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

# QwtScaleWidget(3)

A Widget which contains a scale.

## NAME

QwtScaleWidget - A Widget which contains a scale.

## SYNOPSIS

`#include <qwt_scale_widget.h>`

Inherits QWidget.

### Public Types

enum **LayoutFlag** { **TitleInverted** = 1 }\
 Layout flags of the title.  typedef QFlags\< **LayoutFlag** \> **LayoutFlags**\
 Layout flags of the title.

### Signals

void **scaleDivChanged** ()\
 Signal emitted, whenever the scale division changes.

### Public Member Functions

**QwtScaleWidget** (QWidget \*parent=NULL)\
 Create a scale with the position QwtScaleWidget::Left.  **QwtScaleWidget** (**QwtScaleDraw::Alignment**, QWidget \*parent=NULL)\
 Constructor.  virtual **~QwtScaleWidget** ()\
 Destructor.  void **setTitle** (const QString &**title**)\
 void **setTitle** (const **QwtText** &**title**)\
 **QwtText** **title** () const\
 void **setLayoutFlag** (**LayoutFlag**, bool on)\
 bool **testLayoutFlag** (**LayoutFlag**) const\
 void **setBorderDist** (int dist1, int dist2)\
 int **startBorderDist** () const\
 int **endBorderDist** () const\
 void **getBorderDistHint** (int &start, int &end) const\
 Calculate a hint for the border distances.  void **getMinBorderDist** (int &start, int &end) const\
 void **setMinBorderDist** (int start, int end)\
 void **setMargin** (int)\
 Specify the margin to the colorBar/base line.  int **margin** () const\
 void **setSpacing** (int)\
 Specify the distance between color bar, scale and title.  int **spacing** () const\
 void **setScaleDiv** (const **QwtScaleDiv** &)\
 Assign a scale division.  void **setTransformation** (**QwtTransform** \*)\
 void **setScaleDraw** (**QwtScaleDraw** \*)\
 const **QwtScaleDraw** \* **scaleDraw** () const\
 **QwtScaleDraw** \* **scaleDraw** ()\
 void **setLabelAlignment** (Qt::Alignment)\
 Change the alignment for the labels.  void **setLabelRotation** (double rotation)\
 Change the rotation for the labels. See **QwtScaleDraw::setLabelRotation()**.  void **setColorBarEnabled** (bool)\
 bool **isColorBarEnabled** () const\
 void **setColorBarWidth** (int)\
 int **colorBarWidth** () const\
 void **setColorMap** (const **QwtInterval** &, **QwtColorMap** \*)\
 **QwtInterval** **colorBarInterval** () const\
 const **QwtColorMap** \* **colorMap** () const\
 virtual QSize **sizeHint** () const\
 virtual QSize **minimumSizeHint** () const\
 int **titleHeightForWidth** (int width) const\
 Find the height of the title for a given width.  int **dimForLength** (int length, const QFont &scaleFont) const\
 Find the minimum dimension for a given length. dim is the height, length the width seen in direction of the title.  void **drawColorBar** (QPainter \*painter, const QRectF &) const\
 void **drawTitle** (QPainter \*painter, **QwtScaleDraw::Alignment**, const QRectF &rect) const\
 void **setAlignment** (**QwtScaleDraw::Alignment**)\
 **QwtScaleDraw::Alignment** **alignment** () const\
 QRectF **colorBarRect** (const QRectF &) const\

### Protected Member Functions

virtual void **paintEvent** (QPaintEvent \*)\
 paintEvent  virtual void **resizeEvent** (QResizeEvent \*)\
 void **draw** (QPainter \*) const\
 draw the scale  void **scaleChange** ()\
 Notify a change of the scale.  void **layoutScale** (bool update\_geometry=true)\

## Detailed Description

A Widget which contains a scale.

This Widget can be used to decorate composite widgets with a scale.

## Member Enumeration Documentation

### enum QwtScaleWidget::LayoutFlag

Layout flags of the title.

