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Java example source code file (ImageReader.java)
This example Java source code file (ImageReader.java) is included in the alvinalexander.com
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The ImageReader.java Java example source code
/*
* Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
package javax.imageio;
import java.awt.Point;
import java.awt.Rectangle;
import java.awt.image.BufferedImage;
import java.awt.image.Raster;
import java.awt.image.RenderedImage;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.MissingResourceException;
import java.util.ResourceBundle;
import java.util.Set;
import javax.imageio.spi.ImageReaderSpi;
import javax.imageio.event.IIOReadWarningListener;
import javax.imageio.event.IIOReadProgressListener;
import javax.imageio.event.IIOReadUpdateListener;
import javax.imageio.metadata.IIOMetadata;
import javax.imageio.metadata.IIOMetadataFormatImpl;
import javax.imageio.stream.ImageInputStream;
/**
* An abstract superclass for parsing and decoding of images. This
* class must be subclassed by classes that read in images in the
* context of the Java Image I/O framework.
*
* <p> ImageReader objects are normally instantiated by
* the service provider interface (SPI) class for the specific format.
* Service provider classes (e.g., instances of
* <code>ImageReaderSpi) are registered with the
* <code>IIORegistry, which uses them for format recognition
* and presentation of available format readers and writers.
*
* <p> When an input source is set (using the setInput
* method), it may be marked as "seek forward only". This setting
* means that images contained within the input source will only be
* read in order, possibly allowing the reader to avoid caching
* portions of the input containing data associated with images that
* have been read previously.
*
* @see ImageWriter
* @see javax.imageio.spi.IIORegistry
* @see javax.imageio.spi.ImageReaderSpi
*
*/
public abstract class ImageReader {
/**
* The <code>ImageReaderSpi that instantiated this object,
* or <code>null if its identity is not known or none
* exists. By default it is initialized to <code>null.
*/
protected ImageReaderSpi originatingProvider;
/**
* The <code>ImageInputStream or other
* <code>Object by setInput and retrieved
* by <code>getInput. By default it is initialized to
* <code>null.
*/
protected Object input = null;
/**
* <code>true if the current input source has been marked
* as allowing only forward seeking by <code>setInput. By
* default, the value is <code>false.
*
* @see #minIndex
* @see #setInput
*/
protected boolean seekForwardOnly = false;
/**
* <code>true if the current input source has been marked
* as allowing metadata to be ignored by <code>setInput.
* By default, the value is <code>false.
*
* @see #setInput
*/
protected boolean ignoreMetadata = false;
/**
* The smallest valid index for reading, initially 0. When
* <code>seekForwardOnly is true, various methods
* may throw an <code>IndexOutOfBoundsException on an
* attempt to access data associate with an image having a lower
* index.
*
* @see #seekForwardOnly
* @see #setInput
*/
protected int minIndex = 0;
/**
* An array of <code>Locales which may be used to localize
* warning messages, or <code>null if localization is not
* supported.
*/
protected Locale[] availableLocales = null;
/**
* The current <code>Locale to be used for localization, or
* <code>null if none has been set.
*/
protected Locale locale = null;
/**
* A <code>List of currently registered
* <code>IIOReadWarningListeners, initialized by default to
* <code>null, which is synonymous with an empty
* <code>List.
*/
protected List<IIOReadWarningListener> warningListeners = null;
/**
* A <code>List of the Locales associated with
* each currently registered <code>IIOReadWarningListener,
* initialized by default to <code>null, which is
* synonymous with an empty <code>List.
*/
protected List<Locale> warningLocales = null;
/**
* A <code>List of currently registered
* <code>IIOReadProgressListeners, initialized by default
* to <code>null, which is synonymous with an empty
* <code>List.
*/
protected List<IIOReadProgressListener> progressListeners = null;
/**
* A <code>List of currently registered
* <code>IIOReadUpdateListeners, initialized by default to
* <code>null, which is synonymous with an empty
* <code>List.
*/
protected List<IIOReadUpdateListener> updateListeners = null;
/**
* If <code>true, the current read operation should be
* aborted.
*/
private boolean abortFlag = false;
/**
* Constructs an <code>ImageReader and sets its
* <code>originatingProvider field to the supplied value.
*
* <p> Subclasses that make use of extensions should provide a
* constructor with signature <code>(ImageReaderSpi,
* Object)</code> in order to retrieve the extension object. If
* the extension object is unsuitable, an
* <code>IllegalArgumentException should be thrown.
*
* @param originatingProvider the <code>ImageReaderSpi that is
* invoking this constructor, or <code>null.
*/
protected ImageReader(ImageReaderSpi originatingProvider) {
this.originatingProvider = originatingProvider;
}
/**
* Returns a <code>String identifying the format of the
* input source.
*
* <p> The default implementation returns
* <code>originatingProvider.getFormatNames()[0].
* Implementations that may not have an originating service
* provider, or which desire a different naming policy should
* override this method.
*
* @exception IOException if an error occurs reading the
* information from the input source.
*
* @return the format name, as a <code>String.
*/
public String getFormatName() throws IOException {
return originatingProvider.getFormatNames()[0];
}
/**
* Returns the <code>ImageReaderSpi that was passed in on
* the constructor. Note that this value may be <code>null.
*
* @return an <code>ImageReaderSpi, or null.
*
* @see ImageReaderSpi
*/
public ImageReaderSpi getOriginatingProvider() {
return originatingProvider;
}
/**
* Sets the input source to use to the given
* <code>ImageInputStream or other Object.
* The input source must be set before any of the query or read
* methods are used. If <code>input is null,
* any currently set input source will be removed. In any case,
* the value of <code>minIndex will be initialized to 0.
*
* <p> The seekForwardOnly parameter controls whether
* the value returned by <code>getMinIndex will be
* increased as each image (or thumbnail, or image metadata) is
* read. If <code>seekForwardOnly is true, then a call to
* <code>read(index) will throw an
* <code>IndexOutOfBoundsException if {@code index < this.minIndex};
* otherwise, the value of
* <code>minIndex will be set to index. If
* <code>seekForwardOnly is false, the value of
* <code>minIndex will remain 0 regardless of any read
* operations.
*
* <p> The ignoreMetadata parameter, if set to
* <code>true, allows the reader to disregard any metadata
* encountered during the read. Subsequent calls to the
* <code>getStreamMetadata and
* <code>getImageMetadata methods may return
* <code>null, and an IIOImage returned from
* <code>readAll may return null from their
* <code>getMetadata method. Setting this parameter may
* allow the reader to work more efficiently. The reader may
* choose to disregard this setting and return metadata normally.
*
* <p> Subclasses should take care to remove any cached
* information based on the previous stream, such as header
* information or partially decoded image data.
*
* <p> Use of a general Object other than an
* <code>ImageInputStream is intended for readers that
* interact directly with a capture device or imaging protocol.
* The set of legal classes is advertised by the reader's service
* provider's <code>getInputTypes method; most readers
* will return a single-element array containing only
* <code>ImageInputStream.class to indicate that they
* accept only an <code>ImageInputStream.
*
* <p> The default implementation checks the input
* argument against the list returned by
* <code>originatingProvider.getInputTypes() and fails
* if the argument is not an instance of one of the classes
* in the list. If the originating provider is set to
* <code>null, the input is accepted only if it is an
* <code>ImageInputStream.
*
* @param input the <code>ImageInputStream or other
* <code>Object to use for future decoding.
* @param seekForwardOnly if <code>true, images and metadata
* may only be read in ascending order from this input source.
* @param ignoreMetadata if <code>true, metadata
* may be ignored during reads.
*
* @exception IllegalArgumentException if <code>input is
* not an instance of one of the classes returned by the
* originating service provider's <code>getInputTypes
* method, or is not an <code>ImageInputStream.
*
* @see ImageInputStream
* @see #getInput
* @see javax.imageio.spi.ImageReaderSpi#getInputTypes
*/
public void setInput(Object input,
boolean seekForwardOnly,
boolean ignoreMetadata) {
if (input != null) {
boolean found = false;
if (originatingProvider != null) {
Class[] classes = originatingProvider.getInputTypes();
for (int i = 0; i < classes.length; i++) {
if (classes[i].isInstance(input)) {
found = true;
break;
}
}
} else {
if (input instanceof ImageInputStream) {
found = true;
}
}
if (!found) {
throw new IllegalArgumentException("Incorrect input type!");
}
this.seekForwardOnly = seekForwardOnly;
this.ignoreMetadata = ignoreMetadata;
this.minIndex = 0;
}
this.input = input;
}
/**
* Sets the input source to use to the given
* <code>ImageInputStream or other Object.
* The input source must be set before any of the query or read
* methods are used. If <code>input is null,
* any currently set input source will be removed. In any case,
* the value of <code>minIndex will be initialized to 0.
*
* <p> The seekForwardOnly parameter controls whether
* the value returned by <code>getMinIndex will be
* increased as each image (or thumbnail, or image metadata) is
* read. If <code>seekForwardOnly is true, then a call to
* <code>read(index) will throw an
* <code>IndexOutOfBoundsException if {@code index < this.minIndex};
* otherwise, the value of
* <code>minIndex will be set to index. If
* <code>seekForwardOnly is false, the value of
* <code>minIndex will remain 0 regardless of any read
* operations.
*
* <p> This method is equivalent to setInput(input,
* seekForwardOnly, false)</code>.
*
* @param input the <code>ImageInputStream or other
* <code>Object to use for future decoding.
* @param seekForwardOnly if <code>true, images and metadata
* may only be read in ascending order from this input source.
*
* @exception IllegalArgumentException if <code>input is
* not an instance of one of the classes returned by the
* originating service provider's <code>getInputTypes
* method, or is not an <code>ImageInputStream.
*
* @see #getInput
*/
public void setInput(Object input,
boolean seekForwardOnly) {
setInput(input, seekForwardOnly, false);
}
/**
* Sets the input source to use to the given
* <code>ImageInputStream or other Object.
* The input source must be set before any of the query or read
* methods are used. If <code>input is null,
* any currently set input source will be removed. In any case,
* the value of <code>minIndex will be initialized to 0.
*
* <p> This method is equivalent to setInput(input, false,
* false)</code>.
*
* @param input the <code>ImageInputStream or other
* <code>Object to use for future decoding.
*
* @exception IllegalArgumentException if <code>input is
* not an instance of one of the classes returned by the
* originating service provider's <code>getInputTypes
* method, or is not an <code>ImageInputStream.
*
* @see #getInput
*/
public void setInput(Object input) {
setInput(input, false, false);
}
/**
* Returns the <code>ImageInputStream or other
* <code>Object previously set as the input source. If the
* input source has not been set, <code>null is returned.
*
* @return the <code>Object that will be used for future
* decoding, or <code>null.
