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       QwtAbstractScaleDraw -

       A abstract base class for drawing scales.


       #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:
           enableComponent(), hasComponent

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]

Member Function Documentation

   void QwtAbstractScaleDraw::draw (QPainter *painter, const QPalette &palette) const [virtual]
       Draw the scale. Parameters:
           painter The painter
           palette Palette, text color is used for the labels, foreground color for ticks and

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

       See also:
           drawTick(), drawLabel()

       Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

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

       See also:
           drawTick, drawBackbone

       Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

   virtual void QwtAbstractScaleDraw::drawTick (QPainter *painter, doublevalue, intlen) const
       [protected, pure virtual] Draw a tick
           painter Painter
           value Value of the tick
           len Length of the tick

       See also:
           drawBackbone(), drawLabel()

       Implemented in QwtRoundScaleDraw, and QwtScaleDraw.

   void QwtAbstractScaleDraw::enableComponent (ScaleComponentcomponent, boolenable = true)
       En/Disable a component of the scale
           component Scale component
           enable On/Off

       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:
           setMinimumExtent(), minimumExtent()

       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
       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.

           value Value

           Label string.

       Reimplemented in QwtDialScaleDraw.

   int QwtAbstractScaleDraw::majTickLength () const The same as
   const QwtScaleMap & QwtAbstractScaleDraw::map () const Returns:
           Map how to translate between scale and pixel values

   int QwtAbstractScaleDraw::minimumExtent () const Get the minimum extent
       See also:
           extent(), setMinimumExtent()

   QwtAbstractScaleDraw & QwtAbstractScaleDraw::operator= (const QwtAbstractScaleDraw &other)
       Assignment operator.

   const QwtScaleDiv & QwtAbstractScaleDraw::scaleDiv () const Returns:
           scale division

   QwtScaleMap & QwtAbstractScaleDraw::scaleMap () Returns:
           Map how to translate between scale and pixel values

   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

           minExtent Minimum extent

       See also:
           extent(), minimumExtent()

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

   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.

           spacing Spacing

       See also:

   void QwtAbstractScaleDraw::setTickLength (QwtScaleDiv::TickTypetickType, intlength) Set the
       length of the ticks
           tickType Tick type
           length New length

           the length is limited to [0..1000]

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

   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
       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.

           font Font
           value Value

           Tick label

   int QwtAbstractScaleDraw::tickLength (QwtScaleDiv::TickTypetickType) const Return the length
       of the ticks
       See also:
           setTickLength(), majTickLength()


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