#include <qwt_plot_canvas.h>

Inheritance diagram for QwtPlotCanvas:

Classes
class	PrivateData

Public Types
enum	PaintAttribute { BackingStore = 1 , Opaque = 2 , HackStyledBackground = 4 , ImmediatePaint = 8 }
	Paint attributes/绘制属性 More...

Public Types inherited from QwtPlotAbstractCanvas
enum	FocusIndicator { NoFocusIndicator , CanvasFocusIndicator , ItemFocusIndicator }
	Focus indicator The default setting is NoFocusIndicator. More...

Public Slots
void	replot ()
	Invalidate the paint cache and repaint the canvas.

Public Member Functions
	QwtPlotCanvas (QwtPlot *=NULL)
	Constructor.

virtual	~QwtPlotCanvas ()
	Destructor.

void	setPaintAttribute (PaintAttribute, bool on=true)
	Changing the paint attributes.

bool	testPaintAttribute (PaintAttribute) const
	Test whether a paint attribute is enabled.

const QPixmap *	backingStore () const

Q_INVOKABLE void	invalidateBackingStore ()
	Invalidate the internal backing store.

virtual bool	event (QEvent *) QWT_OVERRIDE
	Qt event handler for QEvent::PolishRequest and QEvent::StyleChange.

Q_INVOKABLE QPainterPath	borderPath (const QRect &) const
	Calculate the painter path for a styled or rounded border.

Public Member Functions inherited from QwtPlotAbstractCanvas
	QwtPlotAbstractCanvas (QWidget *canvasWidget)
	Constructor.

virtual	~QwtPlotAbstractCanvas ()
	Destructor.

QwtPlot *	plot ()
	Return parent plot widget.

const QwtPlot *	plot () const
	Return parent plot widget.

void	setFocusIndicator (FocusIndicator)
	Set the focus indicator.

FocusIndicator	focusIndicator () const

void	setBorderRadius (double)
	Set the radius for the corners of the border frame.

double	borderRadius () const

Protected Member Functions
virtual void	paintEvent (QPaintEvent *) QWT_OVERRIDE
	Paint event.

virtual void	resizeEvent (QResizeEvent *) QWT_OVERRIDE
	Resize event.

virtual void	drawBorder (QPainter *) QWT_OVERRIDE
	Draw the border of the plot canvas.

Protected Member Functions inherited from QwtPlotAbstractCanvas
QWidget *	canvasWidget ()

const QWidget *	canvasWidget () const

virtual void	drawFocusIndicator (QPainter *)
	Draw the focus indication.

virtual void	drawBackground (QPainter *)
	Helper function for the derived plot canvas.

void	fillBackground (QPainter *)
	Helper function for the derived plot canvas.

void	drawCanvas (QPainter *)
	Draw the plot to the canvas.

void	drawStyled (QPainter *, bool)
	Helper function for the derived plot canvas.

void	drawUnstyled (QPainter *)
	Helper function for the derived plot canvas.

QPainterPath	canvasBorderPath (const QRect &rect) const

void	updateStyleSheetInfo ()
	Update the cached information about the current style sheet.

Properties
double	borderRadius

Detailed Description

Canvas of a QwtPlot.

Canvas is the widget where all plot items are displayed

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

Member Enumeration Documentation

◆ PaintAttribute

enum QwtPlotCanvas::PaintAttribute

Paint attributes/绘制属性

The default setting enables BackingStore and Opaque.

