- java.lang.Object
- 
- javax.imageio.plugins.jpeg.JPEGQTable
 
- 
 public class JPEGQTable extends Object A class encapsulating a single JPEG quantization table. The elements appear in natural order (as opposed to zig-zag order). Static variables are provided for the "standard" tables taken from Annex K of the JPEG specification, as well as the default tables conventionally used for visually lossless encoding.For more information about the operation of the standard JPEG plug-in, see the JPEG metadata format specification and usage notes 
- 
- 
Field SummaryFields Modifier and Type Field Description static JPEGQTableK1Div2LuminanceThe sample luminance quantization table given in the JPEG specification, table K.1, with all elements divided by 2.static JPEGQTableK1LuminanceThe sample luminance quantization table given in the JPEG specification, table K.1.static JPEGQTableK2ChrominanceThe sample chrominance quantization table given in the JPEG specification, table K.2.static JPEGQTableK2Div2ChrominanceThe sample chrominance quantization table given in the JPEG specification, table K.1, with all elements divided by 2.
 - 
Constructor SummaryConstructors Constructor Description JPEGQTable(int[] table)Constructs a quantization table from the argument, which must contain 64 elements in natural order (not zig-zag order).
 - 
Method SummaryAll Methods Instance Methods Concrete Methods Modifier and Type Method Description JPEGQTablegetScaledInstance(float scaleFactor, boolean forceBaseline)Returns a new quantization table where the values are multiplied byscaleFactorand then clamped to the range 1..32767 (or to 1..255 ifforceBaselineis true).int[]getTable()Returns a copy of the current quantization table as an array ofints in natural (not zig-zag) order.StringtoString()Returns aStringrepresenting this quantization table.
 
- 
- 
- 
Field Detail- 
K1Luminancepublic static final JPEGQTable K1Luminance The sample luminance quantization table given in the JPEG specification, table K.1. According to the specification, these values produce "good" quality output.- See Also:
- K1Div2Luminance
 
 - 
K1Div2Luminancepublic static final JPEGQTable K1Div2Luminance The sample luminance quantization table given in the JPEG specification, table K.1, with all elements divided by 2. According to the specification, these values produce "very good" quality output. This is the table usually used for "visually lossless" encoding, and is the default luminance table used if the default tables and quality settings are used.- See Also:
- K1Luminance
 
 - 
K2Chrominancepublic static final JPEGQTable K2Chrominance The sample chrominance quantization table given in the JPEG specification, table K.2. According to the specification, these values produce "good" quality output.- See Also:
- K2Div2Chrominance
 
 - 
K2Div2Chrominancepublic static final JPEGQTable K2Div2Chrominance The sample chrominance quantization table given in the JPEG specification, table K.1, with all elements divided by 2. According to the specification, these values produce "very good" quality output. This is the table usually used for "visually lossless" encoding, and is the default chrominance table used if the default tables and quality settings are used.- See Also:
- K2Chrominance
 
 
- 
 - 
Constructor Detail- 
JPEGQTablepublic JPEGQTable(int[] table) Constructs a quantization table from the argument, which must contain 64 elements in natural order (not zig-zag order). A copy is made of the input array.- Parameters:
- table- the quantization table, as an- intarray.
- Throws:
- IllegalArgumentException- if- tableis- nullor- table.lengthis not equal to 64.
 
 
- 
 - 
Method Detail- 
getTablepublic int[] getTable() Returns a copy of the current quantization table as an array ofints in natural (not zig-zag) order.- Returns:
- A copy of the current quantization table.
 
 - 
getScaledInstancepublic JPEGQTable getScaledInstance(float scaleFactor, boolean forceBaseline) Returns a new quantization table where the values are multiplied byscaleFactorand then clamped to the range 1..32767 (or to 1..255 ifforceBaselineis true).Values of scaleFactorless than 1 tend to improve the quality level of the table, and values greater than 1.0 degrade the quality level of the table.- Parameters:
- scaleFactor- multiplication factor for the table.
- forceBaseline- if- true, the values will be clamped to the range 1..255
- Returns:
- a new quantization table that is a linear multiple of the current table.
 
 
- 
 
-