QwtPlotStyling Class Reference

Utility class for reading and writing visual style properties of QwtPlotItem. More...

#include <qwt_plot_styling.h>

Static Public Member Functions
static QColor	color (const QwtPlotItem *item, const QColor &defaultColor=QColor())
	Get the representative color of a plot item.
static bool	setColor (QwtPlotItem *item, const QColor &color)
	Set the color of a plot item.
static QPen	pen (const QwtPlotItem *item)
	Get the pen of a plot item.
static bool	setPen (QwtPlotItem *item, const QPen &pen)
	Set the pen of a plot item.
static QBrush	brush (const QwtPlotItem *item)
	Get the brush of a plot item.
static bool	setBrush (QwtPlotItem *item, const QBrush &brush)
	Set the brush of a plot item.
static void	setSymbol (QwtPlotCurve *curve, QwtSymbol::Style style, const QSize &size=QSize(8, 8))
	Set a symbol on a curve with style and size.
static void	setSymbol (QwtPlotCurve *curve, QwtSymbol::Style style, const QColor &color, const QSize &size=QSize(8, 8))
	Set a symbol on a curve with style, color and size.
static void	setLineStyle (QwtPlotCurve *curve, Qt::PenStyle style, qreal width=0.0)
	Set curve line pen style and width.
static qreal	recommendPenWidth (int pointCount)
	Recommend a pen width based on the number of data points.
static void	forceReplot (QwtPlot *plot)
	Force an immediate replot even when autoReplot is disabled.

Detailed Description

Utility class for reading and writing visual style properties of QwtPlotItem.

QwtPlotStyling provides type-safe static methods to get or set the color, pen, brush, and symbol of any QwtPlotItem, dispatching through the item's rtti to call the correct type-specific API.

Also provides convenience methods for common styling operations such as setting a curve's symbol or recommending pen widths based on data density.

QwtPlotItem* item = ...;
 
// Get color regardless of item type
QColor c = Qwt::QwtPlotStyling::color(item);
 
// Set color uniformly
Qwt::QwtPlotStyling::setColor(item, Qt::red);
 
// Add a symbol to a curve
Qwt::QwtPlotStyling::setSymbol(curve, QwtSymbol::Ellipse, Qt::blue, QSize(6, 6));

See also

QwtPlotItemInfo, QwtPlotDataAccess

Member Function Documentation

brush()

QBrush QwtPlotStyling::brush ( const QwtPlotItem *  item )

static

Get the brush of a plot item.

Parameters

item	Plot item to query

Returns

The primary brush of the item, or a default QBrush if not recognized

color()

QColor QwtPlotStyling::color ( const QwtPlotItem *  item, const QColor &  defaultColor = QColor()  )

static

Get the representative color of a plot item.

Parameters

item	Plot item to query
defaultColor	Color to return if the item type is not recognized

Returns

The primary color of the item (from pen or brush)

Uses the item's rtti to dispatch to the correct type-specific API. For curves, returns the pen color; for bar charts, the brush color; for grids, the major pen color; etc.

forceReplot()

void QwtPlotStyling::forceReplot ( QwtPlot *  plot )

static

Force an immediate replot even when autoReplot is disabled.

Parameters

plot	Target plot

Temporarily enables ImmediatePaint on the canvas (if it is a QwtPlotCanvas), performs a replot, and restores the previous paint attributes.

pen()

QPen QwtPlotStyling::pen ( const QwtPlotItem *  item )

static

Get the pen of a plot item.

Parameters

item	Plot item to query

Returns

The primary pen of the item, or a default QPen if not recognized

recommendPenWidth()

qreal QwtPlotStyling::recommendPenWidth ( int  pointCount )

static

Recommend a pen width based on the number of data points.

Parameters

pointCount

Number of data points in the series

Returns

Recommended pen width

For large datasets (>10000 points), a thinner pen improves rendering performance and visual clarity. For small datasets, a wider pen provides better visibility.

setBrush()

bool QwtPlotStyling::setBrush ( QwtPlotItem *  item, const QBrush &  brush  )

static

Set the brush of a plot item.

Parameters

item	Plot item to modify
brush	New brush to apply

Returns

true if the brush was successfully applied

setColor()

bool QwtPlotStyling::setColor ( QwtPlotItem *  item, const QColor &  color  )

static

Set the color of a plot item.

Parameters

item	Plot item to modify
color	New color to apply

Returns

true if the color was successfully applied

For curves, sets the pen color; for bar charts and histograms, sets both pen color and brush color; for grids, sets the major pen color.

setLineStyle()

void QwtPlotStyling::setLineStyle ( QwtPlotCurve *  curve, Qt::PenStyle  style, qreal  width = 0.0  )

static

Set curve line pen style and width.

Parameters

curve	Target curve
style	Pen style (solid, dashed, dotted, etc.)
width	Pen width (0 = cosmetic)

setPen()

bool QwtPlotStyling::setPen ( QwtPlotItem *  item, const QPen &  pen  )

static

Set the pen of a plot item.

Parameters

item	Plot item to modify
pen	New pen to apply

Returns

true if the pen was successfully applied

setSymbol() [1/2]

void QwtPlotStyling::setSymbol ( QwtPlotCurve *  curve, QwtSymbol::Style  style, const QColor &  color, const QSize &  size = QSize(8, 8)  )

static

Set a symbol on a curve with style, color and size.

Parameters

curve	Target curve
style	Symbol style
color	Symbol fill color
size	Symbol size in pixels

setSymbol() [2/2]

void QwtPlotStyling::setSymbol ( QwtPlotCurve *  curve, QwtSymbol::Style  style, const QSize &  size = QSize(8, 8)  )

static

Set a symbol on a curve with style and size.

Parameters

curve	Target curve
style	Symbol style (ellipse, rect, diamond, etc.)
size	Symbol size in pixels

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The documentation for this class was generated from the following files:

• /home/runner/work/QWT/QWT/src/plot/qwt_plot_styling.h
• /home/runner/work/QWT/QWT/src/plot/qwt_plot_styling.cpp