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Eclipse Platform
Release 3.5

org.eclipse.swt.graphics
Class ImageLoader

java.lang.Object
  extended by 
org.eclipse.swt.graphics.ImageLoader

public class ImageLoader
extends Object

Instances of this class are used to load images from, and save images to, a file or stream.

Currently supported image formats are:

  • BMP (Windows or OS/2 Bitmap)
  • ICO (Windows Icon)
  • JPEG
  • GIF
  • PNG
  • TIFF
ImageLoaders can be used to:
  • load/save single images in all formats
  • load/save multiple images (GIF/ICO/TIFF)
  • load/save animated GIF images
  • load interlaced GIF/PNG images
  • load progressive JPEG images

See Also:
SWT Example: ImageAnalyzer, Sample code and further information

Field Summary
 int backgroundPixel
          the background pixel for the logical screen (this corresponds to the GIF89a Background Color Index value).
  ImageData[] data
          the array of ImageData objects in this ImageLoader.
 int logicalScreenHeight
          the height of the logical screen on which the images reside, in pixels (this corresponds to the GIF89a Logical Screen Height value)
 int logicalScreenWidth
          the width of the logical screen on which the images reside, in pixels (this corresponds to the GIF89a Logical Screen Width value)
 int repeatCount
          the number of times to repeat the display of a sequence of animated images (this corresponds to the commonly-used GIF application extension for "NETSCAPE 2.0 01").
 
Constructor Summary
ImageLoader ()
          Construct a new empty ImageLoader.
 
Method Summary
 void addImageLoaderListener ( ImageLoaderListener listener)
          Adds the listener to the collection of listeners who will be notified when image data is either partially or completely loaded.
 boolean hasListeners ()
          Returns true if the receiver has image loader listeners, and false otherwise.
  ImageData[] load ( InputStream stream)
          Loads an array of ImageData objects from the specified input stream.
  ImageData[] load ( String filename)
          Loads an array of ImageData objects from the file with the specified name.
 void notifyListeners ( ImageLoaderEvent event)
          Notifies all image loader listeners that an image loader event has occurred.
 void removeImageLoaderListener ( ImageLoaderListener listener)
          Removes the listener from the collection of listeners who will be notified when image data is either partially or completely loaded.
 void save ( OutputStream stream, int format)
          Saves the image data in this ImageLoader to the specified stream.
 void save ( String filename, int format)
          Saves the image data in this ImageLoader to a file with the specified name.
 
Methods inherited from class java.lang. Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

data

public 
ImageData[] data
the array of ImageData objects in this ImageLoader. This array is read in when the load method is called, and it is written out when the save method is called


logicalScreenWidth

public int logicalScreenWidth
the width of the logical screen on which the images reside, in pixels (this corresponds to the GIF89a Logical Screen Width value)


logicalScreenHeight

public int logicalScreenHeight
the height of the logical screen on which the images reside, in pixels (this corresponds to the GIF89a Logical Screen Height value)


backgroundPixel

public int backgroundPixel
the background pixel for the logical screen (this corresponds to the GIF89a Background Color Index value). The default is -1 which means 'unspecified background'


repeatCount

public int repeatCount
the number of times to repeat the display of a sequence of animated images (this corresponds to the commonly-used GIF application extension for "NETSCAPE 2.0 01"). The default is 1. A value of 0 means 'display repeatedly'

Constructor Detail

ImageLoader

public ImageLoader()
Construct a new empty ImageLoader.

Method Detail

load

public 
ImageData[] load(
InputStream stream)
Loads an array of ImageData objects from the specified input stream. Throws an error if either an error occurs while loading the images, or if the images are not of a supported type. Returns the loaded image data array.

Parameters:
stream - the input stream to load the images from
Returns:
an array of ImageData objects loaded from the specified input stream
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the stream is null
SWTException -
  • ERROR_IO - if an IO error occurs while reading from the stream
  • ERROR_INVALID_IMAGE - if the image stream contains invalid data
  • ERROR_UNSUPPORTED_FORMAT - if the image stream contains an unrecognized format

load

public 
ImageData[] load(
String filename)
Loads an array of ImageData objects from the file with the specified name. Throws an error if either an error occurs while loading the images, or if the images are not of a supported type. Returns the loaded image data array.

