org.eclipse.swt.graphics
Class ImageLoader
java.lang.Object
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
|
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'
ImageLoader
public ImageLoader()
- Construct a new empty ImageLoader.
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 ImageLoaderListener
s, 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
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