com.google.gwt.canvas.client

## Class Canvas

- 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

- All Implemented Interfaces:
    HasAllDragAndDropHandlers, HasAllFocusHandlers, HasAllGestureHandlers, HasAllKeyHandlers, HasAllMouseHandlers, HasAllTouchHandlers, HasBlurHandlers, HasClickHandlers, HasDoubleClickHandlers, HasDragEndHandlers, HasDragEnterHandlers, HasDragHandlers, HasDragLeaveHandlers, HasDragOverHandlers, HasDragStartHandlers, HasDropHandlers, HasFocusHandlers, HasGestureChangeHandlers, HasGestureEndHandlers, HasGestureStartHandlers, HasKeyDownHandlers, HasKeyPressHandlers, HasKeyUpHandlers, HasMouseDownHandlers, HasMouseMoveHandlers, HasMouseOutHandlers, HasMouseOverHandlers, HasMouseUpHandlers, HasMouseWheelHandlers, HasTouchCancelHandlers, HasTouchEndHandlers, HasTouchMoveHandlers, HasTouchStartHandlers, HasAttachHandlers, HasHandlers, EventListener, Focusable, HasEnabled, HasFocus, HasVisibility, IsWidget, SourcesClickEvents, SourcesFocusEvents, SourcesKeyboardEvents, SourcesMouseEvents

      public class Canvas
      extends FocusWidget

  A widget representing a <canvas> element. This widget may not be supported on all browsers.

- - ### Nested Class Summary

    - ### Nested classes/interfaces inherited from class com.google.gwt.user.client.ui.UIObject

      `UIObject.DebugIdImpl, UIObject.DebugIdImplEnabled`

  - ### Field Summary

    - ### Fields inherited from class com.google.gwt.user.client.ui.UIObject

      `DEBUG_ID_PREFIX`

  - ### Method Summary

    All Methods Static Methods Instance Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `static Canvas` | `createIfSupported()` Return a new `Canvas` if supported, and null otherwise.
    `CanvasElement` | `getCanvasElement()` Returns the attached Canvas Element.
    `Context` | `getContext(java.lang.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.
    `java.lang.String` | `toDataUrl()` Returns a data URL for the current content of the canvas element.
    `java.lang.String` | `toDataUrl(java.lang.String type)` Returns a data URL for the current content of the canvas element, with a specified type.
    `static Canvas` | `wrap(CanvasElement element)` Wrap an existing canvas element.

    - ### Methods inherited from class com.google.gwt.user.client.ui.FocusWidget

      `addBlurHandler, addClickHandler, addClickListener, addDoubleClickHandler, addDragEndHandler, addDragEnterHandler, addDragHandler, addDragLeaveHandler, addDragOverHandler, addDragStartHandler, addDropHandler, addFocusHandler, addFocusListener, addGestureChangeHandler, addGestureEndHandler, addGestureStartHandler, addKeyboardListener, addKeyDownHandler, addKeyPressHandler, addKeyUpHandler, addMouseDownHandler, addMouseListener, addMouseMoveHandler, addMouseOutHandler, addMouseOverHandler, addMouseUpHandler, addMouseWheelHandler, addMouseWheelListener, addTouchCancelHandler, addTouchEndHandler, addTouchMoveHandler, addTouchStartHandler, getFocusImpl, getTabIndex, isEnabled, onAttach, removeClickListener, removeFocusListener, removeKeyboardListener, removeMouseListener, removeMouseWheelListener, setAccessKey, setEnabled, setFocus, setTabIndex`

    - ### Methods inherited from class com.google.gwt.user.client.ui.Widget

      `addAttachHandler, addBitlessDomHandler, addDomHandler, addHandler, asWidget, asWidgetOrNull, createHandlerManager, delegateEvent, doAttachChildren, doDetachChildren, fireEvent, getHandlerCount, getLayoutData, getParent, isAttached, isOrWasAttached, onBrowserEvent, onDetach, onLoad, onUnload, removeFromParent, setLayoutData, sinkEvents, unsinkEvents`

