QwtLinearScaleEngine(3) Qwt User's Guide QwtLinearScaleEngine(3)NAMEQwtLinearScaleEngine-
A scale engine for linear scales.
SYNOPSIS
#include <qwt_scale_engine.h>
Inherits QwtScaleEngine.
Public Types
enum Attribute { NoAttribute = 0, IncludeReference = 1, Symmetric =
2, Floating = 4, Inverted = 8 }
Public Member Functions
int attributes () const
virtual void autoScale (int maxSteps, double &x1, double &x2, double
&stepSize) const
virtual QwtScaleDiv divideScale (double x1, double x2, int
numMajorSteps, int numMinorSteps, double stepSize=0.0) const
double lowerMargin () const
double reference () const
void setAttribute (Attribute, bool on=true)
void setAttributes (int)
void setMargins (double lower, double upper)
void setReference (double reference)
bool testAttribute (Attribute) const
virtual QwtScaleTransformation * transformation () const
double upperMargin () const
Protected Member Functions
QwtDoubleInterval align (const QwtDoubleInterval &, double stepSize)
const
QwtDoubleInterval buildInterval (double v) const
bool contains (const QwtDoubleInterval &, double val) const
double divideInterval (double interval, int numSteps) const
QwtValueList strip (const QwtValueList &, const QwtDoubleInterval &)
const
Detailed Description
A scale engine for linear scales.
ight
The step size will fit into the pattern $t 1,2,5
Member Enumeration Documentation
enum QwtScaleEngine::Attribute [inherited] .IP · 2
IncludeReference
Build a scale which includes the reference() value.
· Symmetric
Build a scale which is symmetric to the reference() value.
· Floating
The endpoints of the scale are supposed to be equal the outmost
included values plus the specified margins (see setMargins()). If
this attribute is *not* set, the endpoints of the scale will be
integer multiples of the step size.
· Inverted
Turn the scale upside down.
See also:
setAttribute(), testAttribute(), reference(), lowerMargin(),
upperMargin()Member Function Documentation
QwtDoubleInterval QwtLinearScaleEngine::align (const QwtDoubleInterval
&interval, doublestepSize) const [protected]
Align an interval to a step size. The limits of an interval are aligned
that both are integer multiples of the step size.
Parameters:
interval Interval
stepSize Step size
Returns:
Aligned interval
int QwtScaleEngine::attributes () const [inherited] Return the scale
attributes
See also:
Attribute, setAttributes(), testAttribute()
void QwtLinearScaleEngine::autoScale (intmaxNumSteps, double &x1, double
&x2, double &stepSize) const [virtual] Align and divide an interval
Parameters:
maxNumSteps Max. number of steps
x1 First limit of the interval (In/Out)
x2 Second limit of the interval (In/Out)
stepSize Step size (Out)
See also:
setAttribute()
Implements QwtScaleEngine.
QwtDoubleInterval QwtScaleEngine::buildInterval (doublev) const [protected,
inherited]
Build an interval for a value. In case of v == 0.0 the interval is
[-0.5, 0.5], otherwide it is [0.5 * v, 1.5 * v]
bool QwtScaleEngine::contains (const QwtDoubleInterval &interval,
doublevalue) const [protected, inherited] Check if an interval
'contains' a value
Parameters:
interval Interval
value Value
See also:
QwtScaleArithmetic::compareEps()
double QwtScaleEngine::divideInterval (doubleintervalSize, intnumSteps)
const [protected, inherited] Calculate a step size for an interval size
Parameters:
intervalSize Interval size
numSteps Number of steps
Returns:
Step size
QwtScaleDiv QwtLinearScaleEngine::divideScale (doublex1, doublex2,
intmaxMajSteps, intmaxMinSteps, doublestepSize = 0.0) const [virtual]
Calculate a scale division. Parameters:
x1 First interval limit
x2 Second interval limit
maxMajSteps Maximum for the number of major steps
maxMinSteps Maximum number of minor steps
stepSize Step size. If stepSize == 0, the scaleEngine calculates
one.
See also:
QwtScaleEngine::stepSize(), QwtScaleEngine::subDivide()
Implements QwtScaleEngine.
double QwtScaleEngine::lowerMargin () const [inherited] Returns:
the margin at the lower end of the scale The default margin is 0.
See also:
setMargins()
double QwtScaleEngine::reference () const [inherited] Returns:
the reference value
See also:
setReference(), setAttribute()
void QwtScaleEngine::setAttribute (Attributeattribute, boolon = true)
[inherited] Change a scale attribute
Parameters:
attribute Attribute to change
on On/Off
See also:
Attribute, testAttribute()
void QwtScaleEngine::setAttributes (intattributes) [inherited] Change the
scale attribute
Parameters:
attributes Set scale attributes
See also:
Attribute, attributes()
void QwtScaleEngine::setMargins (doublelower, doubleupper) [inherited]
Specify margins at the scale's endpoints. Parameters:
lower minimum distance between the scale's lower boundary and the
smallest enclosed value
upper minimum distance between the scale's upper boundary and the
greatest enclosed value
Margins can be used to leave a minimum amount of space between the
enclosed intervals and the boundaries of the scale.
Warning:
· QwtLog10ScaleEngine measures the margins in decades.
See also:
upperMargin(), lowerMargin()
void QwtScaleEngine::setReference (doubler) [inherited]
Specify a reference point. Parameters:
r new reference value
The reference point is needed if options IncludeReference or Symmetric
are active. Its default value is 0.0.
See also:
Attribute
QwtValueList QwtScaleEngine::strip (const QwtValueList &ticks, const
QwtDoubleInterval &interval) const [protected, inherited] Remove ticks
from a list, that are not inside an interval
Parameters:
ticks Tick list
interval Interval
Returns:
Stripped tick list
bool QwtScaleEngine::testAttribute (Attributeattribute) const [inherited]
Check if a attribute is set.
Parameters:
attribute Attribute to be tested
See also:
Attribute, setAttribute()
QwtScaleTransformation * QwtLinearScaleEngine::transformation () const
[virtual] Return a transformation, for linear scales
Implements QwtScaleEngine.
double QwtScaleEngine::upperMargin () const [inherited] Returns:
the margin at the upper end of the scale The default margin is 0.
See also:
setMargins()Author
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Version 5.2.2 Mon Aug 1 2011 QwtLinearScaleEngine(3)
