org.apache.xmlgraphics.image.loader.impl

Class PreloaderJPEG

java.lang.Object

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

org.apache.xmlgraphics.image.loader.impl.PreloaderJPEG

All Implemented Interfaces:

JPEGConstants, ImagePreloader

public class PreloaderJPEG
extends AbstractImagePreloader
implements JPEGConstants

Image preloader for JPEG images.

Field Summary

Fields

Modifier and Type	Field and Description
private static int[]	BYTES_PER_COMPONENT
private static int	EXIF
private static int	II
private static int	JPG_SIG_LENGTH
private static int	MM
private static int	RESOLUTION_UNIT
private static int	X_RESOLUTION
private static int	Y_RESOLUTION

Fields inherited from interface org.apache.xmlgraphics.image.loader.impl.JPEGConstants

APP0, APP1, APP2, APPD, APPE, APPF, EOI, MARK, NULL, SOF0, SOF1, SOF2, SOFA, SOI, SOS

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

DEFAULT_PRIORITY

Constructor Summary

Constructors

Constructor and Description
PreloaderJPEG()

Method Summary

Modifier and Type	Method and Description
private ImageSize	determineSize(javax.imageio.stream.ImageInputStream in, ImageContext context)
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

JPG_SIG_LENGTH

private static final int JPG_SIG_LENGTH

See Also:

Constant Field Values

BYTES_PER_COMPONENT

private static final int[] BYTES_PER_COMPONENT

EXIF

private static final int EXIF

See Also:

Constant Field Values

II

private static final int II

See Also:

Constant Field Values

MM

private static final int MM

See Also:

Constant Field Values

X_RESOLUTION

private static final int X_RESOLUTION

See Also:

Constant Field Values

Y_RESOLUTION

private static final int Y_RESOLUTION

See Also:

Constant Field Values

RESOLUTION_UNIT

private static final int RESOLUTION_UNIT

See Also:

Constant Field Values

Constructor Detail

PreloaderJPEG

public PreloaderJPEG()

Method Detail

preloadImage

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

Specified by:

preloadImage in interface ImagePreloader

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

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

determineSize

private ImageSize determineSize(javax.imageio.stream.ImageInputStream in,
                                ImageContext context)
                         throws java.io.IOException,
                                ImageException

Throws:

java.io.IOException

ImageException