*
* @see ImageInputStream
* @see #setInput
*/
public Object getInput() {
return input;
}
/**
* Returns <code>true if the current input source has been
* marked as seek forward only by passing <code>true as the
* <code>seekForwardOnly argument to the
* <code>setInput method.
*
* @return <code>true if the input source is seek forward
* only.
*
* @see #setInput
*/
public boolean isSeekForwardOnly() {
return seekForwardOnly;
}
/**
* Returns <code>true if the current input source has been
* marked as allowing metadata to be ignored by passing
* <code>true as the ignoreMetadata argument
* to the <code>setInput method.
*
* @return <code>true if the metadata may be ignored.
*
* @see #setInput
*/
public boolean isIgnoringMetadata() {
return ignoreMetadata;
}
/**
* Returns the lowest valid index for reading an image, thumbnail,
* or image metadata. If <code>seekForwardOnly() is
* <code>false, this value will typically remain 0,
* indicating that random access is possible. Otherwise, it will
* contain the value of the most recently accessed index, and
* increase in a monotonic fashion.
*
* @return the minimum legal index for reading.
*/
public int getMinIndex() {
return minIndex;
}
// Localization
/**
* Returns an array of <code>Locales that may be used to
* localize warning listeners and compression settings. A return
* value of <code>null indicates that localization is not
* supported.
*
* <p> The default implementation returns a clone of the
* <code>availableLocales instance variable if it is
* non-<code>null, or else returns null.
*
* @return an array of <code>Locales that may be used as
* arguments to <code>setLocale, or null.
*/
public Locale[] getAvailableLocales() {
if (availableLocales == null) {
return null;
} else {
return (Locale[])availableLocales.clone();
}
}
/**
* Sets the current <code>Locale of this
* <code>ImageReader to the given value. A value of
* <code>null removes any previous setting, and indicates
* that the reader should localize as it sees fit.
*
* @param locale the desired <code>Locale, or
* <code>null.
*
* @exception IllegalArgumentException if <code>locale is
* non-<code>null but is not one of the values returned by
* <code>getAvailableLocales.
*
* @see #getLocale
*/
public void setLocale(Locale locale) {
if (locale != null) {
Locale[] locales = getAvailableLocales();
boolean found = false;
if (locales != null) {
for (int i = 0; i < locales.length; i++) {
if (locale.equals(locales[i])) {
found = true;
break;
}
}
}
if (!found) {
throw new IllegalArgumentException("Invalid locale!");
}
}
this.locale = locale;
}
/**
* Returns the currently set <code>Locale, or
* <code>null if none has been set.
*
* @return the current <code>Locale, or null.
*
* @see #setLocale
*/
public Locale getLocale() {
return locale;
}
// Image queries
/**
* Returns the number of images, not including thumbnails, available
* from the current input source.
*
* <p> Note that some image formats (such as animated GIF) do not
* specify how many images are present in the stream. Thus
* determining the number of images will require the entire stream
* to be scanned and may require memory for buffering. If images
* are to be processed in order, it may be more efficient to
* simply call <code>read with increasing indices until an
* <code>IndexOutOfBoundsException is thrown to indicate
* that no more images are available. The
* <code>allowSearch parameter may be set to
* <code>false to indicate that an exhaustive search is not
* desired; the return value will be <code>-1 to indicate
* that a search is necessary. If the input has been specified
* with <code>seekForwardOnly set to true,
* this method throws an <code>IllegalStateException if
* <code>allowSearch is set to true.
*
* @param allowSearch if <code>true, the true number of
* images will be returned even if a search is required. If
* <code>false, the reader may return -1
* without performing the search.
*
* @return the number of images, as an <code>int, or
* <code>-1 if allowSearch is
* <code>false and a search would be required.
*
* @exception IllegalStateException if the input source has not been set,
* or if the input has been specified with <code>seekForwardOnly
* set to <code>true.
* @exception IOException if an error occurs reading the
* information from the input source.
*
* @see #setInput
*/
public abstract int getNumImages(boolean allowSearch) throws IOException;
/**
* Returns the width in pixels of the given image within the input
* source.
*
* <p> If the image can be rendered to a user-specified size, then
* this method returns the default width.
*
* @param imageIndex the index of the image to be queried.
*
* @return the width of the image, as an <code>int.
*
* @exception IllegalStateException if the input source has not been set.
* @exception IndexOutOfBoundsException if the supplied index is
* out of bounds.
* @exception IOException if an error occurs reading the width
* information from the input source.
*/
public abstract int getWidth(int imageIndex) throws IOException;
/**
* Returns the height in pixels of the given image within the
* input source.
*
* <p> If the image can be rendered to a user-specified size, then
* this method returns the default height.
*
* @param imageIndex the index of the image to be queried.
*
* @return the height of the image, as an <code>int.
*
* @exception IllegalStateException if the input source has not been set.
* @exception IndexOutOfBoundsException if the supplied index is
* out of bounds.
* @exception IOException if an error occurs reading the height
* information from the input source.
*/
public abstract int getHeight(int imageIndex) throws IOException;
/**
* Returns <code>true if the storage format of the given
* image places no inherent impediment on random access to pixels.
* For most compressed formats, such as JPEG, this method should
* return <code>false, as a large section of the image in
* addition to the region of interest may need to be decoded.
*
* <p> This is merely a hint for programs that wish to be
* efficient; all readers must be able to read arbitrary regions
* as specified in an <code>ImageReadParam.
*
* <p> Note that formats that return false from
* this method may nonetheless allow tiling (<i>e.g. Restart
* Markers in JPEG), and random access will likely be reasonably
* efficient on tiles. See {@link #isImageTiled isImageTiled}.
*
* <p> A reader for which all images are guaranteed to support
* easy random access, or are guaranteed not to support easy
* random access, may return <code>true or
* <code>false respectively without accessing any image
* data. In such cases, it is not necessary to throw an exception
* even if no input source has been set or the image index is out
* of bounds.
*
* <p> The default implementation returns false.
*
* @param imageIndex the index of the image to be queried.
*
* @return <code>true if reading a region of interest of
* the given image is likely to be efficient.
*
* @exception IllegalStateException if an input source is required
* to determine the return value, but none has been set.
* @exception IndexOutOfBoundsException if an image must be
* accessed to determine the return value, but the supplied index
* is out of bounds.
* @exception IOException if an error occurs during reading.
*/
public boolean isRandomAccessEasy(int imageIndex) throws IOException {
return false;
}
/**
* Returns the aspect ratio of the given image (that is, its width
* divided by its height) as a <code>float. For images
* that are inherently resizable, this method provides a way to
* determine the appropriate width given a desired height, or vice
* versa. For non-resizable images, the true width and height
* are used.
*
* <p> The default implementation simply returns
* <code>(float)getWidth(imageIndex)/getHeight(imageIndex).
*
* @param imageIndex the index of the image to be queried.
*
* @return a <code>float indicating the aspect ratio of the
* given image.
*
* @exception IllegalStateException if the input source has not been set.
* @exception IndexOutOfBoundsException if the supplied index is
* out of bounds.
* @exception IOException if an error occurs during reading.
*/
public float getAspectRatio(int imageIndex) throws IOException {
return (float)getWidth(imageIndex)/getHeight(imageIndex);
}
/**
* Returns an <code>ImageTypeSpecifier indicating the
* <code>SampleModel and ColorModel which most
* closely represents the "raw" internal format of the image. For
* example, for a JPEG image the raw type might have a YCbCr color
* space even though the image would conventionally be transformed
* into an RGB color space prior to display. The returned value
* should also be included in the list of values returned by
* <code>getImageTypes.
*
* <p> The default implementation simply returns the first entry
* from the list provided by <code>getImageType.
*
* @param imageIndex the index of the image to be queried.
*
* @return an <code>ImageTypeSpecifier.
*
* @exception IllegalStateException if the input source has not been set.
* @exception IndexOutOfBoundsException if the supplied index is
* out of bounds.
* @exception IOException if an error occurs reading the format
* information from the input source.
*/
public ImageTypeSpecifier getRawImageType(int imageIndex)
throws IOException {
return (ImageTypeSpecifier)getImageTypes(imageIndex).next();
}
/**
* Returns an <code>Iterator containing possible image
* types to which the given image may be decoded, in the form of
* <code>ImageTypeSpecifierss. At least one legal image
* type will be returned.
*
* <p> The first element of the iterator should be the most
* "natural" type for decoding the image with as little loss as
* possible. For example, for a JPEG image the first entry should
* be an RGB image, even though the image data is stored
* internally in a YCbCr color space.
*
* @param imageIndex the index of the image to be
* <code>retrieved.
*
* @return an <code>Iterator containing at least one
* <code>ImageTypeSpecifier representing suggested image
* types for decoding the current given image.
*
* @exception IllegalStateException if the input source has not been set.
* @exception IndexOutOfBoundsException if the supplied index is
* out of bounds.
* @exception IOException if an error occurs reading the format
* information from the input source.
*
* @see ImageReadParam#setDestination(BufferedImage)
* @see ImageReadParam#setDestinationType(ImageTypeSpecifier)
*/
public abstract Iterator<ImageTypeSpecifier>
getImageTypes(int imageIndex) throws IOException;
/**
* Returns a default <code>ImageReadParam object
* appropriate for this format. All subclasses should define a
* set of default values for all parameters and return them with
* this call. This method may be called before the input source
* is set.
*
* <p> The default implementation constructs and returns a new
* <code>ImageReadParam object that does not allow source
* scaling (<i>i.e., it returns new
* ImageReadParam()</code>.
*
* @return an <code>ImageReadParam object which may be used
* to control the decoding process using a set of default settings.
*/
public ImageReadParam getDefaultReadParam() {
return new ImageReadParam();
}
/**
* Returns an <code>IIOMetadata object representing the
* metadata associated with the input source as a whole (i.e., not
* associated with any particular image), or <code>null if
* the reader does not support reading metadata, is set to ignore
* metadata, or if no metadata is available.
*
* @return an <code>IIOMetadata object, or null.
*
* @exception IOException if an error occurs during reading.
*/
public abstract IIOMetadata getStreamMetadata() throws IOException;
/**
* Returns an <code>IIOMetadata object representing the
* metadata associated with the input source as a whole (i.e.,
* not associated with any particular image). If no such data
* exists, <code>null is returned.
*
* <p> The resulting metadata object is only responsible for
* returning documents in the format named by
* <code>formatName. Within any documents that are
* returned, only nodes whose names are members of
* <code>nodeNames are required to be returned. In this
* way, the amount of metadata processing done by the reader may
* be kept to a minimum, based on what information is actually
* needed.
*
* <p> If formatName is not the name of a supported
* metadata format, <code>null is returned.
*
* <p> In all cases, it is legal to return a more capable metadata
* object than strictly necessary. The format name and node names
* are merely hints that may be used to reduce the reader's
* workload.
