Wt  4.0.2
Public Member Functions | Static Public Attributes | Protected Member Functions | List of all members
Wt::WVirtualImage Class Reference

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

#include <Wt/WVirtualImage.h>

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

Public Member Functions

 WVirtualImage (int viewPortWidth, int viewPortHeight,::int64_t imageWidth,::int64_t imageHeight, int gridImageSize=256)
 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 ()
 Creates a WCompositeWidget. More...
 
 WCompositeWidget (std::unique_ptr< WWidget > implementation)
 Creates a WCompositeWidget with given implementation. More...
 
virtual std::vector< WWidget * > children () const override
 Returns child widgets. More...
 
virtual std::unique_ptr< WWidgetremoveWidget (WWidget *widget) override
 Removes a child widget.
 
virtual void setObjectName (const std::string &name) override
 Sets an object name. More...
 
virtual std::string objectName () const override
 Returns the object name. More...
 
virtual const std::string id () const override
 Returns the (unique) identifier for this object. 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 void resize (const WLength &width, const WLength &height) override
 Resizes the widget. 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 isEnabled () const override
 Returns whether the widget is enabled. More...
 
virtual void setPopup (bool popup) override
 Lets the widget overlay over other sibling widgets. 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::Auto) 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 WString toolTip () const override
 Returns the tooltip.
 
virtual void setDeferredToolTip (bool enable, TextFormat textFormat=TextFormat::Plain) override
 Enable deferred tooltip. More...
 
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 void load () override
 Loads content just before the widget is used. More...
 
virtual bool loaded () const override
 Returns whether this widget has been loaded. 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 void setFocus (bool focus) override
 Sets focus. More...
 
virtual bool setFirstFocus () override
 Set focus on the widget's first descendant. 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...
 
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 &name) override
 Finds a descendent widget by id.
 
virtual void setSelectable (bool selectable) override
 Sets as selectable. More...
 
virtual void doJavaScript (const std::string &js) override
 Executes the given JavaScript statements when the widget is rendered or updated. More...
 
virtual void propagateSetEnabled (bool enabled) override
 Propagates that a widget was enabled or disabled through children. 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...
 
- Public Member Functions inherited from Wt::WWidget
virtual ~WWidget ()
 Destructor. More...
 
WWidgetparent () const
 Returns the parent 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.
 
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...
 

Static Public Attributes

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

Protected Member Functions

virtual std::unique_ptr< WImagecreateImage (::int64_t x,::int64_t y, int width, int height)
 Creates a grid image for the given rectangle. More...
 
virtual std::unique_ptr< WResourcerender (::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 () override
 Progresses to an Ajax-enabled widget. More...
 
void setImplementation (std::unique_ptr< WWidget > widget)
 Set the implementation widget. More...
 
WWidgetimplementation ()
 Method::Get the implementation widget. More...
 
virtual int boxPadding (Orientation orientation) const override
 Returns the widget's built-in padding. More...
 
virtual int boxBorder (Orientation orientation) const override
 Returns the widget's built-in border width. More...
 
virtual void render (WFlags< RenderFlag > flags) override
 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 ()
 Creates a widget.
 
virtual void dropEvent (WDropEvent dropEvent)
 Handles a drop event. More...
 
void scheduleRender (WFlags< RepaintFlag > flags=None)
 Schedules rerendering of the widget. More...
 
virtual WStatelessSlot * getStateless (Method method) override
 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...
 

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

Wt::WVirtualImage::WVirtualImage ( int  viewPortWidth,
int  viewPortHeight,
::int64_t  imageWidth,
::int64_t  imageHeight,
int  gridImageSize = 256 
)

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

std::unique_ptr< 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()
::int64_t Wt::WVirtualImage::currentBottomRightX ( ) const

Returns the current bottom right X coordinate.

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

Returns the current bottom right Y coordinate.

See also
currentBottomRightX()
::int64_t Wt::WVirtualImage::currentTopLeftX ( ) const

Returns the current top left X coordinate.

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

Returns the current top left Y coordinate.

See also
currentTopLeftX()
void Wt::WVirtualImage::enableDragging ( )

Enables mouse dragging to scroll around the image.

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

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.

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

Returns the virtual image height.

See also
imageWidth(), resizeImage()
::int64_t Wt::WVirtualImage::imageWidth ( ) const

Returns the virtual image width.

See also
imageHeight(), resizeImage()
void Wt::WVirtualImage::redrawAll ( )

Regenerates and redraws the image pieces.

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

std::unique_ptr< 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()
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()
void Wt::WVirtualImage::scroll ( ::int64_t  dx,
::int64_t  dy 
)

Scrolls the viewport of the image over a distance.

See also
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()
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().

int Wt::WVirtualImage::viewPortHeight ( ) const

Returns the viewport height.

See also
viewPortWidth()
int Wt::WVirtualImage::viewPortWidth ( ) const

Returns the viewport width.

See also
viewPortHeight()

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