QSplitterHandle Class

The QSplitterHandle class provides handle functionality for the splitter. More...

Header: #include <QSplitterHandle>
CMake: find_package(Qt6 REQUIRED COMPONENTS Widgets)
target_link_libraries(mytarget PRIVATE Qt6::Widgets)
qmake: QT += widgets
Inherits: QWidget

Public Functions

QSplitterHandle(Qt::Orientation orientation, QSplitter *parent)
virtual ~QSplitterHandle()
bool opaqueResize() const
Qt::Orientation orientation() const
void setOrientation(Qt::Orientation orientation)
QSplitter *splitter() const

Reimplemented Public Functions

virtual QSize sizeHint() const override

Protected Functions

int closestLegalPosition(int pos)
void moveSplitter(int pos)

Reimplemented Protected Functions

virtual bool event(QEvent *event) override
virtual void mouseMoveEvent(QMouseEvent *e) override
virtual void mousePressEvent(QMouseEvent *e) override
virtual void mouseReleaseEvent(QMouseEvent *e) override
virtual void paintEvent(QPaintEvent *) override
virtual void resizeEvent(QResizeEvent *event) override

Detailed Description

QSplitterHandle is typically what people think about when they think about a splitter. It is the handle that is used to resize the widgets.

A typical developer using QSplitter will never have to worry about QSplitterHandle. It is provided for developers who want splitter handles that provide extra features, such as popup menus.

The typical way one would create splitter handles is to subclass QSplitter and then reimplement QSplitter::createHandle() to instantiate the custom splitter handle. For example, a minimum QSplitter subclass might look like this:

class Splitter : public QSplitter
    Splitter(Qt::Orientation orientation, QWidget *parent = nullptr);

    QSplitterHandle *createHandle() override;

The createHandle() implementation simply constructs a custom splitter handle, called Splitter in this example:

QSplitterHandle *Splitter::createHandle()
    return new SplitterHandle(orientation(), this);

Information about a given handle can be obtained using functions like orientation() and opaqueResize(), and is retrieved from its parent splitter. Details like these can be used to give custom handles different appearances depending on the splitter's orientation.

The complexity of a custom handle subclass depends on the tasks that it needs to perform. A simple subclass might only provide a paintEvent() implementation:

void SplitterHandle::paintEvent(QPaintEvent *event)
    QPainter painter(this);
    if (orientation() == Qt::Horizontal) {
        gradient.setStart(rect().left(), rect().height()/2);
        gradient.setFinalStop(rect().right(), rect().height()/2);
    } else {
        gradient.setStart(rect().width()/2, rect().top());
        gradient.setFinalStop(rect().width()/2, rect().bottom());
    painter.fillRect(event->rect(), QBrush(gradient));

In this example, a predefined gradient is set up differently depending on the orientation of the handle. QSplitterHandle provides a reasonable size hint for the handle, so the subclass does not need to provide a reimplementation of sizeHint() unless the handle has special size requirements.

See also QSplitter.

Member Function Documentation

[explicit] QSplitterHandle::QSplitterHandle(Qt::Orientation orientation, QSplitter *parent)

Creates a QSplitter handle with the given orientation and parent.

[virtual noexcept] QSplitterHandle::~QSplitterHandle()


[protected] int QSplitterHandle::closestLegalPosition(int pos)

Returns the closest legal position to pos of the splitter handle. The positions are measured from the left or top edge of the splitter, even for right-to-left languages.

See also QSplitter::closestLegalPosition() and moveSplitter().

[override virtual protected] bool QSplitterHandle::event(QEvent *event)

Reimplements: QWidget::event(QEvent *event).

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

Reimplements: QWidget::mouseMoveEvent(QMouseEvent *event).

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

Reimplements: QWidget::mousePressEvent(QMouseEvent *event).

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

Reimplements: QWidget::mouseReleaseEvent(QMouseEvent *event).

[protected] void QSplitterHandle::moveSplitter(int pos)

Tells the splitter to move this handle to position pos, which is the distance from the left or top edge of the widget.

Note that pos is also measured from the left (or top) for right-to-left languages. This function will map pos to the appropriate position before calling QSplitter::moveSplitter().

See also QSplitter::moveSplitter() and closestLegalPosition().

bool QSplitterHandle::opaqueResize() const

Returns true if widgets are resized dynamically (opaquely) while interactively moving the splitter. Otherwise returns false. This value is controlled by the QSplitter.

See also QSplitter::opaqueResize().

Qt::Orientation QSplitterHandle::orientation() const

Returns the handle's orientation. This is usually propagated from the QSplitter.

See also setOrientation() and QSplitter::orientation().

[override virtual protected] void QSplitterHandle::paintEvent(QPaintEvent *)

Reimplements: QWidget::paintEvent(QPaintEvent *event).

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

Reimplements: QWidget::resizeEvent(QResizeEvent *event).

void QSplitterHandle::setOrientation(Qt::Orientation orientation)

Sets the orientation of the splitter handle to orientation. This is usually propagated from the QSplitter.

See also orientation() and QSplitter::setOrientation().

[override virtual] QSize QSplitterHandle::sizeHint() const

Reimplements an access function for property: QWidget::sizeHint.

QSplitter *QSplitterHandle::splitter() const

Returns the splitter associated with this splitter handle.

See also QSplitter::handle().

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