default implementation simply gives all the space to vbar. The new geometry is given by x, y, w and h.

See also setHBarGeometry().

void Q3ScrollView::setVisible ( bool visible ) [virtual]

Reimplemented from QWidget::setVisible().

QSize Q3ScrollView::sizeHint () const [virtual]

Reimplemented from QWidget::sizeHint().

int Q3ScrollView::topMargin () const

Returns the top margin.

See also setMargins().

void Q3ScrollView::updateContents ( int x, int y, int w, int h )

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

See also repaintContents().

void Q3ScrollView::updateContents ( const QRect & r )

This is an overloaded function.

Updates the contents in rectangle r

void Q3ScrollView::updateContents ()

This is an overloaded function.

void Q3ScrollView::updateScrollBars () [slot]

Updates scroll bars: all possibilities are considered. You should never need to call this in your code.

QScrollBar * Q3ScrollView::verticalScrollBar () const

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.

void Q3ScrollView::verticalSliderPressed () [signal]

This signal is emitted whenever the user presses the vertical slider.

void Q3ScrollView::verticalSliderReleased () [signal]

This signal is emitted whenever the user releases the vertical slider.

QWidget * Q3ScrollView::viewport () const

Returns the viewport widget of the scrollview. This is the widget containing the contents widget or which is the drawing area.

void Q3ScrollView::viewportPaintEvent ( QPaintEvent * pe ) [virtual protected]

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 pe.

void Q3ScrollView::viewportResizeEvent ( QResizeEvent * event ) [virtual protected]

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 event parameter is ignored.

See also QWidget::resizeEvent().

QSize Q3ScrollView::viewportSize ( int x, int y ) const

Returns the viewport size for size (x, y).

The viewport size depends on (x, y) (the size of the contents), the size of this widget and the modes of the horizontal and vertical scroll bars.

This function permits widgets that can trade vertical and horizontal space for each other to control scroll bar appearance better. For example, a word processor or web browser can control the width of the right margin accurately, whether or not there needs to be a vertical scroll bar.

void Q3ScrollView::viewportToContents ( int vx, int vy, int & x, int & y ) const

Translates a point (vx, vy) on the viewport() widget to a point (x, y) in the contents.

QPoint Q3ScrollView::viewportToContents ( const QPoint & vp ) const

This is an overloaded function.

Returns the point on the viewport vp translated to a point in the contents.

void Q3ScrollView::wheelEvent ( QWheelEvent * e ) [virtual protected]

Reimplemented from QWidget::wheelEvent().