--- name: "QwtScaleDraw" section: "3" platform: "linux" package: "libqwt-doc" version: "6.1.4-2" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/QwtScaleDraw" --- # QwtScaleDraw(3) A class for drawing scales. ## NAME QwtScaleDraw - A class for drawing scales. ## SYNOPSIS `#include ` Inherits **QwtAbstractScaleDraw**. Inherited by **QwtDateScaleDraw**. ### Public Types enum **Alignment** { **BottomScale**, **TopScale**, **LeftScale**, **RightScale** }\ ### Public Member Functions **QwtScaleDraw** ()\ Constructor. virtual **~QwtScaleDraw** ()\ Destructor. void **getBorderDistHint** (const QFont &, int &start, int &end) const\ Determine the minimum border distance. int **minLabelDist** (const QFont &) const\ int **minLength** (const QFont &) const\ virtual double **extent** (const QFont &) const\ void **move** (double x, double y)\ void **move** (const QPointF &)\ Move the position of the scale. void **setLength** (double **length**)\ **Alignment** **alignment** () const\ void **setAlignment** (**Alignment**)\ Qt::Orientation **orientation** () const\ QPointF **pos** () const\ double **length** () const\ void **setLabelAlignment** (Qt::Alignment)\ Change the label flags. Qt::Alignment **labelAlignment** () const\ void **setLabelRotation** (double rotation)\ double **labelRotation** () const\ int **maxLabelHeight** (const QFont &) const\ int **maxLabelWidth** (const QFont &) const\ QPointF **labelPosition** (double value) const\ QRectF **labelRect** (const QFont &, double value) const\ QSizeF **labelSize** (const QFont &, double value) const\ QRect **boundingLabelRect** (const QFont &, double value) const\ Find the bounding rectangle for the label. ### Protected Member Functions QTransform **labelTransformation** (const QPointF &, const QSizeF &) const\ virtual void **drawTick** (QPainter \*, double value, double len) const\ virtual void **drawBackbone** (QPainter \*) const\ virtual void **drawLabel** (QPainter \*, double value) const\ ## Detailed Description A class for drawing scales. **QwtScaleDraw** can be used to draw linear or logarithmic scales. A scale has a position, an alignment and a length, which can be specified . The labels can be rotated and aligned to the ticks using **setLabelRotation()** and **setLabelAlignment()**. After a scale division has been specified as a **QwtScaleDiv** object using **QwtAbstractScaleDraw::setScaleDiv(const QwtScaleDiv &s)**, the scale can be drawn with the **QwtAbstractScaleDraw::draw()** member. ## Member Enumeration Documentation ### enum QwtScaleDraw::Alignment Alignment of the scale draw **See also:** **setAlignment()**, **alignment()** **Enumerator** - *BottomScale* *The scale is below.* - *TopScale* *The scale is above.* - *LeftScale* *The scale is left.* - *RightScale* *The scale is right.* ## Constructor & Destructor Documentation ### QwtScaleDraw::QwtScaleDraw () *Constructor. The range of the scale is initialized to \[0, 100\], The position is at (0, 0) with a length of 100. The orientation is QwtAbstractScaleDraw::Bottom.* ## Member Function Documentation ### QwtScaleDraw::Alignment QwtScaleDraw::alignment () const *Return alignment of the scale* **See also:** **setAlignment()** **Returns:** *Alignment of the scale* ### QRect QwtScaleDraw::boundingLabelRect (const QFont & font, double value) const *Find the bounding rectangle for the label. The coordinates of the rectangle are absolute ( calculated from* **pos()** *). in direction of the tick.* **Parameters:** *font Font used for painting* \ *value Value* **Returns:** *Bounding rectangle* **See also:** **labelRect()** ### void QwtScaleDraw::drawBackbone (QPainter \* painter) const` [protected]`, ` [virtual]` *Draws the baseline of the scale* **Parameters:** *painter Painter* **See also:** **drawTick()***,* **drawLabel()** *Implements* **QwtAbstractScaleDraw***.* ### void QwtScaleDraw::drawLabel (QPainter \* painter, double value) const` [protected]`, ` [virtual]` *Draws the label for a major scale tick* **Parameters:** *painter Painter* \ *value Value* **See also:** **drawTick()***,* **drawBackbone()***,* **boundingLabelRect()** *Implements* **QwtAbstractScaleDraw***.* ### void QwtScaleDraw::drawTick (QPainter \* painter, double value, double len) const` [protected]`, ` [virtual]` *Draw a tick* **Parameters:** *painter Painter* \ *value Value of the tick* \ *len Length of the tick* **See also:** **drawBackbone()***,* **drawLabel()** *Implements* **QwtAbstractScaleDraw***.* ### double QwtScaleDraw::extent (const QFont & font) const` [virtual]` *Calculate the width/height that is needed for a vertical/horizontal scale.* *The extent is calculated from the pen width of the backbone, the major tick length, the spacing and the maximum width/height of the labels.* **Parameters:** *font Font used for painting the labels* **Returns:** *Extent* **See also:** **minLength()** *Implements* **QwtAbstractScaleDraw***.* ### void QwtScaleDraw::getBorderDistHint (const QFont & font, int & start, int & end) const *Determine the minimum border distance. This member function returns the minimum space needed to draw the mark labels at the scale's endpoints.* **Parameters:** *font Font* \ *start Start border distance* \ *end End border distance* ### Qt::Alignment QwtScaleDraw::labelAlignment () const **Returns:** *the label flags* **See also:** **setLabelAlignment()***,* **labelRotation()** ### QPointF QwtScaleDraw::labelPosition (double value) const *Find the position, where to paint a label* *The position has a distance that depends on the length of the ticks in direction of the* **alignment()***.