Package com.sun.pdfview.decode
Class DCTDecode
- java.lang.Object
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- com.sun.pdfview.decode.DCTDecode
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public class DCTDecode extends java.lang.Object
decode a DCT encoded array into a byte array. This class uses Java's built-in JPEG image class to do the decoding.
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Constructor Summary
Constructors Constructor Description DCTDecode()
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description protected static java.nio.ByteBuffer
decode(PDFObject dict, java.nio.ByteBuffer buf, PDFObject params)
decode an array of bytes in DCT format.
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Method Detail
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decode
protected static java.nio.ByteBuffer decode(PDFObject dict, java.nio.ByteBuffer buf, PDFObject params) throws PDFParseException
decode an array of bytes in DCT format.DCT is the format used by JPEG images, so this class simply loads the DCT-format bytes as an image, then reads the bytes out of the image to create the array. Unfortunately, their most likely use is to get turned BACK into an image, so this isn't terribly efficient... but is is general... don't hit, please.
The DCT-encoded stream may have 1, 3 or 4 samples per pixel, depending on the colorspace of the image. In decoding, we look for the colorspace in the stream object's dictionary to decide how to decode this image. If no colorspace is present, we guess 3 samples per pixel.
- Parameters:
dict
- the stream dictionarybuf
- the DCT-encoded bufferparams
- the parameters to the decoder (ignored)- Returns:
- the decoded buffer
- Throws:
PDFParseException
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