Eclipse Plug-in Developer Guide (Galileo) - Cursor (Eclipse Platform API Specification)

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Eclipse Platform
Release 3.5

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org.eclipse.swt.graphics
Class Cursor


java.lang.Object
  

org.eclipse.swt.graphics.Resource
      
org.eclipse.swt.graphics.Cursor

public final class Cursor
extends Resource
extends Resource

Instances of this class manage operating system resources that specify the appearance of the on-screen pointer. To create a cursor you specify the device and either a simple cursor style describing one of the standard operating system provided cursors or the image and mask data for the desired appearance.

Application code must explicitly invoke the Cursor.dispose() method to release the operating system resources managed by each instance when those instances are no longer required.

Styles:: CURSOR_ARROW, CURSOR_WAIT, CURSOR_CROSS, CURSOR_APPSTARTING, CURSOR_HELP, CURSOR_SIZEALL, CURSOR_SIZENESW, CURSOR_SIZENS, CURSOR_SIZENWSE, CURSOR_SIZEWE, CURSOR_SIZEN, CURSOR_SIZES, CURSOR_SIZEE, CURSOR_SIZEW, CURSOR_SIZENE, CURSOR_SIZESE, CURSOR_SIZESW, CURSOR_SIZENW, CURSOR_UPARROW, CURSOR_IBEAM, CURSOR_NO, CURSOR_HAND

Note: Only one of the above styles may be specified.

See Also:: Cursor snippets, Sample code and further information

Field Summary

int handle
          the handle to the OS cursor resource (Warning: This field is platform dependent) IMPORTANT: This field is not part of the SWT public API.

Constructor Summary

Cursor ( Device device, ImageData source, ImageData mask, int hotspotX, int hotspotY)
          Constructs a new cursor given a device, image and mask data describing the desired cursor appearance, and the x and y coordinates of the hotspot (that is, the point within the area covered by the cursor which is considered to be where the on-screen pointer is "pointing").

Cursor ( Device device, ImageData source, int hotspotX, int hotspotY)
          Constructs a new cursor given a device, image data describing the desired cursor appearance, and the x and y coordinates of the hotspot (that is, the point within the area covered by the cursor which is considered to be where the on-screen pointer is "pointing").

Cursor ( Device device, int style)
          Constructs a new cursor given a device and a style constant describing the desired cursor appearance.

Method Summary

boolean equals ( Object object)
          Compares the argument to the receiver, and returns true if they represent the same object using a class specific comparison.

int hashCode ()
          Returns an integer hash code for the receiver.

boolean isDisposed ()
          Returns true if the cursor has been disposed, and false otherwise.

String toString ()
          Returns a string containing a concise, human-readable description of the receiver.

static Cursor win32_new ( Device device, int handle)
          Invokes platform specific functionality to allocate a new cursor.

Methods inherited from class org.eclipse.swt.graphics. Resource

dispose, getDevice

Methods inherited from class java.lang. Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Field Detail

handle

public int handle

the handle to the OS cursor resource (Warning: This field is platform dependent)

IMPORTANT: This field is not part of the SWT public API. It is marked public only so that it can be shared within the packages provided by SWT. It is not available on all platforms and should never be accessed from application code.

Constructor Detail

Cursor

public Cursor(
Device device,
              int style)

Constructs a new cursor given a device and a style constant describing the desired cursor appearance.

You must dispose the cursor when it is no longer required.

Parameters:

device - the device on which to allocate the cursor

style - the style of cursor to allocate

Throws:


IllegalArgumentException

ERROR_NULL_ARGUMENT - if device is null and there is no current device
ERROR_INVALID_ARGUMENT - when an unknown style is specified


SWTError

ERROR_NO_HANDLES - if a handle could not be obtained for cursor creation

Cursor

public Cursor(
Device device,
              
ImageData source,
              
ImageData mask,
              int hotspotX,
              int hotspotY)

Constructs a new cursor given a device, image and mask data describing the desired cursor appearance, and the x and y coordinates of the hotspot (that is, the point within the area covered by the cursor which is considered to be where the on-screen pointer is "pointing").

The mask data is allowed to be null, but in this case the source must be an ImageData representing an icon that specifies both color data and mask data.

You must dispose the cursor when it is no longer required.

Parameters:

device - the device on which to allocate the cursor

source - the color data for the cursor

mask - the mask data for the cursor (or null)

hotspotX - the x coordinate of the cursor's hotspot

hotspotY - the y coordinate of the cursor's hotspot

Throws:


IllegalArgumentException

ERROR_NULL_ARGUMENT - if device is null and there is no current device
ERROR_NULL_ARGUMENT - if the source is null
ERROR_NULL_ARGUMENT - if the mask is null and the source does not have a mask
ERROR_INVALID_ARGUMENT - if the source and the mask are not the same size, or if the hotspot is outside the bounds of the image


SWTError

ERROR_NO_HANDLES - if a handle could not be obtained for cursor creation

Cursor

public Cursor(
Device device,
              
ImageData source,
              int hotspotX,
              int hotspotY)

Constructs a new cursor given a device, image data describing the desired cursor appearance, and the x and y coordinates of the hotspot (that is, the point within the area covered by the cursor which is considered to be where the on-screen pointer is "pointing").

You must dispose the cursor when it is no longer required.

Parameters:

device - the device on which to allocate the cursor

source - the image data for the cursor

hotspotX - the x coordinate of the cursor's hotspot

hotspotY - the y coordinate of the cursor's hotspot

Throws:


IllegalArgumentException

ERROR_NULL_ARGUMENT - if device is null and there is no current device
ERROR_NULL_ARGUMENT - if the image is null
ERROR_INVALID_ARGUMENT - if the hotspot is outside the bounds of the image


SWTError

ERROR_NO_HANDLES - if a handle could not be obtained for cursor creation

Since:

3.0

Method Detail

equals

public boolean equals(
Object object)

Compares the argument to the receiver, and returns true if they represent the same object using a class specific comparison.

Overrides:: equals in class Object

Parameters:: object - the object to compare with this object
Returns:: true if the object is the same as this object and false otherwise
See Also:: hashCode()

hashCode

public int hashCode()

Returns an integer hash code for the receiver. Any two objects that return true when passed to equals must return the same value for this method.

Overrides:: hashCode in class Object

Returns:: the receiver's hash
See Also:: equals(java.lang.Object)

isDisposed

public boolean isDisposed()

Returns true if the cursor has been disposed, and false otherwise.

This method gets the dispose state for the cursor. When a cursor has been disposed, it is an error to invoke any other method using the cursor.

Specified by:: isDisposed in class Resource

Returns:: true when the cursor is disposed and false otherwise

toString

public 
String toString()

Returns a string containing a concise, human-readable description of the receiver.

Overrides:: toString in class Object

Returns:: a string representation of the receiver

win32_new

public static 
Cursor win32_new(
Device device,
                               int handle)

Invokes platform specific functionality to allocate a new cursor.

IMPORTANT: This method is not part of the public API for Cursor. It is marked public only so that it can be shared within the packages provided by SWT. It is not available on all platforms, and should never be called from application code.

Parameters:: device - the device on which to allocate the color; handle - the handle for the cursor
Returns:: a new cursor object containing the specified device and handle