Module java.desktop
Package java.awt.image

Class DataBuffer

java.lang.Object
java.awt.image.DataBuffer
Direct Known Subclasses:
DataBufferByte, DataBufferDouble, DataBufferFloat, DataBufferInt, DataBufferShort, DataBufferUShort
public abstract class DataBuffer
extends Object
This class exists to wrap one or more data arrays. Each data array in the DataBuffer is referred to as a bank. Accessor methods for getting and setting elements of the DataBuffer's banks exist with and without a bank specifier. The methods without a bank specifier use the default 0th bank. The DataBuffer can optionally take an offset per bank, so that data in an existing array can be used even if the interesting data doesn't start at array location zero. Getting or setting the 0th element of a bank, uses the (0+offset)th element of the array. The size field specifies how much of the data array is available for use. Size + offset for a given bank should never be greater than the length of the associated data array. The data type of a data buffer indicates the type of the data array(s) and may also indicate additional semantics, e.g. storing unsigned 8-bit data in elements of a byte array. The data type may be TYPE_UNDEFINED or one of the types defined below. Other types may be added in the future. Generally, an object of class DataBuffer will be cast down to one of its data type specific subclasses to access data type specific methods for improved performance. Currently, the Java 2D(tm) API image classes use TYPE_BYTE, TYPE_USHORT, TYPE_INT, TYPE_SHORT, TYPE_FLOAT, and TYPE_DOUBLE DataBuffers to store image data.
See Also:
Raster, SampleModel

  • Field Summary

    Fields 
    Modifier and Type Field Description
    protected int banks
    The number of banks in this DataBuffer.
    protected int dataType
    The data type of this DataBuffer.
    protected int offset
    Offset into default (first) bank from which to get the first element.
    protected int[] offsets
    Offsets into all banks.
    protected int size
    Usable size of all banks.
    static int TYPE_BYTE
    Tag for unsigned byte data.
    static int TYPE_DOUBLE
    Tag for double data.
    static int TYPE_FLOAT
    Tag for float data.
    static int TYPE_INT
    Tag for int data.
    static int TYPE_SHORT
    Tag for signed short data.
    static int TYPE_UNDEFINED
    Tag for undefined data.
    static int TYPE_USHORT
    Tag for unsigned short data.

  • Constructor Summary

    Constructors 
    Modifier Constructor Description
    protected DataBuffer​(int dataType, int size)
    Constructs a DataBuffer containing one bank of the specified data type and size.
    protected DataBuffer​(int dataType, int size, int numBanks)
    Constructs a DataBuffer containing the specified number of banks.
    protected DataBuffer​(int dataType, int size, int numBanks, int offset)
    Constructs a DataBuffer that contains the specified number of banks.
    protected DataBuffer​(int dataType, int size, int numBanks, int[] offsets)
    Constructs a DataBuffer which contains the specified number of banks.

  • Method Summary

    Modifier and Type Method Description
    int getDataType()
    Returns the data type of this DataBuffer.
    static int getDataTypeSize​(int type)
    Returns the size (in bits) of the data type, given a datatype tag.
    int getElem​(int i)
    Returns the requested data array element from the first (default) bank as an integer.
    abstract int getElem​(int bank, int i)
    Returns the requested data array element from the specified bank as an integer.
    double getElemDouble​(int i)
    Returns the requested data array element from the first (default) bank as a double.
    double getElemDouble​(int bank, int i)
    Returns the requested data array element from the specified bank as a double.
    float getElemFloat​(int i)
    Returns the requested data array element from the first (default) bank as a float.
    float getElemFloat​(int bank, int i)
    Returns the requested data array element from the specified bank as a float.
    int getNumBanks()
    Returns the number of banks in this DataBuffer.
    int getOffset()
    Returns the offset of the default bank in array elements.
    int[] getOffsets()
    Returns the offsets (in array elements) of all the banks.
    int getSize()
    Returns the size (in array elements) of all banks.
    void setElem​(int i, int val)
    Sets the requested data array element in the first (default) bank from the given integer.
    abstract void setElem​(int bank, int i, int val)
    Sets the requested data array element in the specified bank from the given integer.
    void setElemDouble​(int i, double val)
    Sets the requested data array element in the first (default) bank from the given double.
    void setElemDouble​(int bank, int i, double val)
    Sets the requested data array element in the specified bank from the given double.
    void setElemFloat​(int i, float val)
    Sets the requested data array element in the first (default) bank from the given float.
    void setElemFloat​(int bank, int i, float val)
    Sets the requested data array element in the specified bank from the given float.