*
* <p> The default implementation simply returns the result of
* calling <code>getStreamMetadata(), after checking that
* the format name is supported. If it is not,
* <code>null is returned.
*
* @param formatName a metadata format name that may be used to retrieve
* a document from the returned <code>IIOMetadata object.
* @param nodeNames a <code>Set containing the names of
* nodes that may be contained in a retrieved document.
*
* @return an <code>IIOMetadata object, or null.
*
* @exception IllegalArgumentException if <code>formatName
* is <code>null.
* @exception IllegalArgumentException if <code>nodeNames
* is <code>null.
* @exception IOException if an error occurs during reading.
*/
public IIOMetadata getStreamMetadata(String formatName,
Set<String> nodeNames)
throws IOException
{
return getMetadata(formatName, nodeNames, true, 0);
}
private IIOMetadata getMetadata(String formatName,
Set nodeNames,
boolean wantStream,
int imageIndex) throws IOException {
if (formatName == null) {
throw new IllegalArgumentException("formatName == null!");
}
if (nodeNames == null) {
throw new IllegalArgumentException("nodeNames == null!");
}
IIOMetadata metadata =
wantStream
? getStreamMetadata()
: getImageMetadata(imageIndex);
if (metadata != null) {
if (metadata.isStandardMetadataFormatSupported() &&
formatName.equals
(IIOMetadataFormatImpl.standardMetadataFormatName)) {
return metadata;
}
String nativeName = metadata.getNativeMetadataFormatName();
if (nativeName != null && formatName.equals(nativeName)) {
return metadata;
}
String[] extraNames = metadata.getExtraMetadataFormatNames();
if (extraNames != null) {
for (int i = 0; i < extraNames.length; i++) {
if (formatName.equals(extraNames[i])) {
return metadata;
}
}
}
}
return null;
}
/**
* Returns an <code>IIOMetadata object containing metadata
* associated with the given image, or <code>null if the
* reader does not support reading metadata, is set to ignore
* metadata, or if no metadata is available.
*
* @param imageIndex the index of the image whose metadata is to
* be retrieved.
*
* @return an <code>IIOMetadata object, or
* <code>null.
*
* @exception IllegalStateException if the input source has not been
* set.
* @exception IndexOutOfBoundsException if the supplied index is
* out of bounds.
* @exception IOException if an error occurs during reading.
*/
public abstract IIOMetadata getImageMetadata(int imageIndex)
throws IOException;
/**
* Returns an <code>IIOMetadata object representing the
* metadata associated with the given image, or <code>null
* if the reader does not support reading metadata or none
* is available.
*
* <p> The resulting metadata object is only responsible for
* returning documents in the format named by
* <code>formatName. Within any documents that are
* returned, only nodes whose names are members of
* <code>nodeNames are required to be returned. In this
* way, the amount of metadata processing done by the reader may
* be kept to a minimum, based on what information is actually
* needed.
*
* <p> If formatName is not the name of a supported
* metadata format, <code>null may be returned.
*
* <p> In all cases, it is legal to return a more capable metadata
* object than strictly necessary. The format name and node names
* are merely hints that may be used to reduce the reader's
* workload.
*
* <p> The default implementation simply returns the result of
* calling <code>getImageMetadata(imageIndex), after
* checking that the format name is supported. If it is not,
* <code>null is returned.
*
* @param imageIndex the index of the image whose metadata is to
* be retrieved.
* @param formatName a metadata format name that may be used to retrieve
* a document from the returned <code>IIOMetadata object.
* @param nodeNames a <code>Set containing the names of
* nodes that may be contained in a retrieved document.
*
* @return an <code>IIOMetadata object, or null.
*
* @exception IllegalStateException if the input source has not been
* set.
* @exception IndexOutOfBoundsException if the supplied index is
* out of bounds.
* @exception IllegalArgumentException if <code>formatName
* is <code>null.
* @exception IllegalArgumentException if <code>nodeNames
* is <code>null.
* @exception IOException if an error occurs during reading.
*/
public IIOMetadata getImageMetadata(int imageIndex,
String formatName,
Set<String> nodeNames)
throws IOException {
return getMetadata(formatName, nodeNames, false, imageIndex);
}
/**
* Reads the image indexed by <code>imageIndex and returns
* it as a complete <code>BufferedImage, using a default
* <code>ImageReadParam. This is a convenience method
* that calls <code>read(imageIndex, null).
*
* <p> The image returned will be formatted according to the first
* <code>ImageTypeSpecifier returned from
* <code>getImageTypes.
*
* <p> Any registered IIOReadProgressListener objects
* will be notified by calling their <code>imageStarted
* method, followed by calls to their <code>imageProgress
* method as the read progresses. Finally their
* <code>imageComplete method will be called.
* <code>IIOReadUpdateListener objects may be updated at
* other times during the read as pixels are decoded. Finally,
* <code>IIOReadWarningListener objects will receive
* notification of any non-fatal warnings that occur during
* decoding.
*
* @param imageIndex the index of the image to be retrieved.
*
* @return the desired portion of the image as a
* <code>BufferedImage.
*
* @exception IllegalStateException if the input source has not been
* set.
* @exception IndexOutOfBoundsException if the supplied index is
* out of bounds.
* @exception IOException if an error occurs during reading.
*/
public BufferedImage read(int imageIndex) throws IOException {
return read(imageIndex, null);
}
/**
* Reads the image indexed by <code>imageIndex and returns
* it as a complete <code>BufferedImage, using a supplied
* <code>ImageReadParam.
*
* <p> The actual BufferedImage returned will be
* chosen using the algorithm defined by the
* <code>getDestination method.
*
* <p> Any registered IIOReadProgressListener objects
* will be notified by calling their <code>imageStarted
* method, followed by calls to their <code>imageProgress
* method as the read progresses. Finally their
* <code>imageComplete method will be called.
* <code>IIOReadUpdateListener objects may be updated at
* other times during the read as pixels are decoded. Finally,
* <code>IIOReadWarningListener objects will receive
* notification of any non-fatal warnings that occur during
* decoding.
*
* <p> The set of source bands to be read and destination bands to
* be written is determined by calling <code>getSourceBands
* and <code>getDestinationBands on the supplied
* <code>ImageReadParam. If the lengths of the arrays
* returned by these methods differ, the set of source bands
* contains an index larger that the largest available source
* index, or the set of destination bands contains an index larger
* than the largest legal destination index, an
* <code>IllegalArgumentException is thrown.
*
* <p> If the supplied ImageReadParam contains
* optional setting values not supported by this reader (<i>e.g.
* source render size or any format-specific settings), they will
* be ignored.
*
* @param imageIndex the index of the image to be retrieved.
* @param param an <code>ImageReadParam used to control
* the reading process, or <code>null.
*
* @return the desired portion of the image as a
* <code>BufferedImage.
*
* @exception IllegalStateException if the input source has not been
* set.
* @exception IndexOutOfBoundsException if the supplied index is
* out of bounds.
* @exception IllegalArgumentException if the set of source and
* destination bands specified by
* <code>param.getSourceBands and
* <code>param.getDestinationBands differ in length or
* include indices that are out of bounds.
* @exception IllegalArgumentException if the resulting image would
* have a width or height less than 1.
* @exception IOException if an error occurs during reading.
*/
public abstract BufferedImage read(int imageIndex, ImageReadParam param)
throws IOException;
/**
* Reads the image indexed by <code>imageIndex and returns
* an <code>IIOImage containing the image, thumbnails, and
* associated image metadata, using a supplied
* <code>ImageReadParam.
*
* <p> The actual BufferedImage referenced by the
* returned <code>IIOImage will be chosen using the
* algorithm defined by the <code>getDestination method.
*
* <p> Any registered IIOReadProgressListener objects
* will be notified by calling their <code>imageStarted
* method, followed by calls to their <code>imageProgress
* method as the read progresses. Finally their
* <code>imageComplete method will be called.
* <code>IIOReadUpdateListener objects may be updated at
* other times during the read as pixels are decoded. Finally,
* <code>IIOReadWarningListener objects will receive
* notification of any non-fatal warnings that occur during
* decoding.
*
* <p> The set of source bands to be read and destination bands to
* be written is determined by calling <code>getSourceBands
* and <code>getDestinationBands on the supplied
* <code>ImageReadParam. If the lengths of the arrays
* returned by these methods differ, the set of source bands
* contains an index larger that the largest available source
* index, or the set of destination bands contains an index larger
* than the largest legal destination index, an
* <code>IllegalArgumentException is thrown.
*
* <p> Thumbnails will be returned in their entirety regardless of
* the region settings.
*
* <p> If the supplied ImageReadParam contains
* optional setting values not supported by this reader (<i>e.g.
* source render size or any format-specific settings), those
* values will be ignored.
*
* @param imageIndex the index of the image to be retrieved.
* @param param an <code>ImageReadParam used to control
* the reading process, or <code>null.
*
* @return an <code>IIOImage containing the desired portion
* of the image, a set of thumbnails, and associated image
* metadata.
*
* @exception IllegalStateException if the input source has not been
* set.
* @exception IndexOutOfBoundsException if the supplied index is
* out of bounds.
* @exception IllegalArgumentException if the set of source and
* destination bands specified by
* <code>param.getSourceBands and
* <code>param.getDestinationBands differ in length or
* include indices that are out of bounds.
* @exception IllegalArgumentException if the resulting image
* would have a width or height less than 1.
* @exception IOException if an error occurs during reading.
*/
public IIOImage readAll(int imageIndex, ImageReadParam param)
throws IOException {
if (imageIndex < getMinIndex()) {
throw new IndexOutOfBoundsException("imageIndex < getMinIndex()!");
}
BufferedImage im = read(imageIndex, param);
ArrayList thumbnails = null;
int numThumbnails = getNumThumbnails(imageIndex);
if (numThumbnails > 0) {
thumbnails = new ArrayList();
for (int j = 0; j < numThumbnails; j++) {
thumbnails.add(readThumbnail(imageIndex, j));
}
}
IIOMetadata metadata = getImageMetadata(imageIndex);
return new IIOImage(im, thumbnails, metadata);
}
/**
* Returns an <code>Iterator containing all the images,
* thumbnails, and metadata, starting at the index given by
* <code>getMinIndex, from the input source in the form of
* <code>IIOImage objects. An Iterator
* containing <code>ImageReadParam objects is supplied; one
* element is consumed for each image read from the input source
* until no more images are available. If the read param
* <code>Iterator runs out of elements, but there are still
* more images available from the input source, default read
* params are used for the remaining images.
*
* <p> If params is null, a default read
* param will be used for all images.
*
* <p> The actual BufferedImage referenced by the
* returned <code>IIOImage will be chosen using the
* algorithm defined by the <code>getDestination method.
