QwtPlotCurve - Man Page

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 }

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 ()

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 ()

• 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:

• 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:

• 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:

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

See also:

• 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:

Render hints.

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

Constructor.

Parameters:

title Title of the curve

Parameters:

title Title of the curve

Destructor.

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()

See also:

See also:

Reimplemented from QwtPlotItem.

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

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

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

Returns:

Curve fitter

See also:

See also:

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

See also:

Draw the complete curve. Parameters:

See also:

Implements QwtPlotItem.

Draw an interval of the curve. Parameters:

See also:

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()

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

See also:

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()

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()

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()

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()

Draw symbols. Parameters:

See also:

Parameters:

painter Painter
xMap x map
yMap y map
pa Polygon

See also:

setBrush(), setBaseline(), setCurveType()

Hide the item.

Initialize data members.

Parameters:

xMap X map
yMap Y map
rect Rectangle in paint coordinates

Returns:

Rectangle in scale coordinates

See also:

transform()

See also:

See also:

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.

boundingRect().right()

boundingRect().bottom()

boundingRect().left()

boundingRect().top()

Calculate the bounding paint rect of 2 maps. Parameters:

Returns:

Bounding rect of the scale maps

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

Return attached plot.

Reimplemented from QwtPlotItem.

Calculate the bounding scale rect of 2 maps. Parameters:

Returns:

Bounding rect of the scale maps

The item will painted according to the coordinates its Axes.

Parameters:

xAxis X Axis
yAxis Y Axis

See also:

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

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()

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()

Parameters:

attribute Curve attribute
on On/Off

/sa CurveAttribute, testCurveAttribute(), setCurveFitter()

Parameters:

curveFitter Curve fitter

Parameters:

curveType Yfx or Xfy

See also:

CurveType, curveType()

Parameters:

data Data

Note:

Internally the data is stored in a QwtPolygonFData object

Parameters:

xData x data
yData y data

Note:

Internally the data is stored in a QwtArrayData object

Parameters:

data Data

See also:

QwtData::copy()

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

Parameters:

attribute Attribute type
on true/false

See also:

testItemAttribute(), ItemAttribute

Parameters:

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

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()

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

Parameters:

hint Render hint
on true/false

See also:

testRenderHint(), RenderHint

Parameters:

style Curve style

See also:

CurveStyle, style()

Assign a symbol. Parameters:

See also:

Parameters:

title Title

See also:

title()

Parameters:

title Title

See also:

title()

Parameters:

on Show if true, otherwise hide

See also:

isVisible(), show(), hide()

The item will painted according to the coordinates its Axes.

Parameters:

axis X Axis

See also:

setAxis(), setYAxis(), xAxis()

The item will painted according to the coordinates its Axes.

Parameters:

axis Y Axis

See also:

setAxis(), setXAxis(), yAxis()

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

Parameters:

z Z-value

See also:

z(), QwtPlotDict::itemList()

Show the item.

See also:

Return the current symbol. See also:

See also:

Parameters:

attribute Attribute type

Returns:

true/false

See also:

setItemAttribute(), ItemAttribute

Return the current paint attributes. See also:

Parameters:

hint Render hint

Returns:

true/false

See also:

setRenderHint(), RenderHint

See also:

Parameters:

xMap X map
yMap Y map
rect Rectangle in scale coordinates

Returns:

Rectangle in paint coordinates

See also:

invTransform()

Update the widget that represents the curve on the legend.

Reimplemented from QwtPlotItem.

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.

Returns:

x-value at position i

Return xAxis.

Returns:

y-value at position i

Return yAxis.

Returns:

setZ(), QwtPlotDict::itemList()