| java.lang.Object
 org.eclipse.jface.resource.DeviceResourceDescriptor
org.eclipse.jface.resource.ImageDescriptor
All known Subclasses: org.eclipse.jface.resource.URLImageDescriptor, org.eclipse.jface.resource.DerivedImageDescriptor, org.eclipse.jface.resource.FileImageDescriptor, org.eclipse.jface.resource.ImageDataImageDescriptor, org.eclipse.jface.resource.CompositeImageDescriptor, org.eclipse.jface.resource.MissingImageDescriptor,
| ImageDescriptor | | abstract public class ImageDescriptor extends DeviceResourceDescriptor (Code) | | An image descriptor is an object that knows how to create
an SWT image. It does not hold onto images or cache them,
but rather just creates them on demand. An image descriptor
is intended to be a lightweight representation of an image
that can be manipulated even when no SWT display exists.
This package defines a concrete image descriptor implementation
which reads an image from a file (FileImageDescriptor).
It also provides abstract framework classes (this one and
CompositeImageDescriptor) which may be subclassed to define
news kinds of image descriptors.
Using this abstract class involves defining a concrete subclass
and providing an implementation for the getImageData
method.
There are two ways to get an Image from an ImageDescriptor. The method
createImage will always return a new Image which must be disposed by
the caller. Alternatively, createResource() returns a shared
Image. When the caller is done with an image obtained from createResource,
they must call destroyResource() rather than disposing the Image directly.
The result of createResource() can be safely cast to an Image.
See Also: org.eclipse.swt.graphics.Image |
| Field Summary | |
| final protected static ImageData | DEFAULT_IMAGE_DATA
A small red square used to warn that an image cannot be created. |
| Constructor Summary | |
| protected | ImageDescriptor()
Constructs an image descriptor. |
| Method Summary | |
| public static ImageDescriptor | createFromFile(Class location, String filename)
Creates and returns a new image descriptor from a file. | | public static ImageDescriptor | createFromImage(Image img)
Creates and returns a new image descriptor for the given image. | | public static ImageDescriptor | createFromImage(Image img, Device theDevice)
Creates and returns a new image descriptor for the given image. | | public static ImageDescriptor | createFromImageData(ImageData data)
Creates and returns a new image descriptor given ImageData
describing the image. | | public static ImageDescriptor | createFromURL(URL url)
Creates and returns a new image descriptor from a URL.
Parameters:
url - The URL of the image file. | | public Image | createImage()
Creates and returns a new SWT image for this image descriptor. | | public Image | createImage(boolean returnMissingImageOnError)
Creates and returns a new SWT image for this image descriptor. | | public Image | createImage(Device device)
Creates and returns a new SWT image for this image descriptor. | | public Image | createImage(boolean returnMissingImageOnError, Device device)
Creates and returns a new SWT image for this image descriptor. | | public Object | createResource(Device device)
| | public static ImageDescriptor | createWithFlags(ImageDescriptor originalImage, int swtFlags)
Creates an ImageDescriptor based on the given original descriptor, but with additional
SWT flags.
Note that this sort of ImageDescriptor is slower and consumes more resources than
a regular image descriptor. | | public void | destroyResource(Object previouslyCreatedObject)
| | abstract public ImageData | getImageData()
Creates and returns a new SWT ImageData object
for this image descriptor. | | public static ImageDescriptor | getMissingImageDescriptor()
Returns the shared image descriptor for a missing image. |
| DEFAULT_IMAGE_DATA | | final protected static ImageData DEFAULT_IMAGE_DATA(Code) | | A small red square used to warn that an image cannot be created.
|
| ImageDescriptor | | protected ImageDescriptor()(Code) | | Constructs an image descriptor.
|
| createFromFile | | public static ImageDescriptor createFromFile(Class location, String filename)(Code) | | Creates and returns a new image descriptor from a file.
Convenience method for
new FileImageDescriptor(location,filename).
Parameters:
location - the class whose resource directory contain the file
Parameters:
filename - the file name a new image descriptor |
| createFromImage | | public static ImageDescriptor createFromImage(Image img)(Code) | | Creates and returns a new image descriptor for the given image. Note
that disposing the original Image will cause the descriptor to become invalid.
since:
3.1
Parameters:
img - image to create a newly created image descriptor |
| createFromImage | | public static ImageDescriptor createFromImage(Image img, Device theDevice)(Code) | | Creates and returns a new image descriptor for the given image. This
method takes the Device that created the Image as an argument, allowing
the original Image to be reused if the descriptor is asked for another
Image on the same device. Note that disposing the original Image will
cause the descriptor to become invalid.
