QwtPlotCurve man page

QwtPlotCurve —

A plot item, that represents a series of points.

Synopsis

#include <qwt_plot_curve.h>

Inherits QwtPlotItem.

Public Types

enum CurveAttribute { Inverted = 1, Fitted = 2 }

enum CurveStyle { NoCurve, Lines, Sticks, Steps, Dots, UserCurve = 100 }

enum CurveType { Yfx, Xfy }

enum ItemAttribute { Legend = 1, AutoScale = 2 }

enum PaintAttribute { PaintFiltered = 1, ClipPolygons = 2 }

enum RenderHint { RenderAntialiased = 1 }

enum RttiValues { Rtti_PlotItem = 0, Rtti_PlotGrid, Rtti_PlotScale, Rtti_PlotMarker, Rtti_PlotCurve, Rtti_PlotHistogram, Rtti_PlotSpectrogram, Rtti_PlotSVG, Rtti_PlotUserItem = 1000 }

Public Member Functions

void attach (QwtPlot *plot)

double baseline () const

virtual QwtDoubleRect boundingRect () const

const QBrush & brush () const

int closestPoint (const QPoint &pos, double *dist=NULL) const

QwtCurveFitter * curveFitter () const

CurveType curveType () const

const QwtData & data () const

QwtData & data ()

int dataSize () const

void detach ()

virtual void draw (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRect &) const

virtual void draw (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, int from, int to) const

void draw (int from, int to) const

void hide ()

QwtDoubleRect invTransform (const QwtScaleMap &, const QwtScaleMap &, const QRect &) const

bool isVisible () const

virtual void itemChanged ()

virtual QWidget * legendItem () const

double maxXValue () const

double maxYValue () const

double minXValue () const

double minYValue () const

QRect paintRect (const QwtScaleMap &, const QwtScaleMap &) const

const QPen & pen () const

QwtPlot * plot () const

QwtPlotCurve (const QwtText &title)

QwtPlotCurve ()

QwtPlotCurve (const QString &title)

virtual int rtti () const

QwtDoubleRect scaleRect (const QwtScaleMap &, const QwtScaleMap &) const

void setAxis (int xAxis, int yAxis)

void setBaseline (double ref)

void setBrush (const QBrush &)

void setCurveAttribute (CurveAttribute, bool on=true)

void setCurveFitter (QwtCurveFitter *)

void setCurveType (CurveType)

void setData (const double *xData, const double *yData, int size)

void setData (const QwtArray< double > &xData, const QwtArray< double > &yData)

void setData (const QPolygonF &data)

void setData (const QwtData &data)

void setItemAttribute (ItemAttribute, bool on=true)

void setPaintAttribute (PaintAttribute, bool on=true)

void setPen (const QPen &)

void setRawData (const double *x, const double *y, int size)

void setRenderHint (RenderHint, bool on=true)

void setStyle (CurveStyle style)

void setSymbol (const QwtSymbol &s)

void setTitle (const QString &title)

void setTitle (const QwtText &title)

virtual void setVisible (bool)

void setXAxis (int axis)

void setYAxis (int axis)

void setZ (double z)

void show ()

CurveStyle style () const

const QwtSymbol & symbol () const

bool testCurveAttribute (CurveAttribute) const

bool testItemAttribute (ItemAttribute) const

bool testPaintAttribute (PaintAttribute) const

bool testRenderHint (RenderHint) const

const QwtText & title () const

QRect transform (const QwtScaleMap &, const QwtScaleMap &, const QwtDoubleRect &) const

virtual void updateLegend (QwtLegend *) const

virtual void updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &)

double x (int i) const

int xAxis () const

double y (int i) const

int yAxis () const

double z () const

virtual ~QwtPlotCurve ()

Protected Member Functions

void closePolyline (const QwtScaleMap &, const QwtScaleMap &, QwtPolygon &) const

virtual void drawCurve (QPainter *p, int style, const QwtScaleMap &xMap, const QwtScaleMap &yMap, int from, int to) const

void drawDots (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, int from, int to) const

void drawLines (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, int from, int to) const

void drawSteps (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, int from, int to) const

void drawSticks (QPainter *p, const QwtScaleMap &xMap, const QwtScaleMap &yMap, int from, int to) const

virtual void drawSymbols (QPainter *p, const QwtSymbol &, const QwtScaleMap &xMap, const QwtScaleMap &yMap, int from, int to) const

void fillCurve (QPainter *, const QwtScaleMap &, const QwtScaleMap &, QwtPolygon &) const

void init ()

Detailed Description

A plot item, that represents a series of points.

