com.sun.media.imageio.plugins.tiff
Class TIFFDecompressor

java.lang.Object
  com.sun.media.imageio.plugins.tiff.TIFFDecompressor

public abstract class TIFFDecompressor

extends Object

A class defining a pluggable TIFF decompressor.

The mapping between source and destination Y coordinates is given by the equations:

 dx = (sx - sourceXOffset)/subsampleX + dstXOffset;
 dy = (sy - sourceYOffset)/subsampleY + dstYOffset;
 

Note that the mapping from source coordinates to destination coordinates is not one-to-one if subsampling is being used, since only certain source pixels are to be copied to the destination. However, * the inverse mapping is always one-to-one:

 sx = (dx - dstXOffset)*subsampleX + sourceXOffset;
 sy = (dy - dstYOffset)*subsampleY + sourceYOffset;
 

Decompressors may be written with various levels of complexity. The most complex decompressors will override the decode method, and will perform all the work of decoding, subsampling, offsetting, clipping, and format conversion. This approach may be the most efficient, since it is possible to avoid the use of extra image buffers, and it may be possible to avoid decoding portions of the image that will not be copied into the destination.

Less ambitious decompressors may override the decodeRaw method, which is responsible for decompressing the entire tile or strip into a byte array (or other appropriate datatype). The default implementation of decode will perform all necessary setup of buffers, call decodeRaw to perform the actual decoding, perform subsampling, and copy the results into the final destination image. Where possible, it will pass the real image buffer to decodeRaw in order to avoid making an extra copy.

Slightly more ambitious decompressors may override decodeRaw, but avoid writing pixels that will be discarded in the subsampling phase.

Field Summary

protected int	activeSrcHeight The height of the source region that will actually be copied into the destination image, taking into account all susbampling, offsetting, and clipping.
protected int	activeSrcMinX The X coordinate of the upper-left source pixel that will actually be copied into the destination image, taking into account all subsampling, offsetting, and clipping.
protected int	activeSrcMinY The Y coordinate of the upper-left source pixel that will actually be copied into the destination image, taking into account all subsampling, offsetting, and clipping.
protected int	activeSrcWidth The width of the source region that will actually be copied into the destination image, taking into account all susbampling, offsetting, and clipping.
protected int[]	bitsPerSample The value of the BitsPerSample tag.
protected int	byteCount The number of bytes of data from the source ImageInputStream to be decompressed.
protected TIFFColorConverter	colorConverter A TIFFColorConverter object describing the color space of the encoded pixel data, or null.
protected char[]	colorMap The value of the ColorMap tag.
protected int	compression The value of the Compression tag.
protected int[]	destinationBands The sequence of destination bands to receive the source data.
protected int	dstHeight The height of the region of the destination image to be written.
protected int	dstMinX The X coordinate of the upper left pixel to be written in the destination image.
protected int	dstMinY The Y coordinate of the upper left pixel to be written in the destination image.
protected int	dstWidth The width of the region of the destination image to be written.
protected int	dstXOffset The horizontal destination offset used, along with sourceXOffset and subsampleX, to map between horizontal source and destination pixel coordinates.
protected int	dstYOffset The vertical destination offset used, along with sourceYOffset and subsampleY, to map between horizontal source and destination pixel coordinates.
protected int[]	extraSamples The value of the ExtraSamples tag.
protected BufferedImage	image The final destination image.
protected IIOMetadata	metadata The IIOMetadata object containing metadata for the current image.
protected long	offset The offset in the source ImageInputStream of the start of the data to be decompressed.
protected int	photometricInterpretation The value of the PhotometricInterpretation tag.
protected boolean	planar true if the image is encoded using separate planes.
protected BufferedImage	rawImage A BufferedImage for the decodeRaw method to write into.
protected ImageReader	reader The ImageReader calling this TIFFDecompressor.
protected int[]	sampleFormat The value of the SampleFormat tag.
protected int	samplesPerPixel The value of the SamplesPerPixel tag.
protected int[]	sourceBands The sequence of source bands that are to be copied into the destination.
protected int	sourceXOffset The source X offset used, along with dstXOffset and subsampleX, to map between horizontal source and destination pixel coordinates.
protected int	sourceYOffset The source Y offset used, along with dstYOffset and subsampleY, to map between vertical source and destination pixel coordinates.
protected int	srcHeight The height of the source region being decoded from the source stream.
protected int	srcMinX The X coordinate of the upper-left pixel of the source region being decoded from the source stream.
protected int	srcMinY The Y coordinate of the upper-left pixel of the source region being decoded from the source stream.
protected int	srcWidth The width of the source region being decoded from the source stream.
protected ImageInputStream	stream The ImageInputStream containing the TIFF source data.
protected int	subsampleX The horizontal subsampling factor.
protected int	subsampleY The vertical subsampling factor.

