Wt::WPaintedWidget Class Reference

A widget that is painted using vector graphics. More...

#include <Wt/WPaintedWidget.h>

Inheritance diagram for Wt::WPaintedWidget:

Public Member Functions
	WPaintedWidget ()
	Create a new painted widget.
	~WPaintedWidget ()
	Destructor.
void	setPreferredMethod (RenderMethod method)
	Sets the preferred rendering method. More...
RenderMethod	preferredMethod () const
	Returns the preferred rendering method. More...
void	update (WFlags< PaintFlag > flags=None)
	Lets the widget repaint itself. More...
virtual void	resize (const WLength &width, const WLength &height) override
	Resizes the widget. More...
void	addArea (std::unique_ptr< WAbstractArea > area)
	Adds an interactive area. More...
void	insertArea (int index, std::unique_ptr< WAbstractArea > area)
	Inserts an interactive area. More...
std::unique_ptr< WAbstractArea >	removeArea (WAbstractArea *area)
	Removes an interactive area. More...
WAbstractArea *	area (int index) const
	Returns the interactive area at the given index. More...
const std::vector< WAbstractArea * >	areas () const
	Returns the interactive areas set for this widget. More...
JSlot &	repaintSlot ()
	A JavaScript slot that repaints the widget when triggered. More...
Public Member Functions inherited from Wt::WInteractWidget
	WInteractWidget ()
	Create an InteractWidget.
EventSignal< WKeyEvent > &	keyWentDown ()
	Event signal emitted when a keyboard key is pushed down. More...
EventSignal< WKeyEvent > &	keyPressed ()
	Event signal emitted when a "character" was entered. More...
EventSignal< WKeyEvent > &	keyWentUp ()
	Event signal emitted when a keyboard key is released. More...
EventSignal &	enterPressed ()
	Event signal emitted when enter was pressed. More...
EventSignal &	escapePressed ()
	Event signal emitted when escape was pressed. More...
EventSignal< WMouseEvent > &	clicked ()
	Event signal emitted when the primary mouse button was clicked on this widget. More...
EventSignal< WMouseEvent > &	doubleClicked ()
	Event signal emitted when the primary mouse button was double clicked on this widget. More...
EventSignal< WMouseEvent > &	mouseWentDown ()
	Event signal emitted when a mouse button was pushed down on this widget. More...
EventSignal< WMouseEvent > &	mouseWentUp ()
	Event signal emitted when a mouse button was released on this widget. More...
EventSignal< WMouseEvent > &	mouseWentOut ()
	Event signal emitted when the mouse went out of this widget. More...
EventSignal< WMouseEvent > &	mouseWentOver ()
	Event signal emitted when the mouse entered this widget. More...
EventSignal< WMouseEvent > &	mouseMoved ()
	Event signal emitted when the mouse moved over this widget. More...
EventSignal< WMouseEvent > &	mouseDragged ()
	Event signal emitted when the mouse is dragged over this widget. More...
EventSignal< WMouseEvent > &	mouseWheel ()
	Event signal emitted when the mouse scroll wheel was used. More...
EventSignal< WTouchEvent > &	touchStarted ()
	Event signal emitted when a finger is placed on the screen. More...
EventSignal< WTouchEvent > &	touchEnded ()
	Event signal emitted when a finger is removed from the screen. More...
EventSignal< WTouchEvent > &	touchMoved ()
	Event signal emitted when a finger, which is already placed on the screen, is moved across the screen. More...
EventSignal< WGestureEvent > &	gestureStarted ()
	Event signal emitted when a gesture is started. More...
EventSignal< WGestureEvent > &	gestureChanged ()
	Event signal emitted when a gesture is changed. More...
EventSignal< WGestureEvent > &	gestureEnded ()
	Event signal emitted when a gesture is ended. More...
void	setDraggable (const std::string &mimeType, WWidget *dragWidget=nullptr, bool isDragWidgetOnly=false, WObject *sourceWidget=nullptr)
	Configure dragging for drag and drop. More...
void	unsetDraggable ()
	Disable drag & drop for this widget. More...
void	setMouseOverDelay (int delay)
	Sets a delay for the mouse over event. More...
int	mouseOverDelay () const
	Returns the mouse over signal delay. More...
virtual void	setPopup (bool popup) override
	Lets the widget overlay over other sibling widgets. More...
virtual void	load () override
	Loads content just before the widget is used. More...
virtual bool	isEnabled () const override
	Returns whether the widget is enabled. More...
Public Member Functions inherited from Wt::WWebWidget
	WWebWidget ()
	Construct a WebWidget.
virtual std::vector< WWidget * >	children () const override
	Returns child widgets. More...
Signal &	childrenChanged ()
	Signal emitted when children have been added or removed. More...
virtual void	setPositionScheme (PositionScheme scheme) override
	Sets the CSS position scheme. More...
virtual PositionScheme	positionScheme () const override
	Returns the CSS position scheme. More...
virtual void	setOffsets (const WLength &offset, WFlags< Side > sides=AllSides) override
	Sets CSS offsets for a non-statically positioned widget. More...
virtual WLength	offset (Side s) const override
	Returns a CSS offset. More...
virtual WLength	width () const override
	Returns the width. More...
virtual WLength	height () const override
	Returns the height. More...
virtual void	setMinimumSize (const WLength &width, const WLength &height) override
	Sets a minimum size. More...
virtual WLength	minimumWidth () const override
	Returns the minimum width. More...
virtual WLength	minimumHeight () const override
	Returns the minimum height. More...
virtual void	setMaximumSize (const WLength &width, const WLength &height) override
	Sets a maximum size. More...
