QwtNullPaintDevice - A null paint device doing nothing.

NAME

QwtNullPaintDevice − A null paint device doing nothing.

SYNOPSIS

#include <qwt_null_paintdevice.h>

Inherits QPaintDevice.

Inherited by QwtGraphic.

Public Types

enum Mode { NormalMode, PolygonPathMode, PathMode }
Render mode.

Public Member Functions

QwtNullPaintDevice ()
Constructor.
virtual ˜QwtNullPaintDevice ()
Destructor.
void setMode (Mode)
Mode mode () const
virtual QPaintEngine * paintEngine () const override
See QPaintDevice::paintEngine()
virtual int metric (PaintDeviceMetric) const override
virtual void drawRects (const QRect *, int)
See QPaintEngine::drawRects()
virtual void drawRects (const QRectF *, int)
See QPaintEngine::drawRects()
virtual void drawLines (const QLine *, int)
See QPaintEngine::drawLines()
virtual void drawLines (const QLineF *, int)
See QPaintEngine::drawLines()
virtual void drawEllipse (const QRectF &)
See QPaintEngine::drawEllipse()
virtual void drawEllipse (const QRect &)
See QPaintEngine::drawEllipse()
virtual void drawPath (const QPainterPath &)
See QPaintEngine::drawPath()
virtual void drawPoints (const QPointF *, int)
See QPaintEngine::drawPoints()
virtual void drawPoints (const QPoint *, int)
See QPaintEngine::drawPoints()
virtual void drawPolygon (const QPointF *, int, QPaintEngine::PolygonDrawMode)
See QPaintEngine::drawPolygon()
virtual void drawPolygon (const QPoint *, int, QPaintEngine::PolygonDrawMode)
See QPaintEngine::drawPolygon()
virtual void drawPixmap (const QRectF &, const QPixmap &, const QRectF &)
See QPaintEngine::drawPixmap()
virtual void drawTextItem (const QPointF &, const QTextItem &)
See QPaintEngine::drawTextItem()
virtual void drawTiledPixmap (const QRectF &, const QPixmap &, const QPointF &)
See QPaintEngine::drawTiledPixmap()
virtual void drawImage (const QRectF &, const QImage &, const QRectF &, Qt::ImageConversionFlags)
See QPaintEngine::drawImage()
virtual void updateState (const QPaintEngineState &)
See QPaintEngine::updateState()

Protected Member Functions

virtual QSize sizeMetrics () const =0

Detailed Description

A null paint device doing nothing.

Sometimes important layout/rendering geometries are not available or changeable from the public Qt class interface. ( f.e hidden in the style implementation ).

QwtNullPaintDevice can be used to manipulate or filter out this information by analyzing the stream of paint primitives.

F.e. QwtNullPaintDevice is used by QwtPlotCanvas to identify styled backgrounds with rounded corners.

Definition at line 32 of file qwt_null_paintdevice.h.

Member Enumeration Documentation

enum QwtNullPaintDevice::Mode

Render mode.

See also

setMode(), mode()

Enumerator
NormalMode

All vector graphic primitives are painted by the corresponding draw methods

PolygonPathMode

Vector graphic primitives ( beside polygons ) are mapped to a QPainterPath and are painted by drawPath. In PathMode mode only a few draw methods are called:

	•		drawPath()
	•		drawPixmap()
	•		drawImage()
	•		drawPolygon()

PathMode

Vector graphic primitives are mapped to a QPainterPath and are painted by drawPath. In PathMode mode only a few draw methods are called:

	•		drawPath()
	•		drawPixmap()
	•		drawImage()

Definition at line 40 of file qwt_null_paintdevice.h.

Constructor & Destructor Documentation

QwtNullPaintDevice::QwtNullPaintDevice ()

Constructor.

Definition at line 367 of file qwt_null_paintdevice.cpp.

QwtNullPaintDevice::˜QwtNullPaintDevice () [virtual]

Destructor.

Definition at line 374 of file qwt_null_paintdevice.cpp.

Member Function Documentation

void QwtNullPaintDevice::drawEllipse (const QRect & rect) [virtual]

See QPaintEngine::drawEllipse()

Definition at line 521 of file qwt_null_paintdevice.cpp.

void QwtNullPaintDevice::drawEllipse (const QRectF & rect) [virtual]

See QPaintEngine::drawEllipse()

Definition at line 515 of file qwt_null_paintdevice.cpp.

void QwtNullPaintDevice::drawImage (const QRectF & rect, const QImage &image, const QRectF & subRect, Qt::ImageConversionFlags flags)[virtual]

See QPaintEngine::drawImage()

Reimplemented in QwtGraphic.

