NAME¶

QwtAbstractScaleDraw - A abstract base class for drawing scales.

SYNOPSIS¶

#include <qwt_abstract_scale_draw.h> Inherited by QwtRoundScaleDraw, and QwtScaleDraw.

Public Types¶

enum ScaleComponent { Backbone = 0x01, Ticks = 0x02, Labels = 0x04 } typedef QFlags< ScaleComponent > ScaleComponents

Public Member Functions¶

QwtAbstractScaleDraw () virtual ~QwtAbstractScaleDraw () void setScaleDiv (const QwtScaleDiv &s) const QwtScaleDiv & scaleDiv () const void setTransformation (QwtScaleTransformation *) const QwtScaleMap & scaleMap () const QwtScaleMap & scaleMap () void enableComponent (ScaleComponent, bool enable=true) bool hasComponent (ScaleComponent) const void setTickLength (QwtScaleDiv::TickType, double length) double tickLength (QwtScaleDiv::TickType) const double maxTickLength () const void setSpacing (double margin) double spacing () const void setPenWidth (int width) int penWidth () const virtual void draw (QPainter *, const QPalette &) const virtual QwtText label (double) const virtual double extent (const QFont &) const =0 void setMinimumExtent (double) double minimumExtent () const

Protected Member Functions¶

virtual void drawTick (QPainter *painter, double value, double len) const =0 virtual void drawBackbone (QPainter *painter) const =0 virtual void drawLabel (QPainter *painter, double value) const =0 void invalidateCache () const QwtText & tickLabel (const QFont &, double value) const

Detailed Description¶

A abstract base class for drawing scales. QwtAbstractScaleDraw can be used to draw linear or logarithmic scales. 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 Typedef Documentation¶

typedef QFlags<ScaleComponent> QwtAbstractScaleDraw::ScaleComponents¶

Scale components.

Member Enumeration Documentation¶

enum QwtAbstractScaleDraw::ScaleComponent Components of a scale¶

See also: Enumerator:

Backbone

Backbone = the line where the ticks are located.

Ticks

Ticks.

Labels

Labels.

Constructor & Destructor Documentation¶

QwtAbstractScaleDraw::QwtAbstractScaleDraw ()¶

Constructor. The range of the scale is initialized to [0, 100], The spacing (distance between ticks and labels) is set to 4, the tick lengths are set to 4,6 and 8 pixels

QwtAbstractScaleDraw::~QwtAbstractScaleDraw () [virtual]¶

Destructor.

Member Function Documentation¶

void QwtAbstractScaleDraw::draw (QPainter *painter, const QPalette &palette) const [virtual]¶

Draw the scale. Parameters:

virtual void QwtAbstractScaleDraw::drawBackbone (QPainter *painter) const [protected, pure virtual] Draws the baseline of the scale¶

Parameters: See also: Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

virtual void QwtAbstractScaleDraw::drawLabel (QPainter *painter, doublevalue) const [protected, pure virtual] Draws the label for a major scale tick¶

Parameters: See also: Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

virtual void QwtAbstractScaleDraw::drawTick (QPainter *painter, doublevalue, doublelen) const [protected, pure virtual] Draw a tick¶

Parameters: See also: Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

void QwtAbstractScaleDraw::enableComponent (ScaleComponentcomponent, boolenable = true) En/Disable a component of the scale¶

Parameters: See also:

virtual double QwtAbstractScaleDraw::extent (const QFont &) const [pure virtual] Calculate the extent¶

The extent is the distcance from the baseline to the outermost pixel of the scale draw in opposite to its orientation. It is at least minimumExtent() pixels. See also: Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

bool QwtAbstractScaleDraw::hasComponent (ScaleComponentcomponent) const Check if a component is enabled¶

See also:

void QwtAbstractScaleDraw::invalidateCache () [protected] Invalidate the cache used by QwtAbstractScaleDraw::tickLabel¶

The cache is invalidated, when a new QwtScaleDiv is set. If the labels need to be changed. while the same QwtScaleDiv is set, invalidateCache() needs to be called manually.

QwtText QwtAbstractScaleDraw::label (doublevalue) const [virtual]¶

Convert a value into its representing label. The value is converted to a plain text using QLocale::system().toString(value). This method is often overloaded by applications to have individual labels. Parameters: Returns: Reimplemented in QwtDialScaleDraw.

double QwtAbstractScaleDraw::maxTickLength () const Returns:¶

Useful for layout calculations See also:

double QwtAbstractScaleDraw::minimumExtent () const Get the minimum extent¶

See also:

int QwtAbstractScaleDraw::penWidth () const Returns:¶

See also: Reimplemented in QwtDialScaleDraw.

const QwtScaleDiv & QwtAbstractScaleDraw::scaleDiv () const Returns:¶

const QwtScaleMap & QwtAbstractScaleDraw::scaleMap () const Returns:¶

QwtScaleMap & QwtAbstractScaleDraw::scaleMap () Returns:¶

void QwtAbstractScaleDraw::setMinimumExtent (doubleminExtent)¶

Set a minimum for the extent. The extent is calculated from the coomponents of the scale draw. In situations, where the labels are changing and the layout depends on the extent (f.e scrolling a scale), setting an upper limit as minimum extent will avoid jumps of the layout. Parameters: See also:

void QwtAbstractScaleDraw::setPenWidth (intwidth)¶

Specify the width of the scale pen. Parameters: See also:

void QwtAbstractScaleDraw::setScaleDiv (const QwtScaleDiv &sd) Change the scale division¶

Parameters:

void QwtAbstractScaleDraw::setSpacing (doublespacing)¶

Set the spacing between tick and labels. The spacing is the distance between ticks and labels. The default spacing is 4 pixels. Parameters: See also:

void QwtAbstractScaleDraw::setTickLength (QwtScaleDiv::TickTypetickType, doublelength) Set the length of the ticks¶

Parameters: Warning:

void QwtAbstractScaleDraw::setTransformation (QwtScaleTransformation *transformation) Change the transformation of the scale¶

Parameters:

double QwtAbstractScaleDraw::spacing () const¶

Get the spacing. The spacing is the distance between ticks and labels. The default spacing is 4 pixels. See also:

const QwtText & QwtAbstractScaleDraw::tickLabel (const QFont &font, doublevalue) const [protected]¶

Convert a value into its representing label and cache it. The conversion between value and label is called very often in the layout and painting code. Unfortunately the calculation of the label sizes might be slow (really slow for rich text in Qt4), so it's necessary to cache the labels. Parameters: Returns:

double QwtAbstractScaleDraw::tickLength (QwtScaleDiv::TickTypetickType) const Return the length of the ticks¶

See also:

Author¶

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