virtual WLength	maximumWidth () const override
	Returns the maximum width. More...
virtual WLength	maximumHeight () const override
	Returns the maximum height. More...
virtual void	setLineHeight (const WLength &height) override
	Sets the CSS line height for contained text.
virtual WLength	lineHeight () const override
	Returns the CSS line height for contained text. More...
virtual void	setFloatSide (Side s) override
	Specifies a CSS float side. More...
virtual Side	floatSide () const override
	Returns the CSS float side. More...
virtual void	setClearSides (WFlags< Side > sides) override
	Sets the sides that should be cleared of floats. More...
virtual WFlags< Side >	clearSides () const override
	Returns the sides that should remain empty. More...
virtual void	setMargin (const WLength &margin, WFlags< Side > sides=AllSides) override
	Sets CSS margins around the widget. More...
virtual WLength	margin (Side side) const override
	Returns a CSS margin set. More...
virtual void	setHiddenKeepsGeometry (bool enabled) override
	Sets whether the widget keeps its geometry when hidden. More...
virtual bool	hiddenKeepsGeometry () const override
	Returns whether the widget keeps its geometry when hidden. More...
virtual void	setHidden (bool hidden, const WAnimation &animation=WAnimation()) override
	Hides or shows the widget. More...
virtual bool	isHidden () const override
	Returns whether the widget is set hidden. More...
virtual bool	isVisible () const override
	Returns whether the widget is visible. More...
virtual void	setDisabled (bool disabled) override
	Sets whether the widget is disabled. More...
virtual bool	isDisabled () const override
	Returns whether the widget is set disabled. More...
virtual bool	isPopup () const override
	Returns whether the widget is overlayed. More...
virtual void	setInline (bool isInline) override
	Sets whether the widget is displayed inline or as a block. More...
virtual bool	isInline () const override
	Returns whether the widget is displayed inline or as block. More...
virtual void	setDecorationStyle (const WCssDecorationStyle &style) override
	Sets a CSS decoration style. More...
virtual WCssDecorationStyle &	decorationStyle () override
	Returns the decoration style of this widget. More...
virtual void	setStyleClass (const WString &styleClass) override
	Sets (one or more) CSS style classes. More...
virtual WString	styleClass () const override
	Returns the CSS style class. More...
virtual void	addStyleClass (const WString &styleClass, bool force=false) override
	Adds a CSS style class. More...
virtual void	removeStyleClass (const WString &styleClass, bool force=false) override
	Removes a CSS style class. More...
virtual bool	hasStyleClass (const WString &styleClass) const override
	Returns whether the widget has a style class.
virtual void	setVerticalAlignment (AlignmentFlag alignment, const WLength &length=WLength()) override
	Sets the vertical alignment. More...
virtual AlignmentFlag	verticalAlignment () const override
	Returns the vertical alignment. More...
virtual WLength	verticalAlignmentLength () const override
	Returns the fixed vertical alignment that was set. More...
virtual void	setToolTip (const WString &text, TextFormat textFormat=TextFormat::Plain) override
	Sets a tooltip. More...
virtual void	setDeferredToolTip (bool enable, TextFormat textFormat=TextFormat::Plain) override
	Enable deferred tooltip. More...
virtual WString	toolTip () const override
	Returns the tooltip.
virtual void	refresh () override
	Refresh the widget. More...
virtual void	setAttributeValue (const std::string &name, const WString &value) override
	Sets an attribute value. More...
virtual WString	attributeValue (const std::string &name) const override
	Returns an attribute value. More...
virtual void	setJavaScriptMember (const std::string &name, const std::string &value) override
	Sets a JavaScript member. More...
virtual std::string	javaScriptMember (const std::string &name) const override
	Returns the value of a JavaScript member. More...
virtual void	callJavaScriptMember (const std::string &name, const std::string &args) override
	Calls a JavaScript member. More...
virtual bool	loaded () const override
	Returns whether this widget has been loaded. More...
virtual void	setId (const std::string &id) override
	Sets the CSS Id. More...
virtual WWidget *	find (const std::string &name) override
	Finds a descendent widget by name. More...
virtual WWidget *	findById (const std::string &id) override
	Finds a descendent widget by id.
virtual void	setSelectable (bool selectable) override
	Sets as selectable. More...
virtual void	doJavaScript (const std::string &javascript) override
	Executes the given JavaScript statements when the widget is rendered or updated. More...
virtual const std::string	id () const override
	Returns the (unique) identifier for this object. More...
void	setLoadLaterWhenInvisible (bool)
	Change the way the widget is loaded when invisible. More...
std::string	htmlTagName () const
	returns the current html tag name More...
void	setHtmlTagName (const std::string &tag)
	set the custom HTML tag name More...
virtual void	setCanReceiveFocus (bool enabled) override
	Sets whether the widget can receive focus. More...
virtual bool	canReceiveFocus () const override
	Returns whether the widget can receive focus. More...
virtual bool	setFirstFocus () override
	Set focus on the widget's first descendant. More...
virtual void	setFocus (bool focus) override
	Sets focus. More...
virtual bool	hasFocus () const override
	Returns whether the widget currently has the focus.