**Enumerator**

- *TitleInverted*

  *The title of vertical scales is painted from top to bottom. Otherwise it is painted from bottom to top.*

## Constructor & Destructor Documentation

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

*Create a scale with the position QwtScaleWidget::Left.*

**Parameters:**

*parent Parent widget*

### QwtScaleWidget::QwtScaleWidget (QwtScaleDraw::Alignment align, QWidget \* parent = `NULL`)` [explicit]`

*Constructor.*

**Parameters:**

*align Alignment.* \
 *parent Parent widget*

## Member Function Documentation

### QwtScaleDraw::Alignment QwtScaleWidget::alignment () const

**Returns:**

*position*

**See also:**

*setPosition()*

### QwtInterval QwtScaleWidget::colorBarInterval () const

**Returns:**

*Value interval for the color bar*

**See also:**

**setColorMap()***,* **colorMap()**

### QRectF QwtScaleWidget::colorBarRect (const QRectF & rect) const

*Calculate the the rectangle for the color bar*

**Parameters:**

*rect Bounding rectangle for all components of the scale*

**Returns:**

*Rectangle for the color bar*

### int QwtScaleWidget::colorBarWidth () const

**Returns:**

*Width of the color bar*

**See also:**

**setColorBarEnabled()***,* **setColorBarEnabled()**

### const QwtColorMap \* QwtScaleWidget::colorMap () const

**Returns:**

*Color map*

**See also:**

**setColorMap()***,* **colorBarInterval()**

### int QwtScaleWidget::dimForLength (int length, const QFont & scaleFont) const

*Find the minimum dimension for a given length. dim is the height, length the width seen in direction of the title.*

**Parameters:**

*length width for horizontal, height for vertical scales* \
 *scaleFont Font of the scale*

**Returns:**

*height for horizontal, width for vertical scales*

### void QwtScaleWidget::drawColorBar (QPainter \* painter, const QRectF & rect) const

*Draw the color bar of the scale widget*

**Parameters:**

*painter Painter* \
 *rect Bounding rectangle for the color bar*

**See also:**

**setColorBarEnabled()**

### void QwtScaleWidget::drawTitle (QPainter \* painter, QwtScaleDraw::Alignment align, const QRectF & rect) const

*Rotate and paint a title according to its position into a given rectangle.*

**Parameters:**

*painter Painter* \
 *align Alignment* \
 *rect Bounding rectangle*

### int QwtScaleWidget::endBorderDist () const

**Returns:**

*end border distance*

**See also:**

**setBorderDist()**

### void QwtScaleWidget::getBorderDistHint (int & start, int & end) const

*Calculate a hint for the border distances. This member function calculates the distance of the scale's endpoints from the widget borders which is required for the mark labels to fit into the widget. The maximum of this distance an the minimum border distance is returned.*

**Parameters:**

*start Return parameter for the border width at the beginning of the scale* \
 *end Return parameter for the border width at the end of the scale*

**Warning:**

- •

  *The minimum border distance depends on the font.*

**See also:**

**setMinBorderDist()***,* **getMinBorderDist()***,* **setBorderDist()**

### void QwtScaleWidget::getMinBorderDist (int & start, int & end) const

*Get the minimum value for the distances of the scale's endpoints from the widget borders.*

**Parameters:**

*start Return parameter for the border width at the beginning of the scale* \
 *end Return parameter for the border width at the end of the scale*

**See also:**

**setMinBorderDist()***,* **getBorderDistHint()**

### bool QwtScaleWidget::isColorBarEnabled () const

**Returns:**

*true, when the color bar is enabled*

**See also:**

**setColorBarEnabled()***,* **setColorBarWidth()**

### void QwtScaleWidget::layoutScale (bool update\_geometry = `true`)` [protected]`

*Recalculate the scale's geometry and layout based on the current geometry and fonts.*

**Parameters:**

*update\_geometry Notify the layout system and call update to redraw the scale*

### int QwtScaleWidget::margin () const

**Returns:**

*margin*

**See also:**

**setMargin()**

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

**Returns:**

*a minimum size hint*

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

*Event handler for resize events*

**Parameters:**

*event Resize event*

### void QwtScaleWidget::scaleChange ()` [protected]`

*Notify a change of the scale. This virtual function can be overloaded by derived classes. The default implementation updates the geometry and repaints the widget.*

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

**Returns:**

*scaleDraw of this scale*

**See also:**

**setScaleDraw()***, QwtScaleDraw::setScaleDraw()*

### QwtScaleDraw \* QwtScaleWidget::scaleDraw ()

**Returns:**

*scaleDraw of this scale*

**See also:**

*QwtScaleDraw::setScaleDraw()*

### void QwtScaleWidget::setAlignment (QwtScaleDraw::Alignment alignment)

*Change the alignment*

**Parameters:**

*alignment New alignment*

**See also:**

**alignment()**

### void QwtScaleWidget::setBorderDist (int dist1, int dist2)

*Specify distances of the scale's endpoints from the widget's borders. The actual borders will never be less than minimum border distance.*

