Package org.apache.xmlgraphics.image.loader.impl.imageio

Class PreloaderImageIO

java.lang.Object

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

org.apache.xmlgraphics.image.loader.impl.imageio.PreloaderImageIO

All Implemented Interfaces:

ImagePreloader

public class PreloaderImageIO
extends AbstractImagePreloader

Image preloader for images supported by ImageIO.

Note: The implementation relies on the presence of a working ImageIO implementation which provides accurate image metadata. This is particularly important for PNG image because the PNG loader relies on that.

Field Summary

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

DEFAULT_PRIORITY

Constructor Summary

Constructors

Constructor	Description
PreloaderImageIO()

Method Summary

Modifier and Type	Method	Description
int	getPriority()	Returns the priority of the preloader.
ImageInfo	preloadImage(String uri, Source src, ImageContext context)	"Preloads" an image, i.e.

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

getHeader

Methods inherited from class java.lang.Object

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

Constructor Detail

PreloaderImageIO

public PreloaderImageIO()

Method Detail

preloadImage

public ImageInfo preloadImage(String uri,
                              Source src,
                              ImageContext context)
                       throws IOException,
                              ImageException

"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:

ImageException

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

getPriority

public int getPriority()

Returns the priority of the preloader. The lower the value, the higher the preloader's priority.

Specified by:

getPriority in interface ImagePreloader

Overrides:

getPriority in class AbstractImagePreloader

Returns:

an integer (default is 1000)