QwtPolarCanvas(3) Qwt User's Guide QwtPolarCanvas(3)

QwtPolarCanvas - Canvas of a QwtPolarPlot.

#include <qwt_polar_canvas.h>

Inherits QFrame.

enum PaintAttribute { BackingStore = 0x01 }
Paint attributes. typedef QFlags< PaintAttribute > PaintAttributes

QwtPolarCanvas (QwtPolarPlot *)
Constructor. virtual ~QwtPolarCanvas ()
Destructor. QwtPolarPlot * plot ()
const QwtPolarPlot * plot () const
void setPaintAttribute (PaintAttribute, bool on=true)
Changing the paint attributes. bool testPaintAttribute (PaintAttribute) const
const QPixmap * backingStore () const
void invalidateBackingStore ()
Invalidate the internal backing store. QwtPointPolar invTransform (const QPoint &) const
QPoint transform (const QwtPointPolar &) const

virtual void paintEvent (QPaintEvent *) override
virtual void resizeEvent (QResizeEvent *) override

Canvas of a QwtPolarPlot.

The canvas is the widget, where all polar items are painted to.


In opposite to QwtPlot all axes are painted on the canvas.

See also


Definition at line 27 of file qwt_polar_canvas.h.

An ORed combination of PaintAttribute values.

Definition at line 50 of file qwt_polar_canvas.h.

Paint attributes. The default setting enables BackingStore

See also

setPaintAttribute(), testPaintAttribute(), backingStore()


Paint double buffered and reuse the content of the pixmap buffer for some spontaneous repaints that happen when a plot gets unhidden, deiconified or changes the focus.

Definition at line 40 of file qwt_polar_canvas.h.


Backing store, might be null

Definition at line 170 of file qwt_polar_canvas.cpp.

QwtPointPolar QwtPolarCanvas::invTransform (const QPoint & pos) const

Translate a point from widget into plot coordinates


pos Point in widget coordinates of the plot canvas


Point in plot coordinates

See also


Definition at line 267 of file qwt_polar_canvas.cpp.

Paint event


event Paint event

Definition at line 186 of file qwt_polar_canvas.cpp.

QwtPolarPlot * QwtPolarCanvas::plot ()


Parent plot widget

Definition at line 97 of file qwt_polar_canvas.cpp.


Parent plot widget

Definition at line 103 of file qwt_polar_canvas.cpp.

Resize event


event Resize event

Definition at line 251 of file qwt_polar_canvas.cpp.

Changing the paint attributes.


attribute Paint attribute
on On/Off

The default setting enables BackingStore

See also

testPaintAttribute(), paintCache()

Definition at line 118 of file qwt_polar_canvas.cpp.

Test whether a paint attribute is enabled


attribute Paint attribute


true if the attribute is enabled

See also


Definition at line 164 of file qwt_polar_canvas.cpp.

Translate a point from plot into widget coordinates


polarPos Point in plot coordinates


Point in widget coordinates

See also


Definition at line 310 of file qwt_polar_canvas.cpp.

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Sun Jul 18 2021 Version 6.2.0