QwtPlotLegendItem(3) Qwt User's Guide QwtPlotLegendItem(3)

QwtPlotLegendItem - A class which draws a legend inside the plot canvas.

#include <qwt_plot_legenditem.h>

Inherits QwtPlotItem.


enum BackgroundMode { LegendBackground, ItemBackground }
Background mode.


QwtPlotLegendItem ()
Constructor. virtual ~QwtPlotLegendItem ()
Destructor. virtual int rtti () const override
void setAlignmentInCanvas (Qt::Alignment)
Set the alignmnet. Qt::Alignment alignmentInCanvas () const
void setOffsetInCanvas (Qt::Orientations, int numPixels)
Set the distance between the legend and the canvas border. int offsetInCanvas (Qt::Orientation) const
void setMaxColumns (uint)
Limit the number of columns. uint maxColumns () const
void setMargin (int)
Set the margin around legend items. int margin () const
void setSpacing (int)
Set the spacing between the legend items. int spacing () const
void setItemMargin (int)
int itemMargin () const
void setItemSpacing (int)
int itemSpacing () const
void setFont (const QFont &)
QFont font () const
void setBorderRadius (double)
double borderRadius () const
void setBorderPen (const QPen &)
QPen borderPen () const
void setBackgroundBrush (const QBrush &)
Set the background brush. QBrush backgroundBrush () const
void setBackgroundMode (BackgroundMode)
Set the background mode. BackgroundMode backgroundMode () const
void setTextPen (const QPen &)
Set the pen for drawing text labels. QPen textPen () const
virtual void draw (QPainter *, const QwtScaleMap &xMap, const QwtScaleMap &yMap, const QRectF &canvasRect) const override
void clearLegend ()
Remove all items from the legend. virtual void updateLegend (const QwtPlotItem *, const QList< QwtLegendData > &) override
virtual QRect geometry (const QRectF &canvasRect) const
virtual QSize minimumSize (const QwtLegendData &) const
virtual int heightForWidth (const QwtLegendData &, int width) const
QList< const QwtPlotItem * > plotItems () const
QList< QRect > legendGeometries (const QwtPlotItem *) const


virtual void drawLegendData (QPainter *, const QwtPlotItem *, const QwtLegendData &, const QRectF &) const
virtual void drawBackground (QPainter *, const QRectF &rect) const

A class which draws a legend inside the plot canvas.

QwtPlotLegendItem can be used to draw a inside the plot canvas. It can be used together with a QwtLegend or instead of it to have more space for the plot canvas.

In opposite to QwtLegend the legend item is not interactive. To identify mouse clicks on a legend item an event filter needs to be installed catching mouse events ob the plot canvas. The geometries of the legend items are available using legendGeometries().

The legend item is aligned to plot canvas according to its alignment() flags. It might have a background for the complete legend ( usually semi transparent ) or for each legend item.

Note

An external QwtLegend with a transparent background on top the plot canvas might be another option with a similar effect.

Definition at line 41 of file qwt_plot_legenditem.h.

Background mode. Depending on the mode the complete legend or each item might have an background.

The default setting is LegendBackground.

See also

setBackgroundMode(), setBackgroundBrush(), drawBackground()

Enumerator

The legend has a background.
Each item has a background.

Definition at line 54 of file qwt_plot_legenditem.h.

Returns

Alignment flags

See also

setAlignmentInCanvas()

Definition at line 223 of file qwt_plot_legenditem.cpp.

Returns

Brush is used to fill the background

See also

setBackgroundBrush(), backgroundMode(), drawBackground()

Definition at line 522 of file qwt_plot_legenditem.cpp.

QwtPlotLegendItem::BackgroundMode QwtPlotLegendItem::backgroundMode () const

Returns

backgroundMode

See also

setBackgroundMode(), backgroundBrush(), drawBackground()

Definition at line 550 of file qwt_plot_legenditem.cpp.

Returns

Pen for drawing the border

See also

setBorderPen(), backgroundBrush()

Definition at line 496 of file qwt_plot_legenditem.cpp.

Returns

Radius of the border

See also

setBorderRadius(), setBorderPen()

Definition at line 472 of file qwt_plot_legenditem.cpp.

Draw the legend

Parameters

painter Painter
xMap x Scale Map
yMap y Scale Map
canvasRect Contents rectangle of the canvas in painter coordinates

Implements QwtPlotItem.

Definition at line 587 of file qwt_plot_legenditem.cpp.

Draw a rounded rect

Parameters

painter Painter
rect Bounding rectangle

See also

setBorderRadius(), setBorderPen(), setBackgroundBrush(), setBackgroundMode()

Definition at line 630 of file qwt_plot_legenditem.cpp.

Draw an entry on the legend

Parameters

painter Qt Painter
plotItem Plot item, represented by the entry
data Attributes of the legend entry
rect Bounding rectangle for the entry

Definition at line 780 of file qwt_plot_legenditem.cpp.

Returns

Font used for drawing the text label

See also

setFont()

Definition at line 389 of file qwt_plot_legenditem.cpp.

Calculate the geometry of the legend on the canvas

Parameters

canvasRect Geometry of the canvas

Returns

Geometry of the legend

Definition at line 650 of file qwt_plot_legenditem.cpp.

Returns

The preferred height, for a width.

Parameters

data Attributes of the legend entry
width Width

Definition at line 862 of file qwt_plot_legenditem.cpp.

