Java javax.imageio.plugins.jpeg Class JPEGQTable（JDK8）

Field Detail

• K1Luminance

  public 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

• K1Div2Luminance

  public 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

• K2Chrominance

  public 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

• K2Div2Chrominance

  public 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

• JPEGQTable

  public 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 the input array.

  Parameters:

  table - the quantization table, as an int array.

  Throws:

  IllegalArgumentException - if table is null or table.length is not equal to 64.

Method Detail

• getTable

  public int[] getTable()

  Returns a copy of the current quantization table as an array of ints in natural (not zig-zag) order.

  Returns:

  A copy of the current quantization table.

• getScaledInstance

  public JPEGQTable getScaledInstance(float scaleFactor,
                                      boolean forceBaseline)

  Returns a new quantization table where the values are multiplied by scaleFactor and then clamped to the range 1..32767 (or to 1..255 if forceBaseline is true).

  Values of scaleFactor less 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.

• toString

  public String toString()

  Returns a String representing this quantization table.

  Overrides:

  toString in class Object

  Returns:

  a String representing this quantization table.