Wt
4.11.0
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A widget that displays an image. More...
#include <Wt/WImage.h>
Public Member Functions | |
WImage () | |
Creates an empty image widget. | |
WImage (const WLink &imageLink) | |
Creates an image widget with a given image link. | |
WImage (const WLink &imageLink, const WString &altText) | |
Creates an image widget with a given image link and alternate text. | |
void | setAlternateText (const WString &text) |
Sets an alternate text. | |
const WString & | alternateText () const |
Returns the alternate text. | |
void | setImageLink (const WLink &link) |
Sets the image link. | |
const WLink & | imageLink () const |
Returns the image link. | |
void | addArea (std::unique_ptr< WAbstractArea > area) |
Adds an interactive area. | |
template<typename Area > | |
Area * | addArea (std::unique_ptr< Area > area) |
Adds an interactive area, returning a raw pointer. | |
void | insertArea (int index, std::unique_ptr< WAbstractArea > area) |
Inserts an interactive area. | |
template<typename Area > | |
Area * | insertArea (int index, std::unique_ptr< Area > area) |
Inserts an interactive area, returning a raw pointer. | |
std::unique_ptr< WAbstractArea > | removeArea (WAbstractArea *area) |
Removes an interactive area. | |
WAbstractArea * | area (int index) const |
Returns the interactive area at the given index. | |
const std::vector< WAbstractArea * > | areas () const |
Returns the interactive areas set for this widget. | |
EventSignal & | imageLoaded () |
Event emitted when the image was loaded. | |
Public Member Functions inherited from Wt::WInteractWidget | |
WInteractWidget () | |
Create an InteractWidget. | |
EventSignal< WKeyEvent > & | keyWentDown () |
Event signal emitted when a keyboard key is pushed down. | |
EventSignal< WKeyEvent > & | keyPressed () |
Event signal emitted when a "character" was entered. | |
EventSignal< WKeyEvent > & | keyWentUp () |
Event signal emitted when a keyboard key is released. | |
EventSignal & | enterPressed () |
Event signal emitted when enter was pressed. | |
EventSignal & | escapePressed () |
Event signal emitted when escape was pressed. | |
EventSignal< WMouseEvent > & | clicked () |
Event signal emitted when the primary mouse button was clicked on this widget. | |
EventSignal< WMouseEvent > & | doubleClicked () |
Event signal emitted when the primary mouse button was double clicked on this widget. | |
EventSignal< WMouseEvent > & | mouseWentDown () |
Event signal emitted when a mouse button was pushed down on this widget. | |
EventSignal< WMouseEvent > & | mouseWentUp () |
Event signal emitted when a mouse button was released on this widget. | |
EventSignal< WMouseEvent > & | mouseWentOut () |
Event signal emitted when the mouse went out of this widget. | |
EventSignal< WMouseEvent > & | mouseWentOver () |
Event signal emitted when the mouse entered this widget. | |
EventSignal< WMouseEvent > & | mouseMoved () |
Event signal emitted when the mouse moved over this widget. | |
EventSignal< WMouseEvent > & | mouseDragged () |
Event signal emitted when the mouse is dragged over this widget. | |
EventSignal< WMouseEvent > & | mouseWheel () |
Event signal emitted when the mouse scroll wheel was used. | |
EventSignal< WTouchEvent > & | touchStarted () |
Event signal emitted when a finger is placed on the screen. | |
EventSignal< WTouchEvent > & | touchEnded () |
Event signal emitted when a finger is removed from the screen. | |
EventSignal< WTouchEvent > & | touchMoved () |
Event signal emitted when a finger, which is already placed on the screen, is moved across the screen. | |
EventSignal< WGestureEvent > & | gestureStarted () |
Event signal emitted when a gesture is started. | |
EventSignal< WGestureEvent > & | gestureChanged () |
Event signal emitted when a gesture is changed. | |
EventSignal< WGestureEvent > & | gestureEnded () |
Event signal emitted when a gesture is ended. | |
void | setDraggable (const std::string &mimeType, WWidget *dragWidget=nullptr, bool isDragWidgetOnly=false, WObject *sourceWidget=nullptr) |
Configure dragging for drag and drop. | |
void | unsetDraggable () |
Disable drag & drop for this widget. | |
void | setMouseOverDelay (int delay) |
Sets a delay for the mouse over event. | |
int | mouseOverDelay () const |
Returns the mouse over signal delay. | |
virtual void | setPopup (bool popup) override |
Lets the widget overlay over other sibling widgets. | |
virtual void | load () override |
Loads content just before the widget is used. | |
virtual bool | isEnabled () const override |
Returns whether the widget is enabled. | |
Public Member Functions inherited from Wt::WWebWidget | |
WWebWidget () | |
Construct a WebWidget. | |
virtual std::vector< WWidget * > | children () const override |
Returns child widgets. | |
Signal & | childrenChanged () |
Signal emitted when children have been added or removed. | |
virtual void | setPositionScheme (PositionScheme scheme) override |