默认设置启用 BackingStore 与 Opaque

See also: setPaintAttribute(), testPaintAttribute()

Enumerator
BackingStore	BackingStore. Paint double buffered reusing the content of the pixmap buffer when possible. 双缓冲绘制，尽可能复用 pixmap 缓存的内容。 Using a backing store might improve the performance significantly, when working with widget overlays (like rubber bands). 使用后备存储可显著提升性能，尤其当存在部件叠加（如 rubber band）时。 Disabling the cache might improve the performance for incremental paints (using QwtPlotDirectPainter). 禁用缓存可能提升增量绘制（如使用 QwtPlotDirectPainter）的性能。 See also backingStore(), invalidateBackingStore()
Opaque	Opaque. Try to fill the complete contents rectangle of the plot canvas. 尝试填充绘图画布的全部内容矩形。 When using styled backgrounds Qt assumes that the canvas doesn't fill its area completely (e.g. 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. 使用样式背景时，Qt 假定画布并未完全填充其区域（例如圆角边框），因而会在画布下方继续填充。若使用渐变填充，这可能成为严重性能瓶颈。 When the Opaque attribute is enabled the canvas tries to identify the gaps with some heuristics and to fill those only. 启用 Opaque 后，画布会通过启发式算法识别空隙并仅填充这些区域。 Warning Will not work for semitransparent backgrounds. 对半透明背景无效。
HackStyledBackground	HackStyledBackground. Try to improve painting of styled backgrounds. 尝试优化样式背景的绘制。 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. QwtPlotCanvas 支持盒模型属性，以便通过样式表自定义布局。遗憾的是，Qt 样式表的设计并未提供处理圆角背景的方案，除 padding 外。 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. 启用 HackStyledBackground 后，画布会通过逆向工程将背景与边框分离：先绘制背景，再绘制边框，使边框获得完美抗锯齿并避免角落像素伪影。
ImmediatePaint	ImmediatePaint. When ImmediatePaint is set replot() calls repaint() instead of update(). 当 ImmediatePaint 被设置时，replot() 将调用 repaint() 而非 update()。 See also replot(), QWidget::repaint(), QWidget::update()

Constructor & Destructor Documentation

◆ QwtPlotCanvas()

QwtPlotCanvas::QwtPlotCanvas ( QwtPlot * plot = NULL )

explicit

Constructor.

Parameters

plot	Parent plot widget

See also: QwtPlot::setCanvas()

Member Function Documentation

◆ backingStore()

const QPixmap * QwtPlotCanvas::backingStore ( ) const

Returns: Backing store, might be null

◆ borderPath()

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

◆ drawBorder()

void QwtPlotCanvas::drawBorder ( QPainter * painter )

protectedvirtual

Draw the border of the plot canvas.

Parameters

painter Painter

See also: setBorderRadius()

Reimplemented from QwtPlotAbstractCanvas.

◆ event()

bool QwtPlotCanvas::event ( QEvent * event )

virtual

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

Parameters

event Qt Event

Returns: See QFrame::event()

◆ paintEvent()

void QwtPlotCanvas::paintEvent ( QPaintEvent * event )

protectedvirtual

Paint event.

Parameters

event Paint event

◆ replot

void QwtPlotCanvas::replot ( )

slot

Invalidate the paint cache and repaint the canvas.

See also: invalidatePaintCache()

◆ resizeEvent()

void QwtPlotCanvas::resizeEvent ( QResizeEvent * event )

protectedvirtual

Resize event.

Parameters

event Resize event

◆ setPaintAttribute()

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

Changing the paint attributes.

Parameters

attribute	Paint attribute
on	On/Off

See also: testPaintAttribute(), backingStore()

◆ testPaintAttribute()

bool QwtPlotCanvas::testPaintAttribute ( PaintAttribute attribute ) const

Test whether a paint attribute is enabled.

Parameters

attribute Paint attribute

Returns: true, when attribute is enabled

See also: setPaintAttribute()

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

/home/runner/work/QWT/QWT/src/qwt_plot_canvas.h
/home/runner/work/QWT/QWT/src/qwt_plot_canvas.cpp

Classes

Public Types

Public Slots

Public Member Functions

Protected Member Functions

Properties

Detailed Description

Member Enumeration Documentation

◆ PaintAttribute

Constructor & Destructor Documentation

◆ QwtPlotCanvas()

Member Function Documentation

◆ backingStore()

◆ borderPath()

◆ drawBorder()

◆ event()

◆ paintEvent()

◆ replot

◆ resizeEvent()

◆ setPaintAttribute()

◆ testPaintAttribute()