An abstract widget that shows a viewport to a virtually large image. More...

#include <Wt/WVirtualImage>

Inheritance diagram for Wt::WVirtualImage:

Public Member Functions
	WVirtualImage (int viewPortWidth, int viewPortHeight, ::int64_t imageWidth, ::int64_t imageHeight, int gridImageSize=256, WContainerWidget *parent=0)
	Creates a viewport for a virtual image. More...

	~WVirtualImage ()
	Destructor.

void	redrawAll ()
	Regenerates and redraws the image pieces. More...

void	enableDragging ()
	Enables mouse dragging to scroll around the image. More...

void	scroll (::int64_t dx, ::int64_t dy)
	Scrolls the viewport of the image over a distance. More...

void	scrollTo (::int64_t x, ::int64_t y)
	Scrolls the viewport of the image to a specific coordinate. More...

::int64_t	imageWidth () const
	Returns the virtual image width. More...

::int64_t	imageHeight () const
	Returns the virtual image height. More...

void	resizeImage (::int64_t w, ::int64_t h)
	Resizes the virtual image. More...

int	viewPortWidth () const
	Returns the viewport width. More...

int	viewPortHeight () const
	Returns the viewport height. More...

int	gridImageSize () const
	Returns the size of a single piece. More...

::int64_t	currentTopLeftX () const
	Returns the current top left X coordinate. More...

::int64_t	currentTopLeftY () const
	Returns the current top left Y coordinate. More...

::int64_t	currentBottomRightX () const
	Returns the current bottom right X coordinate. More...

::int64_t	currentBottomRightY () const
	Returns the current bottom right Y coordinate. More...

Signal< ::int64_t, ::int64_t > &	viewPortChanged ()
	Signal emitted whenever the viewport changes. More...

Public Member Functions inherited from Wt::WCompositeWidget
	WCompositeWidget (WContainerWidget *parent=0)
	Creates a WCompositeWidget. More...

	WCompositeWidget (WWidget implementation, WContainerWidget parent)
	Creates a WCompositeWidget with given implementation. More...

virtual void	setObjectName (const std::string &name)
	Sets an object name. More...

virtual std::string	objectName () const
	Returns the object name. More...

virtual const std::string	id () const
	Returns the (unique) identifier for this object. More...

virtual void	setPositionScheme (PositionScheme scheme)
	Sets the CSS position scheme. More...

virtual PositionScheme	positionScheme () const
	Returns the CSS position scheme. More...

virtual void	setOffsets (const WLength &offset, WFlags< Side > sides=All)
	Sets CSS offsets for a non-statically positioned widget. More...

virtual WLength	offset (Side s) const
	Returns a CSS offset. More...

virtual void	resize (const WLength &width, const WLength &height)
	Resizes the widget. More...

virtual WLength	width () const
	Returns the width. More...

virtual WLength	height () const
	Returns the height. More...

virtual void	setMinimumSize (const WLength &width, const WLength &height)
	Sets a minimum size. More...

virtual WLength	minimumWidth () const
	Returns the minimum width. More...

virtual WLength	minimumHeight () const
	Returns the minimum height. More...

virtual void	setMaximumSize (const WLength &width, const WLength &height)
	Sets a maximum size. More...

virtual WLength	maximumWidth () const
	Returns the maximum width. More...

virtual WLength	maximumHeight () const
	Returns the maximum height. More...

virtual void	setLineHeight (const WLength &height)
	Sets the CSS line height for contained text.

virtual WLength	lineHeight () const
	Returns the CSS line height for contained text. More...

virtual void	setFloatSide (Side s)
	Specifies a CSS float side. More...

virtual Side	floatSide () const
	Returns the CSS float side. More...

virtual void	setClearSides (WFlags< Side > sides)
	Sets the sides that should be cleared of floats. More...

virtual WFlags< Side >	clearSides () const
	Returns the sides that should remain empty. More...

virtual void	setMargin (const WLength &margin, WFlags< Side > sides=All)
	Sets CSS margins around the widget. More...

virtual WLength	margin (Side side) const
	Returns a CSS margin set. More...

virtual void	setHiddenKeepsGeometry (bool enabled)
	Sets whether the widget keeps its geometry when hidden. More...

virtual bool	hiddenKeepsGeometry () const
	Returns whether the widget keeps its geometry when hidden. More...