Sets the CSS position scheme. | |
virtual PositionScheme | positionScheme () const override |
Returns the CSS position scheme. | |
virtual void | setOffsets (const WLength &offset, WFlags< Side > sides=AllSides) override |
Sets CSS offsets for a non-statically positioned widget. | |
virtual WLength | offset (Side s) const override |
Returns a CSS offset. | |
virtual void | resize (const WLength &width, const WLength &height) override |
Resizes the widget. | |
virtual WLength | width () const override |
Returns the width. | |
virtual WLength | height () const override |
Returns the height. | |
virtual void | setMinimumSize (const WLength &width, const WLength &height) override |
Sets a minimum size. | |
virtual WLength | minimumWidth () const override |
Returns the minimum width. | |
virtual WLength | minimumHeight () const override |
Returns the minimum height. | |
virtual void | setMaximumSize (const WLength &width, const WLength &height) override |
Sets a maximum size. | |
virtual WLength | maximumWidth () const override |
Returns the maximum width. | |
virtual WLength | maximumHeight () const override |
Returns the maximum height. | |
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. | |
virtual void | setFloatSide (Side s) override |
Specifies a CSS float side. | |
virtual Side | floatSide () const override |
Returns the CSS float side. | |
virtual void | setClearSides (WFlags< Side > sides) override |
Sets the sides that should be cleared of floats. | |
virtual WFlags< Side > | clearSides () const override |
Returns the sides that should remain empty. | |
virtual void | setMargin (const WLength &margin, WFlags< Side > sides=AllSides) override |
Sets CSS margins around the widget. | |
virtual WLength | margin (Side side) const override |
Returns a CSS margin set. | |
virtual void | setHiddenKeepsGeometry (bool enabled) override |
Sets whether the widget keeps its geometry when hidden. | |
virtual bool | hiddenKeepsGeometry () const override |
Returns whether the widget keeps its geometry when hidden. | |
virtual void | setHidden (bool hidden, const WAnimation &animation=WAnimation()) override |
Hides or shows the widget. | |
virtual bool | isHidden () const override |
Returns whether the widget is set hidden. | |
virtual bool | isVisible () const override |
Returns whether the widget is visible. | |
virtual void | setDisabled (bool disabled) override |
Sets whether the widget is disabled. | |
virtual bool | isDisabled () const override |
Returns whether the widget is set disabled. | |
virtual bool | isPopup () const override |
Returns whether the widget is overlayed. | |
virtual void | setInline (bool isInline) override |
Sets whether the widget is displayed inline or as a block. | |
virtual bool | isInline () const override |
Returns whether the widget is displayed inline or as block. | |
virtual void | setDecorationStyle (const WCssDecorationStyle &style) override |
Sets a CSS decoration style. | |
virtual WCssDecorationStyle & | decorationStyle () override |
Returns the decoration style of this widget. | |
virtual void | setStyleClass (const WString &styleClass) override |
Sets (one or more) CSS style classes. | |
virtual WString | styleClass () const override |
Returns the CSS style class. | |
virtual void | addStyleClass (const WString &styleClass, bool force=false) override |
Adds a CSS style class. | |
virtual void | removeStyleClass (const WString &styleClass, bool force=false) override |
Removes a CSS style class. | |
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. | |
virtual AlignmentFlag | verticalAlignment () const override |
Returns the vertical alignment. | |
virtual WLength | verticalAlignmentLength () const override |
Returns the fixed vertical alignment that was set. | |
virtual void | setToolTip (const WString &text, TextFormat textFormat=TextFormat::Plain) override |
Sets a tooltip. | |
virtual void | setDeferredToolTip (bool enable, TextFormat textFormat=TextFormat::Plain) override |
Enable deferred tooltip. | |
virtual WString | toolTip () const override |
Returns the tooltip. | |
virtual void | refresh () override |
Refresh the widget. | |
virtual void | setAttributeValue (const std::string &name, const WString &value) override |
Sets an attribute value. | |
virtual WString | attributeValue (const std::string &name) const override |
Returns an attribute value. | |
virtual void | setJavaScriptMember (const std::string &name, const std::string &value) override |
Sets a JavaScript member. | |
virtual std::string | javaScriptMember (const std::string &name) const override |
Returns the value of a JavaScript member. | |
virtual void | callJavaScriptMember (const std::string &name, const std::string &args) override |
Calls a JavaScript member. | |
virtual bool | loaded () const override |
Returns whether this widget has been loaded. | |
virtual void | setId (const std::string &id) override |