virtual void	setTabIndex (int index) override
	Sets the tab index. More...
virtual int	tabIndex () const override
	Returns the tab index. More...
EventSignal &	blurred ()
	Signal emitted when the widget lost focus. More...
EventSignal &	focussed ()
	Signal emitted when the widget recieved focus. More...
virtual bool	scrollVisibilityEnabled () const final override
	Returns whether scroll visibility detection is enabled for this widget. More...
virtual void	setScrollVisibilityEnabled (bool enabled) final override
	Sets whether scroll visibility detection is enabled for this widget. More...
virtual int	scrollVisibilityMargin () const final override
	Returns the margin around the viewport within which the widget is considered visible. More...
virtual void	setScrollVisibilityMargin (int margin) final override
	Sets the margin around the viewport within which the widget is considered visible. More...
virtual Signal< bool > &	scrollVisibilityChanged () final override
	Signal triggered when the scroll visibility of this widget changes. More...
virtual bool	isScrollVisible () const final override
	Returns whether this widget is currently considered scroll visible. More...
virtual void	setThemeStyleEnabled (bool enabled) final override
	Sets whether theme styling for a widget is enabled or disabled. More...
virtual bool	isThemeStyleEnabled () const final override
	Returns whether this widget is currently styled by the chosen theme. More...
virtual void	setObjectName (const std::string &name) override
	Sets an object name. More...
void	setFocus ()
	Sets focus. More...
virtual void	setFocus (bool focus)=0
	Sets focus. More...
Public Member Functions inherited from Wt::WWidget
virtual	~WWidget ()
	Destructor. More...
WWidget *	parent () const
	Returns the parent widget.
virtual std::unique_ptr< WWidget >	removeWidget (WWidget *widget)
	Removes a child widget.
template<typename Widget >
std::unique_ptr< Widget >	removeWidget (Widget *widget)
	Removes a child widget. More...
std::unique_ptr< WWidget >	removeFromParent ()
	Removes the widget from its parent. More...
void	setWidth (const WLength &width)
	Sets the width. More...
void	setHeight (const WLength &height)
	Sets the height. More...
virtual void	positionAt (const WWidget *widget, Orientation orientation=Orientation::Vertical)
	Positions a widget next to another widget. More...
virtual void	toggleStyleClass (const WString &styleClass, bool add, bool force=false)
	Toggles a CSS style class.
std::string	jsRef () const
	Returns a JavaScript expression to the corresponding DOM node. More...
void	setFocus ()
	Sets focus. More...
virtual void	acceptDrops (const std::string &mimeType, const WString &hoverStyleClass=WString())
	Sets a mime type to be accepted for dropping. More...
virtual void	stopAcceptDrops (const std::string &mimeType)
	Indicates that a mime type is no longer accepted for dropping. More...
virtual void	htmlText (std::ostream &out)
	Streams the (X)HTML representation. More...
bool	isRendered () const
	Returns whether the widget is rendered. More...
void	hide ()
	Hides the widget. More...
void	animateHide (const WAnimation &animation)
	Hides the widget using an animation. More...
void	show ()
	Shows the widget. More...
void	animateShow (const WAnimation &animation)
	Shows the widget using an animation. More...
void	enable ()
	Enables the widget. More...
void	disable ()
	Disable thes widget. More...
bool	layoutSizeAware () const
	Returns whether the widget is layout size aware. More...
Public Member Functions inherited from Wt::WObject
void	addChild (std::unique_ptr< WObject > child)
	Add a child WObject whose lifetime is determined by this WObject.
template<typename Child >
Child *	addChild (std::unique_ptr< Child > child)
	Add a child WObject, returning a raw pointer. More...
std::unique_ptr< WObject >	removeChild (WObject *child)
	Remove a child WObject, so its lifetime is no longer determined by this WObject.
template<typename Child >
std::unique_ptr< Child >	removeChild (Child *child)
	Remove a child WObject, so its lifetime is no longer determined by this WObject. More...
virtual std::string	objectName () const
	Returns the object name. More...
void	resetLearnedSlots ()
	Resets learned stateless slot implementations. More...
template<class T >
void	resetLearnedSlot (void(T::*method)())
	Resets a learned stateless slot implementation. More...
template<class T >
WStatelessSlot *	implementStateless (void(T::*method)())
	Declares a slot to be stateless and learn client-side behaviour on first invocation. More...
template<class T >
WStatelessSlot *	implementStateless (void(T::*method)(), void(T::*undoMethod)())
	Declares a slot to be stateless and learn client-side behaviour in advance. More...
void	isNotStateless ()
	Marks the current function as not stateless. More...
template<class T >
WStatelessSlot *	implementJavaScript (void(T::*method)(), const std::string &jsCode)
	Provides a JavaScript implementation for a method. More...
Public Member Functions inherited from Wt::Core::observable
	observable () noexcept
	Default constructor.
virtual	~observable ()
	Destructor. More...
template<typename... Args, typename C >
auto	bindSafe (void(C::*method)(Args...)) noexcept
	Protects a method call against object destruction. More...
template<typename... Args, typename C >
auto	bindSafe (void(C::*method)(Args...) const) const noexcept
	Protects a const method call against object destruction. More...
template<typename Function >
auto	bindSafe (const Function &function) noexcept
	Protects a function against object destruction. More...