A curve is the representation of a series of points in the x-y plane. It supports different display styles, interpolation ( f.e. spline ) and symbols.

Usage

a) Assign curve properties
When a curve is created, it is configured to draw black solid lines with in Lines style and no symbols. You can change this by calling setPen(), setStyle() and setSymbol().
b) Connect/Assign data.
QwtPlotCurve gets its points using a QwtData object offering a bridge to the real storage of the points ( like QAbstractItemModel ). There are several convenience classes derived from QwtData, that also store the points inside ( like QStandardItemModel ). QwtPlotCurve also offers a couple of variations of setData(), that build QwtData objects from arrays internally.
c) Attach the curve to a plot
See QwtPlotItem::attach()

Example:

see examples/bode

See also:

QwtPlot, QwtData, QwtSymbol, QwtScaleMap

Member Enumeration Documentation

enum QwtPlotCurve::CurveAttribute Attribute for drawing the curve

·
Fitted ( in combination with the Lines QwtPlotCurve::CurveStyle only )
A QwtCurveFitter tries to interpolate/smooth the curve, before it is painted. Note that curve fitting requires temorary memory for calculating coefficients and additional points. If painting in Fitted mode is slow it might be better to fit the points, before they are passed to QwtPlotCurve.
·
Inverted
For Steps only. Draws a step function from the right to the left.

See also:

setCurveAttribute(), testCurveAttribute(), curveFitter()

enum QwtPlotCurve::CurveStyle Curve styles.

·
NoCurve
Don't draw a curve. Note: This doesn't affect the symbols.
·
Lines
Connect the points with straight lines. The lines might be interpolated depending on the 'Fitted' attribute. Curve fitting can be configured using setCurveFitter().
·
Sticks
Draw vertical(Yfx) or horizontal(Xfy) sticks from a baseline which is defined by setBaseline().
·
Steps
Connect the points with a step function. The step function is drawn from the left to the right or vice versa, depending on the 'Inverted' attribute.
·
Dots
Draw dots at the locations of the data points. Note: This is different from a dotted line (see setPen()), and faster as a curve in NoStyle style and a symbol painting a point.
·
UserCurve
Styles >= UserCurve are reserved for derived classes of QwtPlotCurve that overload drawCurve() with additional application specific curve types.

See also:

setStyle(), style()

enum QwtPlotCurve::CurveType Curve type.

·
Yfx
Draws y as a function of x (the default). The baseline is interpreted as a horizontal line with y = baseline().
·
Xfy
Draws x as a function of y. The baseline is interpreted as a vertical line with x = baseline().

The baseline is used for aligning the sticks, or filling the curve with a brush.

See also:

setCurveType(), curveType(), baseline() brush()

enum QwtPlotItem::ItemAttribute [inherited] Plot Item Attributes

·
Legend
The item is represented on the legend.
·
AutoScale
The boundingRect() of the item is included in the autoscaling calculation.

See also:

setItemAttribute(), testItemAttribute()

enum QwtPlotCurve::PaintAttribute Attributes to modify the drawing algorithm.

·
PaintFiltered
Tries to reduce the data that has to be painted, by sorting out duplicates, or paintings outside the visible area. Might have a notable impact on curves with many close points. Only a couple of very basic filtering algos are implemented.
·
ClipPolygons
Clip polygons before painting them. In situations, where points are far outside the visible area (f.e when zooming deep) this might be a substantial improvement for the painting performance ( especially on Windows ).

The default is, that no paint attributes are enabled.

See also:

setPaintAttribute(), testPaintAttribute()

enum QwtPlotItem::RenderHint [inherited]

Render hints.

enum QwtPlotItem::RttiValues [inherited]

Runtime type information. RttiValues is used to cast plot items, without having to enable runtime type information of the compiler.

Constructor & Destructor Documentation

QwtPlotCurve::QwtPlotCurve () [explicit]

Constructor.

QwtPlotCurve::QwtPlotCurve (const QwtText &title) [explicit] Constructor

Parameters:

title Title of the curve

QwtPlotCurve::QwtPlotCurve (const QString &title) [explicit] Constructor

Parameters:

title Title of the curve

QwtPlotCurve::~QwtPlotCurve () [virtual]

Destructor.

