.TH "QwtPlotHistogram" 3 "Wed Jan 2 2019" "Version 6.1.4" "Qwt User's Guide" \" -*- nroff -*-
.ad l
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.SH NAME
QwtPlotHistogram \- \fBQwtPlotHistogram\fP represents a series of samples, where an interval is associated with a value ( $y = f([x1,x2])$ )\&.  

.SH SYNOPSIS
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.PP
.PP
\fC#include <qwt_plot_histogram\&.h>\fP
.PP
Inherits \fBQwtPlotSeriesItem\fP, and \fBQwtSeriesStore< QwtIntervalSample >\fP\&.
.SS "Public Types"

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.RI "enum \fBHistogramStyle\fP { \fBOutline\fP, \fBColumns\fP, \fBLines\fP, \fBUserStyle\fP = 100 }"
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.SS "Public Member Functions"

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.RI "\fBQwtPlotHistogram\fP (const QString &\fBtitle\fP=QString())"
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.RI "\fBQwtPlotHistogram\fP (const \fBQwtText\fP &\fBtitle\fP)"
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.RI "virtual \fB~QwtPlotHistogram\fP ()"
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.RI "Destructor\&. "
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.RI "virtual int \fBrtti\fP () const"
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.RI "void \fBsetPen\fP (const QColor &, qreal width=0\&.0, Qt::PenStyle=Qt::SolidLine)"
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.RI "void \fBsetPen\fP (const QPen &)"
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.RI "const QPen & \fBpen\fP () const"
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.RI "void \fBsetBrush\fP (const QBrush &)"
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.RI "const QBrush & \fBbrush\fP () const"
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.RI "void \fBsetSamples\fP (const QVector< \fBQwtIntervalSample\fP > &)"
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.RI "void \fBsetSamples\fP (\fBQwtSeriesData\fP< \fBQwtIntervalSample\fP > *)"
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.RI "void \fBsetBaseline\fP (double)"
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.RI "Set the value of the baseline\&. "
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.RI "double \fBbaseline\fP () const"
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.RI "void \fBsetStyle\fP (\fBHistogramStyle\fP \fBstyle\fP)"
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.RI "\fBHistogramStyle\fP \fBstyle\fP () const"
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.RI "void \fBsetSymbol\fP (const \fBQwtColumnSymbol\fP *)"
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.RI "Assign a symbol\&. "
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.RI "const \fBQwtColumnSymbol\fP * \fBsymbol\fP () const"
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.RI "virtual void \fBdrawSeries\fP (QPainter *, const \fBQwtScaleMap\fP &xMap, const \fBQwtScaleMap\fP &yMap, const QRectF &canvasRect, int from, int to) const"
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.RI "virtual QRectF \fBboundingRect\fP () const"
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.RI "virtual \fBQwtGraphic\fP \fBlegendIcon\fP (int index, const QSizeF &) const"
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.SS "Protected Member Functions"

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.RI "virtual \fBQwtColumnRect\fP \fBcolumnRect\fP (const \fBQwtIntervalSample\fP &, const \fBQwtScaleMap\fP &, const \fBQwtScaleMap\fP &) const"
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.RI "virtual void \fBdrawColumn\fP (QPainter *, const \fBQwtColumnRect\fP &, const \fBQwtIntervalSample\fP &) const"
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.RI "void \fBdrawColumns\fP (QPainter *, const \fBQwtScaleMap\fP &xMap, const \fBQwtScaleMap\fP &yMap, int from, int to) const"
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.RI "void \fBdrawOutline\fP (QPainter *, const \fBQwtScaleMap\fP &xMap, const \fBQwtScaleMap\fP &yMap, int from, int to) const"
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.RI "void \fBdrawLines\fP (QPainter *, const \fBQwtScaleMap\fP &xMap, const \fBQwtScaleMap\fP &yMap, int from, int to) const"
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.SH "Detailed Description"
.PP 
\fBQwtPlotHistogram\fP represents a series of samples, where an interval is associated with a value ( $y = f([x1,x2])$ )\&. 