Sets the CSS Id. | |
virtual WWidget * | find (const std::string &name) override |
Finds a descendent widget by name. | |
virtual WWidget * | findById (const std::string &id) override |
Finds a descendent widget by id. | |
virtual void | setSelectable (bool selectable) override |
Sets as selectable. | |
virtual void | doJavaScript (const std::string &javascript) override |
Executes the given JavaScript statements when the widget is rendered or updated. | |
virtual const std::string | id () const override |
Returns the (unique) identifier for this object. | |
void | setLoadLaterWhenInvisible (bool) |
Change the way the widget is loaded when invisible. | |
std::string | htmlTagName () const |
returns the current html tag name | |
void | setHtmlTagName (const std::string &tag) |
set the custom HTML tag name | |
virtual void | setCanReceiveFocus (bool enabled) override |
Sets whether the widget can receive focus. | |
virtual bool | canReceiveFocus () const override |
Returns whether the widget can receive focus. | |
virtual bool | setFirstFocus () override |
Set focus on the widget's first descendant. | |
virtual void | setFocus (bool focus) override |
Sets focus. | |
virtual bool | hasFocus () const override |
Returns whether the widget currently has the focus. | |
virtual void | setTabIndex (int index) override |
Sets the tab index. | |
virtual int | tabIndex () const override |
Returns the tab index. | |
EventSignal & | blurred () |
Signal emitted when the widget lost focus. | |
EventSignal & | focussed () |
Signal emitted when the widget recieved focus. | |
virtual bool | scrollVisibilityEnabled () const final override |
Returns whether scroll visibility detection is enabled for this widget. | |
virtual void | setScrollVisibilityEnabled (bool enabled) final override |
Sets whether scroll visibility detection is enabled for this widget. | |
virtual int | scrollVisibilityMargin () const final override |
Returns the margin around the viewport within which the widget is considered visible. | |
virtual void | setScrollVisibilityMargin (int margin) final override |
Sets the margin around the viewport within which the widget is considered visible. | |
virtual Signal< bool > & | scrollVisibilityChanged () final override |
Signal triggered when the scroll visibility of this widget changes. | |
virtual bool | isScrollVisible () const final override |
Returns whether this widget is currently considered scroll visible. | |
virtual void | setThemeStyleEnabled (bool enabled) final override |
Sets whether theme styling for a widget is enabled or disabled. | |
virtual bool | isThemeStyleEnabled () const final override |
Returns whether this widget is currently styled by the chosen theme. | |
virtual void | setObjectName (const std::string &name) override |
Sets an object name. | |
void | setFocus () |
Sets focus. | |
virtual void | setFocus (bool focus)=0 |
Sets focus. | |
Public Member Functions inherited from Wt::WWidget | |
virtual | ~WWidget () |
Destructor. | |
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. | |
std::unique_ptr< WWidget > | removeFromParent () |
Removes the widget from its parent. | |
void | setWidth (const WLength &width) |
Sets the width. | |
void | setHeight (const WLength &height) |
Sets the height. | |
virtual void | positionAt (const WWidget *widget, Orientation orientation=Orientation::Vertical) |
Positions a widget next to another widget. | |
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. | |
void | setFocus () |
Sets focus. | |
virtual void | acceptDrops (const std::string &mimeType, const WString &hoverStyleClass=WString()) |
Sets a mime type to be accepted for dropping. | |
virtual void | stopAcceptDrops (const std::string &mimeType) |
Indicates that a mime type is no longer accepted for dropping. | |
virtual void | htmlText (std::ostream &out) |
Streams the (X)HTML representation. | |
bool | isRendered () const |
Returns whether the widget is rendered. | |
void | hide () |
Hides the widget. | |
void | animateHide (const WAnimation &animation) |
Hides the widget using an animation. | |
void | show () |
Shows the widget. | |
void | animateShow (const WAnimation &animation) |
Shows the widget using an animation. | |
void | enable () |
Enables the widget. | |
void | disable () |
Disable thes widget. | |
bool | layoutSizeAware () const |
Returns whether the widget is layout size aware. | |
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. | |
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. | |
virtual std::string | objectName () const |
Returns the object name. | |
void | resetLearnedSlots () |
Resets learned stateless slot implementations. | |
template<class T > | |
void | resetLearnedSlot (void(T::*method)()) |
Resets a learned stateless slot implementation. | |
template<class T > | |
WStatelessSlot * | implementStateless (void(T::*method)()) |
Declares a slot to be stateless and learn client-side behaviour on first invocation. | |