Protected Member Functions
WJavaScriptHandle< WTransform >	createJSTransform ()
	Create a WTransform that is accessible from JavaScript, associated with this WPaintedWidget.
WJavaScriptHandle< WBrush >	createJSBrush ()
	Create a WBrush that is accessible from JavaScript, associated with this WPaintedWidget.
WJavaScriptHandle< WPen >	createJSPen ()
	Create a WPen that is accessible from JavaScript, associated with this WPaintedWidget.
WJavaScriptHandle< WPainterPath >	createJSPainterPath ()
	Create a WPainterPath that is accessible from JavaScript, associated with this WPaintedWidget.
WJavaScriptHandle< WRectF >	createJSRect ()
	Create a WRectF that is accessible from JavaScript, associated with this WPaintedWidget.
WJavaScriptHandle< WPointF >	createJSPoint ()
	Create a WPointF that is accessible from JavaScript, associated with this WPaintedWidget.
virtual void	layoutSizeChanged (int width, int height) override
	Virtual method that indicates a size change. More...
virtual RenderMethod	getMethod () const
	Returns the actual method used for rendering. More...
virtual void	paintEvent (WPaintDevice *paintDevice)=0
	Paints the widget. More...
virtual std::unique_ptr< WPaintDevice >	createPaintDevice () const
	Creates a paint device. More...
virtual void	enableAjax () override
	Progresses to an Ajax-enabled widget. More...
virtual void	render (WFlags< RenderFlag > flags) override
	Renders the widget. More...
std::string	objJsRef () const
	Returns a JavaScript reference to the client side representation of the WPaintedWidget. More...
Protected Member Functions inherited from Wt::WInteractWidget
virtual void	propagateSetEnabled (bool enabled) override
	Propagates that a widget was enabled or disabled through children. More...
Protected Member Functions inherited from Wt::WWebWidget
virtual WStatelessSlot *	getStateless (Method method) override
	On-demand stateless slot implementation. More...
Protected Member Functions inherited from Wt::WWidget
void	setLayoutSizeAware (bool sizeAware)
	Sets the widget to be aware of its size set by a layout manager. More...
	WWidget ()
	Creates a widget.
virtual void	dropEvent (WDropEvent dropEvent)
	Handles a drop event. More...
virtual int	boxPadding (Orientation orientation) const
	Returns the widget's built-in padding. More...
virtual int	boxBorder (Orientation orientation) const
	Returns the widget's built-in border width. More...
void	scheduleRender (WFlags< RepaintFlag > flags=None)
	Schedules rerendering of the widget. More...

