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QwtPlotCanvas Class Reference

Canvas of a QwtPlot. More...

#include <qwt_plot_canvas.h>

Inheritance diagram for QwtPlotCanvas:
Inheritance graph
[legend]

Classes

class  PrivateData
 

Public Types

enum  PaintAttribute { BackingStore = 1, Opaque = 2, HackStyledBackground = 4, ImmediatePaint = 8 }
 Paint attributes. More...
 
typedef QFlags< PaintAttributePaintAttributes
 Paint attributes. More...
 
- Public Types inherited from QwtPlotAbstractCanvas
enum  FocusIndicator { NoFocusIndicator, CanvasFocusIndicator, ItemFocusIndicator }
 Focus indicator The default setting is NoFocusIndicator. More...
 

Public Slots

void replot ()
 

Public Member Functions

const QPixmap * backingStore () const
 
Q_INVOKABLE QPainterPath borderPath (const QRect &) const
 
virtual bool event (QEvent *) QWT_OVERRIDE
 
Q_INVOKABLE void invalidateBackingStore ()
 Invalidate the internal backing store. More...
 
 QwtPlotCanvas (QwtPlot *=NULL)
 Constructor. More...
 
void setPaintAttribute (PaintAttribute, bool on=true)
 Changing the paint attributes. More...
 
bool testPaintAttribute (PaintAttribute) const
 
virtual ~QwtPlotCanvas ()
 Destructor. More...
 
- Public Member Functions inherited from QwtPlotAbstractCanvas
double borderRadius () const
 
FocusIndicator focusIndicator () const
 
QwtPlotplot ()
 Return parent plot widget. More...
 
const QwtPlotplot () const
 Return parent plot widget. More...
 
 QwtPlotAbstractCanvas (QWidget *canvasWidget)
 
void setBorderRadius (double)
 
void setFocusIndicator (FocusIndicator)
 
virtual ~QwtPlotAbstractCanvas ()
 

Protected Member Functions

virtual void drawBorder (QPainter *) QWT_OVERRIDE
 
virtual void paintEvent (QPaintEvent *) QWT_OVERRIDE
 
virtual void resizeEvent (QResizeEvent *) QWT_OVERRIDE
 
- Protected Member Functions inherited from QwtPlotAbstractCanvas
QPainterPath borderPath2 (const QRect &rect) const
 
QWidget * canvasWidget ()
 
const QWidget * canvasWidget () const
 
virtual void drawBackground (QPainter *)
 
void drawCanvas (QPainter *)
 
virtual void drawFocusIndicator (QPainter *)
 
void drawStyled (QPainter *, bool)
 
void drawUnstyled (QPainter *)
 
void fillBackground (QPainter *)
 
void updateStyleSheetInfo ()
 Update the cached information about the current style sheet. More...
 

Properties

double borderRadius
 

Private Attributes

PrivateDatad_data
 

Detailed Description

Canvas of a QwtPlot.

Canvas is the widget where all plot items are displayed

See also
QwtPlot::setCanvas(), QwtPlotGLCanvas, QwtPlotOpenGLCanvas

Definition at line 29 of file qwt_plot_canvas.h.

Member Typedef Documentation

Paint attributes.

Definition at line 103 of file qwt_plot_canvas.h.

Member Enumeration Documentation

Paint attributes.

The default setting enables BackingStore and Opaque.

See also
setPaintAttribute(), testPaintAttribute()
Enumerator
BackingStore 

Paint double buffered reusing the content of the pixmap buffer when possible.

Using a backing store might improve the performance significantly, when working with widget overlays ( like rubber bands ). Disabling the cache might improve the performance for incremental paints (using QwtPlotDirectPainter ).

See also
backingStore(), invalidateBackingStore()
Opaque 

Try to fill the complete contents rectangle of the plot canvas.

When using styled backgrounds Qt assumes, that the canvas doesn't fill its area completely ( f.e because of rounded borders ) and fills the area below the canvas. When this is done with gradients it might result in a serious performance bottleneck - depending on the size.

When the Opaque attribute is enabled the canvas tries to identify the gaps with some heuristics and to fill those only.

