QwtPlotCanvas Class Reference

Canvas of a QwtPlot. More...

#include <qwt_plot_canvas.h>

Inheritance diagram for QwtPlotCanvas:

Classes
class	PrivateData

Public Types
enum	PaintAttribute { BackingStore = 1, Opaque = 2, HackStyledBackground = 4, ImmediatePaint = 8 }
	Paint attributes. More...
Public Types inherited from QwtPlotAbstractCanvas
enum	FocusIndicator { NoFocusIndicator, CanvasFocusIndicator, ItemFocusIndicator }
	Focus indicator The default setting is NoFocusIndicator. More...

Public Slots
void	replot ()

Public Member Functions
const QPixmap *	backingStore () const
Q_INVOKABLE QPainterPath	borderPath (const QRect &) const
virtual bool	event (QEvent *) QWT_OVERRIDE
Q_INVOKABLE void	invalidateBackingStore ()
	Invalidate the internal backing store. More...
	QwtPlotCanvas (QwtPlot *=NULL)
	Constructor. More...
void	setPaintAttribute (PaintAttribute, bool on=true)
	Changing the paint attributes. More...
bool	testPaintAttribute (PaintAttribute) const
virtual	~QwtPlotCanvas ()
	Destructor. More...
Public Member Functions inherited from QwtPlotAbstractCanvas
double	borderRadius () const
FocusIndicator	focusIndicator () const
QwtPlot *	plot ()
	Return parent plot widget. More...
const QwtPlot *	plot () const
	QwtPlotAbstractCanvas (QWidget *canvasWidget)
	Constructor. More...
void	setBorderRadius (double)
void	setFocusIndicator (FocusIndicator)
virtual	~QwtPlotAbstractCanvas ()
	Destructor. More...

Protected Member Functions
virtual void	drawBorder (QPainter *) QWT_OVERRIDE
virtual void	paintEvent (QPaintEvent *) QWT_OVERRIDE
virtual void	resizeEvent (QResizeEvent *) QWT_OVERRIDE
Protected Member Functions inherited from QwtPlotAbstractCanvas
QPainterPath	canvasBorderPath (const QRect &rect) const
QWidget *	canvasWidget ()
const QWidget *	canvasWidget () const
virtual void	drawBackground (QPainter *)
	Helper function for the derived plot canvas. More...
void	drawCanvas (QPainter *)
	Draw the plot to the canvas. More...
virtual void	drawFocusIndicator (QPainter *)
void	drawStyled (QPainter *, bool)
	Helper function for the derived plot canvas. More...
void	drawUnstyled (QPainter *)
	Helper function for the derived plot canvas. More...
void	fillBackground (QPainter *)
	Helper function for the derived plot canvas. More...
void	updateStyleSheetInfo ()
	Update the cached information about the current style sheet. More...

Properties
double	borderRadius

Private Attributes
PrivateData *	m_data

Detailed Description

Canvas of a QwtPlot.

Canvas is the widget where all plot items are displayed

See also

QwtPlot::setCanvas(), QwtPlotGLCanvas, QwtPlotOpenGLCanvas

Definition at line 29 of file qwt_plot_canvas.h.

Member Enumeration Documentation

PaintAttribute

enum QwtPlotCanvas::PaintAttribute

Paint attributes.

The default setting enables BackingStore and Opaque.

See also

setPaintAttribute(), testPaintAttribute()

Enumerator
BackingStore	Paint double buffered reusing the content of the pixmap buffer when possible. Using a backing store might improve the performance significantly, when working with widget overlays ( like rubber bands ). Disabling the cache might improve the performance for incremental paints (using QwtPlotDirectPainter ). See also backingStore(), invalidateBackingStore()
Opaque	Try to fill the complete contents rectangle of the plot canvas. When using styled backgrounds Qt assumes, that the canvas doesn't fill its area completely ( f.e because of rounded borders ) and fills the area below the canvas. When this is done with gradients it might result in a serious performance bottleneck - depending on the size. When the Opaque attribute is enabled the canvas tries to identify the gaps with some heuristics and to fill those only. Warning Will not work for semitransparent backgrounds
HackStyledBackground	Try to improve painting of styled backgrounds. QwtPlotCanvas supports the box model attributes for customizing the layout with style sheets. Unfortunately the design of Qt style sheets has no concept how to handle backgrounds with rounded corners - beside of padding. When HackStyledBackground is enabled the plot canvas tries to separate the background from the background border by reverse engineering to paint the background before and the border after the plot items. In this order the border gets perfectly antialiased and you can avoid some pixel artifacts in the corners.
ImmediatePaint	When ImmediatePaint is set replot() calls repaint() instead of update(). See also replot(), QWidget::repaint(), QWidget::update()

Definition at line 44 of file qwt_plot_canvas.h.

