#include <qwt_plot_canvas.h>

Inheritance diagram for QwtPlotCanvas:

Public Types
enum	PaintAttribute { BackingStore = 1 , Opaque = 2 , HackStyledBackground = 4 , ImmediatePaint = 8 }
	Paint attributes. More...

typedef QFlags< PaintAttribute >	PaintAttributes

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
	QwtPlotCanvas (QwtPlot *=NULL)
	Constructor.

virtual	~QwtPlotCanvas ()
	Destructor.

void	setPaintAttribute (PaintAttribute, bool on=true)
	Changing the paint attributes.

bool	testPaintAttribute (PaintAttribute) const

const QPixmap *	backingStore () const

Q_INVOKABLE void	invalidateBackingStore ()
	Invalidate the internal backing store.

virtual bool	event (QEvent *) override

Q_INVOKABLE QPainterPath	borderPath (const QRect &) const

Public Member Functions inherited from QwtPlotAbstractCanvas
	QwtPlotAbstractCanvas (QWidget *canvasWidget)
	Constructor.

virtual	~QwtPlotAbstractCanvas ()
	Destructor.

QwtPlot *	plot ()
	Return parent plot widget.

const QwtPlot *	plot () const
	Return parent plot widget.

void	setFocusIndicator (FocusIndicator)

FocusIndicator	focusIndicator () const

void	setBorderRadius (double)

double	borderRadius () const

Protected Member Functions
virtual void	paintEvent (QPaintEvent *) override

virtual void	resizeEvent (QResizeEvent *) override

virtual void	drawBorder (QPainter *) override

Protected Member Functions inherited from QwtPlotAbstractCanvas
QWidget *	canvasWidget ()

const QWidget *	canvasWidget () const

virtual void	drawFocusIndicator (QPainter *)

virtual void	drawBackground (QPainter *)
	Helper function for the derived plot canvas.

void	fillBackground (QPainter *)
	Helper function for the derived plot canvas.

void	drawCanvas (QPainter *)
	Draw the plot to the canvas.

void	drawStyled (QPainter *, bool)
	Helper function for the derived plot canvas.

void	drawUnstyled (QPainter *)
	Helper function for the derived plot canvas.

QPainterPath	canvasBorderPath (const QRect &rect) const

void	updateStyleSheetInfo ()
	Update the cached information about the current style sheet.

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 Typedef Documentation

◆ PaintAttributes

typedef QFlags<PaintAttribute > QwtPlotCanvas::PaintAttributes

An ORed combination of PaintAttribute values.

Definition at line 102 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 )

overrideprotectedvirtual

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 )

overridevirtual

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 )

overrideprotectedvirtual

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 )

overrideprotectedvirtual

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.

Public Types

Public Slots

Public Member Functions

Protected Member Functions

Detailed Description

Member Typedef Documentation

◆ PaintAttributes

Member Enumeration Documentation

◆ PaintAttribute

Constructor & Destructor Documentation

◆ QwtPlotCanvas()

◆ ~QwtPlotCanvas()

Member Function Documentation

◆ backingStore()

◆ borderPath()

◆ drawBorder()

◆ event()

◆ invalidateBackingStore()

◆ paintEvent()

◆ replot

◆ resizeEvent()

◆ setPaintAttribute()

◆ testPaintAttribute()