---
name: "QwtSlider"
section: "3"
platform: "linux"
package: "libqwt-doc"
version: "6.1.4-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/QwtSlider"
---

# QwtSlider(3)

The Slider Widget.

## NAME

QwtSlider - The Slider Widget.

## SYNOPSIS

`#include <qwt_slider.h>`

Inherits **QwtAbstractSlider**.

### Public Types

enum **ScalePosition** { **NoScale**, **LeadingScale**, **TrailingScale** }\

### Public Member Functions

**QwtSlider** (QWidget \*parent=NULL)\
 **QwtSlider** (Qt::Orientation, QWidget \*parent=NULL)\
 virtual **~QwtSlider** ()\
 Destructor.  void **setOrientation** (Qt::Orientation)\
 Set the orientation.  Qt::Orientation **orientation** () const\
 void **setScalePosition** (**ScalePosition**)\
 Change the position of the scale.  **ScalePosition** **scalePosition** () const\
 void **setTrough** (bool)\
 bool **hasTrough** () const\
 void **setGroove** (bool)\
 bool **hasGroove** () const\
 void **setHandleSize** (const QSize &)\
 Set the slider's handle size.  QSize **handleSize** () const\
 void **setBorderWidth** (int)\
 Change the slider's border width.  int **borderWidth** () const\
 void **setSpacing** (int)\
 Change the spacing between trough and scale.  int **spacing** () const\
 virtual QSize **sizeHint** () const\
 virtual QSize **minimumSizeHint** () const\
 void **setScaleDraw** (**QwtScaleDraw** \*)\
 Set a scale draw.  const **QwtScaleDraw** \* **scaleDraw** () const\
 void **setUpdateInterval** (int)\
 Specify the update interval for automatic scrolling.  int **updateInterval** () const\

### Protected Member Functions

virtual double **scrolledTo** (const QPoint &) const\
 Determine the value for a new position of the slider handle.  virtual bool **isScrollPosition** (const QPoint &) const\
 Determine what to do when the user presses a mouse button.  virtual void **drawSlider** (QPainter \*, const QRect &) const\
 virtual void **drawHandle** (QPainter \*, const QRect &, int pos) const\
 virtual void **mousePressEvent** (QMouseEvent \*)\
 virtual void **mouseReleaseEvent** (QMouseEvent \*)\
 virtual void **resizeEvent** (QResizeEvent \*)\
 virtual void **paintEvent** (QPaintEvent \*)\
 virtual void **changeEvent** (QEvent \*)\
 virtual void **timerEvent** (QTimerEvent \*)\
 virtual void **scaleChange** ()\
 Notify changed scale.  QRect **sliderRect** () const\
 QRect **handleRect** () const\

### Additional Inherited Members

## Detailed Description

The Slider Widget.

**QwtSlider** is a slider widget which operates on an interval of type double. Its position is related to a scale showing the current value.

The slider can be customized by having a through, a groove - or both.

## Member Enumeration Documentation

### enum QwtSlider::ScalePosition

Position of the scale

**See also:**

**QwtSlider()**, **setScalePosition()**, **setOrientation()**

**Enumerator**

- *NoScale*

  *The slider has no scale.*

- *LeadingScale*

  *The scale is right of a vertical or below a horizontal slider.*

- *TrailingScale*

  *The scale is left of a vertical or above a horizontal slider.*

## Constructor & Destructor Documentation

### QwtSlider::QwtSlider (QWidget \* parent = `NULL`)` [explicit]`

*Construct vertical slider in QwtSlider::Trough style with a scale to the left.*

*The scale is initialized to \[0.0, 100.0\] and the value set to 0.0.*

**Parameters:**

*parent Parent widget*

**See also:**

**setOrientation()***,* **setScalePosition()***, setBackgroundStyle()*

### QwtSlider::QwtSlider (Qt::Orientation orientation, QWidget \* parent = `NULL`)` [explicit]`

*Construct a slider in QwtSlider::Trough style*

*When orientation is Qt::Vertical the scale will be aligned to the left - otherwise at the the top of the slider.*

*The scale is initialized to \[0.0, 100.0\] and the value set to 0.0.*

**Parameters:**

*parent Parent widget* \
 *orientation Orientation of the slider.*

## Member Function Documentation

### int QwtSlider::borderWidth () const

**Returns:**

*the border width.*

**See also:**

**setBorderWidth()**

### void QwtSlider::changeEvent (QEvent \* event)` [protected]`, ` [virtual]`

*Handles QEvent::StyleChange and QEvent::FontChange events*

**Parameters:**

*event Change event*

### void QwtSlider::drawHandle (QPainter \* painter, const QRect & handleRect, int pos) const` [protected]`, ` [virtual]`

*Draw the thumb at a position*

**Parameters:**

*painter Painter* \
 *handleRect Bounding rectangle of the handle* \
 *pos Position of the handle marker in widget coordinates*

