.TH "QwtPlotAbstractBarChart" 3 "Wed Jan 2 2019" "Version 6.1.4" "Qwt User's Guide" \" -*- nroff -*-
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.SH NAME
QwtPlotAbstractBarChart \- Abstract base class for bar chart items\&.  

.SH SYNOPSIS
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.PP
.PP
\fC#include <qwt_plot_abstract_barchart\&.h>\fP
.PP
Inherits \fBQwtPlotSeriesItem\fP\&.
.PP
Inherited by \fBQwtPlotBarChart\fP, and \fBQwtPlotMultiBarChart\fP\&.
.SS "Public Types"

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.RI "enum \fBLayoutPolicy\fP { \fBAutoAdjustSamples\fP, \fBScaleSamplesToAxes\fP, \fBScaleSampleToCanvas\fP, \fBFixedSampleSize\fP }"
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.RI "Mode how to calculate the bar width\&. "
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.SS "Public Member Functions"

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.RI "\fBQwtPlotAbstractBarChart\fP (const \fBQwtText\fP &\fBtitle\fP)"
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.RI "virtual \fB~QwtPlotAbstractBarChart\fP ()"
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.RI "Destructor\&. "
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.RI "void \fBsetLayoutPolicy\fP (\fBLayoutPolicy\fP)"
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.RI "\fBLayoutPolicy\fP \fBlayoutPolicy\fP () const"
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.RI "void \fBsetLayoutHint\fP (double)"
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.RI "double \fBlayoutHint\fP () const"
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.RI "void \fBsetSpacing\fP (int)"
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.RI "Set the spacing\&. "
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.RI "int \fBspacing\fP () const"
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.RI "void \fBsetMargin\fP (int)"
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.RI "Set the margin\&. "
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.RI "int \fBmargin\fP () const"
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.RI "void \fBsetBaseline\fP (double)"
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.RI "Set the baseline\&. "
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.RI "double \fBbaseline\fP () const"
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.RI "virtual void \fBgetCanvasMarginHint\fP (const \fBQwtScaleMap\fP &xMap, const \fBQwtScaleMap\fP &yMap, const QRectF &canvasRect, double &left, double &top, double &right, double &bottom) const"
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.RI "Calculate a hint for the canvas margin\&. "
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.SS "Protected Member Functions"

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.RI "double \fBsampleWidth\fP (const \fBQwtScaleMap\fP &map, double canvasSize, double boundingSize, double value) const"
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.SH "Detailed Description"
.PP 
Abstract base class for bar chart items\&. 

In opposite to almost all other plot items bar charts can't be displayed inside of their bounding rectangle and need a special API how to calculate the width of the bars and how they affect the layout of the attached plot\&. 
.SH "Member Enumeration Documentation"
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.SS "enum \fBQwtPlotAbstractBarChart::LayoutPolicy\fP"

.PP
Mode how to calculate the bar width\&. \fBsetLayoutPolicy()\fP, \fBsetLayoutHint()\fP, barWidthHint() 
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\fBEnumerator\fP
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.TP
\fB\fIAutoAdjustSamples \fP\fP
The sample width is calculated by dividing the bounding rectangle by the number of samples\&. The \fBlayoutHint()\fP is used as a minimum width in paint device coordinates\&.
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\fBSee also:\fP
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boundingRectangle() 
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.TP
\fB\fIScaleSamplesToAxes \fP\fP
\fBlayoutHint()\fP defines an interval in axis coordinates 
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\fB\fIScaleSampleToCanvas \fP\fP
The bar width is calculated by multiplying \fBlayoutHint()\fP with the height or width of the canvas\&.
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\fBSee also:\fP
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boundingRectangle() 
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\fB\fIFixedSampleSize \fP\fP
\fBlayoutHint()\fP defines a fixed width in paint device coordinates\&. 
.SH "Constructor & Destructor Documentation"
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.SS "QwtPlotAbstractBarChart::QwtPlotAbstractBarChart (const \fBQwtText\fP & title)\fC [explicit]\fP"
Constructor 
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\fBParameters:\fP
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\fItitle\fP Title of the chart 
.RE
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.SH "Member Function Documentation"
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.SS "double QwtPlotAbstractBarChart::baseline () const"

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\fBReturns:\fP
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Value for the origin of the bar chart 
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\fBSee also:\fP
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\fBsetBaseline()\fP, \fBQwtPlotSeriesItem::orientation()\fP 
.RE
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.SS "void QwtPlotAbstractBarChart::getCanvasMarginHint (const \fBQwtScaleMap\fP & xMap, const \fBQwtScaleMap\fP & yMap, const QRectF & canvasRect, double & left, double & top, double & right, double & bottom) const\fC [virtual]\fP"

