/*
* Copyright 1999-2003 Sun Microsystems, Inc. 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. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
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*/
package javax.imageio;
import java.awt.Dimension;
import java.awt.image.BufferedImage;
/**
* A class describing how a stream is to be decoded. Instances of
* this class or its subclasses are used to supply prescriptive
* "how-to" information to instances of <code>ImageReader</code>.
*
* <p> An image encoded as part of a file or stream may be thought of
* extending out in multiple dimensions: the spatial dimensions of
* width and height, a number of bands, and a number of progressive
* decoding passes. This class allows a contiguous (hyper)rectangular
* subarea of the image in all of these dimensions to be selected for
* decoding. Additionally, the spatial dimensions may be subsampled
* discontinuously. Finally, color and format conversions may be
* specified by controlling the <code>ColorModel</code> and
* <code>SampleModel</code> of the destination image, either by
* providing a <code>BufferedImage</code> or by using an
* <code>ImageTypeSpecifier</code>.
*
* <p> An <code>ImageReadParam</code> object is used to specify how an
* image, or a set of images, will be converted on input from
* a stream in the context of the Java Image I/O framework. A plug-in for a
* specific image format will return instances of
* <code>ImageReadParam</code> from the
* <code>getDefaultReadParam</code> method of its
* <code>ImageReader</code> implementation.
*
* <p> The state maintained by an instance of
* <code>ImageReadParam</code> is independent of any particular image
* being decoded. When actual decoding takes place, the values set in
* the read param are combined with the actual properties of the image
* being decoded from the stream and the destination
* <code>BufferedImage</code> that will receive the decoded pixel
* data. For example, the source region set using
* <code>setSourceRegion</code> will first be intersected with the
* actual valid source area. The result will be translated by the
* value returned by <code>getDestinationOffset</code>, and the
* resulting rectangle intersected with the actual valid destination
* area to yield the destination area that will be written.
*
* <p> The parameters specified by an <code>ImageReadParam</code> are
* applied to an image as follows. First, if a rendering size has
* been set by <code>setSourceRenderSize</code>, the entire decoded
* image is rendered at the size given by
* <code>getSourceRenderSize</code>. Otherwise, the image has its
* natural size given by <code>ImageReader.getWidth</code> and
* <code>ImageReader.getHeight</code>.
*
* <p> Next, the image is clipped against the source region
* specified by <code>getSourceXOffset</code>, <code>getSourceYOffset</code>,
* <code>getSourceWidth</code>, and <code>getSourceHeight</code>.
*
* <p> The resulting region is then subsampled according to the
* factors given in {@link IIOParam#setSourceSubsampling
* <code>IIOParam.setSourceSubsampling</code>}. The first pixel,
* the number of pixels per row, and the number of rows all depend
* on the subsampling settings.
* Call the minimum X and Y coordinates of the resulting rectangle
* (<code>minX</code>, <code>minY</code>), its width <code>w</code>
* and its height <code>h</code>.
*
* <p> This rectangle is offset by
* (<code>getDestinationOffset().x</code>,
* <code>getDestinationOffset().y</code>) and clipped against the
* destination bounds. If no destination image has been set, the
* destination is defined to have a width of
* <code>getDestinationOffset().x</code> + <code>w</code>, and a
* height of <code>getDestinationOffset().y</code> + <code>h</code> so
* that all pixels of the source region may be written to the
* destination.
*
* <p> Pixels that land, after subsampling, within the destination
* image, and that are written in one of the progressive passes
* specified by <code>getSourceMinProgressivePass</code> and
* <code>getSourceNumProgressivePasses</code> are passed along to the
* next step.
*
* <p> Finally, the source samples of each pixel are mapped into
* destination bands according to the algorithm described in the
* comment for <code>setDestinationBands</code>.
*
* <p> Plug-in writers may extend the functionality of
* <code>ImageReadParam</code> by providing a subclass that implements
* additional, plug-in specific interfaces. It is up to the plug-in
* to document what interfaces are available and how they are to be
* used. Readers will silently ignore any extended features of an
* <code>ImageReadParam</code> subclass of which they are not aware.
