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.TH "QwtScaleEngine" 3 "24 May 2008" "Version 5.1.1" "Qwt User's Guide" \" -*- nroff -*-
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Inherited by \fBQwtLinearScaleEngine\fP, and \fBQwtLog10ScaleEngine\fP.
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.SH "Detailed Description"
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Base class for scale engines.
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A scale engine trys to find 'reasonable' ranges and step sizes for scales.
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The layout of the scale can be varied with \fBsetAttribute()\fP.
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Qwt offers implementations for logarithmic (log10) and linear scales. Contributions for other types of scale engines (date/time, log2 ... ) are welcome.
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Definition at line 50 of file qwt_scale_engine.h.
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.RI "enum \fBAttribute\fP { \fBNoAttribute\fP = 0, \fBIncludeReference\fP = 1, \fBSymmetric\fP = 2, \fBFloating\fP = 4, \fBInverted\fP = 8 }"
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.SS "Public Member Functions"
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.RI "\fBQwtScaleEngine\fP ()"
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.RI "virtual \fB~QwtScaleEngine\fP ()"
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.RI "void \fBsetAttribute\fP (\fBAttribute\fP, bool on=true)"
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.RI "bool \fBtestAttribute\fP (\fBAttribute\fP) const"
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.RI "void \fBsetAttributes\fP (int)"
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.RI "int \fBattributes\fP () const"
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.RI "void \fBsetReference\fP (double reference)"
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.RI "double \fBreference\fP () const"
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.RI "void \fBsetMargins\fP (double m1, double m2)"
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.RI "double \fBloMargin\fP () const"
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.RI "double \fBhiMargin\fP () const"
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.RI "virtual void \fBautoScale\fP (int maxNumSteps, double &x1, double &x2, double &stepSize) const =0"
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.RI "virtual \fBQwtScaleDiv\fP \fBdivideScale\fP (double x1, double x2, int maxMajSteps, int maxMinSteps, double stepSize=0.0) const=0"
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.RI "virtual \fBQwtScaleTransformation\fP * \fBtransformation\fP () const=0"
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.SS "Protected Member Functions"
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.RI "bool \fBcontains\fP (const \fBQwtDoubleInterval\fP &, double val) const"
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.RI "QwtValueList \fBstrip\fP (const QwtValueList &, const \fBQwtDoubleInterval\fP &) const"
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.RI "double \fBdivideInterval\fP (double interval, int numSteps) const "
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.RI "\fBQwtDoubleInterval\fP \fBbuildInterval\fP (double v) const"
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.SH "Member Enumeration Documentation"
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.SS "enum \fBQwtScaleEngine::Attribute\fP"
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see \fBQwtScaleEngine::setAttribute\fP, testAttribute
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Definition at line 54 of file qwt_scale_engine.h.
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.SH "Constructor & Destructor Documentation"
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.SS "QwtScaleEngine::QwtScaleEngine ()\fC [explicit]\fP"
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Definition at line 169 of file qwt_scale_engine.cpp.
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.SS "QwtScaleEngine::~QwtScaleEngine ()\fC [virtual]\fP"
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Definition at line 176 of file qwt_scale_engine.cpp.
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.SH "Member Function Documentation"
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.SS "void QwtScaleEngine::setAttribute (\fBAttribute\fP attribute, bool on = \fCtrue\fP)"
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Change a scale attribute
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\fIattribute\fP Attribute to change
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The behaviour of the scale engine can be changed with the following attributes:
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.IP "\fBQwtScaleEngine::IncludeReference \fP" 1c
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Build a scale which includes the reference value.
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.IP "\fBQwtScaleEngine::Symmetric \fP" 1c
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Build a scale which is symmetric to the reference value.
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.IP "\fBQwtScaleEngine::Floating \fP" 1c
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The endpoints of the scale are supposed to be equal the outmost included values plus the specified margins (see \fBsetMargins()\fP). If this attribute is not* set, the endpoints of the scale will be integer multiples of the step size.
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.IP "\fBQwtScaleEngine::Inverted \fP" 1c
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Turn the scale upside down.
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\fBQwtScaleEngine::testAttribute()\fP
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Definition at line 339 of file qwt_scale_engine.cpp.
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.SS "bool QwtScaleEngine::testAttribute (\fBAttribute\fP attribute) const"
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Check if a attribute is set.
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\fIattribute\fP Attribute to be tested
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\fBQwtScaleEngine::setAttribute()\fP for a description of the possible options.
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Definition at line 353 of file qwt_scale_engine.cpp.
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Referenced by QwtLog10ScaleEngine::autoScale(), and QwtLinearScaleEngine::autoScale().
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.SS "void QwtScaleEngine::setAttributes (int attributes)"
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Change the scale attribute
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\fIattributes\fP Set scale attributes
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\fBQwtScaleEngine::attributes()\fP
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Definition at line 364 of file qwt_scale_engine.cpp.
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Referenced by QwtLog10ScaleEngine::divideScale().
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.SS "int QwtScaleEngine::attributes () const"
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Return the scale attributes
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Definition at line 372 of file qwt_scale_engine.cpp.
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Referenced by QwtLog10ScaleEngine::divideScale().
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.SS "void QwtScaleEngine::setReference (double r)"
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Specify a reference point.
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\fIr\fP new reference value
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The reference point is needed if options IncludeRef or Symmetric are active. Its default value is 0.0.
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Definition at line 384 of file qwt_scale_engine.cpp.
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Referenced by QwtLog10ScaleEngine::divideScale().