ImageDescriptor.createFromImage(Image)
since:
3.1
Parameters:
img - image to create
Parameters:
theDevice - the device that was used to create the Image a newly created image descriptor |
| createFromImageData | | public static ImageDescriptor createFromImageData(ImageData data)(Code) | | Creates and returns a new image descriptor given ImageData
describing the image.
since:
3.1
Parameters:
data - contents of the image newly created image descriptor |
| createFromURL | | public static ImageDescriptor createFromURL(URL url)(Code) | | Creates and returns a new image descriptor from a URL.
Parameters:
url - The URL of the image file. a new image descriptor |
| createImage | | public Image createImage()(Code) | | Creates and returns a new SWT image for this image descriptor. Note that
each call returns a new SWT image object. The returned image must be
explicitly disposed using the image's dispose call. The image will not be
automatically garbage collected. A default image is returned in the event
of an error.
Note: this method differs from createResource(Device) in that the returned image
must be disposed directly, whereas an image obtained from createResource(...)
must be disposed by calling destroyResource(...). It is not possible to
mix-and-match. If you obtained the Image from this method, you must not dispose
it by calling destroyResource. Clients are encouraged to use
create/destroyResource and downcast the result to Image rather than using
createImage.
Note: it is still possible for this method to return null
in extreme cases, for example if SWT runs out of image handles.
a new image or null if the image could not becreated |
| createImage | | public Image createImage(boolean returnMissingImageOnError)(Code) | | Creates and returns a new SWT image for this image descriptor. The
returned image must be explicitly disposed using the image's dispose
call. The image will not be automatically garbage collected. In the event
of an error, a default image is returned if
returnMissingImageOnError is true, otherwise
null is returned.
Note: Even if returnMissingImageOnError is true, it is
still possible for this method to return null in extreme
cases, for example if SWT runs out of image handles.
Parameters:
returnMissingImageOnError - flag that determines if a default image is returned on error a new image or null if the image could not becreated |
| createImage | | public Image createImage(Device device)(Code) | | Creates and returns a new SWT image for this image descriptor. The
returned image must be explicitly disposed using the image's dispose
call. The image will not be automatically garbage collected. A default
image is returned in the event of an error.
Note: it is still possible for this method to return null
in extreme cases, for example if SWT runs out of image handles.
Parameters:
device - the device on which to create the image a new image or null if the image could not becreated
since:
2.0 |
| createImage | | public Image createImage(boolean returnMissingImageOnError, Device device)(Code) | | Creates and returns a new SWT image for this image descriptor. The
returned image must be explicitly disposed using the image's dispose
call. The image will not be automatically garbage collected. In the even
of an error, a default image is returned if
returnMissingImageOnError is true, otherwise
null is returned.
Note: Even if returnMissingImageOnError is true, it is
still possible for this method to return null in extreme
cases, for example if SWT runs out of image handles.
Parameters:
returnMissingImageOnError - flag that determines if a default image is returned on error
Parameters:
device - the device on which to create the image a new image or null if the image could not becreated
since:
2.0 |
| createWithFlags | | public static ImageDescriptor createWithFlags(ImageDescriptor originalImage, int swtFlags)(Code) | | Creates an ImageDescriptor based on the given original descriptor, but with additional
SWT flags.
Note that this sort of ImageDescriptor is slower and consumes more resources than
a regular image descriptor. It will also never generate results that look as nice as
a hand-drawn image. Clients are encouraged to supply their own disabled/grayed/etc. images
rather than using a default image and transforming it.
Parameters:
originalImage - image to transform
Parameters:
swtFlags - any flag that can be passed to the flags argument of Image#Image(Device, Image, int) an ImageDescriptor that creates new images by transforming the given image descriptor
See Also: Image.Image(DeviceImageint)
See Also:
since:
3.1 |
| destroyResource | | public void destroyResource(Object previouslyCreatedObject)(Code) | | |
| getImageData | | abstract public ImageData getImageData()(Code) | | Creates and returns a new SWT ImageData object
for this image descriptor.
Note that each call returns a new SWT image data object.
This framework method is declared public so that it is
possible to request an image descriptor's image data without
creating an SWT image object.
Returns null if the image data could not be created.
a new image data or null |
| getMissingImageDescriptor | | public static ImageDescriptor getMissingImageDescriptor()(Code) | | Returns the shared image descriptor for a missing image.
the missing image descriptor |
| Methods inherited from org.eclipse.jface.resource.DeviceResourceDescriptor | abstract public Object createResource(Device device)(Code)(Java Doc)
abstract public void destroyResource(Object previouslyCreatedObject)(Code)(Java Doc)
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