Sources_For_Linux/Qwt/doc/man/man3/QwtNullPaintDevice.3

.TH "QwtNullPaintDevice" 3 "Mon Dec 28 2020" "Version 6.1.6" "Qwt User's Guide" \" -*- nroff -*-
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.SH NAME
QwtNullPaintDevice \- A null paint device doing nothing\&.  

.SH SYNOPSIS
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.PP
.PP
\fC#include <qwt_null_paintdevice\&.h>\fP
.PP
Inherits QPaintDevice\&.
.PP
Inherited by \fBQwtGraphic\fP, and QwtStyleSheetRecorder\&.
.SS "Public Types"

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.RI "enum \fBMode\fP { \fBNormalMode\fP, \fBPolygonPathMode\fP, \fBPathMode\fP }"
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.RI "Render mode\&. "
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.SS "Public Member Functions"

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.RI "\fBQwtNullPaintDevice\fP ()"
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.RI "Constructor\&. "
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.RI "virtual \fB~QwtNullPaintDevice\fP ()"
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.RI "Destructor\&. "
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.RI "void \fBsetMode\fP (\fBMode\fP)"
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.RI "\fBMode\fP \fBmode\fP () const"
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.RI "virtual QPaintEngine * \fBpaintEngine\fP () const"
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.RI "See QPaintDevice::paintEngine() "
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.RI "virtual int \fBmetric\fP (PaintDeviceMetric) const"
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.RI "virtual void \fBdrawRects\fP (const QRect *, int)"
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.RI "See QPaintEngine::drawRects() "
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.RI "virtual void \fBdrawRects\fP (const QRectF *, int)"
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.RI "See QPaintEngine::drawRects() "
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.RI "virtual void \fBdrawLines\fP (const QLine *, int)"
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.RI "See QPaintEngine::drawLines() "
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.RI "virtual void \fBdrawLines\fP (const QLineF *, int)"
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.RI "See QPaintEngine::drawLines() "
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.RI "virtual void \fBdrawEllipse\fP (const QRectF &)"
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.RI "See QPaintEngine::drawEllipse() "
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.RI "virtual void \fBdrawEllipse\fP (const QRect &)"
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.RI "See QPaintEngine::drawEllipse() "
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.RI "virtual void \fBdrawPath\fP (const QPainterPath &)"
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.RI "See QPaintEngine::drawPath() "
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.RI "virtual void \fBdrawPoints\fP (const QPointF *, int)"
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.RI "See QPaintEngine::drawPoints() "
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.RI "virtual void \fBdrawPoints\fP (const QPoint *, int)"
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.RI "See QPaintEngine::drawPoints() "
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.RI "virtual void \fBdrawPolygon\fP (const QPointF *, int, QPaintEngine::PolygonDrawMode)"
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.RI "See QPaintEngine::drawPolygon() "
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.RI "virtual void \fBdrawPolygon\fP (const QPoint *, int, QPaintEngine::PolygonDrawMode)"
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.RI "See QPaintEngine::drawPolygon() "
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.RI "virtual void \fBdrawPixmap\fP (const QRectF &, const QPixmap &, const QRectF &)"
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.RI "See QPaintEngine::drawPixmap() "
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.RI "virtual void \fBdrawTextItem\fP (const QPointF &, const QTextItem &)"
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.RI "See QPaintEngine::drawTextItem() "
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.RI "virtual void \fBdrawTiledPixmap\fP (const QRectF &, const QPixmap &, const QPointF &)"
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.RI "See QPaintEngine::drawTiledPixmap() "
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.RI "virtual void \fBdrawImage\fP (const QRectF &, const QImage &, const QRectF &, Qt::ImageConversionFlags)"
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.RI "See QPaintEngine::drawImage() "
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.RI "virtual void \fBupdateState\fP (const QPaintEngineState &)"
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.RI "See QPaintEngine::updateState() "
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.SS "Protected Member Functions"

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.RI "virtual QSize \fBsizeMetrics\fP () const =0"
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.SH "Detailed Description"
.PP 
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 )\&.
.PP
\fBQwtNullPaintDevice\fP can be used to manipulate or filter out this information by analyzing the stream of paint primitives\&.
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F\&.e\&. \fBQwtNullPaintDevice\fP is used by \fBQwtPlotCanvas\fP to identify styled backgrounds with rounded corners\&. 
.SH "Member Enumeration Documentation"
.PP 
.SS "enum \fBQwtNullPaintDevice::Mode\fP"

.PP
Render mode\&. 
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\fBSee also\fP
.RS 4
\fBsetMode()\fP, \fBmode()\fP 
.RE
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\fBEnumerator\fP
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.TP
\fB\fINormalMode \fP\fP
All vector graphic primitives are painted by the corresponding draw methods 
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\fB\fIPolygonPathMode \fP\fP
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:
.PP
.IP "\(bu" 2
\fBdrawPath()\fP
.IP "\(bu" 2
\fBdrawPixmap()\fP
.IP "\(bu" 2
\fBdrawImage()\fP
.IP "\(bu" 2
\fBdrawPolygon()\fP 
.PP

.TP
\fB\fIPathMode \fP\fP
Vector graphic primitives are mapped to a QPainterPath and are painted by drawPath\&. In PathMode mode only a few draw methods are called:
.PP
.IP "\(bu" 2
\fBdrawPath()\fP
.IP "\(bu" 2
\fBdrawPixmap()\fP
.IP "\(bu" 2
\fBdrawImage()\fP 
.PP

.SH "Member Function Documentation"
.PP 
.SS "int QwtNullPaintDevice::metric (PaintDeviceMetric deviceMetric) const\fC [virtual]\fP"
See QPaintDevice::metric()
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\fBParameters\fP
.RS 4
\fIdeviceMetric\fP Type of metric 
.RE
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\fBReturns\fP
.RS 4
Metric information for the given paint device metric\&.
.RE
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\fBSee also\fP
.RS 4
\fBsizeMetrics()\fP 
.RE
.PP

.SS "\fBQwtNullPaintDevice::Mode\fP QwtNullPaintDevice::mode () const"

.PP
\fBReturns\fP
.RS 4
Render mode 
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.PP
\fBSee also\fP
.RS 4
\fBsetMode()\fP 
.RE
.PP

.SS "void QwtNullPaintDevice::setMode (\fBMode\fP mode)"
Set the render mode
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\fBParameters\fP
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\fImode\fP New mode 
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\fBSee also\fP
.RS 4
\fBmode()\fP 
.RE
.PP

.SS "virtual QSize QwtNullPaintDevice::sizeMetrics () const\fC [protected]\fP, \fC [pure virtual]\fP"

.PP
\fBReturns\fP
.RS 4
Size needed to implement \fBmetric()\fP 
.RE
.PP

.PP
Implemented in \fBQwtGraphic\fP\&.

.SH "Author"
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Generated automatically by Doxygen for Qwt User's Guide from the source code\&.