*
* <p> Any registered IIOReadProgressListener objects
* will be notified by calling their <code>sequenceStarted
* method once. Then, for each image decoded, there will be a
* call to <code>imageStarted, followed by calls to
* <code>imageProgress as the read progresses, and finally
* to <code>imageComplete. The
* <code>sequenceComplete method will be called after the
* last image has been decoded.
* <code>IIOReadUpdateListener objects may be updated at
* other times during the read as pixels are decoded. Finally,
* <code>IIOReadWarningListener objects will receive
* notification of any non-fatal warnings that occur during
* decoding.
*
* <p> The set of source bands to be read and destination bands to
* be written is determined by calling <code>getSourceBands
* and <code>getDestinationBands on the supplied
* <code>ImageReadParam. If the lengths of the arrays
* returned by these methods differ, the set of source bands
* contains an index larger that the largest available source
* index, or the set of destination bands contains an index larger
* than the largest legal destination index, an
* <code>IllegalArgumentException is thrown.
*
* <p> Thumbnails will be returned in their entirety regardless of the
* region settings.
*
* <p> If any of the supplied ImageReadParams contain
* optional setting values not supported by this reader (<i>e.g.
* source render size or any format-specific settings), they will
* be ignored.
*
* @param params an <code>Iterator containing
* <code>ImageReadParam objects.
*
* @return an <code>Iterator representing the
* contents of the input source as <code>IIOImages.
*
* @exception IllegalStateException if the input source has not been
* set.
* @exception IllegalArgumentException if any
* non-<code>null element of params is not an
* <code>ImageReadParam.
* @exception IllegalArgumentException if the set of source and
* destination bands specified by
* <code>param.getSourceBands and
* <code>param.getDestinationBands differ in length or
* include indices that are out of bounds.
* @exception IllegalArgumentException if a resulting image would
* have a width or height less than 1.
* @exception IOException if an error occurs during reading.
*
* @see ImageReadParam
* @see IIOImage
*/
public Iterator<IIOImage>
readAll(Iterator<? extends ImageReadParam> params)
throws IOException
{
List output = new ArrayList();
int imageIndex = getMinIndex();
// Inform IIOReadProgressListeners we're starting a sequence
processSequenceStarted(imageIndex);
while (true) {
// Inform IIOReadProgressListeners and IIOReadUpdateListeners
// that we're starting a new image
ImageReadParam param = null;
if (params != null && params.hasNext()) {
Object o = params.next();
if (o != null) {
if (o instanceof ImageReadParam) {
param = (ImageReadParam)o;
} else {
throw new IllegalArgumentException
("Non-ImageReadParam supplied as part of params!");
}
}
}
BufferedImage bi = null;
try {
bi = read(imageIndex, param);
} catch (IndexOutOfBoundsException e) {
break;
}
ArrayList thumbnails = null;
int numThumbnails = getNumThumbnails(imageIndex);
if (numThumbnails > 0) {
thumbnails = new ArrayList();
for (int j = 0; j < numThumbnails; j++) {
thumbnails.add(readThumbnail(imageIndex, j));
}
}
IIOMetadata metadata = getImageMetadata(imageIndex);
IIOImage im = new IIOImage(bi, thumbnails, metadata);
output.add(im);
++imageIndex;
}
// Inform IIOReadProgressListeners we're ending a sequence
processSequenceComplete();
return output.iterator();
}
/**
* Returns <code>true if this plug-in supports reading
* just a {@link java.awt.image.Raster Raster} of pixel data.
* If this method returns <code>false, calls to
* {@link #readRaster readRaster} or {@link #readTileRaster readTileRaster}
* will throw an <code>UnsupportedOperationException.
*
* <p> The default implementation returns false.
*
* @return <code>true if this plug-in supports reading raw
* <code>Rasters.
*
* @see #readRaster
* @see #readTileRaster
*/
public boolean canReadRaster() {
return false;
}
/**
* Returns a new <code>Raster object containing the raw pixel data
* from the image stream, without any color conversion applied. The
* application must determine how to interpret the pixel data by other
* means. Any destination or image-type parameters in the supplied
* <code>ImageReadParam object are ignored, but all other
* parameters are used exactly as in the {@link #read read}
* method, except that any destination offset is used as a logical rather
* than a physical offset. The size of the returned <code>Raster
* will always be that of the source region clipped to the actual image.
* Logical offsets in the stream itself are ignored.
*
* <p> This method allows formats that normally apply a color
* conversion, such as JPEG, and formats that do not normally have an
* associated colorspace, such as remote sensing or medical imaging data,
* to provide access to raw pixel data.
*
* <p> Any registered readUpdateListeners are ignored, as
* there is no <code>BufferedImage, but all other listeners are
* called exactly as they are for the {@link #read read} method.
*
* <p> If {@link #canReadRaster canReadRaster()} returns
* <code>false, this method throws an
* <code>UnsupportedOperationException.
*
* <p> If the supplied ImageReadParam contains
* optional setting values not supported by this reader (<i>e.g.
* source render size or any format-specific settings), they will
* be ignored.
*
* <p> The default implementation throws an
* <code>UnsupportedOperationException.
*
* @param imageIndex the index of the image to be read.
* @param param an <code>ImageReadParam used to control
* the reading process, or <code>null.
*
* @return the desired portion of the image as a
* <code>Raster.
*
* @exception UnsupportedOperationException if this plug-in does not
* support reading raw <code>Rasters.
* @exception IllegalStateException if the input source has not been
* set.
* @exception IndexOutOfBoundsException if the supplied index is
* out of bounds.
* @exception IOException if an error occurs during reading.
*
* @see #canReadRaster
* @see #read
* @see java.awt.image.Raster
*/
public Raster readRaster(int imageIndex, ImageReadParam param)
throws IOException {
throw new UnsupportedOperationException("readRaster not supported!");
}
/**
* Returns <code>true if the image is organized into
* <i>tiles, that is, equal-sized non-overlapping rectangles.
*
* <p> A reader plug-in may choose whether or not to expose tiling
* that is present in the image as it is stored. It may even
* choose to advertise tiling when none is explicitly present. In
* general, tiling should only be advertised if there is some
* advantage (in speed or space) to accessing individual tiles.
* Regardless of whether the reader advertises tiling, it must be
* capable of reading an arbitrary rectangular region specified in
* an <code>ImageReadParam.
*
* <p> A reader for which all images are guaranteed to be tiled,
* or are guaranteed not to be tiled, may return <code>true
* or <code>false respectively without accessing any image
* data. In such cases, it is not necessary to throw an exception
* even if no input source has been set or the image index is out
* of bounds.
*
* <p> The default implementation just returns false.
*
* @param imageIndex the index of the image to be queried.
*
* @return <code>true if the image is tiled.
*
* @exception IllegalStateException if an input source is required
* to determine the return value, but none has been set.
* @exception IndexOutOfBoundsException if an image must be
* accessed to determine the return value, but the supplied index
* is out of bounds.
* @exception IOException if an error occurs during reading.
*/
public boolean isImageTiled(int imageIndex) throws IOException {
return false;
}
/**
* Returns the width of a tile in the given image.
*
* <p> The default implementation simply returns
* <code>getWidth(imageIndex), which is correct for
* non-tiled images. Readers that support tiling should override
* this method.
*
* @return the width of a tile.
*
* @param imageIndex the index of the image to be queried.
*
* @exception IllegalStateException if the input source has not been set.
* @exception IndexOutOfBoundsException if the supplied index is
* out of bounds.
* @exception IOException if an error occurs during reading.
*/
public int getTileWidth(int imageIndex) throws IOException {
return getWidth(imageIndex);
}
/**
* Returns the height of a tile in the given image.
*
* <p> The default implementation simply returns
* <code>getHeight(imageIndex), which is correct for
* non-tiled images. Readers that support tiling should override
* this method.
*
* @return the height of a tile.
*
* @param imageIndex the index of the image to be queried.
*
* @exception IllegalStateException if the input source has not been set.
* @exception IndexOutOfBoundsException if the supplied index is
* out of bounds.
* @exception IOException if an error occurs during reading.
*/
public int getTileHeight(int imageIndex) throws IOException {
return getHeight(imageIndex);
}
/**
* Returns the X coordinate of the upper-left corner of tile (0,
* 0) in the given image.
*
* <p> A reader for which the tile grid X offset always has the
* same value (usually 0), may return the value without accessing
* any image data. In such cases, it is not necessary to throw an
* exception even if no input source has been set or the image
* index is out of bounds.
*
* <p> The default implementation simply returns 0, which is
* correct for non-tiled images and tiled images in most formats.
* Readers that support tiling with non-(0, 0) offsets should
* override this method.
*
* @return the X offset of the tile grid.
*
* @param imageIndex the index of the image to be queried.
*
* @exception IllegalStateException if an input source is required
* to determine the return value, but none has been set.
* @exception IndexOutOfBoundsException if an image must be
* accessed to determine the return value, but the supplied index
* is out of bounds.
* @exception IOException if an error occurs during reading.
*/
public int getTileGridXOffset(int imageIndex) throws IOException {
return 0;
}
/**
* Returns the Y coordinate of the upper-left corner of tile (0,
* 0) in the given image.
*
* <p> A reader for which the tile grid Y offset always has the
* same value (usually 0), may return the value without accessing
* any image data. In such cases, it is not necessary to throw an
* exception even if no input source has been set or the image
* index is out of bounds.
*
* <p> The default implementation simply returns 0, which is
* correct for non-tiled images and tiled images in most formats.
* Readers that support tiling with non-(0, 0) offsets should
* override this method.
*
* @return the Y offset of the tile grid.
*
* @param imageIndex the index of the image to be queried.
*
* @exception IllegalStateException if an input source is required
* to determine the return value, but none has been set.
* @exception IndexOutOfBoundsException if an image must be
* accessed to determine the return value, but the supplied index
* is out of bounds.
* @exception IOException if an error occurs during reading.
*/
public int getTileGridYOffset(int imageIndex) throws IOException {
return 0;
}
/**
* Reads the tile indicated by the <code>tileX and
* <code>tileY arguments, returning it as a
* <code>BufferedImage. If the arguments are out of range,
* an <code>IllegalArgumentException is thrown. If the
* image is not tiled, the values 0, 0 will return the entire
* image; any other values will cause an
* <code>IllegalArgumentException to be thrown.
*
* <p> This method is merely a convenience equivalent to calling
* <code>read(int, ImageReadParam) with a read param
* specifying a source region having offsets of
* <code>tileX*getTileWidth(imageIndex),
* <code>tileY*getTileHeight(imageIndex) and width and
* height of <code>getTileWidth(imageIndex),
* <code>getTileHeight(imageIndex); and subsampling
* factors of 1 and offsets of 0. To subsample a tile, call
* <code>read with a read param specifying this region
* and different subsampling parameters.