**Parameters:**

*dist1 Left or top Distance* \
 *dist2 Right or bottom distance*

**See also:**

*borderDist()*

### void QwtScaleWidget::setColorBarEnabled (bool on)

*En/disable a color bar associated to the scale*

**See also:**

**isColorBarEnabled()***,* **setColorBarWidth()**

### void QwtScaleWidget::setColorBarWidth (int width)

*Set the width of the color bar*

**Parameters:**

*width Width*

**See also:**

**colorBarWidth()***,* **setColorBarEnabled()**

### void QwtScaleWidget::setColorMap (const QwtInterval & interval, QwtColorMap \* colorMap)

*Set the color map and value interval, that are used for displaying the color bar.*

**Parameters:**

*interval Value interval* \
 *colorMap Color map*

**See also:**

**colorMap()***,* **colorBarInterval()**

### void QwtScaleWidget::setLabelAlignment (Qt::Alignment alignment)

*Change the alignment for the labels.*

**See also:**

**QwtScaleDraw::setLabelAlignment()***,* **setLabelRotation()**

### void QwtScaleWidget::setLabelRotation (double rotation)

*Change the rotation for the labels. See* **QwtScaleDraw::setLabelRotation()***.*

**Parameters:**

*rotation Rotation*

**See also:**

**QwtScaleDraw::setLabelRotation()***, setLabelFlags()*

### void QwtScaleWidget::setLayoutFlag (LayoutFlag flag, bool on)

*Toggle an layout flag*

**Parameters:**

*flag Layout flag* \
 *on true/false*

**See also:**

**testLayoutFlag()***,* **LayoutFlag**

### void QwtScaleWidget::setMargin (int margin)

*Specify the margin to the colorBar/base line.*

**Parameters:**

*margin Margin*

**See also:**

**margin()**

### void QwtScaleWidget::setMinBorderDist (int start, int end)

*Set a minimum value for the distances of the scale's endpoints from the widget borders. This is useful to avoid that the scales are 'jumping', when the tick labels or their positions change often.*

**Parameters:**

*start Minimum for the start border* \
 *end Minimum for the end border*

**See also:**

**getMinBorderDist()***,* **getBorderDistHint()**

### void QwtScaleWidget::setScaleDiv (const QwtScaleDiv & scaleDiv)

*Assign a scale division. The scale division determines where to set the tick marks.*

**Parameters:**

*scaleDiv Scale Division*

**See also:**

*For more information about scale divisions, see* **QwtScaleDiv***.*

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

*Set a scale draw*

*scaleDraw has to be created with new and will be deleted in* **~QwtScaleWidget()** *or the next call of* **setScaleDraw()***. scaleDraw will be initialized with the attributes of the previous scaleDraw object.*

**Parameters:**

*scaleDraw ScaleDraw object*

**See also:**

**scaleDraw()**

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

*Specify the distance between color bar, scale and title.*

**Parameters:**

*spacing Spacing*

**See also:**

**spacing()**

### void QwtScaleWidget::setTitle (const QString & title)

*Give title new text contents*

**Parameters:**

*title New title*

**See also:**

**title()***,* **setTitle(const QwtText &)***;*

### void QwtScaleWidget::setTitle (const QwtText & title)

*Give title new text contents*

**Parameters:**

*title New title*

**See also:**

**title()**

**Warning:**

*The title flags are interpreted in direction of the label, AlignTop, AlignBottom can't be set as the title will always be aligned to the scale.*

### void QwtScaleWidget::setTransformation (QwtTransform \* transformation)

*Set the transformation*

**Parameters:**

*transformation Transformation*

**See also:**

*QwtAbstractScaleDraw::scaleDraw(),* **QwtScaleMap**

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

**Returns:**

*a size hint*

### int QwtScaleWidget::spacing () const

**Returns:**

*distance between scale and title*

**See also:**

**setMargin()**

### int QwtScaleWidget::startBorderDist () const

**Returns:**

*start border distance*

**See also:**

**setBorderDist()**

### bool QwtScaleWidget::testLayoutFlag (LayoutFlag flag) const

*Test a layout flag*

**Parameters:**

*flag Layout flag*

**Returns:**

*true/false*

**See also:**

**setLayoutFlag()***,* **LayoutFlag**

### QwtText QwtScaleWidget::title () const

**Returns:**

*title*

**See also:**

**setTitle()**

### int QwtScaleWidget::titleHeightForWidth (int width) const

*Find the height of the title for a given width.*

**Parameters:**

*width Width*

**Returns:**

*height Height*

## Author

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