Canvas

extends FocusWidget

java.lang.Object
↳	com.google.gwt.user.client.ui.UIObject
	↳	com.google.gwt.user.client.ui.Widget
		↳	com.google.gwt.user.client.ui.FocusWidget
			↳	com.google.gwt.canvas.client.Canvas

Class Overview

A widget representing a <canvas> element.

Experimental API: This API is still under development and is subject to change.

This widget may not be supported on all browsers.

Summary

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Inherited Constants

From class com.google.gwt.user.client.ui.UIObject

Public Methods
static Canvas	createIfSupported() Return a new `Canvas` if supported, and null otherwise.
CanvasElement	getCanvasElement() Returns the attached Canvas Element.
Context	getContext(String contextId) Gets the rendering context that may be used to draw on this canvas.
Context2d	getContext2d() Returns a 2D rendering context.
int	getCoordinateSpaceHeight() Gets the height of the internal canvas coordinate space.
int	getCoordinateSpaceWidth() Gets the width of the internal canvas coordinate space.
static boolean	isSupported() Runtime check for whether the canvas element is supported in this browser.
void	setCoordinateSpaceHeight(int height) Sets the height of the internal canvas coordinate space.
void	setCoordinateSpaceWidth(int width) Sets the width of the internal canvas coordinate space.
String	toDataUrl() Returns a data URL for the current content of the canvas element.
String	toDataUrl(String type) Returns a data URL for the current content of the canvas element, with a specified type.

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Inherited Methods

From class com.google.gwt.user.client.ui.FocusWidget

From class com.google.gwt.user.client.ui.Widget

HandlerRegistration	addAttachHandler(AttachEvent.Handler handler) Adds an `AttachEvent` handler.
final <H extends EventHandler> HandlerRegistration	addDomHandler(H handler, Type<H> type) Adds a native event handler to the widget and sinks the corresponding native event.
final <H extends EventHandler> HandlerRegistration	addHandler(H handler, Type<H> type) Adds this handler to the widget.
Widget	asWidget() Returns the `Widget` aspect of the receiver.
static Widget	asWidgetOrNull(IsWidget w) This convenience method makes a null-safe call to `asWidget()`.
HandlerManager	createHandlerManager() Creates the `HandlerManager` used by this Widget.
void	delegateEvent(Widget target, GwtEvent<?> event) Fires an event on a child widget.
void	doAttachChildren() If a widget contains one or more child widgets that are not in the logical widget hierarchy (the child is physically connected only on the DOM level), it must override this method and call `onAttach()` for each of its child widgets.
void	doDetachChildren() If a widget contains one or more child widgets that are not in the logical widget hierarchy (the child is physically connected only on the DOM level), it must override this method and call `onDetach()` for each of its child widgets.
void	fireEvent(GwtEvent<?> event) Fires the given event to the handlers listening to the event's type.
int	getHandlerCount(Type<?> type) Gets the number of handlers listening to the event type.
Object	getLayoutData() Gets the panel-defined layout data associated with this widget.
Widget	getParent() Gets this widget's parent panel.
boolean	isAttached() Determines whether this widget is currently attached to the browser's document (i.e., there is an unbroken chain of widgets between this widget and the underlying browser document).
final boolean	isOrWasAttached() Has this widget ever been attached?
void	onAttach() This method is called when a widget is attached to the browser's document.
void	onBrowserEvent(Event event) Fired whenever a browser event is received.
void	onDetach() This method is called when a widget is detached from the browser's document.
void	onLoad() This method is called immediately after a widget becomes attached to the browser's document.
void	onUnload() This method is called immediately before a widget will be detached from the browser's document.
void	removeFromParent() Removes this widget from its parent widget, if one exists.
void	setLayoutData(Object layoutData) Sets the panel-defined layout data associated with this widget.
void	sinkEvents(int eventBitsToAdd) Overridden to defer the call to super.sinkEvents until the first time this widget is attached to the dom, as a performance enhancement.

From class com.google.gwt.user.client.ui.UIObject

void	addStyleDependentName(String styleSuffix) Adds a dependent style name by specifying the style name's suffix.
void	addStyleName(String style) Adds a secondary or dependent style name to this object.
static void	ensureDebugId(Element elem, String baseID, String id) Set the debug id of a specific element.
final void	ensureDebugId(String id) Ensure that the main `Element` for this `UIObject` has an ID property set, which allows it to integrate with third-party libraries and test tools.
static void	ensureDebugId(Element elem, String id) Ensure that elem has an ID property set, which allows it to integrate with third-party libraries and test tools.
int	getAbsoluteLeft() Gets the object's absolute left position in pixels, as measured from the browser window's client area.
int	getAbsoluteTop() Gets the object's absolute top position in pixels, as measured from the browser window's client area.
Element	getElement() Gets a handle to the object's underlying DOM element.
int	getOffsetHeight() Gets the object's offset height in pixels.
int	getOffsetWidth() Gets the object's offset width in pixels.
Element	getStyleElement() Template method that returns the element to which style names will be applied.
String	getStyleName() Gets all of the object's style names, as a space-separated list.
static String	getStyleName(Element elem) Gets all of the element's style names, as a space-separated list.
String	getStylePrimaryName() Gets the primary style name associated with the object.
static String	getStylePrimaryName(Element elem) Gets the element's primary style name.
String	getTitle() Gets the title associated with this object.
boolean	isVisible() Determines whether or not this object is visible.
static boolean	isVisible(Element elem)
void	onEnsureDebugId(String baseID) Called when the user sets the id using the `ensureDebugId(String)` method.
void	removeStyleDependentName(String styleSuffix) Removes a dependent style name by specifying the style name's suffix.
void	removeStyleName(String style) Removes a style name.
final void	setElement(Element elem) Sets this object's browser element.
void	setElement(Element elem) Sets this object's browser element.
void	setHeight(String height) Sets the object's height.
void	setPixelSize(int width, int height) Sets the object's size, in pixels, not including decorations such as border, margin, and padding.
void	setSize(String width, String height) Sets the object's size.
void	setStyleDependentName(String styleSuffix, boolean add) Adds or removes a dependent style name by specifying the style name's suffix.
static void	setStyleName(Element elem, String styleName) Clears all of the element's style names and sets it to the given style.
static void	setStyleName(Element elem, String style, boolean add) This convenience method adds or removes a style name for a given element.
void	setStyleName(String style) Clears all of the object's style names and sets it to the given style.
void	setStyleName(String style, boolean add) Adds or removes a style name.
void	setStylePrimaryName(String style) Sets the object's primary style name and updates all dependent style names.
static void	setStylePrimaryName(Element elem, String style) Sets the element's primary style name and updates all dependent style names.
void	setTitle(String title) Sets the title associated with this object.
void	setVisible(boolean visible) Sets whether this object is visible.
static void	setVisible(Element elem, boolean visible)
void	setWidth(String width) Sets the object's width.
void	sinkEvents(int eventBitsToAdd) Adds a set of events to be sunk by this object.
String	toString() This method is overridden so that any object can be viewed in the debugger as an HTML snippet.
void	unsinkEvents(int eventBitsToRemove) Removes a set of events from this object's event list.