QwtPlotGLCanvas Class Reference

An alternative canvas for a QwtPlot derived from QGLWidget. More...

#include <qwt_plot_glcanvas.h>

Inheritance diagram for QwtPlotGLCanvas:

Public Slots
void	replot ()

Public Member Functions
	QwtPlotGLCanvas (QwtPlot *=NULL)
	Constructor. More...
	QwtPlotGLCanvas (const QGLFormat &, QwtPlot *=NULL)
	Constructor. More...
virtual	~QwtPlotGLCanvas ()
	Destructor.
virtual Q_INVOKABLE void	invalidateBackingStore () override
	Invalidate the internal backing store.
Q_INVOKABLE QPainterPath	borderPath (const QRect &) const
virtual bool	event (QEvent *) override
Public Member Functions inherited from QwtPlotAbstractGLCanvas
	QwtPlotAbstractGLCanvas (QWidget *canvasWidget)
	Constructor. More...
virtual	~QwtPlotAbstractGLCanvas ()
	Destructor.
void	setPaintAttribute (PaintAttribute, bool on=true)
	Changing the paint attributes. More...
bool	testPaintAttribute (PaintAttribute) const
void	setFrameStyle (int style)
int	frameStyle () const
void	setFrameShadow (QFrame::Shadow)
QFrame::Shadow	frameShadow () const
void	setFrameShape (QFrame::Shape)
QFrame::Shape	frameShape () const
void	setLineWidth (int)
int	lineWidth () const
void	setMidLineWidth (int)
int	midLineWidth () const
int	frameWidth () const
QRect	frameRect () const
Public Member Functions inherited from QwtPlotAbstractCanvas
	QwtPlotAbstractCanvas (QWidget *canvasWidget)
	Constructor. More...
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	initializeGL () override
	No operation - reserved for some potential use in the future.
virtual void	paintGL () override
	Paint the plot.
virtual void	resizeGL (int width, int height) override
	No operation - reserved for some potential use in the future.
Protected Member Functions inherited from QwtPlotAbstractGLCanvas
void	replot ()
void	draw (QPainter *)
	Helper function for the derived plot canvas.
Protected Member Functions inherited from QwtPlotAbstractCanvas
QWidget *	canvasWidget ()
const QWidget *	canvasWidget () const
virtual void	drawFocusIndicator (QPainter *)
virtual void	drawBorder (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.

Additional Inherited Members
Public Types inherited from QwtPlotAbstractGLCanvas
enum	PaintAttribute { BackingStore = 1 , ImmediatePaint = 8 }
	Paint attributes. More...
typedef QFlags< PaintAttribute >	PaintAttributes
	Paint attributes. More...
Public Types inherited from QwtPlotAbstractCanvas
enum	FocusIndicator { NoFocusIndicator , CanvasFocusIndicator , ItemFocusIndicator }
	Focus indicator The default setting is NoFocusIndicator. More...

Detailed Description

An alternative canvas for a QwtPlot derived from QGLWidget.

QwtPlotGLCanvas implements the very basics to act as canvas inside of a QwtPlot widget. It might be extended to a full featured alternative to QwtPlotCanvas in a future version of Qwt.

Even if QwtPlotGLCanvas is not derived from QFrame it imitates its API. When using style sheets it supports the box model - beside backgrounds with rounded borders.

Since Qt 5.4 QOpenGLWidget is available, that is used by QwtPlotOpenGLCanvas.

See also

QwtPlot::setCanvas(), QwtPlotCanvas, QwtPlotOpenGLCanvas

Note

With Qt4 you might want to use the QPaintEngine::OpenGL paint engine ( see QGL::setPreferredPaintEngine() ). On a Linux test system QPaintEngine::OpenGL2 shows very basic problems like translated geometries.

Another way for getting hardware accelerated graphics is using an OpenGL offscreen buffer ( QwtPlotCanvas::OpenGLBuffer ) with QwtPlotCanvas. Performance is worse, than rendering straight to a QGLWidget, but is usually better integrated into a desktop application.

Definition at line 45 of file qwt_plot_glcanvas.h.

Constructor & Destructor Documentation

QwtPlotGLCanvas() [1/2]

QwtPlotGLCanvas::QwtPlotGLCanvas ( QwtPlot *  plot = NULL )

explicit

Constructor.

Parameters

plot	Parent plot widget

See also

QwtPlot::setCanvas()

Definition at line 56 of file qwt_plot_glcanvas.cpp.

QwtPlotGLCanvas() [2/2]

QwtPlotGLCanvas::QwtPlotGLCanvas ( const QGLFormat &  format, QwtPlot *  plot = NULL  )

explicit

Constructor.

Parameters

format	OpenGL rendering options
plot	Parent plot widget

See also

QwtPlot::setCanvas()

Definition at line 69 of file qwt_plot_glcanvas.cpp.

Member Function Documentation

borderPath()

QPainterPath QwtPlotGLCanvas::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 157 of file qwt_plot_glcanvas.cpp.

event()

bool QwtPlotGLCanvas::event ( QEvent *  event )

overridevirtual

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

Parameters

event

Qt Event

Returns

See QGLWidget::event()

Definition at line 110 of file qwt_plot_glcanvas.cpp.

paintEvent()

void QwtPlotGLCanvas::paintEvent ( QPaintEvent *  event )

overrideprotectedvirtual

Paint event

Parameters

event

Paint event

See also

QwtPlot::drawCanvas()

Definition at line 100 of file qwt_plot_glcanvas.cpp.

replot

void QwtPlotGLCanvas::replot ( )

slot

Invalidate the paint cache and repaint the canvas

See also

invalidatePaintCache()

Definition at line 131 of file qwt_plot_glcanvas.cpp.