Public Types¶

enum Attribute { AtomicPainter = 0x01, FullRepaint = 0x02, CopyBackingStore = 0x04 }
Paint attributes. typedef QFlags< Attribute > Attributes
Paint attributes.

Public Member Functions¶

QwtPlotDirectPainter (QObject *parent=NULL)
Constructor. virtual ~QwtPlotDirectPainter ()
Destructor. void setAttribute (Attribute, bool on)
bool testAttribute (Attribute) const
void setClipping (bool)
bool hasClipping () const
void setClipRegion (const QRegion &)
Assign a clip region and enable clipping. QRegion clipRegion () const
void drawSeries (QwtPlotSeriesItem *, int from, int to)
Draw a set of points of a seriesItem. void reset ()
Close the internal QPainter. virtual bool eventFilter (QObject *, QEvent *)
Event filter.

enum QwtPlotDirectPainter::Attribute¶

Paint attributes.

See also:

Enumerator

AtomicPainter

Initializing a QPainter is an expensive operation. When AtomicPainter is set each call of drawSeries() opens/closes a temporary QPainter. Otherwise QwtPlotDirectPainter tries to use the same QPainter as long as possible.

FullRepaint

When FullRepaint is set the plot canvas is explicitly repainted after the samples have been rendered.

CopyBackingStore

When QwtPlotCanvas::BackingStore is enabled the painter has to paint to the backing store and the widget. In certain situations/environments it might be faster to paint to the backing store only and then copy the backing store to the canvas. This flag can also be useful for settings, where Qt fills the the clip region with the widget background.

QRegion QwtPlotDirectPainter::clipRegion () const¶

Returns:

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void QwtPlotDirectPainter::drawSeries (QwtPlotSeriesItem * seriesItem, int from, int to)¶

Draw a set of points of a seriesItem. When observing an measurement while it is running, new points have to be added to an existing seriesItem. drawSeries() can be used to display them avoiding a complete redraw of the canvas.

Setting plot()->canvas()->setAttribute(Qt::WA_PaintOutsidePaintEvent, true); will result in faster painting, if the paint engine of the canvas widget supports this feature.

Parameters:

bool QwtPlotDirectPainter::hasClipping () const¶

Returns:

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void QwtPlotDirectPainter::setAttribute (Attribute attribute, bool on)¶

Change an attribute

Parameters:

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void QwtPlotDirectPainter::setClipping (bool enable)¶

En/Disables clipping

Parameters:

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void QwtPlotDirectPainter::setClipRegion (const QRegion & region)¶

Assign a clip region and enable clipping. Depending on the environment setting a proper clip region might improve the performance heavily. F.e. on Qt embedded only the clipped part of the backing store will be copied to a ( maybe unaccelerated ) frame buffer device.

Parameters:

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bool QwtPlotDirectPainter::testAttribute (Attribute attribute) const¶

Returns:

Parameters:

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