Parameters:
filename - the name of the file to load the images from
Returns:
an array of ImageData objects loaded from the specified file
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the file name is null
SWTException -
  • ERROR_IO - if an IO error occurs while reading from the file
  • ERROR_INVALID_IMAGE - if the image file contains invalid data
  • ERROR_UNSUPPORTED_FORMAT - if the image file contains an unrecognized format

save

public void save(
OutputStream stream,
                 int format)
Saves the image data in this ImageLoader to the specified stream. The format parameter can have one of the following values:
IMAGE_BMP
Windows BMP file format, no compression
IMAGE_BMP_RLE
Windows BMP file format, RLE compression if appropriate
IMAGE_GIF
GIF file format
IMAGE_ICO
Windows ICO file format
IMAGE_JPEG
JPEG file format
IMAGE_PNG
PNG file format

Parameters:
stream - the output stream to write the images to
format - the format to write the images in
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the stream is null
SWTException -
  • ERROR_IO - if an IO error occurs while writing to the stream
  • ERROR_INVALID_IMAGE - if the image data contains invalid data
  • ERROR_UNSUPPORTED_FORMAT - if the image data cannot be saved to the requested format

save

public void save(
String filename,
                 int format)
Saves the image data in this ImageLoader to a file with the specified name. The format parameter can have one of the following values:
IMAGE_BMP
Windows BMP file format, no compression
IMAGE_BMP_RLE
Windows BMP file format, RLE compression if appropriate
IMAGE_GIF
GIF file format
IMAGE_ICO
Windows ICO file format
IMAGE_JPEG
JPEG file format
IMAGE_PNG
PNG file format

Parameters:
filename - the name of the file to write the images to
format - the format to write the images in
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the file name is null
SWTException -
  • ERROR_IO - if an IO error occurs while writing to the file
  • ERROR_INVALID_IMAGE - if the image data contains invalid data
  • ERROR_UNSUPPORTED_FORMAT - if the image data cannot be saved to the requested format

addImageLoaderListener

public void addImageLoaderListener(
ImageLoaderListener listener)
Adds the listener to the collection of listeners who will be notified when image data is either partially or completely loaded.

An ImageLoaderListener should be added before invoking one of the receiver's load methods. The listener's imageDataLoaded method is called when image data has been partially loaded, as is supported by interlaced GIF/PNG or progressive JPEG images.

Parameters:
listener - the listener which should be notified
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the listener is null
See Also:
ImageLoaderListener, ImageLoaderEvent

removeImageLoaderListener

public void removeImageLoaderListener(
ImageLoaderListener listener)
Removes the listener from the collection of listeners who will be notified when image data is either partially or completely loaded.

Parameters:
listener - the listener which should no longer be notified
Throws:
IllegalArgumentException -
  • ERROR_NULL_ARGUMENT - if the listener is null
See Also:
addImageLoaderListener(ImageLoaderListener)

hasListeners

public boolean hasListeners()
Returns true if the receiver has image loader listeners, and false otherwise.

Returns:
true if there are ImageLoaderListeners, and false otherwise
See Also:
addImageLoaderListener(ImageLoaderListener), removeImageLoaderListener(ImageLoaderListener)

notifyListeners

public void notifyListeners(
ImageLoaderEvent event)
Notifies all image loader listeners that an image loader event has occurred. Pass the specified event object to each listener.

Parameters:
event - the ImageLoaderEvent to send to each ImageLoaderListener

Eclipse Platform
Release 3.5

Guidelines for using Eclipse APIs.

Copyright (c) Eclipse contributors and others 2000, 2008. All rights reserved.


 
 
  Published under the terms of the Eclipse Public License Version 1.0 ("EPL") Design by Interspire