* **Parameters:** *value Value* **Returns:** *Position, where to paint a label* ### QRectF QwtScaleDraw::labelRect (const QFont & font, double value) const *Find the bounding rectangle for the label. The coordinates of the rectangle are relative to spacing + tick length from the backbone in direction of the tick.* **Parameters:** *font Font used for painting* \ *value Value* **Returns:** *Bounding rectangle that is needed to draw a label* ### double QwtScaleDraw::labelRotation () const **Returns:** *the label rotation* **See also:** **setLabelRotation()***,* **labelAlignment()** ### QSizeF QwtScaleDraw::labelSize (const QFont & font, double value) const *Calculate the size that is needed to draw a label* **Parameters:** *font Label font* \ *value Value* **Returns:** *Size that is needed to draw a label* ### QTransform QwtScaleDraw::labelTransformation (const QPointF & pos, const QSizeF & size) const` [protected]` *Calculate the transformation that is needed to paint a label depending on its alignment and rotation.* **Parameters:** *pos Position where to paint the label* \ *size Size of the label* **Returns:** *Transformation matrix* **See also:** **setLabelAlignment()***,* **setLabelRotation()** ### double QwtScaleDraw::length () const **Returns:** *the length of the backbone* **See also:** **setLength()***,* **pos()** ### int QwtScaleDraw::maxLabelHeight (const QFont & font) const **Parameters:** *font Font* **Returns:** *the maximum height of a label* ### int QwtScaleDraw::maxLabelWidth (const QFont & font) const **Parameters:** *font Font* **Returns:** *the maximum width of a label* ### int QwtScaleDraw::minLabelDist (const QFont & font) const *Determine the minimum distance between two labels, that is necessary that the texts don't overlap.* **Parameters:** *font Font* **Returns:** *The maximum width of a label* **See also:** **getBorderDistHint()** ### int QwtScaleDraw::minLength (const QFont & font) const *Calculate the minimum length that is needed to draw the scale* **Parameters:** *font Font used for painting the labels* **Returns:** *Minimum length that is needed to draw the scale* **See also:** **extent()** ### void QwtScaleDraw::move (double x, double y)` [inline]` *Move the position of the scale* **Parameters:** *x X coordinate* \ *y Y coordinate* **See also:** **move(const QPointF &)** ### void QwtScaleDraw::move (const QPointF & pos) *Move the position of the scale. The meaning of the parameter pos depends on the alignment:* - **QwtScaleDraw::LeftScale** *The origin is the topmost point of the backbone. The backbone is a vertical line. Scale marks and labels are drawn at the left of the backbone.* - **QwtScaleDraw::RightScale** *The origin is the topmost point of the backbone. The backbone is a vertical line. Scale marks and labels are drawn at the right of the backbone.* - **QwtScaleDraw::TopScale** *The origin is the leftmost point of the backbone. The backbone is a horizontal line. Scale marks and labels are drawn above the backbone.* - **QwtScaleDraw::BottomScale** *The origin is the leftmost point of the backbone. The backbone is a horizontal line Scale marks and labels are drawn below the backbone.* **Parameters:** *pos Origin of the scale* **See also:** **pos()***,* **setLength()** ### Qt::Orientation QwtScaleDraw::orientation () const *Return the orientation* *TopScale, BottomScale are horizontal (Qt::Horizontal) scales, LeftScale, RightScale are vertical (Qt::Vertical) scales.* **Returns:** *Orientation of the scale* **See also:** **alignment()** ### QPointF QwtScaleDraw::pos () const **Returns:** *Origin of the scale* **See also:** **move()***,* **length()** ### void QwtScaleDraw::setAlignment (Alignment align) *Set the alignment of the scale* **Parameters:** *align Alignment of the scale* *The default alignment is* **QwtScaleDraw::BottomScale** **See also:** **alignment()** ### void QwtScaleDraw::setLabelAlignment (Qt::Alignment alignment) *Change the label flags. Labels are aligned to the point tick length + spacing away from the backbone.* *The alignment is relative to the orientation of the label text. In case of an flags of 0 the label will be aligned depending on the orientation of the scale:* ``` QwtScaleDraw::TopScale: Qt::AlignHCenter | Qt::AlignTop0 QwtScaleDraw::BottomScale: Qt::AlignHCenter | Qt::AlignBottom0 QwtScaleDraw::LeftScale: Qt::AlignLeft | Qt::AlignVCenter0 QwtScaleDraw::RightScale: Qt::AlignRight | Qt::AlignVCenter0 ``` *Changing the alignment is often necessary for rotated labels.* **Parameters:** *alignment Or'd Qt::AlignmentFlags see \* **See also:** **setLabelRotation()***,* **labelRotation()***,* **labelAlignment()** **Warning:** *The various alignments might be confusing. The alignment of the label is not the alignment of the scale and is not the alignment of the flags ( QwtText::flags() ) returned from* **QwtAbstractScaleDraw::label()***.* ### void QwtScaleDraw::setLabelRotation (double rotation) *Rotate all labels.* *When changing the rotation, it might be necessary to adjust the label flags too. Finding a useful combination is often the result of try and error.* **Parameters:** *rotation Angle in degrees. When changing the label rotation, the label flags often needs to be adjusted too.* **See also:** **setLabelAlignment()***,* **labelRotation()***,* **labelAlignment()***.* ### void QwtScaleDraw::setLength (double length) *Set the length of the backbone.* *The length doesn't include the space needed for overlapping labels.* **Parameters:** *length Length of the backbone* **See also:** **move()***,* **minLabelDist()** ## Author *Generated automatically by Doxygen for Qwt User's Guide from the source code.*