java.awt.image
Class MultiPixelPackedSampleModel

java.lang.Object
  java.awt.image.SampleModel
      java.awt.image.MultiPixelPackedSampleModel

public class MultiPixelPackedSampleModel

extends SampleModel

The MultiPixelPackedSampleModel class represents one-banded images and can pack multiple one-sample pixels into one data element. Pixels are not allowed to span data elements. The data type can be DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, or DataBuffer.TYPE_INT. Each pixel must be a power of 2 number of bits and a power of 2 number of pixels must fit exactly in one data element. Pixel bit stride is equal to the number of bits per pixel. Scanline stride is in data elements and the last several data elements might be padded with unused pixels. Data bit offset is the offset in bits from the beginning of the DataBuffer to the first pixel and must be a multiple of pixel bit stride.

The following code illustrates extracting the bits for pixel x, y from DataBuffer data and storing the pixel data in data elements of type dataType:

      int dataElementSize = DataBuffer.getDataTypeSize(dataType);
      int bitnum = dataBitOffset + x*pixelBitStride;
      int element = data.getElem(y*scanlineStride + bitnum/dataElementSize);
      int shift = dataElementSize - (bitnum & (dataElementSize-1))
                  - pixelBitStride;
      int pixel = (element >> shift) & ((1 << pixelBitStride) - 1);
 

Field Summary

(package private) int	bitMask Bitmask that extracts the rightmost pixel of a data element.
(package private) int	dataBitOffset The bit offset into the data array where the first pixel begins.
(package private) int	dataElementSize The size of a data element in bits.
(package private) int	pixelBitStride The number of bits from one pixel to the next.
(package private) int	pixelsPerDataElement The number of pixels that fit in a data element.
(package private) int	scanlineStride ScanlineStride of the data buffer described in data array elements.

Fields inherited from class java.awt.image.SampleModel

dataType, height, numBands, width

Constructor Summary

MultiPixelPackedSampleModel(int dataType, int w, int h, int numberOfBits)
Constructs a MultiPixelPackedSampleModel with the specified data type, width, height and number of bits per pixel.

MultiPixelPackedSampleModel(int dataType, int w, int h, int numberOfBits, int scanlineStride, int dataBitOffset)
Constructs a MultiPixelPackedSampleModel with specified data type, width, height, number of bits per pixel, scanline stride and data bit offset.

Method Summary

SampleModel	createCompatibleSampleModel(int w, int h) Creates a new MultiPixelPackedSampleModel with the specified width and height.
DataBuffer	createDataBuffer() Creates a DataBuffer that corresponds to this MultiPixelPackedSampleModel.
SampleModel	createSubsetSampleModel(int[] bands) Creates a new MultiPixelPackedSampleModel with a subset of the bands of this MultiPixelPackedSampleModel.
boolean	equals(Object o) Indicates whether some other object is "equal to" this one.
int	getBitOffset(int x) Returns the offset, in bits, into the data element in which it is stored for the xth pixel of a scanline.
int	getDataBitOffset() Returns the data bit offset in bits.
Object	getDataElements(int x, int y, Object obj, DataBuffer data) Returns data for a single pixel in a primitive array of type TransferType.
int	getNumDataElements() Returns the number of data elements needed to transfer one pixel via the getDataElements(int, int, java.lang.Object, java.awt.image.DataBuffer) and setDataElements(int, int, java.lang.Object, java.awt.image.DataBuffer) methods.
int	getOffset(int x, int y) Returns the offset of pixel (x, y) in data array elements.
int[]	getPixel(int x, int y, int[] iArray, DataBuffer data) Returns the specified single band pixel in the first element of an int array.
int	getPixelBitStride() Returns the pixel bit stride in bits.
int	getSample(int x, int y, int b, DataBuffer data) Returns as int the sample in a specified band for the pixel located at (x, y).
int[]	getSampleSize() Returns the number of bits per sample for all bands.
int	getSampleSize(int band) Returns the number of bits per sample for the specified band.
int	getScanlineStride() Returns the scanline stride.
int	getTransferType() Returns the TransferType used to transfer pixels by way of the getDataElements and setDataElements methods.
int	hashCode() Returns a hash code value for the object.
void	setDataElements(int x, int y, Object obj, DataBuffer data) Sets the data for a single pixel in the specified DataBuffer from a primitive array of type TransferType.
void	setPixel(int x, int y, int[] iArray, DataBuffer data) Sets a pixel in the DataBuffer using an int array for input.
void	setSample(int x, int y, int b, int s, DataBuffer data) Sets a sample in the specified band for the pixel located at (x, y) in the DataBuffer using an int for input.

Methods inherited from class java.awt.image.SampleModel

getDataElements, getDataType, getHeight, getNumBands, getPixel, getPixel, getPixels, getPixels, getPixels, getSampleDouble, getSampleFloat, getSamples, getSamples, getSamples, getWidth, setDataElements, setPixel, setPixel, setPixels, setPixels, setPixels, setSample, setSample, setSamples, setSamples, setSamples

Methods inherited from class java.lang.Object

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

Field Detail

pixelBitStride

int pixelBitStride

The number of bits from one pixel to the next.

bitMask

int bitMask

Bitmask that extracts the rightmost pixel of a data element.

pixelsPerDataElement

int pixelsPerDataElement

The number of pixels that fit in a data element. Also used as the number of bits per pixel.

dataElementSize

int dataElementSize

The size of a data element in bits.

dataBitOffset

int dataBitOffset

The bit offset into the data array where the first pixel begins.

scanlineStride

int scanlineStride

ScanlineStride of the data buffer described in data array elements.