Constructor Summary

TIFFDecompressor()

Method Summary

void	beginDecoding() This routine is called prior to a sequence of calls to the decode method, in order to allow any necessary tables or other structures to be initialized based on metadata values.
BufferedImage	createRawImage() Creates a BufferedImage whose underlying data array will be suitable for holding the raw decoded output of the decodeRaw method.
void	decode() Decodes the input bit stream (located in the ImageInputStream stream, at offset offset, and continuing for byteCount bytes) into the output BufferedImage image.
abstract void	decodeRaw(byte[] b, int dstOffset, int bitsPerPixel, int scanlineStride) Decodes the source data into the provided byte array b, starting at the offset given by dstOffset.
void	decodeRaw(float[] f, int dstOffset, int bitsPerPixel, int scanlineStride) Decodes the source data into the provided float array f, starting at the offset given by dstOffset.
void	decodeRaw(int[] i, int dstOffset, int bitsPerPixel, int scanlineStride) Decodes the source data into the provided int array i, starting at the offset given by dstOffset.
void	decodeRaw(short[] s, int dstOffset, int bitsPerPixel, int scanlineStride) Decodes the source data into the provided short array s, starting at the offset given by dstOffset.
ImageTypeSpecifier	getRawImageType() Returns an ImageTypeSpecifier describing an image whose underlying data array has the same format as the raw source pixel data.
static ImageTypeSpecifier	getRawImageTypeSpecifier(int photometricInterpretation, int compression, int samplesPerPixel, int[] bitsPerSample, int[] sampleFormat, int[] extraSamples, char[] colorMap) A utility method that returns an ImageTypeSpecifier suitable for decoding an image with the given parameters.
void	setActiveSrcHeight(int activeSrcHeight) Sets the value of the activeSrcHeight field.
void	setActiveSrcMinX(int activeSrcMinX) Sets the value of the activeSrcMinX field.
void	setActiveSrcMinY(int activeSrcMinY) Sets the value of the activeSrcMinY field.
void	setActiveSrcWidth(int activeSrcWidth) Sets the value of the activeSrcWidth field.
void	setBitsPerSample(int[] bitsPerSample) Sets the value of the bitsPerSample field.
void	setByteCount(int byteCount) Sets the value of the byteCount field.
void	setColorConverter(TIFFColorConverter colorConverter) Sets the TIFFColorConverter object describing the color space of the encoded data in the input stream.
void	setColorMap(char[] colorMap) Sets the value of the colorMap field.
void	setCompression(int compression) Sets the value of the compression field.
void	setDestinationBands(int[] destinationBands) Sets the value of the destinationBands field.
void	setDstHeight(int dstHeight) Sets the value of the dstHeight field.
void	setDstMinX(int dstMinX) Sets the value of the dstMinX field.
void	setDstMinY(int dstMinY) Sets the value of the dstMinY field.
void	setDstWidth(int dstWidth) Sets the value of the dstWidth field.
void	setDstXOffset(int dstXOffset) Sets the value of the dstXOffset field.
void	setDstYOffset(int dstYOffset) Sets the value of the dstYOffset field.
void	setExtraSamples(int[] extraSamples) Sets the value of the extraSamples field.
void	setImage(BufferedImage image) Sets the value of the image field.
void	setMetadata(IIOMetadata metadata) Sets the value of the metadata field.
void	setOffset(long offset) Sets the value of the offset field.
void	setPhotometricInterpretation(int photometricInterpretation) Sets the value of the photometricInterpretation field.
void	setPlanar(boolean planar) Sets the value of the planar field.
void	setReader(ImageReader reader) Sets the value of the reader field.
void	setSampleFormat(int[] sampleFormat) Sets the value of the sampleFormat field.
void	setSamplesPerPixel(int samplesPerPixel) Sets the value of the samplesPerPixel field.
void	setSourceBands(int[] sourceBands) Sets the value of the sourceBands field.
void	setSourceXOffset(int sourceXOffset) Sets the value of the sourceXOffset field.
void	setSourceYOffset(int sourceYOffset) Sets the value of the sourceYOffset.
void	setSrcHeight(int srcHeight) Sets the value of the srcHeight field.
void	setSrcMinX(int srcMinX) Sets the value of the srcMinX field.
void	setSrcMinY(int srcMinY) Sets the value of the srcMinY field.
void	setSrcWidth(int srcWidth) Sets the value of the srcWidth field.
void	setStream(ImageInputStream stream) Sets the value of the stream field.
void	setSubsampleX(int subsampleX) Sets the value of the subsampleX field.
void	setSubsampleY(int subsampleY) Sets the value of the subsampleY field.

