org.apache.xmlgraphics.image.loader.impl

Class PreloaderGIF

java.lang.Object

org.apache.xmlgraphics.image.loader.impl.AbstractImagePreloader

org.apache.xmlgraphics.image.loader.impl.PreloaderGIF

All Implemented Interfaces:

ImagePreloader

public class PreloaderGIF
extends AbstractImagePreloader

Image preloader for GIF images.

Field Summary

Fields

Modifier and Type	Field and Description
private static int	GIF_SIG_LENGTH

Fields inherited from interface org.apache.xmlgraphics.image.loader.spi.ImagePreloader

DEFAULT_PRIORITY

Constructor Summary

Constructors

Constructor and Description
PreloaderGIF()

Method Summary

Modifier and Type	Method and Description
private ImageSize	determineSize(byte[] header, ImageContext context, javax.imageio.stream.ImageInputStream in)
private int[]	extractImageMetadata(javax.imageio.stream.ImageInputStream in)
ImageInfo	preloadImage(java.lang.String uri, javax.xml.transform.Source src, ImageContext context) "Preloads" an image, i.e.

Methods inherited from class org.apache.xmlgraphics.image.loader.impl.AbstractImagePreloader

getHeader, getPriority

Methods inherited from class java.lang.Object

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

Field Detail

GIF_SIG_LENGTH

private static final int GIF_SIG_LENGTH

See Also:

Constant Field Values

Constructor Detail

PreloaderGIF

public PreloaderGIF()

Method Detail

preloadImage

public ImageInfo preloadImage(java.lang.String uri,
                              javax.xml.transform.Source src,
                              ImageContext context)
                       throws java.io.IOException

"Preloads" an image, i.e. indentifies whether the source image is supported by this implementation and determines the image's intrinsic size and possibly some additional information. The image is usually not fully loaded at this time to conserve memory. The method returns null if the image was not identified. An ImageException is only thrown if the image is identified but some error has happened while working on the file.

Parameters:

uri - the original (unresolved) URI of the image

src - a image source the image is loaded from

context - the context object that provides configuration information

Returns:

an image info object with the basic information about an image or null if the image is not supported by this implementation

Throws:

java.io.IOException - if an I/O error occurs while preloading the image

determineSize

private ImageSize determineSize(byte[] header,
                                ImageContext context,
                                javax.imageio.stream.ImageInputStream in)
                         throws java.io.IOException

Throws:

java.io.IOException

extractImageMetadata

private int[] extractImageMetadata(javax.imageio.stream.ImageInputStream in)
                            throws java.io.IOException

Throws:

java.io.IOException