Member Function Documentation

void QwtPlotItem::attach (QwtPlot *plot) [inherited]

Attach the item to a plot. This method will attach a QwtPlotItem to the QwtPlot argument. It will first detach the QwtPlotItem from any plot from a previous call to attach (if necessary). If a NULL argument is passed, it will detach from any QwtPlot it was attached to.

Parameters:

plot Plot widget

See also:

QwtPlotItem::detach()

double QwtPlotCurve::baseline () const Return the value of the baseline

See also:

setBaseline()

QwtDoubleRect QwtPlotCurve::boundingRect () const [virtual] Returns the bounding rectangle of the curve data. If there is no bounding rect, like for empty data the rectangle is invalid.

See also:

QwtData::boundingRect(), QwtDoubleRect::isValid()

Reimplemented from QwtPlotItem.

const QBrush & QwtPlotCurve::brush () const

Return the brush used to fill the area between lines and the baseline. See also:

setBrush(), setBaseline(), baseline()

void QwtPlotCurve::closePolyline (const QwtScaleMap &xMap, const QwtScaleMap &yMap, QwtPolygon &pa) const [protected]

Complete a polygon to be a closed polygon including the area between the original polygon and the baseline. Parameters:

xMap X map
yMap Y map
pa Polygon to be completed

int QwtPlotCurve::closestPoint (const QPoint &pos, double *dist = NULL) const Find the closest curve point for a specific position

Parameters:

pos Position, where to look for the closest curve point
dist If dist != NULL, closestPoint() returns the distance between the position and the clostest curve point

Returns:

Index of the closest curve point, or -1 if none can be found ( f.e when the curve has no points )

Note:

closestPoint() implements a dumb algorithm, that iterates over all points

QwtCurveFitter * QwtPlotCurve::curveFitter () const Get the curve fitter. If curve fitting is disabled NULL is returned.

Returns:

Curve fitter

QwtPlotCurve::CurveType QwtPlotCurve::curveType () const Return the curve type

See also:

CurveType, setCurveType()

QwtData & QwtPlotCurve::data () [inline] Returns

the the curve data

const QwtData & QwtPlotCurve::data () const [inline] Returns

the the curve data

int QwtPlotCurve::dataSize () const Return the size of the data arrays

See also:

setData()

void QwtPlotItem::detach () [inline, inherited]

This method detaches a QwtPlotItem from any QwtPlot it has been associated with. detach() is equivalent to calling attach( NULL )

See also:

attach( QwtPlot* plot )

void QwtPlotCurve::draw (QPainter *painter, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRect &canvasRect) const [virtual]

Draw the complete curve. Parameters:

painter Painter
xMap Maps x-values into pixel coordinates.
yMap Maps y-values into pixel coordinates.

See also:

drawCurve(), drawSymbols()

Implements QwtPlotItem.

void QwtPlotCurve::draw (QPainter *painter, const QwtScaleMap &xMap, const QwtScaleMap &yMap, intfrom, intto) const [virtual]

Draw an interval of the curve. Parameters:

painter Painter
xMap maps x-values into pixel coordinates.
yMap maps y-values into pixel coordinates.
from index of the first point to be painted
to index of the last point to be painted. If to < 0 the curve will be painted to its last point.

See also:

drawCurve(), drawSymbols(),

void QwtPlotCurve::draw (intfrom, intto) const

Draw a set of points of a curve. When observing an measurement while it is running, new points have to be added to an existing curve. drawCurve can be used to display them avoiding a complete redraw of the canvas.

Setting plot()->canvas()->setAttribute(Qt::WA_PaintOutsidePaintEvent, true); will result in faster painting, if the paint engine of the canvas widget supports this feature.

Parameters:

from Index of the first point to be painted
to Index of the last point to be painted. If to < 0 the curve will be painted to its last point.

See also:

drawCurve(), drawSymbols()

void QwtPlotCurve::drawCurve (QPainter *painter, intstyle, const QwtScaleMap &xMap, const QwtScaleMap &yMap, intfrom, intto) const [protected, virtual]

Draw the line part (without symbols) of a curve interval. Parameters:

painter Painter
style curve style, see QwtPlotCurve::CurveStyle
xMap x map
yMap y map
from index of the first point to be painted
to index of the last point to be painted

See also:

draw(), drawDots(), drawLines(), drawSteps(), drawSticks()

void QwtPlotCurve::drawDots (QPainter *painter, const QwtScaleMap &xMap, const QwtScaleMap &yMap, intfrom, intto) const [protected] Draw dots

Parameters:

painter Painter
xMap x map
yMap y map
from index of the first point to be painted
to index of the last point to be painted

See also:

draw(), drawCurve(), drawSticks(), drawLines(), drawSteps()

void QwtPlotCurve::drawLines (QPainter *painter, const QwtScaleMap &xMap, const QwtScaleMap &yMap, intfrom, intto) const [protected]

Draw lines. If the CurveAttribute Fitted is enabled a QwtCurveFitter tries to interpolate/smooth the curve, before it is painted.

