Class TIFFDecompressor

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

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.

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.

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

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.

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.

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; 
 

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.

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.

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.

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.

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.

Returns: an ImageTypeSpecifier.

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.

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.

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.

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.

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.

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.

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.

Parameters: colorConverter a TIFFColorConverter object, or null.

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.

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

Parameters: compression the compression type.

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.

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.

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.

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.

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.

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.

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.

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.

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

Parameters: image the destination BufferedImage.

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.

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.

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.

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.

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

Parameters: reader the current ImageReader.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.