virtual void	setHidden (bool hidden, const WAnimation &animation=WAnimation())
	Hides or shows the widget. More...

virtual bool	isHidden () const
	Returns whether the widget is set hidden. More...

virtual bool	isVisible () const
	Returns whether the widget is visible. More...

virtual void	setDisabled (bool disabled)
	Sets whether the widget is disabled. More...

virtual bool	isDisabled () const
	Returns whether the widget is set disabled. More...

virtual bool	isEnabled () const
	Returns whether the widget is enabled. More...

virtual void	setPopup (bool popup)
	Lets the widget overlay over other sibling widgets. More...

virtual bool	isPopup () const
	Returns whether the widget is overlayed. More...

virtual void	setInline (bool isInline)
	Sets whether the widget is displayed inline or as a block. More...

virtual bool	isInline () const
	Returns whether the widget is displayed inline or as block. More...

virtual void	setDecorationStyle (const WCssDecorationStyle &style)
	Sets a CSS decoration style. More...

virtual WCssDecorationStyle &	decorationStyle ()
	Returns the decoration style of this widget. More...

virtual void	setStyleClass (const WString &styleClass)
	Sets (one or more) CSS style classes. More...

virtual WString	styleClass () const
	Returns the CSS style class. More...

virtual void	addStyleClass (const WString &styleClass, bool force=false)
	Adds a CSS style class. More...

virtual void	removeStyleClass (const WString &styleClass, bool force=false)
	Removes a CSS style class. More...

virtual bool	hasStyleClass (const WString &styleClass) const
	Returns whether the widget has a style class.

virtual void	setVerticalAlignment (AlignmentFlag alignment, const WLength &length=WLength::Auto)
	Sets the vertical alignment. More...

virtual AlignmentFlag	verticalAlignment () const
	Returns the vertical alignment. More...

virtual WLength	verticalAlignmentLength () const
	Returns the fixed vertical alignment that was set. More...

virtual void	setToolTip (const WString &text, TextFormat textFormat=PlainText)
	Sets a tooltip. More...

virtual WString	toolTip () const
	Returns the tooltip.

virtual void	setDeferredToolTip (bool enable, TextFormat textFormat=PlainText)
	Enable deferred tooltip. More...

virtual void	refresh ()
	Refresh the widget. More...

virtual void	setAttributeValue (const std::string &name, const WString &value)
	Sets an attribute value. More...

virtual WString	attributeValue (const std::string &name) const
	Returns an attribute value. More...

virtual void	setJavaScriptMember (const std::string &name, const std::string &value)
	Sets a JavaScript member. More...

virtual std::string	javaScriptMember (const std::string &name) const
	Returns the value of a JavaScript member. More...

virtual void	callJavaScriptMember (const std::string &name, const std::string &args)
	Calls a JavaScript member. More...

virtual void	load ()
	Loads content just before the widget is used. More...

virtual bool	loaded () const
	Returns whether this widget has been loaded. More...

virtual void	setCanReceiveFocus (bool enabled)
	Sets whether the widget can receive focus. More...

virtual bool	canReceiveFocus () const
	Returns whether the widget can receive focus. More...

virtual void	setFocus (bool focus)
	Sets focus. More...

virtual bool	setFirstFocus ()
	Set focus on the widget's first descendant. More...

virtual bool	hasFocus () const
	Returns whether the widget currently has the focus.

virtual void	setTabIndex (int index)
	Sets the tab index. More...

virtual int	tabIndex () const
	Returns the tab index. More...

virtual void	setId (const std::string &id)
	Sets the CSS Id. More...

virtual WWidget *	find (const std::string &name)
	Finds a descendent widget by name. More...

virtual WWidget *	findById (const std::string &name)
	Finds a descendent widget by id.

virtual void	setSelectable (bool selectable)
	Sets as selectable. More...

virtual void	doJavaScript (const std::string &js)
	Executes the given JavaScript statements when the widget is rendered or updated. More...

virtual void	propagateSetEnabled (bool enabled)
	Propagates that a widget was enabled or disabled through children. More...

virtual bool	scrollVisibilityEnabled () const WT_CXX11ONLY(final override)
	Returns whether scroll visibility detection is enabled for this widget. More...

virtual void	setScrollVisibilityEnabled (bool enabled) WT_CXX11ONLY(final override)
	Sets whether scroll visibility detection is enabled for this widget. More...