    Methods declared in class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Field Details

  • Constructor Details

    • DataBuffer

      protected DataBuffer​(int dataType, int size)
      Constructs a DataBuffer containing one bank of the specified data type and size.
      Parameters:
      dataType - the data type of this DataBuffer
      size - the size of the banks

    • DataBuffer

      protected DataBuffer​(int dataType, int size, int numBanks)
      Constructs a DataBuffer containing the specified number of banks. Each bank has the specified size and an offset of 0.
      Parameters:
      dataType - the data type of this DataBuffer
      size - the size of the banks
      numBanks - the number of banks in this DataBuffer

    • DataBuffer

      protected DataBuffer​(int dataType, int size, int numBanks, int offset)
      Constructs a DataBuffer that contains the specified number of banks. Each bank has the specified datatype, size and offset.
      Parameters:
      dataType - the data type of this DataBuffer
      size - the size of the banks
      numBanks - the number of banks in this DataBuffer
      offset - the offset for each bank

    • DataBuffer

      protected DataBuffer​(int dataType, int size, int numBanks, int[] offsets)
      Constructs a DataBuffer which contains the specified number of banks. Each bank has the specified datatype and size. The offset for each bank is specified by its respective entry in the offsets array.
      Parameters:
      dataType - the data type of this DataBuffer
      size - the size of the banks
      numBanks - the number of banks in this DataBuffer
      offsets - an array containing an offset for each bank.
      Throws:
      ArrayIndexOutOfBoundsException - if numBanks does not equal the length of offsets

  • Method Details

    • getDataTypeSize

      public static int getDataTypeSize​(int type)
      Returns the size (in bits) of the data type, given a datatype tag.
      Parameters:
      type - the value of one of the defined datatype tags
      Returns:
      the size of the data type
      Throws:
      IllegalArgumentException - if type is less than zero or greater than TYPE_DOUBLE

    • getDataType

      public int getDataType()
      Returns the data type of this DataBuffer.
      Returns:
      the data type of this DataBuffer.

    • getSize

      public int getSize()
      Returns the size (in array elements) of all banks.
      Returns:
      the size of all banks.

    • getOffset

      public int getOffset()
      Returns the offset of the default bank in array elements.
      Returns:
      the offset of the default bank.

    • getOffsets

      public int[] getOffsets()
      Returns the offsets (in array elements) of all the banks.
      Returns:
      the offsets of all banks.

    • getNumBanks

      public int getNumBanks()
      Returns the number of banks in this DataBuffer.
      Returns:
      the number of banks.

    • getElem

      public int getElem​(int i)
      Returns the requested data array element from the first (default) bank as an integer.
      Parameters:
      i - the index of the requested data array element
      Returns:
      the data array element at the specified index.
      See Also:
      setElem(int, int), setElem(int, int, int)

    • getElem

      public abstract int getElem​(int bank, int i)
      Returns the requested data array element from the specified bank as an integer.
      Parameters:
      bank - the specified bank
      i - the index of the requested data array element
      Returns:
      the data array element at the specified index from the specified bank at the specified index.
      See Also:
      setElem(int, int), setElem(int, int, int)

