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

The focus is related to the complete canvas. Paint the focus indicator using paintFocus()
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).

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.


Qwt User's Guide Version 5.2.2 Mon Aug 1 2011