The representation depends on the \fBstyle()\fP and an optional \fBsymbol()\fP that is displayed for each interval\&.
.PP
\fBNote:\fP
.RS 4
The term 'histogram' is used in a different way in the areas of digital image processing and statistics\&. Wikipedia introduces the terms 'image histogram' and 'color histogram' to avoid confusions\&. While 'image histograms' can be displayed by a \fBQwtPlotCurve\fP there is no applicable plot item for a 'color histogram' yet\&.
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\fBSee also:\fP
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\fBQwtPlotBarChart\fP, \fBQwtPlotMultiBarChart\fP 
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.SH "Member Enumeration Documentation"
.PP 
.SS "enum \fBQwtPlotHistogram::HistogramStyle\fP"
Histogram styles\&. The default style is \fBQwtPlotHistogram::Columns\fP\&.
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\fBSee also:\fP
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\fBsetStyle()\fP, \fBstyle()\fP, \fBsetSymbol()\fP, \fBsymbol()\fP, \fBsetBaseline()\fP 
.RE
.PP

.PP
\fBEnumerator\fP
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.TP
\fB\fIOutline \fP\fP
Draw an outline around the area, that is build by all intervals using the \fBpen()\fP and fill it with the \fBbrush()\fP\&. The outline style requires, that the intervals are in increasing order and not overlapping\&. 
.TP
\fB\fIColumns \fP\fP
Draw a column for each interval\&. When a \fBsymbol()\fP has been set the symbol is used otherwise the column is displayed as plain rectangle using \fBpen()\fP and \fBbrush()\fP\&. 
.TP
\fB\fILines \fP\fP
Draw a simple line using the \fBpen()\fP for each interval\&. 
.TP
\fB\fIUserStyle \fP\fP
Styles >= UserStyle are reserved for derived classes that overload \fBdrawSeries()\fP with additional application specific ways to display a histogram\&. 
.SH "Constructor & Destructor Documentation"
.PP 
.SS "QwtPlotHistogram::QwtPlotHistogram (const QString & title = \fCQString()\fP)\fC [explicit]\fP"
Constructor 
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\fBParameters:\fP
.RS 4
\fItitle\fP Title of the histogram\&. 
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.SS "QwtPlotHistogram::QwtPlotHistogram (const \fBQwtText\fP & title)\fC [explicit]\fP"
Constructor 
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\fBParameters:\fP
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\fItitle\fP Title of the histogram\&. 
.RE
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.SH "Member Function Documentation"
.PP 
.SS "double QwtPlotHistogram::baseline () const"

.PP
\fBReturns:\fP
.RS 4
Value of the baseline 
.RE
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\fBSee also:\fP
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\fBsetBaseline()\fP 
.RE
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.SS "QRectF QwtPlotHistogram::boundingRect () const\fC [virtual]\fP"

.PP
\fBReturns:\fP
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Bounding rectangle of all samples\&. For an empty series the rectangle is invalid\&. 
.RE
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.PP
Reimplemented from \fBQwtPlotSeriesItem\fP\&.
.SS "const QBrush & QwtPlotHistogram::brush () const"

.PP
\fBReturns:\fP
.RS 4
Brush used in a \fBstyle()\fP depending way\&. 
.RE
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\fBSee also:\fP
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\fBsetPen()\fP, \fBbrush()\fP 
.RE
.PP

.SS "\fBQwtColumnRect\fP QwtPlotHistogram::columnRect (const \fBQwtIntervalSample\fP & sample, const \fBQwtScaleMap\fP & xMap, const \fBQwtScaleMap\fP & yMap) const\fC [protected]\fP, \fC [virtual]\fP"
Calculate the area that is covered by a sample
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\fBParameters:\fP
.RS 4
\fIsample\fP Sample 
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\fIxMap\fP Maps x-values into pixel coordinates\&. 
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\fIyMap\fP Maps y-values into pixel coordinates\&.
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\fBReturns:\fP
.RS 4
Rectangle, that is covered by a sample 
.RE
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.SS "void QwtPlotHistogram::drawColumn (QPainter * painter, const \fBQwtColumnRect\fP & rect, const \fBQwtIntervalSample\fP & sample) const\fC [protected]\fP, \fC [virtual]\fP"
Draw a column for a sample in Columns \fBstyle()\fP\&.
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When a \fBsymbol()\fP has been set the symbol is used otherwise the column is displayed as plain rectangle using \fBpen()\fP and \fBbrush()\fP\&.
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\fBParameters:\fP
.RS 4
\fIpainter\fP Painter 
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\fIrect\fP Rectangle where to paint the column in paint device coordinates 
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\fIsample\fP Sample to be displayed
.RE
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\fBNote:\fP
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In applications, where different intervals need to be displayed in a different way ( f\&.e different colors or even using different symbols) it is recommended to overload \fBdrawColumn()\fP\&. 
.RE
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.SS "void QwtPlotHistogram::drawColumns (QPainter * painter, const \fBQwtScaleMap\fP & xMap, const \fBQwtScaleMap\fP & yMap, int from, int to) const\fC [protected]\fP"
Draw a histogram in Columns \fBstyle()\fP
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\fBParameters:\fP
.RS 4
\fIpainter\fP Painter 
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\fIxMap\fP Maps x-values into pixel coordinates\&. 
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\fIyMap\fP Maps y-values into pixel coordinates\&. 
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\fIfrom\fP Index of the first sample to be painted 
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\fIto\fP Index of the last sample to be painted\&. If to < 0 the histogram will be painted to its last point\&.
.RE
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\fBSee also:\fP
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\fBsetStyle()\fP, \fBstyle()\fP, \fBsetSymbol()\fP, \fBdrawColumn()\fP 
.RE
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.SS "void QwtPlotHistogram::drawLines (QPainter * painter, const \fBQwtScaleMap\fP & xMap, const \fBQwtScaleMap\fP & yMap, int from, int to) const\fC [protected]\fP"
Draw a histogram in Lines \fBstyle()\fP
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\fBParameters:\fP
.RS 4
\fIpainter\fP Painter 
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\fIxMap\fP Maps x-values into pixel coordinates\&. 
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\fIyMap\fP Maps y-values into pixel coordinates\&. 
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\fIfrom\fP Index of the first sample to be painted 
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\fIto\fP Index of the last sample to be painted\&. If to < 0 the histogram will be painted to its last point\&.
.RE
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\fBSee also:\fP
.RS 4
\fBsetStyle()\fP, \fBstyle()\fP, \fBsetPen()\fP 
.RE
.PP