    • setElem

      public void setElem​(int i, int val)
      Sets the requested data array element in the first (default) bank from the given integer.
      Parameters:
      i - the specified index into the data array
      val - the data to set the element at the specified index in the data array
      See Also:
      getElem(int), getElem(int, int)

    • setElem

      public abstract void setElem​(int bank, int i, int val)
      Sets the requested data array element in the specified bank from the given integer.
      Parameters:
      bank - the specified bank
      i - the specified index into the data array
      val - the data to set the element in the specified bank at the specified index in the data array
      See Also:
      getElem(int), getElem(int, int)

    • getElemFloat

      public float getElemFloat​(int i)
      Returns the requested data array element from the first (default) bank as a float. The implementation in this class is to cast getElem(i) to a float. Subclasses may override this method if another implementation is needed.
      Parameters:
      i - the index of the requested data array element
      Returns:
      a float value representing the data array element at the specified index.
      See Also:
      setElemFloat(int, float), setElemFloat(int, int, float)

    • getElemFloat

      public float getElemFloat​(int bank, int i)
      Returns the requested data array element from the specified bank as a float. The implementation in this class is to cast getElem(int, int) to a float. Subclasses can override this method if another implementation is needed.
      Parameters:
      bank - the specified bank
      i - the index of the requested data array element
      Returns:
      a float value representing the data array element from the specified bank at the specified index.
      See Also:
      setElemFloat(int, float), setElemFloat(int, int, float)

    • setElemFloat

      public void setElemFloat​(int i, float val)
      Sets the requested data array element in the first (default) bank from the given float. The implementation in this class is to cast val to an int and call setElem(int, int). Subclasses can override this method if another implementation is needed.
      Parameters:
      i - the specified index
      val - the value to set the element at the specified index in the data array
      See Also:
      getElemFloat(int), getElemFloat(int, int)

    • setElemFloat

      public void setElemFloat​(int bank, int i, float val)
      Sets the requested data array element in the specified bank from the given float. The implementation in this class is to cast val to an int and call setElem(int, int). Subclasses can override this method if another implementation is needed.
      Parameters:
      bank - the specified bank
      i - the specified index
      val - the value to set the element in the specified bank at the specified index in the data array
      See Also:
      getElemFloat(int), getElemFloat(int, int)

    • getElemDouble

      public double getElemDouble​(int i)
      Returns the requested data array element from the first (default) bank as a double. The implementation in this class is to cast getElem(int) to a double. Subclasses can override this method if another implementation is needed.
      Parameters:
      i - the specified index
      Returns:
      a double value representing the element at the specified index in the data array.
      See Also:
      setElemDouble(int, double), setElemDouble(int, int, double)

    • getElemDouble

      public double getElemDouble​(int bank, int i)
      Returns the requested data array element from the specified bank as a double. The implementation in this class is to cast getElem(bank, i) to a double. Subclasses may override this method if another implementation is needed.
      Parameters:
      bank - the specified bank
      i - the specified index
      Returns:
      a double value representing the element from the specified bank at the specified index in the data array.
      See Also:
      setElemDouble(int, double), setElemDouble(int, int, double)

    • setElemDouble

      public void setElemDouble​(int i, double val)
      Sets the requested data array element in the first (default) bank from the given double. The implementation in this class is to cast val to an int and call setElem(int, int). Subclasses can override this method if another implementation is needed.
      Parameters:
      i - the specified index
      val - the value to set the element at the specified index in the data array
      See Also:
      getElemDouble(int), getElemDouble(int, int)

    • setElemDouble

      public void setElemDouble​(int bank, int i, double val)
      Sets the requested data array element in the specified bank from the given double. The implementation in this class is to cast val to an int and call setElem(int, int). Subclasses can override this method if another implementation is needed.
      Parameters:
      bank - the specified bank
      i - the specified index
      val - the value to set the element in the specified bank at the specified index of the data array
      See Also:
      getElemDouble(int), getElemDouble(int, int)