*
* <p> The default implementation returns the entire image if
* <code>tileX and tileY are 0, or throws
* an <code>IllegalArgumentException otherwise.
*
* @param imageIndex the index of the image to be retrieved.
* @param tileX the column index (starting with 0) of the tile
* to be retrieved.
* @param tileY the row index (starting with 0) of the tile
* to be retrieved.
*
* @return the tile as a <code>BufferedImage.
*
* @exception IllegalStateException if the input source has not been
* set.
* @exception IndexOutOfBoundsException if <code>imageIndex
* is out of bounds.
* @exception IllegalArgumentException if the tile indices are
* out of bounds.
* @exception IOException if an error occurs during reading.
*/
public BufferedImage readTile(int imageIndex,
int tileX, int tileY) throws IOException {
if ((tileX != 0) || (tileY != 0)) {
throw new IllegalArgumentException("Invalid tile indices");
}
return read(imageIndex);
}
/**
* Returns a new <code>Raster object containing the raw
* pixel data from the tile, without any color conversion applied.
* The application must determine how to interpret the pixel data by other
* means.
*
* <p> If {@link #canReadRaster canReadRaster()} returns
* <code>false, this method throws an
* <code>UnsupportedOperationException.
*
* <p> The default implementation checks if reading
* <code>Rasters is supported, and if so calls {@link
* #readRaster readRaster(imageIndex, null)} if
* <code>tileX and tileY are 0, or throws an
* <code>IllegalArgumentException otherwise.
*
* @param imageIndex the index of the image to be retrieved.
* @param tileX the column index (starting with 0) of the tile
* to be retrieved.
* @param tileY the row index (starting with 0) of the tile
* to be retrieved.
*
* @return the tile as a <code>Raster.
*
* @exception UnsupportedOperationException if this plug-in does not
* support reading raw <code>Rasters.
* @exception IllegalArgumentException if the tile indices are
* out of bounds.
* @exception IllegalStateException if the input source has not been
* set.
* @exception IndexOutOfBoundsException if <code>imageIndex
* is out of bounds.
* @exception IOException if an error occurs during reading.
*
* @see #readTile
* @see #readRaster
* @see java.awt.image.Raster
*/
public Raster readTileRaster(int imageIndex,
int tileX, int tileY) throws IOException {
if (!canReadRaster()) {
throw new UnsupportedOperationException
("readTileRaster not supported!");
}
if ((tileX != 0) || (tileY != 0)) {
throw new IllegalArgumentException("Invalid tile indices");
}
return readRaster(imageIndex, null);
}
// RenderedImages
/**
* Returns a <code>RenderedImage object that contains the
* contents of the image indexed by <code>imageIndex. By
* default, the returned image is simply the
* <code>BufferedImage returned by read(imageIndex,
* param)</code>.
*
* <p> The semantics of this method may differ from those of the
* other <code>read methods in several ways. First, any
* destination image and/or image type set in the
* <code>ImageReadParam may be ignored. Second, the usual
* listener calls are not guaranteed to be made, or to be
* meaningful if they are. This is because the returned image may
* not be fully populated with pixel data at the time it is
* returned, or indeed at any time.
*
* <p> If the supplied ImageReadParam contains
* optional setting values not supported by this reader (<i>e.g.
* source render size or any format-specific settings), they will
* be ignored.
*
* <p> The default implementation just calls
* {@link #read read(imageIndex, param)}.
*
* @param imageIndex the index of the image to be retrieved.
* @param param an <code>ImageReadParam used to control
* the reading process, or <code>null.
*
* @return a <code>RenderedImage object providing a view of
* the image.
*
* @exception IllegalStateException if the input source has not been
* set.
* @exception IndexOutOfBoundsException if the supplied index is
* out of bounds.
* @exception IllegalArgumentException if the set of source and
* destination bands specified by
* <code>param.getSourceBands and
* <code>param.getDestinationBands differ in length or
* include indices that are out of bounds.
* @exception IllegalArgumentException if the resulting image
* would have a width or height less than 1.
* @exception IOException if an error occurs during reading.
*/
public RenderedImage readAsRenderedImage(int imageIndex,
ImageReadParam param)
throws IOException {
return read(imageIndex, param);
}
// Thumbnails
/**
* Returns <code>true if the image format understood by
* this reader supports thumbnail preview images associated with
* it. The default implementation returns <code>false.
*
* <p> If this method returns false,
* <code>hasThumbnails and getNumThumbnails
* will return <code>false and 0,
* respectively, and <code>readThumbnail will throw an
* <code>UnsupportedOperationException, regardless of their
* arguments.
*
* <p> A reader that does not support thumbnails need not
* implement any of the thumbnail-related methods.
*
* @return <code>true if thumbnails are supported.
*/
public boolean readerSupportsThumbnails() {
return false;
}
/**
* Returns <code>true if the given image has thumbnail
* preview images associated with it. If the format does not
* support thumbnails (<code>readerSupportsThumbnails
* returns <code>false), false will be
* returned regardless of whether an input source has been set or
* whether <code>imageIndex is in bounds.
*
* <p> The default implementation returns true if
* <code>getNumThumbnails returns a value greater than 0.
*
* @param imageIndex the index of the image being queried.
*
* @return <code>true if the given image has thumbnails.
*
* @exception IllegalStateException if the reader supports
* thumbnails but the input source has not been set.
* @exception IndexOutOfBoundsException if the reader supports
* thumbnails but <code>imageIndex is out of bounds.
* @exception IOException if an error occurs during reading.
*/
public boolean hasThumbnails(int imageIndex) throws IOException {
return getNumThumbnails(imageIndex) > 0;
}
/**
* Returns the number of thumbnail preview images associated with
* the given image. If the format does not support thumbnails,
* (<code>readerSupportsThumbnails returns
* <code>false), 0 will be returned regardless
* of whether an input source has been set or whether
* <code>imageIndex is in bounds.
*
* <p> The default implementation returns 0 without checking its
* argument.
*
* @param imageIndex the index of the image being queried.
*
* @return the number of thumbnails associated with the given
* image.
*
* @exception IllegalStateException if the reader supports
* thumbnails but the input source has not been set.
* @exception IndexOutOfBoundsException if the reader supports
* thumbnails but <code>imageIndex is out of bounds.
* @exception IOException if an error occurs during reading.
*/
public int getNumThumbnails(int imageIndex)
throws IOException {
return 0;
}
/**
* Returns the width of the thumbnail preview image indexed by
* <code>thumbnailIndex, associated with the image indexed
* by <code>ImageIndex.
*
* <p> If the reader does not support thumbnails,
* (<code>readerSupportsThumbnails returns
* <code>false), an UnsupportedOperationException
* will be thrown.
*
* <p> The default implementation simply returns
* <code>readThumbnail(imageindex,
* thumbnailIndex).getWidth()</code>. Subclasses should therefore
* override this method if possible in order to avoid forcing the
* thumbnail to be read.
*
* @param imageIndex the index of the image to be retrieved.
* @param thumbnailIndex the index of the thumbnail to be retrieved.
*
* @return the width of the desired thumbnail as an <code>int.
*
* @exception UnsupportedOperationException if thumbnails are not
* supported.
* @exception IllegalStateException if the input source has not been set.
* @exception IndexOutOfBoundsException if either of the supplied
* indices are out of bounds.
* @exception IOException if an error occurs during reading.
*/
public int getThumbnailWidth(int imageIndex, int thumbnailIndex)
throws IOException {
return readThumbnail(imageIndex, thumbnailIndex).getWidth();
}
/**
* Returns the height of the thumbnail preview image indexed by
* <code>thumbnailIndex, associated with the image indexed
* by <code>ImageIndex.
*
* <p> If the reader does not support thumbnails,
* (<code>readerSupportsThumbnails returns
* <code>false), an UnsupportedOperationException
* will be thrown.
*
* <p> The default implementation simply returns
* <code>readThumbnail(imageindex,
* thumbnailIndex).getHeight()</code>. Subclasses should
* therefore override this method if possible in order to avoid
* forcing the thumbnail to be read.
*
* @param imageIndex the index of the image to be retrieved.
* @param thumbnailIndex the index of the thumbnail to be retrieved.
*
* @return the height of the desired thumbnail as an <code>int.
*
* @exception UnsupportedOperationException if thumbnails are not
* supported.
* @exception IllegalStateException if the input source has not been set.
* @exception IndexOutOfBoundsException if either of the supplied
* indices are out of bounds.
* @exception IOException if an error occurs during reading.
*/
public int getThumbnailHeight(int imageIndex, int thumbnailIndex)
throws IOException {
return readThumbnail(imageIndex, thumbnailIndex).getHeight();
}
/**
* Returns the thumbnail preview image indexed by
* <code>thumbnailIndex, associated with the image indexed
* by <code>ImageIndex as a BufferedImage.
*
* <p> Any registered IIOReadProgressListener objects
* will be notified by calling their
* <code>thumbnailStarted, thumbnailProgress,
* and <code>thumbnailComplete methods.
*
* <p> If the reader does not support thumbnails,
* (<code>readerSupportsThumbnails returns
* <code>false), an UnsupportedOperationException
* will be thrown regardless of whether an input source has been
* set or whether the indices are in bounds.
*
* <p> The default implementation throws an
* <code>UnsupportedOperationException.
*
* @param imageIndex the index of the image to be retrieved.
* @param thumbnailIndex the index of the thumbnail to be retrieved.
*
* @return the desired thumbnail as a <code>BufferedImage.
*
* @exception UnsupportedOperationException if thumbnails are not
* supported.
* @exception IllegalStateException if the input source has not been set.
* @exception IndexOutOfBoundsException if either of the supplied
* indices are out of bounds.
* @exception IOException if an error occurs during reading.
*/
public BufferedImage readThumbnail(int imageIndex,
int thumbnailIndex)
throws IOException {
throw new UnsupportedOperationException("Thumbnails not supported!");
}
// Abort
/**
* Requests that any current read operation be aborted. The
* contents of the image following the abort will be undefined.
*
* <p> Readers should call clearAbortRequest at the
* beginning of each read operation, and poll the value of
* <code>abortRequested regularly during the read.
*/
public synchronized void abort() {
this.abortFlag = true;
}
/**
* Returns <code>true if a request to abort the current
* read operation has been made since the reader was instantiated or
* <code>clearAbortRequest was called.
*
* @return <code>true if the current read operation should
* be aborted.
*
* @see #abort
* @see #clearAbortRequest
*/
protected synchronized boolean abortRequested() {
return this.abortFlag;
}
/**
* Clears any previous abort request. After this method has been
* called, <code>abortRequested will return
* <code>false.
