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 = 1, Ticks = 2, Labels = 4 }

Public Member Functions¶

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

Protected Member Functions¶

virtual void drawBackbone (QPainter *painter) const =0 virtual void drawLabel (QPainter *painter, double value) const =0 virtual void drawTick (QPainter *painter, double value, int len) 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 Enumeration Documentation¶

enum QwtAbstractScaleDraw::ScaleComponent Components of a scale¶

•

Backbone

•

Ticks

•

Labels

See also:

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 (const QwtAbstractScaleDraw &other)¶

Copy constructor.

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, intlen) 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 int QwtAbstractScaleDraw::extent (const QPen &, 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, QwtAbstractScaleDraw::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.

int QwtAbstractScaleDraw::majTickLength () const The same as QwtAbstractScaleDraw::tickLength(QwtScaleDiv::MajorTick).¶

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

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

See also:

QwtAbstractScaleDraw & QwtAbstractScaleDraw::operator= (const QwtAbstractScaleDraw &other)¶

Assignment operator.

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

QwtScaleMap & QwtAbstractScaleDraw::scaleMap () Returns:¶

void QwtAbstractScaleDraw::setMinimumExtent (intminExtent)¶

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

Parameters:

void QwtAbstractScaleDraw::setSpacing (intspacing)¶

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, intlength) Set the length of the ticks¶

Parameters: Warning:

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

Parameters:

int 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:

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

See also:

Author¶

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