Parameters:

painter Painter
xMap x map
yMap y map
from index of the first point to be painted
to index of the last point to be painted

See also:

setCurveAttribute(), setCurveFitter(), draw(), drawLines(), drawDots(), drawSteps(), drawSticks()

void QwtPlotCurve::drawSteps (QPainter *painter, const QwtScaleMap &xMap, const QwtScaleMap &yMap, intfrom, intto) const [protected] Draw step function

The direction of the steps depends on Inverted attribute.

Parameters:

painter Painter
xMap x map
yMap y map
from index of the first point to be painted
to index of the last point to be painted

See also:

CurveAttribute, setCurveAttribute(), draw(), drawCurve(), drawDots(), drawLines(), drawSticks()

void QwtPlotCurve::drawSticks (QPainter *painter, const QwtScaleMap &xMap, const QwtScaleMap &yMap, intfrom, intto) const [protected] Draw sticks

Parameters:

painter Painter
xMap x map
yMap y map
from index of the first point to be painted
to index of the last point to be painted

See also:

draw(), drawCurve(), drawDots(), drawLines(), drawSteps()

void QwtPlotCurve::drawSymbols (QPainter *painter, const QwtSymbol &symbol, const QwtScaleMap &xMap, const QwtScaleMap &yMap, intfrom, intto) const [protected, virtual]

Draw symbols. Parameters:

painter Painter
symbol Curve symbol
xMap x map
yMap y map
from index of the first point to be painted
to index of the last point to be painted

See also:

setSymbol(), draw(), drawCurve()

void QwtPlotCurve::fillCurve (QPainter *painter, const QwtScaleMap &xMap, const QwtScaleMap &yMap, QwtPolygon &pa) const [protected] Fill the area between the curve and the baseline with the curve brush

Parameters:

painter Painter
xMap x map
yMap y map
pa Polygon

See also:

setBrush(), setBaseline(), setCurveType()

void QwtPlotItem::hide () [inherited]

Hide the item.

void QwtPlotCurve::init () [protected]

Initialize data members.

QwtDoubleRect QwtPlotItem::invTransform (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRect &rect) const [inherited] Transform a rectangle from paint to scale coordinates

Parameters:

xMap X map
yMap Y map
rect Rectangle in paint coordinates

Returns:

Rectangle in scale coordinates

See also:

transform()

bool QwtPlotItem::isVisible () const [inherited] Returns

true if visible

See also:

setVisible(), show(), hide()

void QwtPlotItem::itemChanged () [virtual, inherited] Update the legend and call QwtPlot::autoRefresh for the parent plot.

See also:

updateLegend()

QWidget * QwtPlotItem::legendItem () const [virtual, inherited]

Allocate the widget that represents the item on the legend. The default implementation is made for QwtPlotCurve and returns a QwtLegendItem(), but an item could be represented by any type of widget, by overloading legendItem() and updateLegend().

Returns:

QwtLegendItem()

See also:

updateLegend() QwtLegend()

Implements QwtLegendItemManager.

double QwtPlotCurve::maxXValue () const [inline]

boundingRect().right()

double QwtPlotCurve::maxYValue () const [inline]

boundingRect().bottom()

double QwtPlotCurve::minXValue () const [inline]

boundingRect().left()

double QwtPlotCurve::minYValue () const [inline]

boundingRect().top()

QRect QwtPlotItem::paintRect (const QwtScaleMap &xMap, const QwtScaleMap &yMap) const [inherited]

Calculate the bounding paint rect of 2 maps. Parameters:

xMap X map
yMap X map

Returns:

Bounding rect of the scale maps

const QPen & QwtPlotCurve::pen () const

Return the pen used to draw the lines. See also:

setPen(), brush()

QwtPlot * QwtPlotItem::plot () const [inherited]

Return attached plot.

int QwtPlotCurve::rtti () const [virtual] Returns

QwtPlotItem::Rtti_PlotCurve

Reimplemented from QwtPlotItem.

