man QwtDiMap (Fonctions bibliothèques) -

NAME

QwtDiMap -

SYNOPSIS



Inherited by QwtScaleDraw.

Detailed Description

Map a double interval into an integer interval.

The QwtDiMap class maps an interval of type double into an interval of type int. It consists of two intervals D = [d1, d2] (double) and I = [i1, i2] (int), which are specified with the QwtDiMap::setDblRange and QwtDiMap::setIntRange members. The point d1 is mapped to the point i1, and d2 is mapped to i2. Any point inside or outside D can be mapped to a point inside or outside I using QwtDiMap::transform or QwtDiMap::limTransform or vice versa using QwtPlot::invTransform. D can be scaled linearly or logarithmically, as specified with QwtDiMap::setDblRange.

Usage 

#include <qwt_dimap.h>

QwtDiMap map;
int ival;
double dval;

map.setDblRange(0.0, 3.1415);   // Assign an interval of type double with
                // linear mapping
map.setIntRange(0,100);         // Assign an integer interval

ival = map.transform(1.0);      // obtain integer value corresponding to 1.0
dval = map.invTransform(7);    // obtain double value corresponding to 77




Definition at line 46 of file qwt_dimap.h.

Public Member Functions
QwtDiMap ()



QwtDiMap (int i1, int i2, double d1, double d2, bool lg=FALSE)



~QwtDiMap ()



bool contains (double x) const



bool contains (int x) const



void setIntRange (int i1, int i2)



void setDblRange (double d1, double d2, bool lg=FALSE)



int transform (double x) const



double invTransform (int i) const



int limTransform (double x) const



double xTransform (double x) const



double d1 () const



double d2 () const



int i1 () const



int i2 () const



bool logarithmic () const




Public Attributes
QT_STATIC_CONST double LogMin = 1.0e-150



QT_STATIC_CONST double LogMax = 1.0e150




Constructor & Destructor Documentation


QwtDiMap::QwtDiMap ()

Constructor. 


The double and integer intervals are both set to [0,1]. Definition at line 20 of file qwt_dimap.cpp.

QwtDiMap::QwtDiMap (int i1, int i2, double d1, double d2, bool logarithmic = FALSE)

Constructor. 


Constructs a QwtDiMap instance with initial integer and double intervals


Parameters:
i1 first border of integer interval 



i2 second border of integer interval 



d1 first border of double interval 



d2 second border of double interval 



logarithmic logarithmic mapping, TRUE or FALSE. 


Definition at line 43 of file qwt_dimap.cpp.


References setDblRange().

QwtDiMap::~QwtDiMap ()

Destructor. 


Definition at line 54 of file qwt_dimap.cpp.

Member Function Documentation


bool QwtDiMap::contains (int x) const

Returns:
TRUE if a value x lies inside or at the border of the map's integer range 


Parameters:
x value 


Definition at line 73 of file qwt_dimap.cpp.

bool QwtDiMap::contains (double x) const

Returns:
TRUE if a value x lies inside or at the border of the map's double range. 


Parameters:
x value 


Definition at line 63 of file qwt_dimap.cpp.

double QwtDiMap::d1 () const

Returns:
the first border of the double interval 


Definition at line 86 of file qwt_dimap.h.


Referenced by QwtSlider::getValue(), and QwtSlider::xyPosition().

double QwtDiMap::d2 () const

Returns:
the second border of the double interval 


Definition at line 94 of file qwt_dimap.h.


Referenced by QwtSlider::getValue(), and QwtSlider::xyPosition().

int QwtDiMap::i1 () const

Returns:
the second border of the integer interval 


Definition at line 102 of file qwt_dimap.h.


Referenced by QwtScaleDraw::drawBackbone(), QwtSlider::getScrollMode(), QwtSlider::getValue(), and QwtSlider::xyPosition().

int QwtDiMap::i2 () const

Returns:
the second border of the integer interval 


Definition at line 110 of file qwt_dimap.h.


Referenced by QwtScaleDraw::drawBackbone(), QwtSlider::getScrollMode(), QwtSlider::getValue(), and QwtSlider::xyPosition().

double QwtDiMap::invTransform (int y) const

Transform an integer value into a double value. 


Parameters:
y integer value to be transformed 


Returns:

linear mapping:

d1 + (d2 - d1) / (i2 - i1) * (y - i1) 

logarithmic mapping:

d1 + (d2 - d1) / log(i2 / i1) * log(y / i1) 




Definition at line 132 of file qwt_dimap.cpp.


Referenced by QwtSlider::getValue(), QwtPlotPicker::invTransform(), and QwtPlot::invTransform().

int QwtDiMap::limTransform (double x) const

Transform and limit. 


The function is similar to QwtDiMap::transform, but limits the input value to the nearest border of the map's double interval if it lies outside that interval.


Parameters:
x value to be transformed 


Returns:
transformed value 


Definition at line 155 of file qwt_dimap.cpp.


References transform().


Referenced by QwtThermo::drawThermo().

bool QwtDiMap::logarithmic () const

Returns:
TRUE if the double interval is scaled logarithmically 


Definition at line 118 of file qwt_dimap.h.

void QwtDiMap::setDblRange (double d1, double d2, bool lg = FALSE)

Specify the borders of the double interval. 


Parameters:
d1 first border 



d2 second border 



lg logarithmic (TRUE) or linear (FALSE) scaling 


Definition at line 84 of file qwt_dimap.cpp.


Referenced by QwtPlot::canvasMap(), QwtDiMap(), QwtThermo::setRange(), and QwtScaleDraw::setScale().

void QwtDiMap::setIntRange (int i1, int i2)

Specify the borders of the integer interval. 


Parameters:
i1 first border 



i2 second border 


Definition at line 116 of file qwt_dimap.cpp.


Referenced by QwtPlot::canvasMap(), QwtSlider::layoutSlider(), QwtThermo::layoutThermo(), QwtScaleDraw::setAngleRange(), and QwtScaleDraw::setGeometry().

int QwtDiMap::transform (double x) const

Transform a point in double interval into an point in the integer interval. 


Parameters:
x value 


Returns:

linear mapping:

rint(i1 + (i2 - i1) / (d2 - d1) * (x - d1)) 

logarithmic mapping:

rint(i1 + (i2 - i1) / log(d2 / d1) * log(x / d1)) 




Warning:
The specified point is allowed to lie outside the intervals. If you want to limit the returned value, use QwtDiMap::limTransform. 


Definition at line 136 of file qwt_dimap.h.


Referenced by QwtCurve::closePolyline(), QwtGrid::draw(), QwtCurve::drawDots(), QwtCurve::drawLines(), QwtCurve::drawSteps(), QwtCurve::drawSticks(), QwtCurve::drawSymbols(), QwtScaleDraw::drawTick(), QwtScaleDraw::labelPlacement(), limTransform(), QwtPlotPicker::transform(), QwtPlot::transform(), and QwtSlider::xyPosition().

double QwtDiMap::xTransform (double x) const

Exact transformation. 


This function is similar to QwtDiMap::transform, but makes the integer interval appear to be double. 


Parameters:
x value to be transformed 


Returns:

linear mapping:

i1 + (i2 - i1) / (d2 - d1) * (x - d1) 

logarithmic mapping:

i1 + (i2 - i1) / log(d2 / d1) * log(x / d1) 




Definition at line 185 of file qwt_dimap.cpp.


Referenced by QwtPlot::closestCurve(), QwtPlot::closestMarker(), and QwtCurve::drawSpline().

Author

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