QwtPlotCanvas Class Reference

#include <qwt_plot_canvas.h>

List of all members.

Public Types
enum	FocusIndicator {   NoFocusIndicator,   CanvasFocusIndicator,   ItemFocusIndicator }
enum	PaintAttribute {   BackingStore = 1,   Opaque = 2,   HackStyledBackground = 4,   ImmediatePaint = 8 }
typedef QFlags< PaintAttribute >	PaintAttributes
Public Member Functions
const QPixmap *	backingStore () const
QBitmap	borderMask (const QSize &) const
QPainterPath	borderPath (const QRect &rect) const
double	borderRadius () const
virtual bool	event (QEvent *)
FocusIndicator	focusIndicator () const
void	invalidateBackingStore ()
QwtPlot *	plot ()
const QwtPlot *	plot () const
	QwtPlotCanvas (QwtPlot *)
void	replot ()
void	setBorderRadius (double)
void	setFocusIndicator (FocusIndicator)
void	setPaintAttribute (PaintAttribute, bool on=true)
bool	testPaintAttribute (PaintAttribute) const
virtual	~QwtPlotCanvas ()
Protected Member Functions
virtual void	drawBorder (QPainter *)
virtual void	drawFocusIndicator (QPainter *)
virtual void	paintEvent (QPaintEvent *)
virtual void	resizeEvent (QResizeEvent *)
void	updateStyleSheetInfo ()

---

Detailed Description

Canvas of a QwtPlot.

See also:

QwtPlot

---

Member Typedef Documentation

typedef QFlags<PaintAttribute> QwtPlotCanvas::PaintAttributes

Paint attributes.

---

Member Enumeration Documentation

enum QwtPlotCanvas::FocusIndicator

Focus indicator.

• NoFocusIndicator
  Don't paint a focus indicator

• CanvasFocusIndicator
  The focus is related to the complete canvas. Paint the focus indicator using paintFocus()

• 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.

See also:

setFocusIndicator(), focusIndicator(), paintFocus()

enum QwtPlotCanvas::PaintAttribute

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 workin with widget overlays ( like rubberbands ). 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 seperate the background from the background border by reverse engeneering to paint the background before and the border after the plot items. In this order the border gets prefectly 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()

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Constructor & Destructor Documentation

QwtPlotCanvas::QwtPlotCanvas

(

QwtPlot *

plot

)

[explicit]

Sets a cross cursor, enables QwtPlotCanvas::BackingStore.

QwtPlotCanvas::~QwtPlotCanvas

(

)

[virtual]

Destructor.

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Member Function Documentation

const QPixmap * QwtPlotCanvas::backingStore

(

)

const

Returns:

Backing store, might be null

QBitmap QwtPlotCanvas::borderMask

(

const QSize &

size

)

const

Calculate a mask, that can be used to clip away the border frame

Parameters:

size	Size including the frame

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:

rect	Bounding rectangle of the canvas

Returns:

Painter path, that can be used for clipping

double QwtPlotCanvas::borderRadius

(

)

const

Returns:

Radius for the corners of the border frame

See also:

setBorderRadius()

void QwtPlotCanvas::drawBorder

(

QPainter *

painter

)

[protected, virtual]

Draw the border of the plot canvas

Parameters:

painter

Painter

See also:

setBorderRadius(), QFrame::drawFrame()

void QwtPlotCanvas::drawFocusIndicator

(

QPainter *

painter

)

[protected, virtual]

Draw the focus indication

Parameters:

painter

Painter

bool QwtPlotCanvas::event

(

QEvent *

event

)

[virtual]

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

Parameters:

event

Qt Event

QwtPlotCanvas::FocusIndicator QwtPlotCanvas::focusIndicator

(

)

const

Returns:

Focus indicator

See also:

FocusIndicator, setFocusIndicator()

void QwtPlotCanvas::invalidateBackingStore

(

)

Invalidate the internal backing store.

void QwtPlotCanvas::paintEvent

(

QPaintEvent *

event

)

[protected, virtual]

Paint event

Parameters:

event

Paint event

QwtPlot * QwtPlotCanvas::plot

(

)

Return parent plot widget.

const QwtPlot * QwtPlotCanvas::plot

(

)

const

Return parent plot widget.

void QwtPlotCanvas::replot

(

)

Invalidate the paint cache and repaint the canvas

See also:

invalidatePaintCache()

void QwtPlotCanvas::resizeEvent

(

QResizeEvent *

event

)

[protected, virtual]

Resize event

Parameters:

event

Resize event

void QwtPlotCanvas::setBorderRadius

(

double

radius

)

Set the radius for the corners of the border frame

Parameters:

radius

Radius of a rounded corner

See also:

borderRadius()

void QwtPlotCanvas::setFocusIndicator

(

FocusIndicator

focusIndicator

)

Set the focus indicator

See also:

FocusIndicator, focusIndicator()

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

Changing the paint attributes.

Parameters:

attribute	Paint attribute
on	On/Off

See also:

testPaintAttribute(), backingStore()

bool QwtPlotCanvas::testPaintAttribute

(

PaintAttribute

attribute

)

const

Test wether a paint attribute is enabled

Parameters:

attribute

Paint attribute

Returns:

true if the attribute is enabled

See also:

setPaintAttribute()

void QwtPlotCanvas::updateStyleSheetInfo

(

)

[protected]

Update the cached informations about the current style sheet.