Constructor & Destructor Documentation

QwtPlotCanvas()

QwtPlotCanvas::QwtPlotCanvas ( QwtPlot *  plot = NULL )

explicit

Constructor.

Parameters

plot	Parent plot widget

See also

QwtPlot::setCanvas()

Definition at line 41 of file qwt_plot_canvas.cpp.

~QwtPlotCanvas()

QwtPlotCanvas::~QwtPlotCanvas ( )

virtual

Destructor.

Definition at line 57 of file qwt_plot_canvas.cpp.

Member Function Documentation

backingStore()

const QPixmap * QwtPlotCanvas::backingStore

(

)

const

Returns

Backing store, might be null

Definition at line 133 of file qwt_plot_canvas.cpp.

borderPath()

QPainterPath QwtPlotCanvas::borderPath

(

const QRect &

rect

)

const

Calculate the painter path for a styled or rounded border

When the canvas has no styled background or rounded borders the painter path is empty.

Parameters

rect	Bounding rectangle of the canvas

Returns

Painter path, that can be used for clipping

Definition at line 320 of file qwt_plot_canvas.cpp.

drawBorder()

void QwtPlotCanvas::drawBorder ( QPainter *  painter )

protectedvirtual

Draw the border of the plot canvas

Parameters

painter

Painter

See also

setBorderRadius()

Reimplemented from QwtPlotAbstractCanvas.

Definition at line 276 of file qwt_plot_canvas.cpp.

event()

bool QwtPlotCanvas::event ( QEvent *  event )

virtual

Qt event handler for QEvent::PolishRequest and QEvent::StyleChange

Parameters

event

Qt Event

Returns

See QFrame::event()

Definition at line 151 of file qwt_plot_canvas.cpp.

invalidateBackingStore()

void QwtPlotCanvas::invalidateBackingStore

(

)

Invalidate the internal backing store.

Definition at line 139 of file qwt_plot_canvas.cpp.

paintEvent()

void QwtPlotCanvas::paintEvent ( QPaintEvent *  event )

protectedvirtual

Paint event

Parameters

event

Paint event

Definition at line 178 of file qwt_plot_canvas.cpp.

replot

void QwtPlotCanvas::replot ( )

slot

Invalidate the paint cache and repaint the canvas

See also

invalidatePaintCache()

Definition at line 301 of file qwt_plot_canvas.cpp.

resizeEvent()

void QwtPlotCanvas::resizeEvent ( QResizeEvent *  event )

protectedvirtual

Resize event

Parameters

event

Resize event

Definition at line 291 of file qwt_plot_canvas.cpp.

setPaintAttribute()

void QwtPlotCanvas::setPaintAttribute	(	PaintAttribute	attribute,
		bool	on = true
	)

Changing the paint attributes.

Parameters

attribute	Paint attribute
on	On/Off

See also

testPaintAttribute(), backingStore()

Definition at line 70 of file qwt_plot_canvas.cpp.

testPaintAttribute()

bool QwtPlotCanvas::testPaintAttribute

(

PaintAttribute

attribute

)

const

Test whether a paint attribute is enabled

Parameters

attribute

Paint attribute

Returns

true, when attribute is enabled

See also

setPaintAttribute()

Definition at line 127 of file qwt_plot_canvas.cpp.

Member Data Documentation

m_data

PrivateData* QwtPlotCanvas::m_data

private

Definition at line 127 of file qwt_plot_canvas.h.

Property Documentation

borderRadius

double QwtPlotCanvas::borderRadius

readwrite

Definition at line 33 of file qwt_plot_canvas.h.

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

• qwt_plot_canvas.h
• qwt_plot_canvas.cpp