    - ### Methods inherited from class com.google.gwt.user.client.ui.UIObject

      `addStyleDependentName, addStyleName, ensureDebugId, ensureDebugId, ensureDebugId, getAbsoluteLeft, getAbsoluteTop, getElement, getOffsetHeight, getOffsetWidth, getStyleElement, getStyleName, getStyleName, getStylePrimaryName, getStylePrimaryName, getTitle, isVisible, isVisible, onEnsureDebugId, removeStyleDependentName, removeStyleName, resolvePotentialElement, setElement, setElement, setHeight, setPixelSize, setSize, setStyleDependentName, setStyleName, setStyleName, setStyleName, setStyleName, setStylePrimaryName, setStylePrimaryName, setTitle, setVisible, setVisible, setWidth, sinkBitlessEvent, toString`

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

    - ### Methods inherited from interface com.google.gwt.event.shared.HasHandlers

      `fireEvent`

- - ### Method Detail

    - #### createIfSupported

          public static Canvas createIfSupported()

      Return a new `Canvas` if supported, and null otherwise.
      Returns:
        a new `Canvas` if supported, and null otherwise

    - #### wrap

          public static Canvas wrap(CanvasElement element)

      Wrap an existing canvas element. The element must already be attached to the document. If the element is removed from the document, you must call `RootPanel.detachNow(Widget)`. Note: This method can return null if there is no support for canvas by the current browser.
      Parameters:
        `element` - the element to wrap
      Returns:
        the `Canvas` widget or null if canvas is not supported by the current browser.

    - #### isSupported

          public static boolean isSupported()

      Runtime check for whether the canvas element is supported in this browser.
      Returns:
        whether the canvas element is supported

    - #### getCanvasElement

          public CanvasElement getCanvasElement()

      Returns the attached Canvas Element.
      Returns:
        the Canvas Element

    - #### getContext

          public Context getContext(java.lang.String contextId)

      Gets the rendering context that may be used to draw on this canvas.
      Parameters:
        `contextId` - the context id as a String
      Returns:
        the canvas rendering context

    - #### getContext2d

          public Context2d getContext2d()

      Returns a 2D rendering context. This is a convenience method, see `getContext(String)`.
      Returns:
        a 2D canvas rendering context

    - #### getCoordinateSpaceHeight

          public int getCoordinateSpaceHeight()

      Gets the height of the internal canvas coordinate space.
      Returns:
        the height, in pixels
      See Also:
        `setCoordinateSpaceHeight(int)`

    - #### getCoordinateSpaceWidth

          public int getCoordinateSpaceWidth()

      Gets the width of the internal canvas coordinate space.
      Returns:
        the width, in pixels
      See Also:
        `setCoordinateSpaceWidth(int)`

    - #### setCoordinateSpaceHeight

          public void setCoordinateSpaceHeight(int height)

      Sets the height of the internal canvas coordinate space.
      Parameters:
        `height` - the height, in pixels
      See Also:
        `getCoordinateSpaceHeight()`

    - #### setCoordinateSpaceWidth

          public void setCoordinateSpaceWidth(int width)

      Sets the width of the internal canvas coordinate space.
      Parameters:
        `width` - the width, in pixels
      See Also:
        `getCoordinateSpaceWidth()`

    - #### toDataUrl

          public java.lang.String toDataUrl()

      Returns a data URL for the current content of the canvas element.
      Returns:
        a data URL for the current content of this element.

    - #### toDataUrl

          public java.lang.String toDataUrl(java.lang.String type)

      Returns a data URL for the current content of the canvas element, with a specified type.
      Parameters:
        `type` - the type of the data url, e.g., image/jpeg or image/png.
      Returns:
        a data URL for the current content of this element with the specified type.