Qwt User's Guide 5.2.2
Public Types | Public Member Functions | Protected Member Functions

QwtPlotCanvas Class Reference

Canvas of a QwtPlot. More...

#include <qwt_plot_canvas.h>

List of all members.

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 QwtPlotplot () const
QwtPlotplot ()
 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:
QwtPlot

Member Enumeration Documentation

Focus indicator.

  • 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()

Paint attributes.

  • 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]

Destructor.


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.

Parameters:
painterPainter
See also:
QwtPlot::drawCanvas(), setPaintAttributes(), testPaintAttributes()
void QwtPlotCanvas::drawContents ( QPainter *  painter) [protected, virtual]

Redraw the canvas, and focus rect

Parameters:
painterPainter
void QwtPlotCanvas::drawFocusIndicator ( QPainter *  painter) [protected, virtual]

Draw the focus indication

Parameters:
painterPainter
QwtPlotCanvas::FocusIndicator QwtPlotCanvas::focusIndicator ( ) const
Returns:
Focus indicator
See also:
FocusIndicator, setFocusIndicator()
void QwtPlotCanvas::hideEvent ( QHideEvent *  event) [protected, virtual]

Hide event

Parameters:
eventHide 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

Parameters:
eventPaint 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:
invalidatePaintCache()
void QwtPlotCanvas::setFocusIndicator ( FocusIndicator  focusIndicator)

Set the focus indicator

See also:
FocusIndicator, focusIndicator()
void QwtPlotCanvas::setPaintAttribute ( PaintAttribute  attribute,
bool  on = true 
)

Changing the paint attributes.

Parameters:
attributePaint attribute
onOn/Off

The default setting enables PaintCached and PaintPacked

See also:
testPaintAttribute(), drawCanvas(), drawContents(), paintCache()
bool QwtPlotCanvas::testPaintAttribute ( PaintAttribute  attribute) const

Test wether a paint attribute is enabled

Parameters:
attributePaint attribute
Returns:
true if the attribute is enabled
See also:
setPaintAttribute()