virtual int	scrollVisibilityMargin () const WT_CXX11ONLY(final override)
	Returns the margin around the viewport within which the widget is considered visible. More...

virtual void	setScrollVisibilityMargin (int margin) WT_CXX11ONLY(final override)
	Sets the margin around the viewport within which the widget is considered visible. More...

virtual Signal< bool > &	scrollVisibilityChanged () WT_CXX11ONLY(final override)
	Signal triggered when the scroll visibility of this widget changes. More...

virtual bool	isScrollVisible () const WT_CXX11ONLY(final override)
	Returns whether this widget is currently considered scroll visible. More...

virtual void	setThemeStyleEnabled (bool enabled)
	Sets whether theme styling for a widget is enabled or disabled. More...

virtual bool	isThemeStyleEnabled () const
	Returns whether this widget is currently styled by the chosen theme. More...

Public Member Functions inherited from Wt::WWidget
virtual	~WWidget ()
	Destructor. More...

WWidget *	parent () const
	Returns the parent widget. More...

virtual void	removeChild (WObject *child)
	Removes a child object. 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=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
	WObject (WObject *parent=0)
	Create a WObject with a given parent object. More...

virtual	~WObject ()
	Destructor. 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...

void	addChild (WObject *child)
	Adds a child object. More...

const std::vector< WObject * > &	children () const
	Returns the children.

WObject *	parent () const
	Returns the parent object.

Static Public Attributes
static const ::int64_t	Infinite = std::numeric_limits< ::int64_t >::max()
	Special value for imageWidth or imageHeight.

Protected Member Functions
virtual WImage *	createImage (::int64_t x, ::int64_t y, int width, int height)
	Creates a grid image for the given rectangle. More...

virtual WResource *	render (::int64_t x, ::int64_t y, int width, int height)
	Render a grid image for the given rectangle. More...

Protected Member Functions inherited from Wt::WCompositeWidget
virtual void	enableAjax ()
	Progresses to an Ajax-enabled widget. More...

void	setImplementation (WWidget *widget)
	Set the implementation widget. More...

WWidget *	implementation ()
	Get the implementation widget. 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...

virtual void	render (WFlags< RenderFlag > flags)
	Renders the widget. 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...

virtual void	layoutSizeChanged (int width, int height)
	Virtual method that indicates a size change. More...

	WWidget (WContainerWidget *parent=0)
	Creates a widget. More...

virtual void	dropEvent (WDropEvent dropEvent)
	Handles a drop event. More...

void	scheduleRender (WFlags< RepaintFlag > flags=0)
	Schedules rerendering of the widget. More...

virtual WStatelessSlot *	getStateless (Method method)
	On-demand stateless slot implementation. 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::WWidget
static WString	tr (const char *key)
	Short hand for WString::tr() More...

Static Protected Member Functions inherited from Wt::WObject
static WObject *	sender ()
	Returns the sender of the current slot call. More...

Detailed Description

An abstract widget that shows a viewport to a virtually large image.

WVirtualImage is an abstract class which renders a large image in small pieces. The large image is broken down, and rendered as a grid of smaller square images parts.

The WVirtualImage may provide interactive navigation using the mouse, by reacting to dragging of the mouse on the image.

The WVirtualImage renders pieces in and bordering the current viewport. In this way, provided the individual pieces load sufficiently fast, the user has effectively the impression of scrolling through a single large image, without glitches. Whenever the image is navigated, if necessary, new images are rendered to maintain the border. Images that are too far from the current viewport are pruned away, so that browser memory remains bounded.

To use this class, you must reimplement one of two virtual methods to specify the contents of each grid piece. Either you provide a suitable WImage for every grid piece, or you provide a WResource which renders the contents for a WImage for every grid piece.

The total image dimensions are (0, 0) to (imageWidth, imageHeight) for a finite image, and become unbounded (including negative numbers) for each dimension which is Infinite.

CSS

Styling through CSS is not applicable.

Constructor & Destructor Documentation

◆ WVirtualImage()

Wt::WVirtualImage::WVirtualImage	(	int	viewPortWidth,
		int	viewPortHeight,
		::int64_t	imageWidth,
		::int64_t	imageHeight,
		int	gridImageSize = `256`,
		WContainerWidget *	parent = `0`
	)

Creates a viewport for a virtual image.