Methods inherited from class java.lang.Object

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

Field Detail

reader

protected ImageReader reader

The ImageReader calling this TIFFDecompressor.

metadata

protected IIOMetadata metadata

The IIOMetadata object containing metadata for the current image.

photometricInterpretation

protected int photometricInterpretation

The value of the PhotometricInterpretation tag. Legal values are BaselineTIFFTagSet.PHOTOMETRIC_INTERPRETATION_WHITE_IS_ZERO, BaselineTIFFTagSet.PHOTOMETRIC_INTERPRETATION_BLACK_IS_ZERO, BaselineTIFFTagSet.PHOTOMETRIC_INTERPRETATION_RGB, BaselineTIFFTagSet.PHOTOMETRIC_INTERPRETATION_PALETTE_COLOR, BaselineTIFFTagSet.PHOTOMETRIC_INTERPRETATION_TRANSPARENCY_MASK, BaselineTIFFTagSet.PHOTOMETRIC_INTERPRETATION_Y_CB_CR, BaselineTIFFTagSet.PHOTOMETRIC_INTERPRETATION_CIELAB, BaselineTIFFTagSet.PHOTOMETRIC_INTERPRETATION_ICCLAB, or other value defined by a TIFF extension.

compression

protected int compression

The value of the Compression tag. Legal values are BaselineTIFFTagSet.COMPRESSION_NONE, BaselineTIFFTagSet.COMPRESSION_CCITT_RLE, BaselineTIFFTagSet.COMPRESSION_CCITT_T_4, BaselineTIFFTagSet.COMPRESSION_CCITT_T_6, BaselineTIFFTagSet.COMPRESSION_LZW, BaselineTIFFTagSet.COMPRESSION_OLD_JPEG, BaselineTIFFTagSet.COMPRESSION_JPEG, BaselineTIFFTagSet.COMPRESSION_ZLIB, BaselineTIFFTagSet.COMPRESSION_PACKBITS, BaselineTIFFTagSet.COMPRESSION_DEFLATE, or other value defined by a TIFF extension.

planar

protected boolean planar

true if the image is encoded using separate planes.

samplesPerPixel

protected int samplesPerPixel

The value of the SamplesPerPixel tag.

bitsPerSample

protected int[] bitsPerSample

The value of the BitsPerSample tag.

sampleFormat

protected int[] sampleFormat

The value of the SampleFormat tag. Legal values are BaselineTIFFTagSet.SAMPLE_FORMAT_UNSIGNED_INTEGER, BaselineTIFFTagSet.SAMPLE_FORMAT_SIGNED_INTEGER, BaselineTIFFTagSet.SAMPLE_FORMAT_FLOATING_POINT, BaselineTIFFTagSet.SAMPLE_FORMAT_UNDEFINED, or other value defined by a TIFF extension.

extraSamples

protected int[] extraSamples

The value of the ExtraSamples tag. Legal values are BaselineTIFFTagSet.EXTRA_SAMPLES_UNSPECIFIED, BaselineTIFFTagSet.EXTRA_SAMPLES_ASSOCIATED_ALPHA, BaselineTIFFTagSet.EXTRA_SAMPLES_UNASSOCIATED_ALPHA, or other value defined by a TIFF extension.

colorMap

protected char[] colorMap

The value of the ColorMap tag.

stream

protected ImageInputStream stream

The ImageInputStream containing the TIFF source data.

offset

protected long offset

The offset in the source ImageInputStream of the start of the data to be decompressed.