*
* @see #abort
* @see #abortRequested
*/
protected synchronized void clearAbortRequest() {
this.abortFlag = false;
}
// Listeners
// Add an element to a list, creating a new list if the
// existing list is null, and return the list.
static List addToList(List l, Object elt) {
if (l == null) {
l = new ArrayList();
}
l.add(elt);
return l;
}
// Remove an element from a list, discarding the list if the
// resulting list is empty, and return the list or null.
static List removeFromList(List l, Object elt) {
if (l == null) {
return l;
}
l.remove(elt);
if (l.size() == 0) {
l = null;
}
return l;
}
/**
* Adds an <code>IIOReadWarningListener to the list of
* registered warning listeners. If <code>listener is
* <code>null, no exception will be thrown and no action
* will be taken. Messages sent to the given listener will be
* localized, if possible, to match the current
* <code>Locale. If no Locale has been set,
* warning messages may be localized as the reader sees fit.
*
* @param listener an <code>IIOReadWarningListener to be registered.
*
* @see #removeIIOReadWarningListener
*/
public void addIIOReadWarningListener(IIOReadWarningListener listener) {
if (listener == null) {
return;
}
warningListeners = addToList(warningListeners, listener);
warningLocales = addToList(warningLocales, getLocale());
}
/**
* Removes an <code>IIOReadWarningListener from the list of
* registered error listeners. If the listener was not previously
* registered, or if <code>listener is null,
* no exception will be thrown and no action will be taken.
*
* @param listener an IIOReadWarningListener to be unregistered.
*
* @see #addIIOReadWarningListener
*/
public void removeIIOReadWarningListener(IIOReadWarningListener listener) {
if (listener == null || warningListeners == null) {
return;
}
int index = warningListeners.indexOf(listener);
if (index != -1) {
warningListeners.remove(index);
warningLocales.remove(index);
if (warningListeners.size() == 0) {
warningListeners = null;
warningLocales = null;
}
}
}
/**
* Removes all currently registered
* <code>IIOReadWarningListener objects.
*
* <p> The default implementation sets the
* <code>warningListeners and warningLocales
* instance variables to <code>null.
*/
public void removeAllIIOReadWarningListeners() {
warningListeners = null;
warningLocales = null;
}
/**
* Adds an <code>IIOReadProgressListener to the list of
* registered progress listeners. If <code>listener is
* <code>null, no exception will be thrown and no action
* will be taken.
*
* @param listener an IIOReadProgressListener to be registered.
*
* @see #removeIIOReadProgressListener
*/
public void addIIOReadProgressListener(IIOReadProgressListener listener) {
if (listener == null) {
return;
}
progressListeners = addToList(progressListeners, listener);
}
/**
* Removes an <code>IIOReadProgressListener from the list
* of registered progress listeners. If the listener was not
* previously registered, or if <code>listener is
* <code>null, no exception will be thrown and no action
* will be taken.
*
* @param listener an IIOReadProgressListener to be unregistered.
*
* @see #addIIOReadProgressListener
*/
public void
removeIIOReadProgressListener (IIOReadProgressListener listener) {
if (listener == null || progressListeners == null) {
return;
}
progressListeners = removeFromList(progressListeners, listener);
}
/**
* Removes all currently registered
* <code>IIOReadProgressListener objects.
*
* <p> The default implementation sets the
* <code>progressListeners instance variable to
* <code>null.
*/
public void removeAllIIOReadProgressListeners() {
progressListeners = null;
}
/**
* Adds an <code>IIOReadUpdateListener to the list of
* registered update listeners. If <code>listener is
* <code>null, no exception will be thrown and no action
* will be taken. The listener will receive notification of pixel
* updates as images and thumbnails are decoded, including the
* starts and ends of progressive passes.
*
* <p> If no update listeners are present, the reader may choose
* to perform fewer updates to the pixels of the destination
* images and/or thumbnails, which may result in more efficient
* decoding.
*
* <p> For example, in progressive JPEG decoding each pass
* contains updates to a set of coefficients, which would have to
* be transformed into pixel values and converted to an RGB color
* space for each pass if listeners are present. If no listeners
* are present, the coefficients may simply be accumulated and the
* final results transformed and color converted one time only.
*
* <p> The final results of decoding will be the same whether or
* not intermediate updates are performed. Thus if only the final
* image is desired it may be preferable not to register any
* <code>IIOReadUpdateListeners. In general, progressive
* updating is most effective when fetching images over a network
* connection that is very slow compared to local CPU processing;
* over a fast connection, progressive updates may actually slow
* down the presentation of the image.
*
* @param listener an IIOReadUpdateListener to be registered.
*
* @see #removeIIOReadUpdateListener
*/
public void
addIIOReadUpdateListener(IIOReadUpdateListener listener) {
if (listener == null) {
return;
}
updateListeners = addToList(updateListeners, listener);
}
/**
* Removes an <code>IIOReadUpdateListener from the list of
* registered update listeners. If the listener was not
* previously registered, or if <code>listener is
* <code>null, no exception will be thrown and no action
* will be taken.
*
* @param listener an IIOReadUpdateListener to be unregistered.
*
* @see #addIIOReadUpdateListener
*/
public void removeIIOReadUpdateListener(IIOReadUpdateListener listener) {
if (listener == null || updateListeners == null) {
return;
}
updateListeners = removeFromList(updateListeners, listener);
}
/**
* Removes all currently registered
* <code>IIOReadUpdateListener objects.
*
* <p> The default implementation sets the
* <code>updateListeners instance variable to
* <code>null.
*/
public void removeAllIIOReadUpdateListeners() {
updateListeners = null;
}
/**
* Broadcasts the start of an sequence of image reads to all
* registered <code>IIOReadProgressListeners by calling
* their <code>sequenceStarted method. Subclasses may use
* this method as a convenience.
*
* @param minIndex the lowest index being read.
*/
protected void processSequenceStarted(int minIndex) {
if (progressListeners == null) {
return;
}
int numListeners = progressListeners.size();
for (int i = 0; i < numListeners; i++) {
IIOReadProgressListener listener =
(IIOReadProgressListener)progressListeners.get(i);
listener.sequenceStarted(this, minIndex);
}
}
/**
* Broadcasts the completion of an sequence of image reads to all
* registered <code>IIOReadProgressListeners by calling
* their <code>sequenceComplete method. Subclasses may use
* this method as a convenience.
*/
protected void processSequenceComplete() {
if (progressListeners == null) {
return;
}
int numListeners = progressListeners.size();
for (int i = 0; i < numListeners; i++) {
IIOReadProgressListener listener =
(IIOReadProgressListener)progressListeners.get(i);
listener.sequenceComplete(this);
}
}
/**
* Broadcasts the start of an image read to all registered
* <code>IIOReadProgressListeners by calling their
* <code>imageStarted method. Subclasses may use this
* method as a convenience.
*
* @param imageIndex the index of the image about to be read.
*/
protected void processImageStarted(int imageIndex) {
if (progressListeners == null) {
return;
}
int numListeners = progressListeners.size();
for (int i = 0; i < numListeners; i++) {
IIOReadProgressListener listener =
(IIOReadProgressListener)progressListeners.get(i);
listener.imageStarted(this, imageIndex);
}
}
/**
* Broadcasts the current percentage of image completion to all
* registered <code>IIOReadProgressListeners by calling
* their <code>imageProgress method. Subclasses may use
* this method as a convenience.
*
* @param percentageDone the current percentage of completion,
* as a <code>float.
*/
protected void processImageProgress(float percentageDone) {
if (progressListeners == null) {
return;
}
int numListeners = progressListeners.size();
for (int i = 0; i < numListeners; i++) {
IIOReadProgressListener listener =
(IIOReadProgressListener)progressListeners.get(i);
listener.imageProgress(this, percentageDone);
}
}
/**
* Broadcasts the completion of an image read to all registered
* <code>IIOReadProgressListeners by calling their
* <code>imageComplete method. Subclasses may use this
* method as a convenience.
*/
protected void processImageComplete() {
if (progressListeners == null) {
return;
}
int numListeners = progressListeners.size();
for (int i = 0; i < numListeners; i++) {
IIOReadProgressListener listener =
(IIOReadProgressListener)progressListeners.get(i);
listener.imageComplete(this);
}
}
/**
* Broadcasts the start of a thumbnail read to all registered
* <code>IIOReadProgressListeners by calling their
* <code>thumbnailStarted method. Subclasses may use this
* method as a convenience.
*
* @param imageIndex the index of the image associated with the
* thumbnail.
* @param thumbnailIndex the index of the thumbnail.
*/
protected void processThumbnailStarted(int imageIndex,
int thumbnailIndex) {
if (progressListeners == null) {
return;
}
int numListeners = progressListeners.size();
for (int i = 0; i < numListeners; i++) {
IIOReadProgressListener listener =
(IIOReadProgressListener)progressListeners.get(i);
listener.thumbnailStarted(this, imageIndex, thumbnailIndex);
}
}
/**
* Broadcasts the current percentage of thumbnail completion to
* all registered <code>IIOReadProgressListeners by calling
* their <code>thumbnailProgress method. Subclasses may
* use this method as a convenience.
*
* @param percentageDone the current percentage of completion,
* as a <code>float.
*/
protected void processThumbnailProgress(float percentageDone) {
if (progressListeners == null) {
return;
}
int numListeners = progressListeners.size();
for (int i = 0; i < numListeners; i++) {
IIOReadProgressListener listener =
(IIOReadProgressListener)progressListeners.get(i);
listener.thumbnailProgress(this, percentageDone);
}
}
/**
* Broadcasts the completion of a thumbnail read to all registered
* <code>IIOReadProgressListeners by calling their
* <code>thumbnailComplete method. Subclasses may use this
* method as a convenience.
*/
protected void processThumbnailComplete() {
if (progressListeners == null) {
return;
}
int numListeners = progressListeners.size();
for (int i = 0; i < numListeners; i++) {
IIOReadProgressListener listener =
(IIOReadProgressListener)progressListeners.get(i);
listener.thumbnailComplete(this);
}
}
/**
* Broadcasts that the read has been aborted to all registered
* <code>IIOReadProgressListeners by calling their
* <code>readAborted method. Subclasses may use this
* method as a convenience.
*/
protected void processReadAborted() {
if (progressListeners == null) {
return;
}
int numListeners = progressListeners.size();
for (int i = 0; i < numListeners; i++) {
IIOReadProgressListener listener =
(IIOReadProgressListener)progressListeners.get(i);
listener.readAborted(this);
}
}
/**
* Broadcasts the beginning of a progressive pass to all
* registered <code>IIOReadUpdateListeners by calling their
* <code>passStarted method. Subclasses may use this
* method as a convenience.
*
* @param theImage the <code>BufferedImage being updated.
* @param pass the index of the current pass, starting with 0.
* @param minPass the index of the first pass that will be decoded.
* @param maxPass the index of the last pass that will be decoded.
* @param minX the X coordinate of the upper-left pixel included
* in the pass.
