Public Types¶

enum PaintAttribute { BackingStore = 1, Opaque = 2, HackStyledBackground = 4, ImmediatePaint = 8 }
Paint attributes. enum FocusIndicator { NoFocusIndicator, CanvasFocusIndicator, ItemFocusIndicator }
Focus indicator The default setting is NoFocusIndicator. typedef QFlags< PaintAttribute > PaintAttributes
Paint attributes.

Public Slots¶

void replot ()

Public Member Functions¶

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

Protected Member Functions¶

virtual void paintEvent (QPaintEvent *)
virtual void resizeEvent (QResizeEvent *)
virtual void drawFocusIndicator (QPainter *)
virtual void drawBorder (QPainter *)
void updateStyleSheetInfo ()
Update the cached information about the current style sheet.

enum QwtPlotCanvas::FocusIndicator¶

Focus indicator The default setting is NoFocusIndicator.

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Enumerator

NoFocusIndicator

Don't paint a focus indicator.

CanvasFocusIndicator

The focus is related to the complete canvas. Paint the focus indicator using drawFocusIndicator()

ItemFocusIndicator

The focus is related to an item (curve, point, ...) on the canvas. It is up to the application to display a focus indication using f.e. highlighting.

enum QwtPlotCanvas::PaintAttribute¶

Paint attributes. The default setting enables BackingStore and Opaque.

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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 ).

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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:

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().

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QwtPlotCanvas::QwtPlotCanvas (QwtPlot * plot = NULL) [explicit]¶

Constructor.

Parameters:

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const QPixmap * QwtPlotCanvas::backingStore () const¶

Returns:

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:

Returns:

double QwtPlotCanvas::borderRadius () const¶

Returns:

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void QwtPlotCanvas::drawBorder (QPainter * painter) [protected], [virtual]¶

Draw the border of the plot canvas

Parameters:

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void QwtPlotCanvas::drawFocusIndicator (QPainter * painter) [protected], [virtual]¶

Draw the focus indication

Parameters:

bool QwtPlotCanvas::event (QEvent * event) [virtual]¶

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

Parameters:

Returns:

QwtPlotCanvas::FocusIndicator QwtPlotCanvas::focusIndicator () const¶

Returns:

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void QwtPlotCanvas::paintEvent (QPaintEvent * event) [protected], [virtual]¶

Paint event

Parameters:

void QwtPlotCanvas::replot () [slot]¶

Invalidate the paint cache and repaint the canvas

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void QwtPlotCanvas::resizeEvent (QResizeEvent * event) [protected], [virtual]¶

Resize event

Parameters:

void QwtPlotCanvas::setBorderRadius (double radius)¶

Set the radius for the corners of the border frame

Parameters:

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void QwtPlotCanvas::setFocusIndicator (FocusIndicator focusIndicator)¶

Set the focus indicator

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

Changing the paint attributes.

Parameters:

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bool QwtPlotCanvas::testPaintAttribute (PaintAttribute attribute) const¶

Test whether a paint attribute is enabled

Parameters:

Returns:

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