byteCount

protected int byteCount

The number of bytes of data from the source ImageInputStream to be decompressed.

srcMinX

protected int srcMinX

The X coordinate of the upper-left pixel of the source region being decoded from the source stream. This value is not affected by source subsampling.

srcMinY

protected int srcMinY

The Y coordinate of the upper-left pixel of the source region being decoded from the source stream. This value is not affected by source subsampling.

srcWidth

protected int srcWidth

The width of the source region being decoded from the source stream. This value is not affected by source subsampling.

srcHeight

protected int srcHeight

The height of the source region being decoded from the source stream. This value is not affected by source subsampling.

sourceXOffset

protected int sourceXOffset

The source X offset used, along with dstXOffset and subsampleX, to map between horizontal source and destination pixel coordinates.

dstXOffset

protected int dstXOffset

The horizontal destination offset used, along with sourceXOffset and subsampleX, to map between horizontal source and destination pixel coordinates. See the comment for sourceXOffset for the mapping equations.

sourceYOffset

protected int sourceYOffset

The source Y offset used, along with dstYOffset and subsampleY, to map between vertical source and destination pixel coordinates.

dstYOffset

protected int dstYOffset

The vertical destination offset used, along with sourceYOffset and subsampleY, to map between horizontal source and destination pixel coordinates. See the comment for sourceYOffset for the mapping equations.

subsampleX

protected int subsampleX

The horizontal subsampling factor. A factor of 1 means that every column is copied to the destination; a factor of 2 means that every second column is copied, etc.

subsampleY

protected int subsampleY

The vertical subsampling factor. A factor of 1 means that every row is copied to the destination; a factor of 2 means that every second row is copied, etc.

sourceBands

protected int[] sourceBands

The sequence of source bands that are to be copied into the destination.

destinationBands

protected int[] destinationBands

The sequence of destination bands to receive the source data.

rawImage

protected BufferedImage rawImage

A BufferedImage for the decodeRaw method to write into.

image

protected BufferedImage image

The final destination image.

dstMinX

protected int dstMinX

The X coordinate of the upper left pixel to be written in the destination image.

dstMinY

protected int dstMinY

The Y coordinate of the upper left pixel to be written in the destination image.

dstWidth

protected int dstWidth

The width of the region of the destination image to be written.

dstHeight

protected int dstHeight

The height of the region of the destination image to be written.

activeSrcMinX

protected int activeSrcMinX

The X coordinate of the upper-left source pixel that will actually be copied into the destination image, taking into account all subsampling, offsetting, and clipping. That is, the pixel at (activeSrcMinX, activeSrcMinY) is to be copied into the destination pixel at (dstMinX, dstMinY).

The pixels in the source region to be copied are those with X coordinates of the form activeSrcMinX + k*subsampleX, where k is an integer such that 0 <= k < dstWidth.

activeSrcMinY

protected int activeSrcMinY

The Y coordinate of the upper-left source pixel that will actually be copied into the destination image, taking into account all subsampling, offsetting, and clipping.

The pixels in the source region to be copied are those with Y coordinates of the form activeSrcMinY + k*subsampleY, where k is an integer such that 0 <= k < dstHeight.

activeSrcWidth

protected int activeSrcWidth

The width of the source region that will actually be copied into the destination image, taking into account all susbampling, offsetting, and clipping.

The active source width will always be equal to (dstWidth - 1)*subsampleX + 1.

activeSrcHeight

protected int activeSrcHeight

The height of the source region that will actually be copied into the destination image, taking into account all susbampling, offsetting, and clipping.

The active source height will always be equal to (dstHeight - 1)*subsampleY + 1.

colorConverter

protected TIFFColorConverter colorConverter

A TIFFColorConverter object describing the color space of the encoded pixel data, or null.

Constructor Detail

TIFFDecompressor

public TIFFDecompressor()

Method Detail

getRawImageTypeSpecifier

public static ImageTypeSpecifier getRawImageTypeSpecifier(int photometricInterpretation,
                                                          int compression,
                                                          int samplesPerPixel,
                                                          int[] bitsPerSample,
                                                          int[] sampleFormat,
                                                          int[] extraSamples,
                                                          char[] colorMap)

A utility method that returns an ImageTypeSpecifier suitable for decoding an image with the given parameters.