Additional Inherited Members
Public Types inherited from Wt::WObject
typedef void(WObject::*	Method) ()
	Typedef for a WObject method without arguments.
Static Public Member Functions inherited from Wt::WWebWidget
static std::string	jsStringLiteral (const std::string &v, char delimiter='\'')
	Turn a CharEncoding::UTF8 encoded string into a JavaScript string literal. More...
Static Public Member Functions inherited from Wt::WWidget
static WString	tr (const char *key)
	Short hand for WString::tr() More...

Detailed Description

A widget that is painted using vector graphics.

A painted widget is rendered from basic drawing primitives. Rendering is done not on the server but on the browser, using different rendering methods:

Browser	Methods	Default method
Firefox 1.5+	HtmlCanvas, InlineSVG, PngImage	HtmlCanvas
Internet Explorer 6.0+	InlineVML, PngImage	InlineVML
Internet Explorer 9+	HtmlCanvas, InlineSVG, PngImage	HtmlCanvas
Safari	HtmlCanvas, InlineSVG, PngImage	HtmlCanvas
Opera	InlineSVG, HtmlCanvas*, PngImage	InlineSVG
other	?	HtmlCanvas, PngImage

* HtmlCanvas occasionally suffers from rendering artefacts in Opera.

The different rendering methods correspond to different WPaintDevice implementations, from which this widget choses a suitable one depending on the browser capabilities and configuration.

If no JavaScript is available, the JavaScript-based HtmlCanvas will not be used, and InlineSVG will be used instead. The method used may be changed by using setPreferredMethod().

In some browsers, InlineSVG requires that the document is rendered as XHTML. This must be enabled in the configuration file using the <send-xhtml-mime-type> option. By default, this option is off. Firefox 4 and Chrome do support svg in normal html mode.

