Wt  4.0.2
Public Member Functions | Protected Member Functions | List of all members
Wt::WPaintedWidget Class Referenceabstract

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

#include <Wt/WPaintedWidget.h>

Inheritance diagram for Wt::WPaintedWidget:
Inheritance graph
[legend]

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< WAbstractArearemoveArea (WAbstractArea *area)
 Removes an interactive area. More...
 
WAbstractAreaarea (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...
 
JSlotrepaintSlot ()
 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...
 
EventSignalenterPressed ()
 Event signal emitted when enter was pressed. More...
 
EventSignalescapePressed ()
 Event signal emitted when escape was pressed. More...
 
EventSignal< WMouseEvent > & clicked ()
 Event signal emitted when a mouse key was clicked on this widget. More...
 
EventSignal< WMouseEvent > & doubleClicked ()
 Event signal emitted when a mouse key was double clicked on this widget. More...
 
EventSignal< WMouseEvent > & mouseWentDown ()
 Event signal emitted when a mouse key was pushed down on this widget. More...
 
EventSignal< WMouseEvent > & mouseWentUp ()
 Event signal emitted when a mouse key 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...
 
SignalchildrenChanged ()
 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< SideclearSides () 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 WCssDecorationStyledecorationStyle () 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 WWidgetfind (const std::string &name) override
 Finds a descendent widget by name. More...
 
virtual WWidgetfindById (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...
 
EventSignalblurred ()
 Signal emitted when the widget lost focus. More...
 
EventSignalfocussed ()
 Signal emitted when the widget recieved focus. More...
 
virtual bool scrollVisibilityEnabled () const finaloverride
 Returns whether scroll visibility detection is enabled for this widget. More...
 
virtual void setScrollVisibilityEnabled (bool enabled) finaloverride
 Sets whether scroll visibility detection is enabled for this widget. More...
 
virtual int scrollVisibilityMargin () const finaloverride
 Returns the margin around the viewport within which the widget is considered visible. More...
 
virtual void setScrollVisibilityMargin (int margin) finaloverride
 Sets the margin around the viewport within which the widget is considered visible. More...
 
virtual Signal< bool > & scrollVisibilityChanged () finaloverride
 Signal triggered when the scroll visibility of this widget changes. More...
 
virtual bool isScrollVisible () const finaloverride
 Returns whether this widget is currently considered scroll visible. More...
 
virtual void setThemeStyleEnabled (bool enabled) finaloverride
 Sets whether theme styling for a widget is enabled or disabled. More...
 
virtual bool isThemeStyleEnabled () const finaloverride
 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...
 
- Public Member Functions inherited from Wt::WWidget
virtual ~WWidget ()
 Destructor. More...
 
WWidgetparent () const
 Returns the parent widget.
 
virtual std::unique_ptr< WWidgetremoveWidget (WWidget *widget)
 Removes a child widget.
 
std::unique_ptr< WWidgetremoveFromParent ()
 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< WObjectremoveChild (WObject *child)
 Remove a child WObject, so its lifetime is no longer determined by this WObject.
 
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...
 

Protected Member Functions

WJavaScriptHandle< WTransformcreateJSTransform ()
 Create a WTransform that is accessible from JavaScript, associated with this WPaintedWidget.
 
WJavaScriptHandle< WBrushcreateJSBrush ()
 Create a WBrush that is accessible from JavaScript, associated with this WPaintedWidget.
 
WJavaScriptHandle< WPencreateJSPen ()
 Create a WPen that is accessible from JavaScript, associated with this WPaintedWidget.
 
WJavaScriptHandle< WPainterPathcreateJSPainterPath ()
 Create a WPainterPath that is accessible from JavaScript, associated with this WPaintedWidget.
 
WJavaScriptHandle< WRectFcreateJSRect ()
 Create a WRectF that is accessible from JavaScript, associated with this WPaintedWidget.
 
WJavaScriptHandle< WPointFcreateJSPoint ()
 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< WPaintDevicecreatePaintDevice () 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:

BrowserMethods Default method
Firefox 1.5+HtmlCanvas, InlineSVG, PngImage HtmlCanvas
Internet Explorer 6.0+InlineVML, PngImage InlineVML
Internet Explorer 9+HtmlCanvas, InlineSVG, PngImage HtmlCanvas
SafariHtmlCanvas, InlineSVG, PngImage HtmlCanvas
OperaInlineSVG, 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()
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

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

Returns the interactive areas set for this widget.

See also
addArea()
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.

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.

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.

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 *)
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.

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.
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::WCartesianChart, Wt::Chart::WPieChart, and Wt::Chart::WAxisSliderWidget.

RenderMethod Wt::WPaintedWidget::preferredMethod ( ) const

Returns the preferred rendering method.

See also
setPreferredMethod(Method)
std::unique_ptr< WAbstractArea > Wt::WPaintedWidget::removeArea ( WAbstractArea area)

Removes an interactive area.

Removes the area from this widget.

See also
addArea(WAbstractArea *)
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.

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()
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.

void Wt::WPaintedWidget::setPreferredMethod ( RenderMethod  method)

Sets the preferred rendering method.

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

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.


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