* Also, they may ignore any optional features that they normally
* disable when creating their own <code>ImageReadParam</code>
* instances via <code>getDefaultReadParam</code>.
*
* <p> Note that unless a query method exists for a capability, it must
* be supported by all <code>ImageReader</code> implementations
* (<i>e.g.</i> source render size is optional, but subsampling must be
* supported).
*
*
* @see ImageReader
* @see ImageWriter
* @see ImageWriteParam
*/
public class ImageReadParam extends IIOParam {
/**
* <code>true</code> if this <code>ImageReadParam</code> allows
* the source rendering dimensions to be set. By default, the
* value is <code>false</code>. Subclasses must set this value
* manually.
*
* <p> <code>ImageReader</code>s that do not support setting of
* the source render size should set this value to
* <code>false</code>.
*/
protected boolean canSetSourceRenderSize = false;
/**
* The desired rendering width and height of the source, if
* <code>canSetSourceRenderSize</code> is <code>true</code>, or
* <code>null</code>.
*
* <p> <code>ImageReader</code>s that do not support setting of
* the source render size may ignore this value.
*/
protected Dimension sourceRenderSize = null;
/**
* The current destination <code>BufferedImage</code>, or
* <code>null</code> if none has been set. By default, the value
* is <code>null</code>.
*/
protected BufferedImage destination = null;
/**
* The set of destination bands to be used, as an array of
* <code>int</code>s. By default, the value is <code>null</code>,
* indicating all destination bands should be written in order.
*/
protected int[] destinationBands = null;
/**
* The minimum index of a progressive pass to read from the
* source. By default, the value is set to 0, which indicates
* that passes starting with the first available pass should be
* decoded.
*
* <p> Subclasses should ensure that this value is
* non-negative.
*/
protected int minProgressivePass = 0;
/**
* The maximum number of progressive passes to read from the
* source. By default, the value is set to
* <code>Integer.MAX_VALUE</code>, which indicates that passes up
* to and including the last available pass should be decoded.
*
* <p> Subclasses should ensure that this value is positive.
* Additionally, if the value is not
* <code>Integer.MAX_VALUE</code>, then <code>minProgressivePass +
* numProgressivePasses - 1</code> should not exceed
* <code>Integer.MAX_VALUE</code>.
*/
protected int numProgressivePasses = Integer.MAX_VALUE;
/**
* Constructs an <code>ImageReadParam</code>.
*/
public ImageReadParam() {}
// Comment inherited
public void setDestinationType(ImageTypeSpecifier destinationType) {
super.setDestinationType(destinationType);
setDestination(null);
}
/**
* Supplies a <code>BufferedImage</code> to be used as the
* destination for decoded pixel data. The currently set image
* will be written to by the <code>read</code>,
* <code>readAll</code>, and <code>readRaster</code> methods, and
* a reference to it will be returned by those methods.
*
* <p> Pixel data from the aforementioned methods will be written
* starting at the offset specified by
* <code>getDestinationOffset</code>.
*
* <p> If <code>destination</code> is <code>null</code>, a
* newly-created <code>BufferedImage</code> will be returned by
* those methods.
*
* <p> At the time of reading, the image is checked to verify that
* its <code>ColorModel</code> and <code>SampleModel</code>
* correspond to one of the <code>ImageTypeSpecifier</code>s
* returned from the <code>ImageReader</code>'s
* <code>getImageTypes</code> method. If it does not, the reader
* will throw an <code>IIOException</code>.
*
* @param destination the BufferedImage to be written to, or
* <code>null</code>.
*
* @see #getDestination
*/
public void setDestination(BufferedImage destination) {
this.destination = destination;
}
/**
* Returns the <code>BufferedImage</code> currently set by the
* <code>setDestination</code> method, or <code>null</code>
* if none is set.
*
* @return the BufferedImage to be written to.
*
* @see #setDestination
*/
public BufferedImage getDestination() {
return destination;
}
/**
* Sets the indices of the destination bands where data
* will be placed. Duplicate indices are not allowed.
*
* <p> A <code>null</code> value indicates that all destination
* bands will be used.