The PngImage is the most portable rendering method, and may be the fastest if the painting is of high complexity and/or the image is fairly small.

To use a WPaintedWidget, you must derive from it and reimplement paintEvent(WPaintDevice *paintDevice). To paint on a WPaintDevice, you will need to use a WPainter. Repainting is triggered by calling the update() method.

Usage example:

class MyPaintedWidget : public Wt::WPaintedWidget
{
public:
  MyPaintedWidget()
    : Wt::WPaintedWidget()
      foo_(100)
  {
     resize(200, 200); // provide a default size
  }
 
  void setFoo(int foo) {
     foo_ = foo;
     update(); // trigger a repaint
  }
 
protected:
  void paintEvent(Wt::WPaintDevice *paintDevice) {
    Wt::WPainter painter(paintDevice);
    painter.drawLine(20, 20, foo_, foo_);
    ...
  }
 
private:
  int foo_;
};

CSS

Styling through CSS is not applicable.

Note

A WPaintedWidget requires that it is given a size using resize() or by a layout manager.

Client side interaction and repainting

If the widget is drawn as an HTML canvas element, i.e. the method is HtmlCanvas, a WPaintedWidget can expose certain objects to be modified client side.

See also

WJavaScriptHandle, WJavaScriptExposableObject

WImage

Member Function Documentation

addArea()

void Wt::WPaintedWidget::addArea

(

std::unique_ptr< WAbstractArea >

area

)

Adds an interactive area.

Adds the area which listens to events in a specific region of the widget. Areas are organized in a list, to which the given area is appended. When areas overlap, the area with the lowest index receives the event.

Note

When defining at least one area, no more events will propagate to the widget itself. As a work-around, you can emulate this by listening for events on a WRectArea that corresponds to the whole widget, and which is added as the last area (catching all events that were not caught by preceding areas).

See also

insertArea(int, WAbstractArea *)

area()

WAbstractArea * Wt::WPaintedWidget::area

(

int

index

)

const

Returns the interactive area at the given index.

Returns 0 if index was invalid.

See also

insertArea(int, WAbstractArea *)

areas()

const std::vector< WAbstractArea * > Wt::WPaintedWidget::areas

(

)

const

Returns the interactive areas set for this widget.

See also

addArea()

createPaintDevice()

std::unique_ptr< WPaintDevice > Wt::WPaintedWidget::createPaintDevice ( ) const

protectedvirtual

Creates a paint device.

Although it's usually not necessary to call this function, you may want to reimplement this function to customize or specialize the device used for painting the widget.

enableAjax()

void Wt::WPaintedWidget::enableAjax ( )

overrideprotectedvirtual

Progresses to an Ajax-enabled widget.

This method is called when the progressive bootstrap method is used, and support for AJAX has been detected. The default behavior will upgrade the widget's event handling to use AJAX instead of full page reloads, and propagate the call to its children.

You may want to reimplement this method if you want to make changes to widget when AJAX is enabled. You should always call the base implementation.

See also

WApplication::enableAjax()

Reimplemented from Wt::WWebWidget.

getMethod()

RenderMethod Wt::WPaintedWidget::getMethod ( ) const

protectedvirtual

Returns the actual method used for rendering.

The default method considers browser capabilites and the preferred method to make an actual choice for the implementation.

You may want to reimplement this method to override this choice.

insertArea()

void Wt::WPaintedWidget::insertArea	(	int	index,
		std::unique_ptr< WAbstractArea >	area
	)

Inserts an interactive area.

Inserts the area which listens to events in the coresponding area of the widget. Areas are organized in a list, and the area is inserted at index index. When areas overlap, the area with the lowest index receives the event.

Note

When defining at least one area, no more events will propagate to the widget itself. As a work-around, you can emulate this by listening for events on a WRectArea that corresponds to the whole widget, and which is added as the last area (catching all events that were not caught by preceding areas).

See also

addArea(WAbstractArea *)

layoutSizeChanged()

void Wt::WPaintedWidget::layoutSizeChanged ( int  width, int  height  )

overrideprotectedvirtual

Virtual method that indicates a size change.