Parameters:

photometricInterpretation - the value of the PhotometricInterpretation field.

compression - the value of the Compression field.

samplesPerPixel - the value of the SamplesPerPixel field.

bitsPerSample - the value of the BitsPerSample field.

sampleFormat - the value of the SampleFormat field.

extraSamples - the value of the ExtraSamples field.

colorMap - the value of the ColorMap field.

Returns:

a suitable ImageTypeSpecifier, or null if it is not possible to create one.

setReader

public void setReader(ImageReader reader)

Sets the value of the reader field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

reader - the current ImageReader.

setMetadata

public void setMetadata(IIOMetadata metadata)

Sets the value of the metadata field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

metadata - the IIOMetadata object for the image being read.

setPhotometricInterpretation

public void setPhotometricInterpretation(int photometricInterpretation)

Sets the value of the photometricInterpretation field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

photometricInterpretation - the photometric interpretation value.

setCompression

public void setCompression(int compression)

Sets the value of the compression field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

compression - the compression type.

setPlanar

public void setPlanar(boolean planar)

Sets the value of the planar field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

planar - true if the image to be decoded is stored in planar format.

setSamplesPerPixel

public void setSamplesPerPixel(int samplesPerPixel)

Sets the value of the samplesPerPixel field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

samplesPerPixel - the number of samples in each source pixel.

setBitsPerSample

public void setBitsPerSample(int[] bitsPerSample)

Sets the value of the bitsPerSample field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

bitsPerSample - the number of bits for each source image sample.

setSampleFormat

public void setSampleFormat(int[] sampleFormat)

Sets the value of the sampleFormat field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

sampleFormat - the format of the source image data, for example unsigned integer or floating-point.

setExtraSamples

public void setExtraSamples(int[] extraSamples)

Sets the value of the extraSamples field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

extraSamples - the interpretation of any samples in the source file beyond those used for basic color or grayscale information.

setColorMap

public void setColorMap(char[] colorMap)

Sets the value of the colorMap field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

colorMap - the color map to apply to the source data, as an array of chars.

setStream

public void setStream(ImageInputStream stream)

Sets the value of the stream field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

stream - the ImageInputStream to be read.

setOffset

public void setOffset(long offset)

Sets the value of the offset field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

offset - the offset of the beginning of the compressed data.

setByteCount

public void setByteCount(int byteCount)

Sets the value of the byteCount field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

byteCount - the number of bytes of compressed data.

setSrcMinX

public void setSrcMinX(int srcMinX)

Sets the value of the srcMinX field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

srcMinX - the minimum X coordinate of the source region being decoded, irrespective of how it will be copied into the destination.

setSrcMinY

public void setSrcMinY(int srcMinY)

Sets the value of the srcMinY field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

srcMinY - the minimum Y coordinate of the source region being decoded, irrespective of how it will be copied into the destination.

setSrcWidth

public void setSrcWidth(int srcWidth)

Sets the value of the srcWidth field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

srcWidth - the width of the source region being decoded, irrespective of how it will be copied into the destination.

setSrcHeight

public void setSrcHeight(int srcHeight)

Sets the value of the srcHeight field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

srcHeight - the height of the source region being decoded, irrespective of how it will be copied into the destination.

setSourceXOffset

public void setSourceXOffset(int sourceXOffset)

Sets the value of the sourceXOffset field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

sourceXOffset - the horizontal source offset to be used when mapping between source and destination coordinates.

setDstXOffset

public void setDstXOffset(int dstXOffset)

Sets the value of the dstXOffset field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

dstXOffset - the horizontal destination offset to be used when mapping between source and destination coordinates.

setSourceYOffset

public void setSourceYOffset(int sourceYOffset)

Sets the value of the sourceYOffset.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

sourceYOffset - the vertical source offset to be used when mapping between source and destination coordinates.

setDstYOffset

public void setDstYOffset(int dstYOffset)

Sets the value of the dstYOffset field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

dstYOffset - the vertical destination offset to be used when mapping between source and destination coordinates.

setSubsampleX

public void setSubsampleX(int subsampleX)

Sets the value of the subsampleX field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

subsampleX - the horizontal subsampling factor.

Throws:

IllegalArgumentException - if subsampleX is less than or equal to 0.

setSubsampleY

public void setSubsampleY(int subsampleY)

Sets the value of the subsampleY field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

subsampleY - the vertical subsampling factor.