QwtDoubleRect QwtPlotItem::scaleRect (const QwtScaleMap &xMap, const QwtScaleMap &yMap) const [inherited]

Calculate the bounding scale rect of 2 maps. Parameters:

xMap X map
yMap X map

Returns:

Bounding rect of the scale maps

void QwtPlotItem::setAxis (intxAxis, intyAxis) [inherited] Set X and Y axis

The item will painted according to the coordinates its Axes.

Parameters:

xAxis X Axis
yAxis Y Axis

See also:

setXAxis(), setYAxis(), xAxis(), yAxis()

void QwtPlotCurve::setBaseline (doublereference)

Set the value of the baseline. The baseline is needed for filling the curve with a brush or the Sticks drawing style. The default value is 0.0. The interpretation of the baseline depends on the CurveType. With QwtPlotCurve::Yfx, the baseline is interpreted as a horizontal line at y = baseline(), with QwtPlotCurve::Yfy, it is interpreted as a vertical line at x = baseline().

Parameters:

reference baseline

See also:

baseline(), setBrush(), setStyle(), setCurveType()

void QwtPlotCurve::setBrush (const QBrush &brush)

Assign a brush. In case of brush.style() != QBrush::NoBrush and style() != QwtPlotCurve::Sticks the area between the curve and the baseline will be filled.

In case !brush.color().isValid() the area will be filled by pen.color(). The fill algorithm simply connects the first and the last curve point to the baseline. So the curve data has to be sorted (ascending or descending).

Parameters:

brush New brush

See also:

brush(), setBaseline(), baseline()

void QwtPlotCurve::setCurveAttribute (CurveAttributeattribute, boolon = true) Specify an attribute for drawing the curve

Parameters:

attribute Curve attribute
on On/Off

/sa CurveAttribute, testCurveAttribute(), setCurveFitter()

void QwtPlotCurve::setCurveFitter (QwtCurveFitter *curveFitter) Assign a curve fitter setCurveFitter(NULL) disables curve fitting.

Parameters:

curveFitter Curve fitter

void QwtPlotCurve::setCurveType (CurveTypecurveType) Assign the curve type

Parameters:

curveType Yfx or Xfy

See also:

CurveType, curveType()

void QwtPlotCurve::setData (const QPolygonF &data) Initialize data with an array of points (explicitly shared).

Parameters:

data Data

Note:

Internally the data is stored in a QwtPolygonFData object

void QwtPlotCurve::setData (const QwtArray< double > &xData, const QwtArray< double > &yData) Initialize data with x- and y-arrays (explicitly shared) ( Builds an QwtArrayData object internally )

Parameters:

xData x data
yData y data

Note:

Internally the data is stored in a QwtArrayData object

void QwtPlotCurve::setData (const QwtData &data) Initialize data with a pointer to QwtData.

Parameters:

data Data

See also:

QwtData::copy()

void QwtPlotCurve::setData (const double *xData, const double *yData, intsize) Set data by copying x- and y-values from specified memory blocks. Contrary to setCurveRawData(), this function makes a 'deep copy' of the data.

Parameters:

xData Pointer to x values
yData Pointer to y values
size Size of xData and yData

Note:

Internally the data is stored in a QwtArrayData object

void QwtPlotItem::setItemAttribute (ItemAttributeattribute, boolon = true) [inherited] Toggle an item attribute

Parameters:

attribute Attribute type
on true/false

See also:

testItemAttribute(), ItemAttribute

void QwtPlotCurve::setPaintAttribute (PaintAttributeattribute, boolon = true) Specify an attribute how to draw the curve

Parameters:

attribute Paint attribute
on On/Off /sa PaintAttribute, testPaintAttribute()

void QwtPlotCurve::setPen (const QPen &pen) Assign a pen

The width of non cosmetic pens is scaled according to the resolution of the paint device.

Parameters:

pen New pen

See also:

pen(), brush(), QwtPainter::scaledPen()

void QwtPlotCurve::setRawData (const double *xData, const double *yData, intsize)

Initialize the data by pointing to memory blocks which are not managed by QwtPlotCurve. setRawData is provided for efficiency. It is important to keep the pointers during the lifetime of the underlying QwtCPointerData class.

