| Qwt User's Guide
    5.2.3
    | 
#include <qwt_double_range.h>

| Public Member Functions | |
| QwtDoubleRange () | |
| virtual | ~QwtDoubleRange () | 
| virtual void | fitValue (double) | 
| virtual void | incPages (int) | 
| virtual void | incValue (int) | 
| bool | isValid () const | 
| double | maxValue () const | 
| double | minValue () const | 
| int | pageSize () const | 
| bool | periodic () const | 
| void | setPeriodic (bool tf) | 
| void | setRange (double vmin, double vmax, double vstep=0.0, int pagesize=1) | 
| void | setStep (double) | 
| void | setValid (bool) | 
| virtual void | setValue (double) | 
| double | step () const | 
| double | value () const | 
| Protected Member Functions | |
| double | exactPrevValue () const | 
| double | exactValue () const | 
| double | prevValue () const | 
| virtual void | rangeChange () | 
| virtual void | stepChange () | 
| virtual void | valueChange () | 
A class which controls a value within an interval.
This class is useful as a base class or a member for sliders. It represents an interval of type double within which a value can be moved. The value can be either an arbitrary point inside the interval (see QwtDoubleRange::setValue), or it can be fitted into a step raster (see QwtDoubleRange::fitValue and QwtDoubleRange::incValue).
As a special case, a QwtDoubleRange can be periodic, which means that a value outside the interval will be mapped to a value inside the interval when QwtDoubleRange::setValue(), QwtDoubleRange::fitValue(), QwtDoubleRange::incValue() or QwtDoubleRange::incPages() are called.
| QwtDoubleRange::QwtDoubleRange | ( | ) | 
The range is initialized to [0.0, 100.0], the step size to 1.0, and the value to 0.0.
| 
 | protected | 
Returns the exact value.
The exact value is the value which QwtDoubleRange::value would return if the value were not adjusted to the step raster. It differs from the current value only if QwtDoubleRange::fitValue or QwtDoubleRange::incValue have been used before. This function is intended for internal use in derived classes.
| 
 | virtual | 
Adjust the value to the closest point in the step raster.
| x | value | 
new value := x + n * (max. value - min. value)with an integer number n.
Reimplemented in QwtAbstractSlider.
| 
 | virtual | 
Increment the value by a specified number of pages.
| nPages | Number of pages to increment. A negative number decrements the value. | 
| 
 | virtual | 
Increment the value by a specified number of steps.
| nSteps | Number of steps to increment | 
Reimplemented in QwtAbstractSlider.
| double QwtDoubleRange::maxValue | ( | ) | const | 
Returns the value of the second border of the range.
maxValue returns the value which has been specified as the second parameter in QwtDoubleRange::setRange.
| double QwtDoubleRange::minValue | ( | ) | const | 
Returns the value at the first border of the range.
minValue returns the value which has been specified as the first parameter in setRange().
| bool QwtDoubleRange::periodic | ( | ) | const | 
Returns true if the range is periodic.
| 
 | protectedvirtual | 
Notify a change of the range.
This virtual function is called whenever the range changes. The default implementation does nothing.
Reimplemented in QwtDial, QwtCounter, and QwtSlider.
| void QwtDoubleRange::setPeriodic | ( | bool | tf | ) | 
Make the range periodic.
When the range is periodic, the value will be set to a point inside the interval such that
point = value + n * width
if the user tries to set a new value which is outside the range. If the range is nonperiodic (the default), values outside the range will be clipped.
| tf | true for a periodic range | 
| void QwtDoubleRange::setRange | ( | double | vmin, | 
| double | vmax, | ||
| double | vstep = 0.0, | ||
| int | pageSize = 1 | ||
| ) | 
Specify range and step size.
| vmin | lower boundary of the interval | 
| vmax | higher boundary of the interval | 
| vstep | step width | 
| pageSize | page size in steps | 
| void QwtDoubleRange::setStep | ( | double | vstep | ) | 
Change the step raster.
| vstep | new step width | 
Reimplemented in QwtCounter.
| 
 | virtual | 
Set a new value without adjusting to the step raster.
| x | new value | 
new value := x + n * (max. value - min. value)with an integer number n.
Reimplemented in QwtCounter, and QwtAbstractSlider.
| double QwtDoubleRange::step | ( | ) | const | 
| 
 | protectedvirtual | 
Notify a change of the step size.
This virtual function is called whenever the step size changes. The default implementation does nothing.
| 
 | protectedvirtual | 
Notify a change of value.
This virtual function is called whenever the value changes. The default implementation does nothing.
Reimplemented in QwtDial, QwtAbstractSlider, QwtSlider, and QwtWheel.
 1.8.1
 1.8.1