Definition at line 596 of file qwt_null_paintdevice.cpp.

void QwtNullPaintDevice::drawLines (const QLine * lines, int lineCount)[virtual]

See QPaintEngine::drawLines()

Definition at line 499 of file qwt_null_paintdevice.cpp.

void QwtNullPaintDevice::drawLines (const QLineF * lines, int lineCount)[virtual]

See QPaintEngine::drawLines()

Definition at line 507 of file qwt_null_paintdevice.cpp.

void QwtNullPaintDevice::drawPath (const QPainterPath & path) [virtual]

See QPaintEngine::drawPath()

Reimplemented in QwtGraphic.

Definition at line 527 of file qwt_null_paintdevice.cpp.

void QwtNullPaintDevice::drawPixmap (const QRectF & rect, const QPixmap &pm, const QRectF & subRect) [virtual]

See QPaintEngine::drawPixmap()

Reimplemented in QwtGraphic.

Definition at line 569 of file qwt_null_paintdevice.cpp.

void QwtNullPaintDevice::drawPoints (const QPoint * points, int pointCount)[virtual]

See QPaintEngine::drawPoints()

Definition at line 541 of file qwt_null_paintdevice.cpp.

void QwtNullPaintDevice::drawPoints (const QPointF * points, intpointCount) [virtual]

See QPaintEngine::drawPoints()

Definition at line 533 of file qwt_null_paintdevice.cpp.

void QwtNullPaintDevice::drawPolygon (const QPoint * points, intpointCount, QPaintEngine::PolygonDrawMode mode) [virtual]

See QPaintEngine::drawPolygon()

Definition at line 559 of file qwt_null_paintdevice.cpp.

void QwtNullPaintDevice::drawPolygon (const QPointF * points, intpointCount, QPaintEngine::PolygonDrawMode mode) [virtual]

See QPaintEngine::drawPolygon()

Definition at line 549 of file qwt_null_paintdevice.cpp.

void QwtNullPaintDevice::drawRects (const QRect * rects, int rectCount)[virtual]

See QPaintEngine::drawRects()

Definition at line 483 of file qwt_null_paintdevice.cpp.

void QwtNullPaintDevice::drawRects (const QRectF * rects, int rectCount)[virtual]

See QPaintEngine::drawRects()

Definition at line 491 of file qwt_null_paintdevice.cpp.

void QwtNullPaintDevice::drawTextItem (const QPointF & pos, const QTextItem& textItem) [virtual]

See QPaintEngine::drawTextItem()

Definition at line 578 of file qwt_null_paintdevice.cpp.

void QwtNullPaintDevice::drawTiledPixmap (const QRectF & rect, constQPixmap & pixmap, const QPointF & subRect) [virtual]

See QPaintEngine::drawTiledPixmap()

Definition at line 586 of file qwt_null_paintdevice.cpp.

int QwtNullPaintDevice::metric (PaintDeviceMetric deviceMetric) const[override], [virtual]

See QPaintDevice::metric()

Parameters

deviceMetric Type of metric

Returns

Metric information for the given paint device metric.

See also

sizeMetrics()

Definition at line 422 of file qwt_null_paintdevice.cpp.

QwtNullPaintDevice::Mode QwtNullPaintDevice::mode () const

Returns

Render mode

See also

setMode()

Definition at line 395 of file qwt_null_paintdevice.cpp.

QPaintEngine * QwtNullPaintDevice::paintEngine () const [override],[virtual]

See QPaintDevice::paintEngine()

Definition at line 401 of file qwt_null_paintdevice.cpp.

void QwtNullPaintDevice::setMode (Mode mode)

Set the render mode

Parameters

mode New mode

See also

mode()

Definition at line 386 of file qwt_null_paintdevice.cpp.

virtual QSize QwtNullPaintDevice::sizeMetrics () const [protected], [purevirtual]

Returns

Size needed to implement metric()

Implemented in QwtGraphic.

void QwtNullPaintDevice::updateState (const QPaintEngineState & state)[virtual]

See QPaintEngine::updateState()

Reimplemented in QwtGraphic.

Definition at line 607 of file qwt_null_paintdevice.cpp.

Author

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Updated 2026-06-01 - jenkler.se | uex.se