QwtPlotCanvas man page

QwtPlotCanvas —

Canvas of a QwtPlot.  


#include <qwt_plot_canvas.h>

Public Types

enum FocusIndicator { NoFocusIndicator, CanvasFocusIndicator, ItemFocusIndicator }
enum PaintAttribute { PaintCached =  1, PaintPacked =  2 }

Public Member Functions

FocusIndicator focusIndicator () const
void invalidatePaintCache ()
QPixmap * paintCache ()
const QPixmap * paintCache () const
const QwtPlot * plot () const
QwtPlot * plot ()
QwtPlotCanvas (QwtPlot *)
void replot ()
void setFocusIndicator (FocusIndicator)
void setPaintAttribute (PaintAttribute, bool on=true)
bool testPaintAttribute (PaintAttribute) const
virtual ~QwtPlotCanvas ()

Protected Member Functions

void drawCanvas (QPainter *painter=NULL)
virtual void drawContents (QPainter *)
virtual void drawFocusIndicator (QPainter *)
virtual void hideEvent (QHideEvent *)
virtual void paintEvent (QPaintEvent *)

Detailed Description

Canvas of a QwtPlot.

See also:


Member Enumeration Documentation

enum QwtPlotCanvas::FocusIndicator

Focus indicator. .IP "·" 2 NoFocusIndicator
Don't paint a focus indicator

  • CanvasFocusIndicator
    The focus is related to the complete canvas. Paint the focus indicator using paintFocus()
  • ItemFocusIndicator
    The focus is related to an item (curve, point, ...) on the canvas. It is up to the application to display a focus indication using f.e. highlighting.

See also:

setFocusIndicator(), focusIndicator(), paintFocus()

enum QwtPlotCanvas::PaintAttribute

Paint attributes. .IP "·" 2 PaintCached
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. Disabling the cache will improve the performance for incremental paints (using QwtPlotCurve::draw).

  • PaintPacked
    Suppress system background repaints and paint it together with the canvas contents. Painting packed might avoid flickering for expensive repaints, when there is a notable gap between painting the background and the plot contents.

The default setting enables PaintCached and PaintPacked

See also:

setPaintAttribute(), testPaintAttribute(), paintCache()

Constructor & Destructor Documentation

QwtPlotCanvas::QwtPlotCanvas (QwtPlot *plot) [explicit]

Sets a cross cursor, enables QwtPlotCanvas::PaintCached.

QwtPlotCanvas::~QwtPlotCanvas () [virtual]


Member Function Documentation

void QwtPlotCanvas::drawCanvas (QPainter *painter = NULL) [protected] Draw the the canvas

Paints all plot items to the contentsRect(), using QwtPlot::drawCanvas and updates the paint cache.


painter Painter

See also:

QwtPlot::drawCanvas(), setPaintAttributes(), testPaintAttributes()

void QwtPlotCanvas::drawContents (QPainter *painter) [protected, virtual] Redraw the canvas, and focus rect


painter Painter

void QwtPlotCanvas::drawFocusIndicator (QPainter *painter) [protected, virtual] Draw the focus indication


painter Painter

QwtPlotCanvas::FocusIndicator QwtPlotCanvas::focusIndicator () const Returns

Focus indicator

See also:

FocusIndicator, setFocusIndicator()

void QwtPlotCanvas::hideEvent (QHideEvent *event) [protected, virtual] Hide event


event Hide event

void QwtPlotCanvas::invalidatePaintCache ()

Invalidate the internal paint cache.

const QPixmap * QwtPlotCanvas::paintCache () const

Return the paint cache, might be null.

QPixmap * QwtPlotCanvas::paintCache ()

Return the paint cache, might be null.

void QwtPlotCanvas::paintEvent (QPaintEvent *event) [protected, virtual] Paint event


event Paint event

const QwtPlot * QwtPlotCanvas::plot () const

Return parent plot widget.

QwtPlot * QwtPlotCanvas::plot ()

Return parent plot widget.

void QwtPlotCanvas::replot () Invalidate the paint cache and repaint the canvas

See also:


void QwtPlotCanvas::setFocusIndicator (FocusIndicatorfocusIndicator) Set the focus indicator

See also:

FocusIndicator, focusIndicator()

void QwtPlotCanvas::setPaintAttribute (PaintAttributeattribute, boolon = true)

Changing the paint attributes. Parameters:

attribute Paint attribute
on On/Off

The default setting enables PaintCached and PaintPacked

See also:

testPaintAttribute(), drawCanvas(), drawContents(), paintCache()

bool QwtPlotCanvas::testPaintAttribute (PaintAttributeattribute) const Test wether a paint attribute is enabled


attribute Paint attribute


true if the attribute is enabled

See also:



Generated automatically by Doxygen for Qwt User's Guide from the source code.


Mon Aug 1 2011 Version 5.2.2 Qwt User's Guide