Class JPEGQuality
java.lang.Object
com.twelvemonkeys.imageio.metadata.jpeg.JPEGQuality
Determines an approximate JPEG compression quality value from the quantization tables.
- Version:
- $Id: JPEGQuality.java,v 1.0 16.02.12 17:07 haraldk Exp$
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Field Summary
FieldsModifier and TypeFieldDescription(package private) static final int
(package private) static final int
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Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionprivate static int
getJPEGQuality
(int[][] quantizationTables) static float
getJPEGQuality
(List<JPEGSegment> segments) Determines an approximate JPEG compression quality value from the quantization tables.static float
getJPEGQuality
(ImageInputStream input) Determines an approximate JPEG compression quality value from the quantization tables.static JPEGQTable[]
getQTables
(List<JPEGSegment> segments) private static int[][]
getQuantizationTables
(List<JPEGSegment> dqtSegments) static void
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Field Details
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NUM_QUANT_TABLES
static final int NUM_QUANT_TABLES- See Also:
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DCT_SIZE_2
static final int DCT_SIZE_2- See Also:
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Constructor Details
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JPEGQuality
public JPEGQuality()
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Method Details
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getJPEGQuality
Determines an approximate JPEG compression quality value from the quantization tables. The value will be in the range[0...1]
, where1
is the best possible value.- Parameters:
segments
- a list of JPEG segments containing the DQT quantization tables.- Returns:
- a float in the range
[0...1]
, representing the JPEG quality, or-1
if the quality can't be determined. - Throws:
IIOException
- if a JPEG format error is found during parsing.IOException
- if an I/O exception occurs during parsing.- See Also:
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getJPEGQuality
Determines an approximate JPEG compression quality value from the quantization tables. The value will be in the range[0...1]
, where1
is the best possible value.- Parameters:
input
- an image input stream containing JPEG data.- Returns:
- a float in the range
[0...1]
, representing the JPEG quality, or-1
if the quality can't be determined. - Throws:
IIOException
- if a JPEG format error is found during parsing.IOException
- if an I/O exception occurs during parsing.- See Also:
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getJPEGQuality
- Throws:
IOException
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getQTables
- Throws:
IOException
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getQuantizationTables
- Throws:
IOException
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main
- Throws:
IOException
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