Abstract base class for bar chart items. More...

#include <qwt_plot_abstract_barchart.h>

Inheritance diagram for QwtPlotAbstractBarChart:

Classes
class	PrivateData
Public Types
enum	LayoutPolicy { AutoAdjustSamples, ScaleSamplesToAxes, ScaleSampleToCanvas, FixedSampleSize }
	Mode how to calculate the bar width. More...
Public Member Functions
double	baseline () const
virtual void	getCanvasMarginHint (const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect, double &left, double &top, double &right, double &bottom) const
	Calculate a hint for the canvas margin.
double	layoutHint () const
LayoutPolicy	layoutPolicy () const
int	margin () const
	QwtPlotAbstractBarChart (const QwtText &title)
void	setBaseline (double)
	Set the baseline.
void	setLayoutHint (double)
void	setLayoutPolicy (LayoutPolicy)
void	setMargin (int)
	Set the margin.
void	setSpacing (int)
	Set the spacing.
int	spacing () const
virtual	~QwtPlotAbstractBarChart ()
	Destructor.
Protected Member Functions
double	sampleWidth (const QwtScaleMap &map, double canvasSize, double dataSize, double value) const
Private Attributes
PrivateData *	d_data

Detailed Description

Abstract base class for bar chart items.

In opposite to almost all other plot items bar charts can't be displayed inside of their bounding rectangle and need a special API how to calculate the width of the bars and how they affect the layout of the attached plot.

Definition at line 25 of file qwt_plot_abstract_barchart.h.

Member Enumeration Documentation

enum QwtPlotAbstractBarChart::LayoutPolicy

Mode how to calculate the bar width.

setLayoutPolicy(), setLayoutHint(), barWidthHint()

Enumerator:

AutoAdjustSamples	The sample width is calculated by dividing the bounding rectangle by the number of samples. The layoutHint() is used as a minimum width in paint device coordinates. See also: boundingRectangle()
ScaleSamplesToAxes	layoutHint() defines an interval in axis coordinates
ScaleSampleToCanvas	The bar width is calculated by multiplying layoutHint() with the height or width of the canvas. See also: boundingRectangle()
FixedSampleSize	layoutHint() defines a fixed width in paint device coordinates.

Definition at line 33 of file qwt_plot_abstract_barchart.h.

Constructor & Destructor Documentation

QwtPlotAbstractBarChart::QwtPlotAbstractBarChart ( const QwtText & title ) [explicit]

Constructor

Parameters:

title Title of the chart

Definition at line 47 of file qwt_plot_abstract_barchart.cpp.

QwtPlotAbstractBarChart::~QwtPlotAbstractBarChart ( ) [virtual]

Destructor.

Definition at line 59 of file qwt_plot_abstract_barchart.cpp.

Member Function Documentation

double QwtPlotAbstractBarChart::baseline ( ) const

Returns:: Value for the origin of the bar chart

See also:: setBaseline(), QwtPlotSeriesItem::orientation()

Definition at line 207 of file qwt_plot_abstract_barchart.cpp.

void QwtPlotAbstractBarChart::getCanvasMarginHint	(	const QwtScaleMap &	xMap,
		const QwtScaleMap &	yMap,
		const QRectF &	canvasRect,
		double &	left,
		double &	top,
		double &	right,
		double &	bottom
	)		const `[virtual]`

Calculate a hint for the canvas margin.

Bar charts need to reserve some space for displaying the bars for the first and the last sample. The hint is calculated from the layoutHint() depending on the layoutPolicy().

The margins are in target device coordinates ( pixels on screen )

Parameters:

xMap	Maps x-values into pixel coordinates.
yMap	Maps y-values into pixel coordinates.
canvasRect	Contents rectangle of the canvas in painter coordinates
left	Returns the left margin
top	Returns the top margin
right	Returns the right margin
bottom	Returns the bottom margin

Returns:: Margin

See also:: layoutPolicy(), layoutHint(), QwtPlotItem::Margins QwtPlot::getCanvasMarginsHint(), QwtPlot::updateCanvasMargins()

Reimplemented from QwtPlotItem.

Definition at line 288 of file qwt_plot_abstract_barchart.cpp.

double QwtPlotAbstractBarChart::layoutHint ( ) const

The combination of layoutPolicy() and layoutHint() define how the width of the bars is calculated

Returns:: Layout policy of the chart item

See also:: LayoutPolicy, setLayoutHint(), layoutPolicy()

Definition at line 118 of file qwt_plot_abstract_barchart.cpp.

QwtPlotAbstractBarChart::LayoutPolicy QwtPlotAbstractBarChart::layoutPolicy ( ) const

The combination of layoutPolicy() and layoutHint() define how the width of the bars is calculated

Returns:: Layout policy of the chart item

See also:: setLayoutPolicy(), layoutHint()

Definition at line 88 of file qwt_plot_abstract_barchart.cpp.

int QwtPlotAbstractBarChart::margin ( ) const

Returns:: Margin between the outmost bars and the contentsRect() of the canvas.

See also:: setMargin(), spacing()

Definition at line 175 of file qwt_plot_abstract_barchart.cpp.

double QwtPlotAbstractBarChart::sampleWidth	(	const QwtScaleMap &	map,
		double	canvasSize,
		double	boundingSize,
		double	value
	)		const `[protected]`

Calculate the width for a sample in paint device coordinates

Parameters:

map	Scale map for the corresponding scale
canvasSize	Size of the canvas in paint device coordinates
boundingSize	Bounding size of the chart in plot coordinates ( used in AutoAdjustSamples mode )
value	Value of the sample

Returns:: Sample width

See also:: layoutPolicy(), layoutHint()

Definition at line 224 of file qwt_plot_abstract_barchart.cpp.

void QwtPlotAbstractBarChart::setBaseline ( double value )

Set the baseline.

The baseline is the origin for the chart. Each bar is painted from the baseline in the direction of the sample value. In case of a horizontal orientation() the baseline is interpreted as x - otherwise as y - value.

The default value for the baseline is 0.

Parameters:

value Value for the baseline