This method propagates the client-side width and height of the widget when the widget is contained by a layout manager and setLayoutSizeAware(true) was called.

See also

setLayoutSizeAware()

Reimplemented from Wt::WWidget.

objJsRef()

std::string Wt::WPaintedWidget::objJsRef ( ) const

protected

Returns a JavaScript reference to the client side representation of the WPaintedWidget.

The client side representation exposes the following interface:

{
  canvas: exposes the underlying HTML canvas element
  repaint: a function that, when called, will repaint the widget without a server roundtrip
}

Note

The method should be HtmlCanvas and there has to be at least one WJavaScriptHandle associated with this WPaintedWidget in order for this reference to be valid.

paintEvent()

virtual void Wt::WPaintedWidget::paintEvent ( WPaintDevice *  paintDevice )

protectedpure virtual

Paints the widget.

You should reimplement this method to paint the contents of the widget, using the given paintDevice.

Implemented in Wt::Chart::WPieChart, Wt::Chart::WCartesianChart, Wt::Chart::WAxisSliderWidget, and Wt::Auth::Mfa::TotpQrCode.

preferredMethod()

RenderMethod Wt::WPaintedWidget::preferredMethod

(

)

const

Returns the preferred rendering method.

See also

setPreferredMethod(Method)

removeArea()

std::unique_ptr< WAbstractArea > Wt::WPaintedWidget::removeArea

(

WAbstractArea *

area

)

Removes an interactive area.

Removes the area from this widget.

See also

addArea(WAbstractArea *)

render()

void Wt::WPaintedWidget::render ( WFlags< RenderFlag >  flags )

overrideprotectedvirtual

Renders the widget.

This function renders the widget (or an update for the widget), after this has been scheduled using scheduleRender().

The default implementation will render the widget by serializing changes to JavaScript and HTML. You may want to reimplement this widget if you have been postponing some of the layout / rendering implementation until the latest moment possible. In that case you should make sure you call the base implementation however.

Reimplemented from Wt::WWebWidget.

Reimplemented in Wt::Chart::WCartesianChart, and Wt::Chart::WAxisSliderWidget.

repaintSlot()

JSlot& Wt::WPaintedWidget::repaintSlot

(

)

A JavaScript slot that repaints the widget when triggered.

This is useful for client-side initiated repaints. You may want to use this if you want to add interaction or animation to your WPaintedWidget.

Note

This feature is currently only supported if the method is HtmlCanvas. This will not cause a server roundtrip. Instead, the resulting JavaScript of paintEvent() will be re-executed on the client side.

See also

objJsRef()

resize()

void Wt::WPaintedWidget::resize ( const WLength &  width, const WLength &  height  )

overridevirtual

Resizes the widget.

Specifies a fixed size for this widget, setting CSS width and height properties. By default a widget has automatic width and height, which sets a size for the widget following CSS rules.

When the widget is not managed by a layout manager, the automatic (natural) size of a widget depends on whether they widget is a block or inline widget:

• a block widget takes by default the width of the parent, and the height that it needs based on its contents
• an inline widget takes the width and height that it needs based on its contents (possibly wrapping over multiple lines). The width and height of an inline widget cannot be changed (by the letter of CSS, although most browsers will react to it in varying ways).

When inserted in a layout manager, the size set will be used as a widget's preferred size, but the widget may be given a different size by the layout manager based on available space and stretch factors. The actual size given by a layout manager may be retrieved by making the widget "layout size aware", using setLayoutSizeAware(). If you have defined a "wtResize()" JavaScript method for the widget, then this method will also be called.

The default width and height of a widget is WLength::Auto.

See also

width(), height()

Reimplemented from Wt::WWebWidget.

setPreferredMethod()

void Wt::WPaintedWidget::setPreferredMethod

(

RenderMethod

method

)

Sets the preferred rendering method.

When method is supported by the browser, then it is chosen for rendering.

update()

void Wt::WPaintedWidget::update

(

WFlags< PaintFlag >

flags = None

)

Lets the widget repaint itself.

Repainting is not immediate, but happens after when the event loop is exited.

Unless a Wt::PaintFlag::Update paint flag is set, the widget is first cleared.