Throws:

IllegalArgumentException - if subsampleY is less than or equal to 0.

setSourceBands

public void setSourceBands(int[] sourceBands)

Sets the value of the sourceBands field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

sourceBands - an array of ints specifying the source bands to be read.

setDestinationBands

public void setDestinationBands(int[] destinationBands)

Sets the value of the destinationBands field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

destinationBands - an array of ints specifying the destination bands to be written.

setImage

public void setImage(BufferedImage image)

Sets the value of the image field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

image - the destination BufferedImage.

setDstMinX

public void setDstMinX(int dstMinX)

Sets the value of the dstMinX field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

dstMinX - the minimum X coordinate of the destination region.

setDstMinY

public void setDstMinY(int dstMinY)

Sets the value of the dstMinY field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

dstMinY - the minimum Y coordinate of the destination region.

setDstWidth

public void setDstWidth(int dstWidth)

Sets the value of the dstWidth field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

dstWidth - the width of the destination region.

setDstHeight

public void setDstHeight(int dstHeight)

Sets the value of the dstHeight field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

dstHeight - the height of the destination region.

setActiveSrcMinX

public void setActiveSrcMinX(int activeSrcMinX)

Sets the value of the activeSrcMinX field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

activeSrcMinX - the minimum X coordinate of the active source region.

setActiveSrcMinY

public void setActiveSrcMinY(int activeSrcMinY)

Sets the value of the activeSrcMinY field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

activeSrcMinY - the minimum Y coordinate of the active source region.

setActiveSrcWidth

public void setActiveSrcWidth(int activeSrcWidth)

Sets the value of the activeSrcWidth field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

activeSrcWidth - the width of the active source region.

setActiveSrcHeight

public void setActiveSrcHeight(int activeSrcHeight)

Sets the value of the activeSrcHeight field.

If this method is called, the beginDecoding method must be called prior to calling any of the decode methods.

Parameters:

activeSrcHeight - the height of the active source region.

setColorConverter

public void setColorConverter(TIFFColorConverter colorConverter)

Sets the TIFFColorConverter object describing the color space of the encoded data in the input stream. If no TIFFColorConverter is set, no conversion will be performed.

Parameters:

colorConverter - a TIFFColorConverter object, or null.

getRawImageType

public ImageTypeSpecifier getRawImageType()

Returns an ImageTypeSpecifier describing an image whose underlying data array has the same format as the raw source pixel data.

Returns:

an ImageTypeSpecifier.

createRawImage

public BufferedImage createRawImage()

Creates a BufferedImage whose underlying data array will be suitable for holding the raw decoded output of the decodeRaw method.

The default implementation calls getRawImageType, and calls the resulting ImageTypeSpecifier's createBufferedImage method.

Returns:

a BufferedImage whose underlying data array has the same format as the raw source pixel data, or null if it is not possible to create such an image.

decodeRaw

public abstract void decodeRaw(byte[] b,
                               int dstOffset,
                               int bitsPerPixel,
                               int scanlineStride)
                        throws IOException

Decodes the source data into the provided byte array b, starting at the offset given by dstOffset. Each pixel occupies bitsPerPixel bits, with no padding between pixels. Scanlines are separated by scanlineStride bytes.

Parameters:

b - a byte array to be written.

dstOffset - the starting offset in b to be written.

bitsPerPixel - the number of bits for each pixel.

scanlineStride - the number of bytes to advance between that starting pixels of each scanline.

Throws:

IOException - if an error occurs reading from the source ImageInputStream.

decodeRaw

public void decodeRaw(short[] s,
                      int dstOffset,
                      int bitsPerPixel,
                      int scanlineStride)
               throws IOException

Decodes the source data into the provided short array s, starting at the offset given by dstOffset. Each pixel occupies bitsPerPixel bits, with no padding between pixels. Scanlines are separated by scanlineStride shorts

The default implementation calls decodeRaw(byte[] b, ...) and copies the resulting data into s.

Parameters:

s - a short array to be written.

dstOffset - the starting offset in s to be written.

bitsPerPixel - the number of bits for each pixel.

scanlineStride - the number of shorts to advance between that starting pixels of each scanline.