*
* <p> Choosing a destination band subset will not affect the
* number of bands in the output image of a read if no destination
* image is specified; the created destination image will still
* have the same number of bands as if this method had never been
* called. If a different number of bands in the destination
* image is desired, an image must be supplied using the
* <code>ImageReadParam.setDestination</code> method.
*
* <p> At the time of reading or writing, an
* <code>IllegalArgumentException</code> will be thrown by the
* reader or writer if a value larger than the largest destination
* band index has been specified, or if the number of source bands
* and destination bands to be used differ. The
* <code>ImageReader.checkReadParamBandSettings</code> method may
* be used to automate this test.
*
* @param destinationBands an array of integer band indices to be
* used.
*
* @exception IllegalArgumentException if <code>destinationBands</code>
* contains a negative or duplicate value.
*
* @see #getDestinationBands
* @see #getSourceBands
* @see ImageReader#checkReadParamBandSettings
*/
public void setDestinationBands(int[] destinationBands) {
if (destinationBands == null) {
this.destinationBands = null;
} else {
int numBands = destinationBands.length;
for (int i = 0; i < numBands; i++) {
int band = destinationBands[i];
if (band < 0) {
throw new IllegalArgumentException("Band value < 0!");
}
for (int j = i + 1; j < numBands; j++) {
if (band == destinationBands[j]) {
throw new IllegalArgumentException("Duplicate band value!");
}
}
}
this.destinationBands = (int[])destinationBands.clone();
}
}
/**
* Returns the set of band indices where data will be placed.
* If no value has been set, <code>null</code> is returned to
* indicate that all destination bands will be used.
*
* @return the indices of the destination bands to be used,
* or <code>null</code>.
*
* @see #setDestinationBands
*/
public int[] getDestinationBands() {
if (destinationBands == null) {
return null;
} else {
return (int[])(destinationBands.clone());
}
}
/**
* Returns <code>true</code> if this reader allows the source
* image to be rendered at an arbitrary size as part of the
* decoding process, by means of the
* <code>setSourceRenderSize</code> method. If this method
* returns <code>false</code>, calls to
* <code>setSourceRenderSize</code> will throw an
* <code>UnsupportedOperationException</code>.
*
* @return <code>true</code> if setting source rendering size is
* supported.
*
* @see #setSourceRenderSize
*/
public boolean canSetSourceRenderSize() {
return canSetSourceRenderSize;
}
/**
* If the image is able to be rendered at an arbitrary size, sets
* the source width and height to the supplied values. Note that
* the values returned from the <code>getWidth</code> and
* <code>getHeight</code> methods on <code>ImageReader</code> are
* not affected by this method; they will continue to return the
* default size for the image. Similarly, if the image is also
* tiled the tile width and height are given in terms of the default
* size.
*
* <p> Typically, the width and height should be chosen such that
* the ratio of width to height closely approximates the aspect
* ratio of the image, as returned from
* <code>ImageReader.getAspectRatio</code>.
*
* <p> If this plug-in does not allow the rendering size to be
* set, an <code>UnsupportedOperationException</code> will be
* thrown.
*
* <p> To remove the render size setting, pass in a value of
* <code>null</code> for <code>size</code>.
*
* @param size a <code>Dimension</code> indicating the desired
* width and height.
*
* @exception IllegalArgumentException if either the width or the
* height is negative or 0.
* @exception UnsupportedOperationException if image resizing
* is not supported by this plug-in.
*
* @see #getSourceRenderSize
* @see ImageReader#getWidth
* @see ImageReader#getHeight
* @see ImageReader#getAspectRatio
*/
public void setSourceRenderSize(Dimension size)
throws UnsupportedOperationException {
if (!canSetSourceRenderSize()) {
throw new UnsupportedOperationException
("Can't set source render size!");
}
if (size == null) {
this.sourceRenderSize = null;
} else {
if (size.width <= 0 || size.height <= 0) {
throw new IllegalArgumentException("width or height <= 0!");
}
this.sourceRenderSize = (Dimension)size.clone();
}
}
/**
* Returns the width and height of the source image as it
* will be rendered during decoding, if they have been set via the
* <code>setSourceRenderSize</code> method. A
* <code>null</code>value indicates that no setting has been made.