Returns

Margin around each item

See also

setItemMargin(), itemSpacing(), margin(), spacing()

Definition at line 335 of file qwt_plot_legenditem.cpp.

Returns

Spacing inside of each item

See also

setItemSpacing(), itemMargin(), margin(), spacing()

Definition at line 363 of file qwt_plot_legenditem.cpp.

QList< QRect > QwtPlotLegendItem::legendGeometries (const QwtPlotItem * plotItem) const

Returns

Geometries of the items of a plot item

Note

Usually a plot item has only one entry on the legend

Definition at line 895 of file qwt_plot_legenditem.cpp.

Returns

Margin around the legend items

See also

setMargin(), spacing(), itemMargin(), itemSpacing()

Definition at line 280 of file qwt_plot_legenditem.cpp.

Returns

Maximum number of columns

See also

maxColumns(), QwtDynGridLayout::maxColumns()

Definition at line 251 of file qwt_plot_legenditem.cpp.

Minimum size hint needed to display an entry

Parameters

data Attributes of the legend entry

Returns

Minimum size

Definition at line 823 of file qwt_plot_legenditem.cpp.

Parameters

orientation Qt::Horizontal is for the left/right, Qt::Vertical for the top/bottom padding.

Returns

Distance between the legend and the canvas border

See also

setOffsetInCanvas()

Definition at line 444 of file qwt_plot_legenditem.cpp.

QList< const QwtPlotItem * > QwtPlotLegendItem::plotItems () const

Returns

All plot items with an entry on the legend

Note

A plot item might have more than one entry on the legend

Definition at line 886 of file qwt_plot_legenditem.cpp.

Returns

QwtPlotItem::Rtti_PlotLegend

Reimplemented from QwtPlotItem.

Definition at line 192 of file qwt_plot_legenditem.cpp.

Set the alignmnet. Alignment means the position of the legend relative to the geometry of the plot canvas.

Parameters

alignment Alignment flags

See also

alignmentInCanvas(), setMaxColumns()

Note

To align a legend with many items horizontally the number of columns need to be limited

Definition at line 210 of file qwt_plot_legenditem.cpp.

Set the background brush. The brush is used to fill the background

Parameters

brush Brush

See also

backgroundBrush(), setBackgroundMode(), drawBackground()

Definition at line 509 of file qwt_plot_legenditem.cpp.

Set the background mode. Depending on the mode the complete legend or each item might have an background.

The default setting is LegendBackground.

See also

backgroundMode(), setBackgroundBrush(), drawBackground()

Definition at line 537 of file qwt_plot_legenditem.cpp.

Set the pen for drawing the border

Parameters

pen Border pen

See also

borderPen(), setBackgroundBrush()

Definition at line 483 of file qwt_plot_legenditem.cpp.

Set the radius for the border

Parameters

radius A value <= 0 defines a rectangular border

See also

borderRadius(), setBorderPen()

Definition at line 457 of file qwt_plot_legenditem.cpp.

Change the font used for drawing the text label

Parameters

font Legend font

See also

font()

Definition at line 374 of file qwt_plot_legenditem.cpp.

Set the margin around each item

Parameters

margin Margin

See also

itemMargin(), setItemSpacing(), setMargin(), setSpacing()

Definition at line 319 of file qwt_plot_legenditem.cpp.

Set the spacing inside of each item

Parameters

spacing Spacing

See also

itemSpacing(), setItemMargin(), setMargin(), setSpacing()

Definition at line 346 of file qwt_plot_legenditem.cpp.

Set the margin around legend items. The default setting for the margin is 0.

Parameters

margin Margin in pixels

See also

margin(), setSpacing(), setItemMargin(), setItemSpacing

Definition at line 264 of file qwt_plot_legenditem.cpp.

Limit the number of columns. When aligning the legend horizontally ( Qt::AlignLeft, Qt::AlignRight ) the number of columns needs to be limited to avoid, that the width of the legend grows with an increasing number of entries.

Parameters

maxColumns Maximum number of columns. 0 means unlimited.

See also

maxColumns(), QwtDynGridLayout::setMaxColumns()

Definition at line 238 of file qwt_plot_legenditem.cpp.

Set the distance between the legend and the canvas border. The default setting is 10 pixels.

Parameters

orientations Qt::Horizontal is for the left/right, Qt::Vertical for the top/bottom offset.
numPixels Distance in pixels

See also

setMargin()

Definition at line 405 of file qwt_plot_legenditem.cpp.

Set the spacing between the legend items.

Parameters

spacing Spacing in pixels

See also

spacing(), setMargin()

Definition at line 294 of file qwt_plot_legenditem.cpp.

Set the pen for drawing text labels.

Parameters

pen Text pen

See also

textPen(), setFont()

Definition at line 561 of file qwt_plot_legenditem.cpp.

Returns

Spacing between the legend items

See also

setSpacing(), margin(), itemSpacing(), itemMargin()

Definition at line 308 of file qwt_plot_legenditem.cpp.

Returns

Pen for drawing text labels

See also

setTextPen(), font()

Definition at line 574 of file qwt_plot_legenditem.cpp.

Update the legend items according to modifications of a plot item

Parameters

plotItem Plot item
data Attributes of the legend entries

Reimplemented from QwtPlotItem.

Definition at line 697 of file qwt_plot_legenditem.cpp.

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