template<class T > | |
WStatelessSlot * | implementStateless (void(T::*method)(), void(T::*undoMethod)()) |
Declares a slot to be stateless and learn client-side behaviour in advance. | |
void | isNotStateless () |
Marks the current function as not stateless. | |
template<class T > | |
WStatelessSlot * | implementJavaScript (void(T::*method)(), const std::string &jsCode) |
Provides a JavaScript implementation for a method. | |
Public Member Functions inherited from Wt::Core::observable | |
observable () noexcept | |
Default constructor. | |
virtual | ~observable () |
Destructor. | |
template<typename... Args, typename C > | |
auto | bindSafe (void(C::*method)(Args...)) noexcept |
Protects a method call against object destruction. | |
template<typename... Args, typename C > | |
auto | bindSafe (void(C::*method)(Args...) const) const noexcept |
Protects a const method call against object destruction. | |
template<typename Function > | |
auto | bindSafe (const Function &function) noexcept |
Protects a function against object destruction. | |
Protected Member Functions | |
virtual void | render (WFlags< RenderFlag > flags) override |
Renders the widget. | |
Protected Member Functions inherited from Wt::WInteractWidget | |
virtual void | propagateSetEnabled (bool enabled) override |
Propagates that a widget was enabled or disabled through children. | |
Protected Member Functions inherited from Wt::WWebWidget | |
virtual void | enableAjax () override |
Progresses to an Ajax-enabled widget. | |
virtual WStatelessSlot * | getStateless (Method method) override |
On-demand stateless slot implementation. | |
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. | |
virtual void | layoutSizeChanged (int width, int height) |
Virtual method that indicates a size change. | |
WWidget () | |
Creates a widget. | |
virtual void | dropEvent (WDropEvent dropEvent) |
Handles a drop event. | |
virtual int | boxPadding (Orientation orientation) const |
Returns the widget's built-in padding. | |
virtual int | boxBorder (Orientation orientation) const |
Returns the widget's built-in border width. | |
void | scheduleRender (WFlags< RepaintFlag > flags=None) |
Schedules rerendering of the widget. | |
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. | |
Static Public Member Functions inherited from Wt::WWidget | |
static WString | tr (const char *key) |
Short hand for WString::tr() | |
A widget that displays an image.
The image may be specified either as a URL, or may be dynamically generated by a WResource.
You may listen to events by attaching event listeners to signals such as clicked(). Since mouse events pass the coordinates through a WMouseEvent object, it is possible to react to clicks in specific parts of the image. An alternative is to define interactive areas on the image using addArea(), which in addition allows to have customized tool tips for certain image areas (using WAbstractArea::setToolTip()).
Usage example:
WImage is an inline widget.
The widget corresponds to the HTML <img>
tag and does not provide styling. It can be styled using inline or external CSS as appropriate.
Creates an image widget with a given image link.
The imageLink
may link to a URL or resource.
Creates an image widget with a given image link and alternate text.
The imageLink
may link to a URL or resource.
Adds an interactive area, returning a raw pointer.
This is implemented as:
void Wt::WImage::addArea | ( | std::unique_ptr< WAbstractArea > | area | ) |
Adds an interactive area.
Adds the area
which listens to events in a specific region of the image. Areas are organized in an indexed list, to which the given area
is appended. When areas overlap, the area with the lowest index receives the event.
Ownership of the area
is transferred to the image.
Returns the alternate text.
WAbstractArea * Wt::WImage::area | ( | int | index | ) | const |
Returns the interactive area at the given index.
Returns 0
if index
was invalid.
const std::vector< WAbstractArea * > Wt::WImage::areas | ( | ) | const |
Returns the interactive areas set for this widget.
Inserts an interactive area, returning a raw pointer.
This is implemented as:
void Wt::WImage::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 image. 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.
Ownership of the area
is transferred to the image.
std::unique_ptr< WAbstractArea > Wt::WImage::removeArea | ( | WAbstractArea * | area | ) |
Removes an interactive area.
Removes the area
from this widget.
|
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.
Sets an alternate text.
The alternate text should provide a fallback for browsers that do not display an image. If no sensible fallback text can be provided, an empty text is preferred over nonsense.
This should not be confused with toolTip() text, which provides additional information that is displayed when the mouse hovers over the image.
The default alternate text is an empty text ("").