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.SS "double QwtScaleEngine::reference () const"
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\fBQwtScaleEngine::setReference()\fP, QwtScaleEngine::setOptions()
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Definition at line 393 of file qwt_scale_engine.cpp.
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Referenced by QwtLog10ScaleEngine::autoScale(), QwtLinearScaleEngine::autoScale(), and QwtLog10ScaleEngine::divideScale().
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.SS "void QwtScaleEngine::setMargins (double mlo, double mhi)"
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Specify margins at the scale's endpoints.
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\fImlo\fP minimum distance between the scale's lower boundary and the smallest enclosed value
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\fImhi\fP minimum distance between the scale's upper boundary and the greatest enclosed value
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Margins can be used to leave a minimum amount of space between the enclosed intervals and the boundaries of the scale.
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\fBQwtLog10ScaleEngine\fP measures the margins in decades.
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\fBQwtScaleEngine::hiMargin\fP, \fBQwtScaleEngine::loMargin\fP
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Definition at line 219 of file qwt_scale_engine.cpp.
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Referenced by QwtLog10ScaleEngine::divideScale().
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.SS "double QwtScaleEngine::loMargin () const"
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the margin at the lower end of the scale The default margin is 0.
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\fBQwtScaleEngine::setMargins()\fP
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Definition at line 187 of file qwt_scale_engine.cpp.
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Referenced by QwtLog10ScaleEngine::autoScale(), QwtLinearScaleEngine::autoScale(), and QwtLog10ScaleEngine::divideScale().
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.SS "double QwtScaleEngine::hiMargin () const"
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the margin at the upper end of the scale The default margin is 0.
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\fBQwtScaleEngine::setMargins()\fP
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Definition at line 198 of file qwt_scale_engine.cpp.
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Referenced by QwtLog10ScaleEngine::autoScale(), QwtLinearScaleEngine::autoScale(), and QwtLog10ScaleEngine::divideScale().
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.SS "virtual void QwtScaleEngine::autoScale (int maxNumSteps, double & x1, double & x2, double & stepSize) const\fC [pure virtual]\fP"
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Align and divide an interval
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\fImaxNumSteps\fP Max. number of steps
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\fIx1\fP First limit of the interval (In/Out)
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\fIx2\fP Second limit of the interval (In/Out)
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\fIstepSize\fP Step size (Return value)
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Implemented in \fBQwtLinearScaleEngine\fP, and \fBQwtLog10ScaleEngine\fP.
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.SS "virtual \fBQwtScaleDiv\fP QwtScaleEngine::divideScale (double x1, double x2, int maxMajSteps, int maxMinSteps, double stepSize = \fC0.0\fP) const\fC [pure virtual]\fP"
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Calculate a scale division.
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\fIx1\fP First interval limit
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\fIx2\fP Second interval limit
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\fImaxMajSteps\fP Maximum for the number of major steps
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\fImaxMinSteps\fP Maximum number of minor steps
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\fIstepSize\fP Step size. If stepSize == 0.0, the scaleEngine calculates one.
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Implemented in \fBQwtLinearScaleEngine\fP, and \fBQwtLog10ScaleEngine\fP.
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.SS "virtual \fBQwtScaleTransformation\fP* QwtScaleEngine::transformation () const\fC [pure virtual]\fP"
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Implemented in \fBQwtLinearScaleEngine\fP, and \fBQwtLog10ScaleEngine\fP.
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.SS "bool QwtScaleEngine::contains (const \fBQwtDoubleInterval\fP & interval, double value) const\fC [protected]\fP"
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Check if an interval 'contains' a value
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\fIinterval\fP Interval
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\fBQwtScaleArithmetic::compareEps\fP
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Definition at line 251 of file qwt_scale_engine.cpp.
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References QwtScaleArithmetic::compareEps(), QwtDoubleInterval::isValid(), QwtDoubleInterval::maxValue(), QwtDoubleInterval::minValue(), and QwtDoubleInterval::width().
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Referenced by strip().
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.SS "QwtValueList QwtScaleEngine::strip (const QwtValueList & ticks, const \fBQwtDoubleInterval\fP & interval) const\fC [protected]\fP"
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Remove ticks from a list, that are not inside an interval
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\fIticks\fP Tick list
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\fIinterval\fP Interval
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Definition at line 280 of file qwt_scale_engine.cpp.
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References contains(), and QwtDoubleInterval::isValid().
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.SS "double QwtScaleEngine::divideInterval (double intervalSize, int numSteps) const\fC [protected]\fP"
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Calculate a step size for an interval size
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\fIintervalSize\fP Interval size
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\fInumSteps\fP Number of steps
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Definition at line 233 of file qwt_scale_engine.cpp.
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References QwtScaleArithmetic::ceil125(), and QwtScaleArithmetic::divideEps().
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Referenced by QwtLog10ScaleEngine::autoScale(), QwtLinearScaleEngine::autoScale(), QwtLog10ScaleEngine::divideScale(), and QwtLinearScaleEngine::divideScale().
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.SS "\fBQwtDoubleInterval\fP QwtScaleEngine::buildInterval (double v) const\fC [protected]\fP"
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Build an interval for a value.
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In case of v == 0.0 the interval is [-0.5, 0.5], otherwide it is [0.5 * v, 1.5 * v]
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Definition at line 309 of file qwt_scale_engine.cpp.
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Referenced by QwtLog10ScaleEngine::autoScale(), and QwtLinearScaleEngine::autoScale().
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