* @param minY the X coordinate of the upper-left pixel included
* in the pass.
* @param periodX the horizontal separation between pixels.
* @param periodY the vertical separation between pixels.
* @param bands an array of <code>ints indicating the
* set of affected bands of the destination.
*/
protected void processPassStarted(BufferedImage theImage,
int pass,
int minPass, int maxPass,
int minX, int minY,
int periodX, int periodY,
int[] bands) {
if (updateListeners == null) {
return;
}
int numListeners = updateListeners.size();
for (int i = 0; i < numListeners; i++) {
IIOReadUpdateListener listener =
(IIOReadUpdateListener)updateListeners.get(i);
listener.passStarted(this, theImage, pass,
minPass,
maxPass,
minX, minY,
periodX, periodY,
bands);
}
}
/**
* Broadcasts the update of a set of samples to all registered
* <code>IIOReadUpdateListeners by calling their
* <code>imageUpdate method. Subclasses may use this
* method as a convenience.
*
* @param theImage the <code>BufferedImage being updated.
* @param minX the X coordinate of the upper-left pixel included
* in the pass.
* @param minY the X coordinate of the upper-left pixel included
* in the pass.
* @param width the total width of the area being updated, including
* pixels being skipped if <code>periodX > 1.
* @param height the total height of the area being updated,
* including pixels being skipped if <code>periodY > 1.
* @param periodX the horizontal separation between pixels.
* @param periodY the vertical separation between pixels.
* @param bands an array of <code>ints indicating the
* set of affected bands of the destination.
*/
protected void processImageUpdate(BufferedImage theImage,
int minX, int minY,
int width, int height,
int periodX, int periodY,
int[] bands) {
if (updateListeners == null) {
return;
}
int numListeners = updateListeners.size();
for (int i = 0; i < numListeners; i++) {
IIOReadUpdateListener listener =
(IIOReadUpdateListener)updateListeners.get(i);
listener.imageUpdate(this,
theImage,
minX, minY,
width, height,
periodX, periodY,
bands);
}
}
/**
* Broadcasts the end of a progressive pass to all
* registered <code>IIOReadUpdateListeners by calling their
* <code>passComplete method. Subclasses may use this
* method as a convenience.
*
* @param theImage the <code>BufferedImage being updated.
*/
protected void processPassComplete(BufferedImage theImage) {
if (updateListeners == null) {
return;
}
int numListeners = updateListeners.size();
for (int i = 0; i < numListeners; i++) {
IIOReadUpdateListener listener =
(IIOReadUpdateListener)updateListeners.get(i);
listener.passComplete(this, theImage);
}
}
/**
* Broadcasts the beginning of a thumbnail progressive pass to all
* registered <code>IIOReadUpdateListeners by calling their
* <code>thumbnailPassStarted method. Subclasses may use this
* method as a convenience.
*
* @param theThumbnail the <code>BufferedImage thumbnail
* being updated.
* @param pass the index of the current pass, starting with 0.
* @param minPass the index of the first pass that will be decoded.
* @param maxPass the index of the last pass that will be decoded.
* @param minX the X coordinate of the upper-left pixel included
* in the pass.
* @param minY the X coordinate of the upper-left pixel included
* in the pass.
* @param periodX the horizontal separation between pixels.
* @param periodY the vertical separation between pixels.
* @param bands an array of <code>ints indicating the
* set of affected bands of the destination.
*/
protected void processThumbnailPassStarted(BufferedImage theThumbnail,
int pass,
int minPass, int maxPass,
int minX, int minY,
int periodX, int periodY,
int[] bands) {
if (updateListeners == null) {
return;
}
int numListeners = updateListeners.size();
for (int i = 0; i < numListeners; i++) {
IIOReadUpdateListener listener =
(IIOReadUpdateListener)updateListeners.get(i);
listener.thumbnailPassStarted(this, theThumbnail, pass,
minPass,
maxPass,
minX, minY,
periodX, periodY,
bands);
}
}
/**
* Broadcasts the update of a set of samples in a thumbnail image
* to all registered <code>IIOReadUpdateListeners by
* calling their <code>thumbnailUpdate method. Subclasses may
* use this method as a convenience.
*
* @param theThumbnail the <code>BufferedImage thumbnail
* being updated.
* @param minX the X coordinate of the upper-left pixel included
* in the pass.
* @param minY the X coordinate of the upper-left pixel included
* in the pass.
* @param width the total width of the area being updated, including
* pixels being skipped if <code>periodX > 1.
* @param height the total height of the area being updated,
* including pixels being skipped if <code>periodY > 1.
* @param periodX the horizontal separation between pixels.
* @param periodY the vertical separation between pixels.
* @param bands an array of <code>ints indicating the
* set of affected bands of the destination.
*/
protected void processThumbnailUpdate(BufferedImage theThumbnail,
int minX, int minY,
int width, int height,
int periodX, int periodY,
int[] bands) {
if (updateListeners == null) {
return;
}
int numListeners = updateListeners.size();
for (int i = 0; i < numListeners; i++) {
IIOReadUpdateListener listener =
(IIOReadUpdateListener)updateListeners.get(i);
listener.thumbnailUpdate(this,
theThumbnail,
minX, minY,
width, height,
periodX, periodY,
bands);
}
}
/**
* Broadcasts the end of a thumbnail progressive pass to all
* registered <code>IIOReadUpdateListeners by calling their
* <code>thumbnailPassComplete method. Subclasses may use this
* method as a convenience.
*
* @param theThumbnail the <code>BufferedImage thumbnail
* being updated.
*/
protected void processThumbnailPassComplete(BufferedImage theThumbnail) {
if (updateListeners == null) {
return;
}
int numListeners = updateListeners.size();
for (int i = 0; i < numListeners; i++) {
IIOReadUpdateListener listener =
(IIOReadUpdateListener)updateListeners.get(i);
listener.thumbnailPassComplete(this, theThumbnail);
}
}
/**
* Broadcasts a warning message to all registered
* <code>IIOReadWarningListeners by calling their
* <code>warningOccurred method. Subclasses may use this
* method as a convenience.
*
* @param warning the warning message to send.
*
* @exception IllegalArgumentException if <code>warning
* is <code>null.
*/
protected void processWarningOccurred(String warning) {
if (warningListeners == null) {
return;
}
if (warning == null) {
throw new IllegalArgumentException("warning == null!");
}
int numListeners = warningListeners.size();
for (int i = 0; i < numListeners; i++) {
IIOReadWarningListener listener =
(IIOReadWarningListener)warningListeners.get(i);
listener.warningOccurred(this, warning);
}
}
/**
* Broadcasts a localized warning message to all registered
* <code>IIOReadWarningListeners by calling their
* <code>warningOccurred method with a string taken
* from a <code>ResourceBundle. Subclasses may use this
* method as a convenience.
*
* @param baseName the base name of a set of
* <code>ResourceBundles containing localized warning
* messages.
* @param keyword the keyword used to index the warning message
* within the set of <code>ResourceBundles.
*
* @exception IllegalArgumentException if <code>baseName
* is <code>null.
* @exception IllegalArgumentException if <code>keyword
* is <code>null.
* @exception IllegalArgumentException if no appropriate
* <code>ResourceBundle may be located.
* @exception IllegalArgumentException if the named resource is
* not found in the located <code>ResourceBundle.
* @exception IllegalArgumentException if the object retrieved
* from the <code>ResourceBundle is not a
* <code>String.
*/
protected void processWarningOccurred(String baseName,
String keyword) {
if (warningListeners == null) {
return;
}
if (baseName == null) {
throw new IllegalArgumentException("baseName == null!");
}
if (keyword == null) {
throw new IllegalArgumentException("keyword == null!");
}
int numListeners = warningListeners.size();
for (int i = 0; i < numListeners; i++) {
IIOReadWarningListener listener =
(IIOReadWarningListener)warningListeners.get(i);
Locale locale = (Locale)warningLocales.get(i);
if (locale == null) {
locale = Locale.getDefault();
}
/**
* If an applet supplies an implementation of ImageReader and
* resource bundles, then the resource bundle will need to be
* accessed via the applet class loader. So first try the context
* class loader to locate the resource bundle.
* If that throws MissingResourceException, then try the
* system class loader.
*/
ClassLoader loader = (ClassLoader)
java.security.AccessController.doPrivileged(
new java.security.PrivilegedAction() {
public Object run() {
return Thread.currentThread().getContextClassLoader();
}
});
ResourceBundle bundle = null;
try {
bundle = ResourceBundle.getBundle(baseName, locale, loader);
} catch (MissingResourceException mre) {
try {
bundle = ResourceBundle.getBundle(baseName, locale);
} catch (MissingResourceException mre1) {
throw new IllegalArgumentException("Bundle not found!");
}
}
String warning = null;
try {
warning = bundle.getString(keyword);
} catch (ClassCastException cce) {
throw new IllegalArgumentException("Resource is not a String!");
} catch (MissingResourceException mre) {
throw new IllegalArgumentException("Resource is missing!");
}
listener.warningOccurred(this, warning);
}
}
// State management
/**
* Restores the <code>ImageReader to its initial state.
*
* <p> The default implementation calls setInput(null,
* false)</code>, setLocale(null),
* <code>removeAllIIOReadUpdateListeners(),
* <code>removeAllIIOReadWarningListeners(),
* <code>removeAllIIOReadProgressListeners(), and
* <code>clearAbortRequest.
*/
public void reset() {
setInput(null, false, false);
setLocale(null);
removeAllIIOReadUpdateListeners();
removeAllIIOReadProgressListeners();
removeAllIIOReadWarningListeners();
clearAbortRequest();
}
/**
* Allows any resources held by this object to be released. The
* result of calling any other method (other than
* <code>finalize) subsequent to a call to this method
* is undefined.
*
* <p>It is important for applications to call this method when they
* know they will no longer be using this <code>ImageReader.
* Otherwise, the reader may continue to hold on to resources
* indefinitely.
*
* <p>The default implementation of this method in the superclass does
* nothing. Subclass implementations should ensure that all resources,
* especially native resources, are released.
*/
public void dispose() {
}
// Utility methods
/**
* A utility method that may be used by readers to compute the
* region of the source image that should be read, taking into
* account any source region and subsampling offset settings in
* the supplied <code>ImageReadParam. The actual
* subsampling factors, destination size, and destination offset
* are <em>not taken into consideration, thus further
* clipping must take place. The {@link #computeRegions computeRegions}
* method performs all necessary clipping.
*
* @param param the <code>ImageReadParam being used, or
* <code>null.
* @param srcWidth the width of the source image.
* @param srcHeight the height of the source image.
*
* @return the source region as a <code>Rectangle.