.SS "void QwtPlotHistogram::drawOutline (QPainter * painter, const \fBQwtScaleMap\fP & xMap, const \fBQwtScaleMap\fP & yMap, int from, int to) const\fC [protected]\fP"
Draw a histogram in Outline \fBstyle()\fP
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\fBParameters:\fP
.RS 4
\fIpainter\fP Painter 
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\fIxMap\fP Maps x-values into pixel coordinates\&. 
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\fIyMap\fP Maps y-values into pixel coordinates\&. 
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\fIfrom\fP Index of the first sample to be painted 
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\fIto\fP Index of the last sample to be painted\&. If to < 0 the histogram will be painted to its last point\&.
.RE
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\fBSee also:\fP
.RS 4
\fBsetStyle()\fP, \fBstyle()\fP 
.RE
.PP
\fBWarning:\fP
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The outline style requires, that the intervals are in increasing order and not overlapping\&. 
.RE
.PP

.SS "void QwtPlotHistogram::drawSeries (QPainter * painter, const \fBQwtScaleMap\fP & xMap, const \fBQwtScaleMap\fP & yMap, const QRectF & canvasRect, int from, int to) const\fC [virtual]\fP"
Draw a subset of the histogram samples
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\fBParameters:\fP
.RS 4
\fIpainter\fP Painter 
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\fIxMap\fP Maps x-values into pixel coordinates\&. 
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\fIyMap\fP Maps y-values into pixel coordinates\&. 
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\fIcanvasRect\fP Contents rectangle of the canvas 
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\fIfrom\fP Index of the first sample to be painted 
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\fIto\fP Index of the last sample to be painted\&. If to < 0 the series will be painted to its last sample\&.
.RE
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\fBSee also:\fP
.RS 4
\fBdrawOutline()\fP, \fBdrawLines()\fP, \fBdrawColumns\fP 
.RE
.PP

.PP
Implements \fBQwtPlotSeriesItem\fP\&.
.SS "\fBQwtGraphic\fP QwtPlotHistogram::legendIcon (int index, const QSizeF & size) const\fC [virtual]\fP"
A plain rectangle without pen using the \fBbrush()\fP
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\fBParameters:\fP
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\fIindex\fP Index of the legend entry ( ignored as there is only one ) 
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\fIsize\fP Icon size 
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\fBReturns:\fP
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A graphic displaying the icon
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\fBSee also:\fP
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\fBQwtPlotItem::setLegendIconSize()\fP, \fBQwtPlotItem::legendData()\fP 
.RE
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.PP
Reimplemented from \fBQwtPlotItem\fP\&.
.SS "const QPen & QwtPlotHistogram::pen () const"

.PP
\fBReturns:\fP
.RS 4
Pen used in a \fBstyle()\fP depending way\&. 
.RE
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\fBSee also:\fP
.RS 4
\fBsetPen()\fP, \fBbrush()\fP 
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.SS "int QwtPlotHistogram::rtti () const\fC [virtual]\fP"

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\fBReturns:\fP
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\fBQwtPlotItem::Rtti_PlotHistogram\fP 
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.PP
Reimplemented from \fBQwtPlotItem\fP\&.
.SS "void QwtPlotHistogram::setBaseline (double value)"