Warning
Will not work for semitransparent backgrounds
HackStyledBackground 

Try to improve painting of styled backgrounds.

QwtPlotCanvas supports the box model attributes for customizing the layout with style sheets. Unfortunately the design of Qt style sheets has no concept how to handle backgrounds with rounded corners - beside of padding.

When HackStyledBackground is enabled the plot canvas tries to separate the background from the background border by reverse engineering to paint the background before and the border after the plot items. In this order the border gets perfectly antialiased and you can avoid some pixel artifacts in the corners.

ImmediatePaint 

When ImmediatePaint is set replot() calls repaint() instead of update().

See also
replot(), QWidget::repaint(), QWidget::update()

Definition at line 44 of file qwt_plot_canvas.h.

Constructor & Destructor Documentation

QwtPlotCanvas::QwtPlotCanvas ( QwtPlot plot = NULL)
explicit

Constructor.

Parameters
plotParent plot widget
See also
QwtPlot::setCanvas()

Definition at line 41 of file qwt_plot_canvas.cpp.

QwtPlotCanvas::~QwtPlotCanvas ( )
virtual

Destructor.

Definition at line 53 of file qwt_plot_canvas.cpp.

Member Function Documentation

const QPixmap * QwtPlotCanvas::backingStore ( ) const
Returns
Backing store, might be null

Definition at line 129 of file qwt_plot_canvas.cpp.

QPainterPath QwtPlotCanvas::borderPath ( const QRect &  rect) const

Calculate the painter path for a styled or rounded border

When the canvas has no styled background or rounded borders the painter path is empty.

Parameters
rectBounding rectangle of the canvas
Returns
Painter path, that can be used for clipping

Definition at line 316 of file qwt_plot_canvas.cpp.

void QwtPlotCanvas::drawBorder ( QPainter *  painter)
protectedvirtual

Draw the border of the plot canvas

Parameters
painterPainter
See also
setBorderRadius()

Reimplemented from QwtPlotAbstractCanvas.

Definition at line 272 of file qwt_plot_canvas.cpp.

bool QwtPlotCanvas::event ( QEvent *  event)
virtual

Qt event handler for QEvent::PolishRequest and QEvent::StyleChange

Parameters
eventQt Event
Returns
See QFrame::event()

Definition at line 147 of file qwt_plot_canvas.cpp.

void QwtPlotCanvas::invalidateBackingStore ( )

Invalidate the internal backing store.

Definition at line 135 of file qwt_plot_canvas.cpp.

void QwtPlotCanvas::paintEvent ( QPaintEvent *  event)
protectedvirtual

Paint event

Parameters
eventPaint event

Definition at line 174 of file qwt_plot_canvas.cpp.

void QwtPlotCanvas::replot ( )
slot

Invalidate the paint cache and repaint the canvas

See also
invalidatePaintCache()

Definition at line 297 of file qwt_plot_canvas.cpp.

void QwtPlotCanvas::resizeEvent ( QResizeEvent *  event)
protectedvirtual

Resize event

Parameters
eventResize event

Definition at line 287 of file qwt_plot_canvas.cpp.

void QwtPlotCanvas::setPaintAttribute ( PaintAttribute  attribute,
bool  on = true 
)

Changing the paint attributes.

Parameters
attributePaint attribute
onOn/Off
See also
testPaintAttribute(), backingStore()

Definition at line 66 of file qwt_plot_canvas.cpp.

bool QwtPlotCanvas::testPaintAttribute ( PaintAttribute  attribute) const

Test whether a paint attribute is enabled

Parameters
attributePaint attribute
Returns
true, when attribute is enabled
See also
setPaintAttribute()

Definition at line 123 of file qwt_plot_canvas.cpp.

Member Data Documentation

PrivateData* QwtPlotCanvas::d_data
private

Definition at line 128 of file qwt_plot_canvas.h.

Property Documentation

double QwtPlotCanvas::borderRadius
readwrite

Definition at line 33 of file qwt_plot_canvas.h.


The documentation for this class was generated from the following files:


plotjuggler
Author(s): Davide Faconti
autogenerated on Sun Dec 6 2020 04:02:50