### void QwtSlider::drawSlider (QPainter \* painter, const QRect & sliderRect) const` [protected]`, ` [virtual]`

*Draw the slider into the specified rectangle.*

**Parameters:**

*painter Painter* \
 *sliderRect Bounding rectangle of the slider*

### QRect QwtSlider::handleRect () const` [protected]`

**Returns:**

*Bounding rectangle of the slider handle*

### QSize QwtSlider::handleSize () const

**Returns:**

*Size of the handle.*

**See also:**

**setHandleSize()**

### bool QwtSlider::hasGroove () const

**Returns:**

*True, when the groove is visisble*

**See also:**

**setGroove()***,* **hasTrough()**

### bool QwtSlider::hasTrough () const

**Returns:**

*True, when the trough is visisble*

**See also:**

**setTrough()***,* **hasGroove()**

### bool QwtSlider::isScrollPosition (const QPoint & pos) const` [protected]`, ` [virtual]`

*Determine what to do when the user presses a mouse button.*

**Parameters:**

*pos Mouse position*

**Return values:**

*True,when* **handleRect()** *contains pos*

**See also:**

**scrolledTo()**

*Implements* **QwtAbstractSlider***.*

### QSize QwtSlider::minimumSizeHint () const` [virtual]`

**Returns:**

*Minimum size hint*

**See also:**

**sizeHint()**

### void QwtSlider::mousePressEvent (QMouseEvent \* event)` [protected]`, ` [virtual]`

*Mouse press event handler*

**Parameters:**

*event Mouse event*

*Reimplemented from* **QwtAbstractSlider***.*

### void QwtSlider::mouseReleaseEvent (QMouseEvent \* event)` [protected]`, ` [virtual]`

*Mouse release event handler*

**Parameters:**

*event Mouse event*

*Reimplemented from* **QwtAbstractSlider***.*

### Qt::Orientation QwtSlider::orientation () const

**Returns:**

*Orientation*

**See also:**

**setOrientation()**

### void QwtSlider::paintEvent (QPaintEvent \* event)` [protected]`, ` [virtual]`

*Qt paint event handler*

**Parameters:**

*event Paint event*

### void QwtSlider::resizeEvent (QResizeEvent \* event)` [protected]`, ` [virtual]`

*Qt resize event handler*

**Parameters:**

*event Resize event*

### const QwtScaleDraw \* QwtSlider::scaleDraw () const

**Returns:**

*the scale draw of the slider*

**See also:**

**setScaleDraw()**

### QwtSlider::ScalePosition QwtSlider::scalePosition () const

**Returns:**

*Position of the scale*

**See also:**

**setScalePosition()**

### double QwtSlider::scrolledTo (const QPoint & pos) const` [protected]`, ` [virtual]`

*Determine the value for a new position of the slider handle.*

**Parameters:**

*pos Mouse position*

**Returns:**

*Value for the mouse position*

**See also:**

**isScrollPosition()**

*Implements* **QwtAbstractSlider***.*

### void QwtSlider::setBorderWidth (int width)

*Change the slider's border width. The border width is used for drawing the slider handle and the trough.*

**Parameters:**

*width Border width*

**See also:**

**borderWidth()**

### void QwtSlider::setGroove (bool on)

*En/Disable the groove*

*The slider can be cutomized by showing a groove for the handle.*

**Parameters:**

*on When true, the groove is visible*

**See also:**

**hasGroove()***, setThrough()*

### void QwtSlider::setHandleSize (const QSize & size)

*Set the slider's handle size. When the size is empty the slider handle will be painted with a default size depending on its* **orientation()** *and backgroundStyle().*

**Parameters:**

*size New size*

**See also:**

**handleSize()**

### void QwtSlider::setOrientation (Qt::Orientation orientation)

*Set the orientation.*

**Parameters:**

*orientation Allowed values are Qt::Horizontal and Qt::Vertical.*

**See also:**

**orientation()***,* **scalePosition()**

### void QwtSlider::setScaleDraw (QwtScaleDraw \* scaleDraw)

*Set a scale draw. For changing the labels of the scales, it is necessary to derive from* **QwtScaleDraw** *and overload* **QwtScaleDraw::label()***.*

**Parameters:**

*scaleDraw ScaleDraw object, that has to be created with new and will be deleted in* **~QwtSlider()** *or the next call of* **setScaleDraw()***.*

**See also:**

*scaleDraw()*

### void QwtSlider::setScalePosition (ScalePosition scalePosition)

*Change the position of the scale.*

**Parameters:**

*scalePosition Position of the scale.*

**See also:**

**ScalePosition***,* **scalePosition()**

### void QwtSlider::setSpacing (int spacing)

*Change the spacing between trough and scale. A spacing of 0 means, that the backbone of the scale is covered by the trough.*

*The default setting is 4 pixels.*

**Parameters:**

*spacing Number of pixels*

**See also:**

**spacing()***;*

### void QwtSlider::setTrough (bool on)

*En/Disable the trough*

*The slider can be cutomized by showing a trough for the handle.*

**Parameters:**

*on When true, the groove is visible*

**See also:**

**hasTrough()***,* **setGroove()**

### void QwtSlider::setUpdateInterval (int interval)

*Specify the update interval for automatic scrolling. The minimal accepted value is 50 ms.*

**Parameters:**

*interval Update interval in milliseconds*

**See also:**

**setUpdateInterval()**

### QSize QwtSlider::sizeHint () const` [virtual]`

**Returns:**

**minimumSizeHint()**

### QRect QwtSlider::sliderRect () const` [protected]`

**Returns:**

*Bounding rectangle of the slider - without the scale*

### int QwtSlider::spacing () const

**Returns:**

*Number of pixels between slider and scale*

**See also:**

**setSpacing()**

### void QwtSlider::timerEvent (QTimerEvent \* event)` [protected]`, ` [virtual]`

*Timer event handler*

*Handles the timer, when the mouse stays pressed inside the* **sliderRect()***.*

**Parameters:**

*event Mouse event*

### int QwtSlider::updateInterval () const

**Returns:**

*Update interval in milliseconds for automatic scrolling*

**See also:**

**setUpdateInterval()**

## Author

*Generated automatically by Doxygen for Qwt User's Guide from the source code.*