You must specify the size of the viewport, and the size of the virtual image. The latter dimensions may be the special value Infinite, indicating that in one or more dimensions, the image size is infinite (in practice limited by the maximum integer value).

In addition, you must specify the size of each square grid item. The default is 256 by 256.

Member Function Documentation

◆ createImage()

WImage * Wt::WVirtualImage::createImage	(	::int64_t	x,
		::int64_t	y,
		int	width,
		int	height
	)

protectedvirtual

Creates a grid image for the given rectangle.

Create the image which spans image coordinates with left upper corner (x, y) and given width and height.

Width and height will not necesarilly equal gridImageSize(), if the the image is not infinite sized.

The default implementation calls render() and creates an image for the resource returned.

You should override this method if you wish to serve for example static image content.

See also: render()

◆ currentBottomRightX()

::int64_t Wt::WVirtualImage::currentBottomRightX ( ) const

Returns the current bottom right X coordinate.

See also: currentBottomRightY()

◆ currentBottomRightY()

::int64_t Wt::WVirtualImage::currentBottomRightY ( ) const

Returns the current bottom right Y coordinate.

See also: currentBottomRightX()

◆ currentTopLeftX()

::int64_t Wt::WVirtualImage::currentTopLeftX ( ) const

Returns the current top left X coordinate.

See also: currentTopLeftY()

◆ currentTopLeftY()

::int64_t Wt::WVirtualImage::currentTopLeftY ( ) const

Returns the current top left Y coordinate.

See also: currentTopLeftX()

◆ enableDragging()

void Wt::WVirtualImage::enableDragging ( )

Enables mouse dragging to scroll around the image.

The cursor is changed to a 'move' symbol to indicate the interactivity.

◆ gridImageSize()

int Wt::WVirtualImage::gridImageSize ( ) const

Returns the size of a single piece.

This is the size of a side of the square pieces that is used to render the visible part of the image.

◆ imageHeight()

::int64_t Wt::WVirtualImage::imageHeight ( ) const

Returns the virtual image height.

See also: imageWidth(), resizeImage()

◆ imageWidth()

::int64_t Wt::WVirtualImage::imageWidth ( ) const

Returns the virtual image width.

See also: imageHeight(), resizeImage()

◆ redrawAll()

void Wt::WVirtualImage::redrawAll ( )

Regenerates and redraws the image pieces.

This method invalidates all current grid images, and recreates them.

◆ render()

WResource * Wt::WVirtualImage::render	(	::int64_t	x,
		::int64_t	y,
		int	width,
		int	height
	)

protectedvirtual

Render a grid image for the given rectangle.

Returns a resource that streams an image which renders the rectangle which spans image coordinates with left upper corner (x, y) and given width and height.

Width and height will not necesarilly equal to gridImageSize(), if the the image is not infinite sized.

The default implementation throws an Exception. You must reimplement this method unless you reimplement createImage().

See also: createImage()

◆ resizeImage()

void Wt::WVirtualImage::resizeImage	(	::int64_t	w,
		::int64_t	h
	)

Resizes the virtual image.

This sets a new virtual size for the image. The viewport size sets the visible portion of the image.

See also: imageWidth(), imageHeight()

◆ scroll()

void Wt::WVirtualImage::scroll	(	::int64_t	dx,
		::int64_t	dy
	)

Scrolls the viewport of the image over a distance.

See also: scrollTo()

◆ scrollTo()

void Wt::WVirtualImage::scrollTo	(	::int64_t	x,
		::int64_t	y
	)

Scrolls the viewport of the image to a specific coordinate.

Scroll the viewport so that its top left coordinate becomes (x, y).

See also: scroll()

◆ viewPortChanged()

Signal< ::int64_t, ::int64_t >& Wt::WVirtualImage::viewPortChanged ( )

Signal emitted whenever the viewport changes.

The viewport can be changed by the user dragging the image or through the API methods scrollTo() and scroll().

◆ viewPortHeight()

int Wt::WVirtualImage::viewPortHeight ( ) const

Returns the viewport height.

See also: viewPortWidth()

◆ viewPortWidth()

int Wt::WVirtualImage::viewPortWidth ( ) const

Returns the viewport width.

See also: viewPortHeight()

Public Member Functions

Static Public Attributes

Protected Member Functions

Additional Inherited Members