.PP
Set the value of the baseline\&. Each column representing an \fBQwtIntervalSample\fP is defined by its interval and the interval between baseline and the value of the sample\&.
.PP
The default value of the baseline is 0\&.0\&.
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\fBParameters:\fP
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\fIvalue\fP Value of the baseline 
.RE
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\fBSee also:\fP
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\fBbaseline()\fP 
.RE
.PP

.SS "void QwtPlotHistogram::setBrush (const QBrush & brush)"
Assign a brush, that is used in a \fBstyle()\fP depending way\&.
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\fBParameters:\fP
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\fIbrush\fP New brush 
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\fBSee also:\fP
.RS 4
\fBpen()\fP, \fBbrush()\fP 
.RE
.PP

.SS "void QwtPlotHistogram::setPen (const QColor & color, qreal width = \fC0\&.0\fP, Qt::PenStyle style = \fCQt::SolidLine\fP)"
Build and assign a pen
.PP
In Qt5 the default pen width is 1\&.0 ( 0\&.0 in Qt4 ) what makes it non cosmetic ( see QPen::isCosmetic() )\&. This method has been introduced to hide this incompatibility\&.
.PP
\fBParameters:\fP
.RS 4
\fIcolor\fP Pen color 
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\fIwidth\fP Pen width 
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\fIstyle\fP Pen style
.RE
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\fBSee also:\fP
.RS 4
\fBpen()\fP, \fBbrush()\fP 
.RE
.PP

.SS "void QwtPlotHistogram::setPen (const QPen & pen)"
Assign a pen, that is used in a \fBstyle()\fP depending way\&.
.PP
\fBParameters:\fP
.RS 4
\fIpen\fP New pen 
.RE
.PP
\fBSee also:\fP
.RS 4
\fBpen()\fP, \fBbrush()\fP 
.RE
.PP

.SS "void QwtPlotHistogram::setSamples (const QVector< \fBQwtIntervalSample\fP > & samples)"
Initialize data with an array of samples\&. 
.PP
\fBParameters:\fP
.RS 4
\fIsamples\fP Vector of points 
.RE
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.SS "void QwtPlotHistogram::setSamples (\fBQwtSeriesData\fP< \fBQwtIntervalSample\fP > * data)"
Assign a series of samples
.PP
\fBsetSamples()\fP is just a wrapper for \fBsetData()\fP without any additional value - beside that it is easier to find for the developer\&.
.PP
\fBParameters:\fP
.RS 4
\fIdata\fP Data 
.RE
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\fBWarning:\fP
.RS 4
The item takes ownership of the data object, deleting it when its not used anymore\&. 
.RE
.PP

.SS "void QwtPlotHistogram::setStyle (\fBHistogramStyle\fP style)"
Set the histogram's drawing style
.PP
\fBParameters:\fP
.RS 4
\fIstyle\fP Histogram style 
.RE
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\fBSee also:\fP
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\fBHistogramStyle\fP, \fBstyle()\fP 
.RE
.PP

.SS "void QwtPlotHistogram::setSymbol (const \fBQwtColumnSymbol\fP * symbol)"

.PP
Assign a symbol\&. In Column style an optional symbol can be assigned, that is responsible for displaying the rectangle that is defined by the interval and the distance between \fBbaseline()\fP and value\&. When no symbol has been defined the area is displayed as plain rectangle using \fBpen()\fP and \fBbrush()\fP\&.
.PP
\fBSee also:\fP
.RS 4
\fBstyle()\fP, \fBsymbol()\fP, \fBdrawColumn()\fP, \fBpen()\fP, \fBbrush()\fP
.RE
.PP
\fBNote:\fP
.RS 4
In applications, where different intervals need to be displayed in a different way ( f\&.e different colors or even using different symbols) it is recommended to overload \fBdrawColumn()\fP\&. 
.RE
.PP

.SS "\fBQwtPlotHistogram::HistogramStyle\fP QwtPlotHistogram::style () const"

.PP
\fBReturns:\fP
.RS 4
Style of the histogram 
.RE
.PP
\fBSee also:\fP
.RS 4
\fBHistogramStyle\fP, \fBsetStyle()\fP 
.RE
.PP

.SS "const \fBQwtColumnSymbol\fP * QwtPlotHistogram::symbol () const"

.PP
\fBReturns:\fP
.RS 4
Current symbol or NULL, when no symbol has been assigned 
.RE
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\fBSee also:\fP
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\fBsetSymbol()\fP 
.RE
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.SH "Author"
.PP 
Generated automatically by Doxygen for Qwt User's Guide from the source code\&.