.PP
Calculate a hint for the canvas margin\&. Bar charts need to reserve some space for displaying the bars for the first and the last sample\&. The hint is calculated from the \fBlayoutHint()\fP depending on the \fBlayoutPolicy()\fP\&.
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The margins are in target device coordinates ( pixels on screen )
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\fBParameters:\fP
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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 in painter coordinates 
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\fIleft\fP Returns the left margin 
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\fItop\fP Returns the top margin 
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\fIright\fP Returns the right margin 
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\fIbottom\fP Returns the bottom margin
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\fBReturns:\fP
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Margin
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\fBSee also:\fP
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\fBlayoutPolicy()\fP, \fBlayoutHint()\fP, \fBQwtPlotItem::Margins\fP \fBQwtPlot::getCanvasMarginsHint()\fP, \fBQwtPlot::updateCanvasMargins()\fP 
.RE
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.PP
Reimplemented from \fBQwtPlotItem\fP\&.
.SS "double QwtPlotAbstractBarChart::layoutHint () const"
The combination of \fBlayoutPolicy()\fP and \fBlayoutHint()\fP define how the width of the bars is calculated
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\fBReturns:\fP
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Layout policy of the chart item 
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\fBSee also:\fP
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\fBLayoutPolicy\fP, \fBsetLayoutHint()\fP, \fBlayoutPolicy()\fP 
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.SS "\fBQwtPlotAbstractBarChart::LayoutPolicy\fP QwtPlotAbstractBarChart::layoutPolicy () const"
The combination of \fBlayoutPolicy()\fP and \fBlayoutHint()\fP define how the width of the bars is calculated
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\fBReturns:\fP
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Layout policy of the chart item 
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\fBSee also:\fP
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\fBsetLayoutPolicy()\fP, \fBlayoutHint()\fP 
.RE
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.SS "int QwtPlotAbstractBarChart::margin () const"

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\fBReturns:\fP
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Margin between the outmost bars and the contentsRect() of the canvas\&.
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\fBSee also:\fP
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\fBsetMargin()\fP, \fBspacing()\fP 
.RE
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.SS "double QwtPlotAbstractBarChart::sampleWidth (const \fBQwtScaleMap\fP & map, double canvasSize, double boundingSize, double value) const\fC [protected]\fP"
Calculate the width for a sample in paint device coordinates
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\fBParameters:\fP
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\fImap\fP Scale map for the corresponding scale 
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\fIcanvasSize\fP Size of the canvas in paint device coordinates 
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\fIboundingSize\fP Bounding size of the chart in plot coordinates ( used in AutoAdjustSamples mode ) 
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\fIvalue\fP Value of the sample
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\fBReturns:\fP
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Sample width 
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\fBSee also:\fP
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\fBlayoutPolicy()\fP, \fBlayoutHint()\fP 
.RE
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.SS "void QwtPlotAbstractBarChart::setBaseline (double value)"

.PP
Set the baseline\&. The baseline is the origin for the chart\&. Each bar is painted from the baseline in the direction of the sample value\&. In case of a horizontal \fBorientation()\fP the baseline is interpreted as x - otherwise as y - value\&.
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The default value for the baseline is 0\&.
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\fBParameters:\fP
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\fIvalue\fP Value for the baseline
.RE
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\fBSee also:\fP
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\fBbaseline()\fP, \fBQwtPlotSeriesItem::orientation()\fP 
.RE
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.SS "void QwtPlotAbstractBarChart::setLayoutHint (double hint)"
The combination of \fBlayoutPolicy()\fP and \fBlayoutHint()\fP define how the width of the bars is calculated
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\fBParameters:\fP
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\fIhint\fP Layout hint
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\fBSee also:\fP
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\fBLayoutPolicy\fP, \fBlayoutPolicy()\fP, \fBlayoutHint()\fP 
.RE
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.SS "void QwtPlotAbstractBarChart::setLayoutPolicy (\fBLayoutPolicy\fP policy)"
The combination of \fBlayoutPolicy()\fP and \fBlayoutHint()\fP define how the width of the bars is calculated
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\fBParameters:\fP
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\fIpolicy\fP Layout policy
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\fBSee also:\fP
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\fBlayoutPolicy()\fP, \fBlayoutHint()\fP 
.RE
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.SS "void QwtPlotAbstractBarChart::setMargin (int margin)"

.PP
Set the margin\&. The margin is the distance between the outmost bars and the contentsRect() of the canvas\&. The default setting is 5 pixels\&.
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\fBParameters:\fP
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\fImargin\fP Margin
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\fBSee also:\fP
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\fBspacing()\fP, \fBmargin()\fP 
.RE
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.SS "void QwtPlotAbstractBarChart::setSpacing (int spacing)"

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Set the spacing\&. The spacing is the distance between 2 samples ( bars for \fBQwtPlotBarChart\fP or a group of bars for \fBQwtPlotMultiBarChart\fP ) in paint device coordinates\&.
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\fBSee also:\fP
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\fBspacing()\fP 
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.SS "int QwtPlotAbstractBarChart::spacing () const"

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\fBReturns:\fP
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Spacing between 2 samples ( bars or groups of bars ) 
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\fBSee also:\fP
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\fBsetSpacing()\fP, \fBmargin()\fP 
.RE
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.SH "Author"
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Generated automatically by Doxygen for Qwt User's Guide from the source code\&.