*/
protected static Rectangle getSourceRegion(ImageReadParam param,
int srcWidth,
int srcHeight) {
Rectangle sourceRegion = new Rectangle(0, 0, srcWidth, srcHeight);
if (param != null) {
Rectangle region = param.getSourceRegion();
if (region != null) {
sourceRegion = sourceRegion.intersection(region);
}
int subsampleXOffset = param.getSubsamplingXOffset();
int subsampleYOffset = param.getSubsamplingYOffset();
sourceRegion.x += subsampleXOffset;
sourceRegion.y += subsampleYOffset;
sourceRegion.width -= subsampleXOffset;
sourceRegion.height -= subsampleYOffset;
}
return sourceRegion;
}
/**
* Computes the source region of interest and the destination
* region of interest, taking the width and height of the source
* image, an optional destination image, and an optional
* <code>ImageReadParam into account. The source region
* begins with the entire source image. Then that is clipped to
* the source region specified in the <code>ImageReadParam,
* if one is specified.
*
* <p> If either of the destination offsets are negative, the
* source region is clipped so that its top left will coincide
* with the top left of the destination image, taking subsampling
* into account. Then the result is clipped to the destination
* image on the right and bottom, if one is specified, taking
* subsampling and destination offsets into account.
*
* <p> Similarly, the destination region begins with the source
* image, is translated to the destination offset given in the
* <code>ImageReadParam if there is one, and finally is
* clipped to the destination image, if there is one.
*
* <p> If either the source or destination regions end up having a
* width or height of 0, an <code>IllegalArgumentException
* is thrown.
*
* <p> The {@link #getSourceRegion getSourceRegion>}
* method may be used if only source clipping is desired.
*
* @param param an <code>ImageReadParam, or null.
* @param srcWidth the width of the source image.
* @param srcHeight the height of the source image.
* @param image a <code>BufferedImage that will be the
* destination image, or <code>null.
* @param srcRegion a <code>Rectangle that will be filled with
* the source region of interest.
* @param destRegion a <code>Rectangle that will be filled with
* the destination region of interest.
* @exception IllegalArgumentException if <code>srcRegion
* is <code>null.
* @exception IllegalArgumentException if <code>dstRegion
* is <code>null.
* @exception IllegalArgumentException if the resulting source or
* destination region is empty.
*/
protected static void computeRegions(ImageReadParam param,
int srcWidth,
int srcHeight,
BufferedImage image,
Rectangle srcRegion,
Rectangle destRegion) {
if (srcRegion == null) {
throw new IllegalArgumentException("srcRegion == null!");
}
if (destRegion == null) {
throw new IllegalArgumentException("destRegion == null!");
}
// Start with the entire source image
srcRegion.setBounds(0, 0, srcWidth, srcHeight);
// Destination also starts with source image, as that is the
// maximum extent if there is no subsampling
destRegion.setBounds(0, 0, srcWidth, srcHeight);
// Clip that to the param region, if there is one
int periodX = 1;
int periodY = 1;
int gridX = 0;
int gridY = 0;
if (param != null) {
Rectangle paramSrcRegion = param.getSourceRegion();
if (paramSrcRegion != null) {
srcRegion.setBounds(srcRegion.intersection(paramSrcRegion));
}
periodX = param.getSourceXSubsampling();
periodY = param.getSourceYSubsampling();
gridX = param.getSubsamplingXOffset();
gridY = param.getSubsamplingYOffset();
srcRegion.translate(gridX, gridY);
srcRegion.width -= gridX;
srcRegion.height -= gridY;
destRegion.setLocation(param.getDestinationOffset());
}
// Now clip any negative destination offsets, i.e. clip
// to the top and left of the destination image
if (destRegion.x < 0) {
int delta = -destRegion.x*periodX;
srcRegion.x += delta;
srcRegion.width -= delta;
destRegion.x = 0;
}
if (destRegion.y < 0) {
int delta = -destRegion.y*periodY;
srcRegion.y += delta;
srcRegion.height -= delta;
destRegion.y = 0;
}
// Now clip the destination Region to the subsampled width and height
int subsampledWidth = (srcRegion.width + periodX - 1)/periodX;
int subsampledHeight = (srcRegion.height + periodY - 1)/periodY;
destRegion.width = subsampledWidth;
destRegion.height = subsampledHeight;
// Now clip that to right and bottom of the destination image,
// if there is one, taking subsampling into account
if (image != null) {
Rectangle destImageRect = new Rectangle(0, 0,
image.getWidth(),
image.getHeight());
destRegion.setBounds(destRegion.intersection(destImageRect));
if (destRegion.isEmpty()) {
throw new IllegalArgumentException
("Empty destination region!");
}
int deltaX = destRegion.x + subsampledWidth - image.getWidth();
if (deltaX > 0) {
srcRegion.width -= deltaX*periodX;
}
int deltaY = destRegion.y + subsampledHeight - image.getHeight();
if (deltaY > 0) {
srcRegion.height -= deltaY*periodY;
}
}
if (srcRegion.isEmpty() || destRegion.isEmpty()) {
throw new IllegalArgumentException("Empty region!");
}
}
/**
* A utility method that may be used by readers to test the
* validity of the source and destination band settings of an
* <code>ImageReadParam. This method may be called as soon
* as the reader knows both the number of bands of the source
* image as it exists in the input stream, and the number of bands
* of the destination image that being written.
*
* <p> The method retrieves the source and destination band
* setting arrays from param using the <code>getSourceBands
* and <code>getDestinationBandsmethods (or considers them
* to be <code>null if param is
* <code>null). If the source band setting array is
* <code>null, it is considered to be equal to the array
* <code>{ 0, 1, ..., numSrcBands - 1 }, and similarly for
* the destination band setting array.
*
* <p> The method then tests that both arrays are equal in length,
* and that neither array contains a value larger than the largest
* available band index.
*
* <p> Any failure results in an
* <code>IllegalArgumentException being thrown; success
* results in the method returning silently.
*
* @param param the <code>ImageReadParam being used to read
* the image.
* @param numSrcBands the number of bands of the image as it exists
* int the input source.
* @param numDstBands the number of bands in the destination image
* being written.
*
* @exception IllegalArgumentException if <code>param
* contains an invalid specification of a source and/or
* destination band subset.
*/
protected static void checkReadParamBandSettings(ImageReadParam param,
int numSrcBands,
int numDstBands) {
// A null param is equivalent to srcBands == dstBands == null.
int[] srcBands = null;
int[] dstBands = null;
if (param != null) {
srcBands = param.getSourceBands();
dstBands = param.getDestinationBands();
}
int paramSrcBandLength =
(srcBands == null) ? numSrcBands : srcBands.length;
int paramDstBandLength =
(dstBands == null) ? numDstBands : dstBands.length;
if (paramSrcBandLength != paramDstBandLength) {
throw new IllegalArgumentException("ImageReadParam num source & dest bands differ!");
}
if (srcBands != null) {
for (int i = 0; i < srcBands.length; i++) {
if (srcBands[i] >= numSrcBands) {
throw new IllegalArgumentException("ImageReadParam source bands contains a value >= the number of source bands!");
}
}
}
if (dstBands != null) {
for (int i = 0; i < dstBands.length; i++) {
if (dstBands[i] >= numDstBands) {
throw new IllegalArgumentException("ImageReadParam dest bands contains a value >= the number of dest bands!");
}
}
}
}
/**
* Returns the <code>BufferedImage to which decoded pixel
* data should be written. The image is determined by inspecting
* the supplied <code>ImageReadParam if it is
* non-<code>null; if its getDestination
* method returns a non-<code>null value, that image is
* simply returned. Otherwise,
* <code>param.getDestinationType method is called to
* determine if a particular image type has been specified. If
* so, the returned <code>ImageTypeSpecifier is used after
* checking that it is equal to one of those included in
* <code>imageTypes.
*
* <p> If param is null or the above
* steps have not yielded an image or an
* <code>ImageTypeSpecifier, the first value obtained from
* the <code>imageTypes parameter is used. Typically, the
* caller will set <code>imageTypes to the value of
* <code>getImageTypes(imageIndex).
*
* <p> Next, the dimensions of the image are determined by a call
* to <code>computeRegions. The actual width and height of
* the image being decoded are passed in as the <code>width
* and <code>height parameters.
*
* @param param an <code>ImageReadParam to be used to get
* the destination image or image type, or <code>null.
* @param imageTypes an <code>Iterator of
* <code>ImageTypeSpecifiers indicating the legal image
* types, with the default first.
* @param width the true width of the image or tile begin decoded.
* @param height the true width of the image or tile being decoded.
*
* @return the <code>BufferedImage to which decoded pixel
* data should be written.
*
* @exception IIOException if the <code>ImageTypeSpecifier
* specified by <code>param does not match any of the legal
* ones from <code>imageTypes.
* @exception IllegalArgumentException if <code>imageTypes
* is <code>null or empty, or if an object not of type
* <code>ImageTypeSpecifier is retrieved from it.
* @exception IllegalArgumentException if the resulting image would
* have a width or height less than 1.
* @exception IllegalArgumentException if the product of
* <code>width and height is greater than
* <code>Integer.MAX_VALUE.
*/
protected static BufferedImage
getDestination(ImageReadParam param,
Iterator<ImageTypeSpecifier> imageTypes,
int width, int height)
throws IIOException {
if (imageTypes == null || !imageTypes.hasNext()) {
throw new IllegalArgumentException("imageTypes null or empty!");
}
if ((long)width*height > Integer.MAX_VALUE) {
throw new IllegalArgumentException
("width*height > Integer.MAX_VALUE!");
}
BufferedImage dest = null;
ImageTypeSpecifier imageType = null;
// If param is non-null, use it
if (param != null) {
// Try to get the image itself
dest = param.getDestination();
if (dest != null) {
return dest;
}
// No image, get the image type
imageType = param.getDestinationType();
}
// No info from param, use fallback image type
if (imageType == null) {
Object o = imageTypes.next();
if (!(o instanceof ImageTypeSpecifier)) {
throw new IllegalArgumentException
("Non-ImageTypeSpecifier retrieved from imageTypes!");
}
imageType = (ImageTypeSpecifier)o;
} else {
boolean foundIt = false;
while (imageTypes.hasNext()) {
ImageTypeSpecifier type =
(ImageTypeSpecifier)imageTypes.next();
if (type.equals(imageType)) {
foundIt = true;
break;
}
}
if (!foundIt) {
throw new IIOException
("Destination type from ImageReadParam does not match!");
}
}
Rectangle srcRegion = new Rectangle(0,0,0,0);
Rectangle destRegion = new Rectangle(0,0,0,0);
computeRegions(param,
width,
height,
null,
srcRegion,
destRegion);
int destWidth = destRegion.x + destRegion.width;
int destHeight = destRegion.y + destRegion.height;
// Create a new image based on the type specifier
return imageType.createBufferedImage(destWidth, destHeight);
}
}
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