Throws:

IOException - if an error occurs reading from the source ImageInputStream.

decodeRaw

public void decodeRaw(int[] i,
                      int dstOffset,
                      int bitsPerPixel,
                      int scanlineStride)
               throws IOException

Decodes the source data into the provided int array i, starting at the offset given by dstOffset. Each pixel occupies bitsPerPixel bits, with no padding between pixels. Scanlines are separated by scanlineStride ints.

The default implementation calls decodeRaw(byte[] b, ...) and copies the resulting data into i.

Parameters:

i - an int array to be written.

dstOffset - the starting offset in i to be written.

bitsPerPixel - the number of bits for each pixel.

scanlineStride - the number of ints to advance between that starting pixels of each scanline.

Throws:

IOException - if an error occurs reading from the source ImageInputStream.

decodeRaw

public void decodeRaw(float[] f,
                      int dstOffset,
                      int bitsPerPixel,
                      int scanlineStride)
               throws IOException

Decodes the source data into the provided float array f, starting at the offset given by dstOffset. Each pixel occupies bitsPerPixel bits, with no padding between pixels. Scanlines are separated by scanlineStride floats.

The default implementation calls decodeRaw(byte[] b, ...) and copies the resulting data into f.

Parameters:

f - a float array to be written.

dstOffset - the starting offset in f to be written.

bitsPerPixel - the number of bits for each pixel.

scanlineStride - the number of floats to advance between that starting pixels of each scanline.

Throws:

IOException - if an error occurs reading from the source ImageInputStream.

beginDecoding

public void beginDecoding()

This routine is called prior to a sequence of calls to the decode method, in order to allow any necessary tables or other structures to be initialized based on metadata values. This routine is guaranteed to be called any time the metadata values have changed.

The default implementation computes tables used by the decode method to rescale components to different bit depths. Thus, if this method is overridden, it is important for the subclass method to call super(), unless it overrides decode as well.

decode

public void decode()
            throws IOException

Decodes the input bit stream (located in the ImageInputStream stream, at offset offset, and continuing for byteCount bytes) into the output BufferedImage image.

The default implementation analyzes the destination image to determine if it is suitable as the destination for the decodeRaw method. If not, a suitable image is created. Next, decodeRaw is called to perform the actual decoding, and the results are copied into the destination image if necessary. Subsampling and offsetting are performed automatically.

The precise responsibilities of this routine are as follows. The input bit stream is defined by the instance variables stream, offset, and byteCount. These bits contain the data for the region of the source image defined by srcMinX, srcMinY, srcWidth, and srcHeight.

The source data is required to be subsampling, starting at the sourceXOffsetth column and including every subsampleXth pixel thereafter (and similarly for sourceYOffset and subsampleY).

Pixels are copied into the destination with an addition shift of (dstXOffset, dstYOffset). The complete set of formulas relating the source and destination coordinate spaces are:

 dx = (sx - sourceXOffset)/subsampleX + dstXOffset;
 dy = (sy - sourceYOffset)/subsampleY + dstYOffset; 
 

Only source pixels such that (sx - sourceXOffset) % subsampleX == 0 and (sy - sourceYOffset) % subsampleY == 0 are copied.

The inverse mapping, from destination to source coordinates, is one-to-one:

 sx = (dx - dstXOffset)*subsampleX + sourceXOffset;
 sy = (dy - dstYOffset)*subsampleY + sourceYOffset;
 

The region of the destination image to be updated is given by the instance variables dstMinX, dstMinY, dstWidth, and dstHeight.

It is possible that not all of the source data being read will contribute to the destination image. For example, the destination offsets could be set such that some of the source pixels land outside of the bounds of the image. As a convenience, the bounds of the active source region (that is, the region of the strip or tile being read that actually contributes to the destination image, taking clipping into account) are available as activeSrcMinX, activeSrcMinY, activeSrcWidth and activeSrcHeight. Thus, the source pixel at (activeSrcMinX, activeSrcMinY) will map to the destination pixel (dstMinX, dstMinY).

The sequence of source bands given by sourceBands are to be copied into the sequence of bands in the destination given by destinationBands.

Some standard tag information is provided the instance variables photometricInterpretation, compression, samplesPerPixel, bitsPerSample, sampleFormat, extraSamples, and colorMap.

In practice, unless there is a significant performance advantage to be gained by overriding this routine, most users will prefer to use the default implementation of this routine, and instead override the decodeRaw and/or getRawImageType methods.

Throws:

IOException - if an error occurs in decodeRaw.