Parameters:

xData pointer to x data
yData pointer to y data
size size of x and y

Note:

Internally the data is stored in a QwtCPointerData object

void QwtPlotItem::setRenderHint (RenderHinthint, boolon = true) [inherited] Toggle an render hint

Parameters:

hint Render hint
on true/false

See also:

testRenderHint(), RenderHint

void QwtPlotCurve::setStyle (CurveStylestyle) Set the curve's drawing style

Parameters:

style Curve style

See also:

CurveStyle, style()

void QwtPlotCurve::setSymbol (const QwtSymbol &symbol)

Assign a symbol. Parameters:

symbol Symbol

See also:

symbol()

void QwtPlotItem::setTitle (const QwtText &title) [inherited] Set a new title

Parameters:

title Title

See also:

title()

void QwtPlotItem::setTitle (const QString &title) [inherited] Set a new title

Parameters:

title Title

See also:

title()

void QwtPlotItem::setVisible (boolon) [virtual, inherited] Show/Hide the item

Parameters:

on Show if true, otherwise hide

See also:

isVisible(), show(), hide()

void QwtPlotItem::setXAxis (intaxis) [inherited] Set the X axis

The item will painted according to the coordinates its Axes.

Parameters:

axis X Axis

See also:

setAxis(), setYAxis(), xAxis()

void QwtPlotItem::setYAxis (intaxis) [inherited] Set the Y axis

The item will painted according to the coordinates its Axes.

Parameters:

axis Y Axis

See also:

setAxis(), setXAxis(), yAxis()

void QwtPlotItem::setZ (doublez) [inherited]

Set the z value. Plot items are painted in increasing z-order.

Parameters:

z Z-value

See also:

z(), QwtPlotDict::itemList()

void QwtPlotItem::show () [inherited]

Show the item.

QwtPlotCurve::CurveStyle QwtPlotCurve::style () const Return the current style

See also:

CurveStyle, setStyle()

const QwtSymbol & QwtPlotCurve::symbol () const

Return the current symbol. See also:

setSymbol()

bool QwtPlotCurve::testCurveAttribute (CurveAttributeattribute) const Returns

true, if attribute is enabled

See also:

CurveAttribute, setCurveAttribute()

bool QwtPlotItem::testItemAttribute (ItemAttributeattribute) const [inherited] Test an item attribute

Parameters:

attribute Attribute type

Returns:

true/false

See also:

setItemAttribute(), ItemAttribute

bool QwtPlotCurve::testPaintAttribute (PaintAttributeattribute) const

Return the current paint attributes. See also:

PaintAttribute, setPaintAttribute()

bool QwtPlotItem::testRenderHint (RenderHinthint) const [inherited] Test a render hint

Parameters:

hint Render hint

Returns:

true/false

See also:

setRenderHint(), RenderHint

const QwtText & QwtPlotItem::title () const [inherited] Returns

Title of the item

See also:

setTitle()

QRect QwtPlotItem::transform (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QwtDoubleRect &rect) const [inherited] Transform a rectangle

Parameters:

xMap X map
yMap Y map
rect Rectangle in scale coordinates

Returns:

Rectangle in paint coordinates

See also:

invTransform()

void QwtPlotCurve::updateLegend (QwtLegend *legend) const [virtual]

Update the widget that represents the curve on the legend.

Reimplemented from QwtPlotItem.

void QwtPlotItem::updateScaleDiv (const QwtScaleDiv &, const QwtScaleDiv &) [virtual, inherited]

Update the item to changes of the axes scale division. Update the item, when the axes of plot have changed. The default implementation does nothing, but items that depend on the scale division (like QwtPlotGrid()) have to reimplement updateScaleDiv()

Parameters:

xScaleDiv Scale division of the x-axis
yScaleDiv Scale division of the y-axis

See also:

QwtPlot::updateAxes()

Reimplemented in QwtPlotGrid, and QwtPlotScaleItem.

double QwtPlotCurve::x (inti) const [inline] Parameters

i index

Returns:

x-value at position i

int QwtPlotItem::xAxis () const [inherited]

Return xAxis.

double QwtPlotCurve::y (inti) const [inline] Parameters

i index

Returns:

y-value at position i

int QwtPlotItem::yAxis () const [inherited]

Return yAxis.

double QwtPlotItem::z () const [inherited] Plot items are painted in increasing z-order.

Returns:

setZ(), QwtPlotDict::itemList()

Author

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Mon Aug 1 2011 Version 5.2.2 Qwt User's Guide