*
* @return the rendered width and height of the source image
* as a <code>Dimension</code>.
*
* @see #setSourceRenderSize
*/
public Dimension getSourceRenderSize() {
return (sourceRenderSize == null) ?
null : (Dimension)sourceRenderSize.clone();
}
/**
* Sets the range of progressive passes that will be decoded.
* Passes outside of this range will be ignored.
*
* <p> A progressive pass is a re-encoding of the entire image,
* generally at progressively higher effective resolutions, but
* requiring greater transmission bandwidth. The most common use
* of progressive encoding is found in the JPEG format, where
* successive passes include more detailed representations of the
* high-frequency image content.
*
* <p> The actual number of passes to be decoded is determined
* during decoding, based on the number of actual passes available
* in the stream. Thus if <code>minPass + numPasses - 1</code> is
* larger than the index of the last available passes, decoding
* will end with that pass.
*
* <p> A value of <code>numPasses</code> of
* <code>Integer.MAX_VALUE</code> indicates that all passes from
* <code>minPass</code> forward should be read. Otherwise, the
* index of the last pass (<i>i.e.</i>, <code>minPass + numPasses
* - 1</code>) must not exceed <code>Integer.MAX_VALUE</code>.
*
* <p> There is no <code>unsetSourceProgressivePasses</code>
* method; the same effect may be obtained by calling
* <code>setSourceProgressivePasses(0, Integer.MAX_VALUE)</code>.
*
* @param minPass the index of the first pass to be decoded.
* @param numPasses the maximum number of passes to be decoded.
*
* @exception IllegalArgumentException if <code>minPass</code> is
* negative, <code>numPasses</code> is negative or 0, or
* <code>numPasses</code> is smaller than
* <code>Integer.MAX_VALUE</code> but <code>minPass +
* numPasses - 1</code> is greater than
* <code>INTEGER.MAX_VALUE</code>.
*
* @see #getSourceMinProgressivePass
* @see #getSourceMaxProgressivePass
*/
public void setSourceProgressivePasses(int minPass, int numPasses) {
if (minPass < 0) {
throw new IllegalArgumentException("minPass < 0!");
}
if (numPasses <= 0) {
throw new IllegalArgumentException("numPasses <= 0!");
}
if ((numPasses != Integer.MAX_VALUE) &&
(((minPass + numPasses - 1) & 0x80000000) != 0)) {
throw new IllegalArgumentException
("minPass + numPasses - 1 > INTEGER.MAX_VALUE!");
}
this.minProgressivePass = minPass;
this.numProgressivePasses = numPasses;
}
/**
* Returns the index of the first progressive pass that will be
* decoded. If no value has been set, 0 will be returned (which is
* the correct value).
*
* @return the index of the first pass that will be decoded.
*
* @see #setSourceProgressivePasses
* @see #getSourceNumProgressivePasses
*/
public int getSourceMinProgressivePass() {
return minProgressivePass;
}
/**
* If <code>getSourceNumProgressivePasses</code> is equal to
* <code>Integer.MAX_VALUE</code>, returns
* <code>Integer.MAX_VALUE</code>. Otherwise, returns
* <code>getSourceMinProgressivePass() +
* getSourceNumProgressivePasses() - 1</code>.
*
* @return the index of the last pass to be read, or
* <code>Integer.MAX_VALUE</code>.
*/
public int getSourceMaxProgressivePass() {
if (numProgressivePasses == Integer.MAX_VALUE) {
return Integer.MAX_VALUE;
} else {
return minProgressivePass + numProgressivePasses - 1;
}
}
/**
* Returns the number of the progressive passes that will be
* decoded. If no value has been set,
* <code>Integer.MAX_VALUE</code> will be returned (which is the
* correct value).
*
* @return the number of the passes that will be decoded.
*
* @see #setSourceProgressivePasses
* @see #getSourceMinProgressivePass
*/
public int getSourceNumProgressivePasses() {
return numProgressivePasses;
}
}