QwtPlotDirectPainter(3) | Qwt User's Guide | QwtPlotDirectPainter(3) |
NAME¶
QwtPlotDirectPainter - Painter object trying to paint incrementally.SYNOPSIS¶
#include <qwt_plot_directpainter.h>Public Types¶
enum Attribute { AtomicPainter = 0x01, FullRepaint = 0x02, CopyBackingStore = 0x04 }
Public Member Functions¶
QwtPlotDirectPainter (QObject *parent=NULL)
Detailed Description¶
Painter object trying to paint incrementally.Incremental painting will only help when no
replot is triggered by another operation ( like changing scales ) and nothing
needs to be erased.
Member Typedef Documentation¶
typedef QFlags<Attribute> QwtPlotDirectPainter::Attributes¶
Paint attributes.Member Enumeration Documentation¶
enum QwtPlotDirectPainter::Attribute¶
Paint attributes. See also:setAttribute(), testAttribute(),
drawSeries()
- 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 explicitely 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 backingstore to the canvas. This flag can also be useful for settings, where Qt fills the the clip region with the widget background.
Constructor & Destructor Documentation¶
QwtPlotDirectPainter::QwtPlotDirectPainter (QObject *parent = NULL)¶
Constructor.QwtPlotDirectPainter::~QwtPlotDirectPainter () [virtual]¶
Destructor.Member Function Documentation¶
QRegion QwtPlotDirectPainter::clipRegion () const Returns:¶
Currently set clip region.
See also:
setClipRegion(), setClipping(),
hasClipping()
void QwtPlotDirectPainter::drawSeries (QwtPlotAbstractSeriesItem *seriesItem, intfrom, intto)¶
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:seriesItem Item to be painted
from Index of the first point to be painted
to Index of the last point to be painted. If to < 0 the series will be
painted to its last point.
bool QwtPlotDirectPainter::eventFilter (QObject *, QEvent *event) [virtual]¶
Event filter.bool QwtPlotDirectPainter::hasClipping () const Returns:¶
true, when clipping is enabled
See also:
setClipping(), clipRegion(),
setClipRegion()
void QwtPlotDirectPainter::reset ()¶
Close the internal QPainter.void QwtPlotDirectPainter::setAttribute (Attributeattribute, boolon) Change an attribute¶
Parameters:attribute Attribute to change
on On/Off
See also:
Attribute, testAttribute()
void QwtPlotDirectPainter::setClipping (boolenable) En/Disables clipping¶
Parameters:enable Enables clipping is true,
disable it otherwise
See also:
hasClipping(), clipRegion(),
setClipRegion()
void QwtPlotDirectPainter::setClipRegion (const QRegion ®ion)¶
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:region Clip region
See also:
clipRegion(), hasClipping(),
setClipping()
bool QwtPlotDirectPainter::testAttribute (Attributeattribute) const Check if a attribute is set.¶
Parameters:attribute Attribute to be tested
See also:
Attribute, setAttribute()
Author¶
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