Constructor Detail

MultiPixelPackedSampleModel

public MultiPixelPackedSampleModel(int dataType,
                                   int w,
                                   int h,
                                   int numberOfBits)

Constructs a MultiPixelPackedSampleModel with the specified data type, width, height and number of bits per pixel.

Parameters:

dataType - the data type for storing samples

w - the width, in pixels, of the region of image data described

h - the height, in pixels, of the region of image data described

numberOfBits - the number of bits per pixel

Throws:

IllegalArgumentException - if dataType is not either DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, or DataBuffer.TYPE_INT

MultiPixelPackedSampleModel

public MultiPixelPackedSampleModel(int dataType,
                                   int w,
                                   int h,
                                   int numberOfBits,
                                   int scanlineStride,
                                   int dataBitOffset)

Constructs a MultiPixelPackedSampleModel with specified data type, width, height, number of bits per pixel, scanline stride and data bit offset.

Parameters:

dataType - the data type for storing samples

w - the width, in pixels, of the region of image data described

h - the height, in pixels, of the region of image data described

numberOfBits - the number of bits per pixel

scanlineStride - the line stride of the image data

dataBitOffset - the data bit offset for the region of image data described

Throws:

RasterFormatException - if the number of bits per pixel is not a power of 2 or if a power of 2 number of pixels do not fit in one data element.

IllegalArgumentException - if w or h is not greater than 0

IllegalArgumentException - if dataType is not either DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, or DataBuffer.TYPE_INT

Method Detail

createCompatibleSampleModel

public SampleModel createCompatibleSampleModel(int w,
                                               int h)

Creates a new MultiPixelPackedSampleModel with the specified width and height. The new MultiPixelPackedSampleModel has the same storage data type and number of bits per pixel as this MultiPixelPackedSampleModel.

Specified by:

createCompatibleSampleModel in class SampleModel

Parameters:

w - the specified width

h - the specified height

Returns:

a SampleModel with the specified width and height and with the same storage data type and number of bits per pixel as this MultiPixelPackedSampleModel.

Throws:

IllegalArgumentException - if w or h is not greater than 0

createDataBuffer

public DataBuffer createDataBuffer()

Creates a DataBuffer that corresponds to this MultiPixelPackedSampleModel. The DataBuffer object's data type and size is consistent with this MultiPixelPackedSampleModel. The DataBuffer has a single bank.

Specified by:

createDataBuffer in class SampleModel

Returns:

a DataBuffer with the same data type and size as this MultiPixelPackedSampleModel.

getNumDataElements

public int getNumDataElements()

Returns the number of data elements needed to transfer one pixel via the getDataElements(int, int, java.lang.Object, java.awt.image.DataBuffer) and setDataElements(int, int, java.lang.Object, java.awt.image.DataBuffer) methods. For a MultiPixelPackedSampleModel, this is one.

Specified by:

getNumDataElements in class SampleModel

Returns:

the number of data elements.

See Also:

SampleModel.getDataElements(int, int, Object, DataBuffer), SampleModel.getDataElements(int, int, int, int, Object, DataBuffer), SampleModel.setDataElements(int, int, Object, DataBuffer), SampleModel.setDataElements(int, int, int, int, Object, DataBuffer), SampleModel.getTransferType()

getSampleSize

public int[] getSampleSize()

Returns the number of bits per sample for all bands.

Specified by:

getSampleSize in class SampleModel

Returns:

the number of bits per sample.

getSampleSize

public int getSampleSize(int band)

Returns the number of bits per sample for the specified band.

Specified by:

getSampleSize in class SampleModel

Parameters:

band - the specified band

Returns:

the number of bits per sample for the specified band.

getOffset

public int getOffset(int x,
                     int y)

Returns the offset of pixel (x, y) in data array elements.

Returns:

the offset of the specified pixel.

getBitOffset

public int getBitOffset(int x)

Returns the offset, in bits, into the data element in which it is stored for the xth pixel of a scanline. This offset is the same for all scanlines.

Parameters:

x - the specified pixel

Returns:

the bit offset of the specified pixel.

getScanlineStride

public int getScanlineStride()

Returns the scanline stride.

Returns:

the scanline stride of this MultiPixelPackedSampleModel.

getPixelBitStride

public int getPixelBitStride()

Returns the pixel bit stride in bits. This value is the same as the number of bits per pixel.

Returns:

the pixelBitStride of this MultiPixelPackedSampleModel.

getDataBitOffset

public int getDataBitOffset()

Returns the data bit offset in bits.

Returns:

the dataBitOffset of this MultiPixelPackedSampleModel.

getTransferType

public int getTransferType()

Returns the TransferType used to transfer pixels by way of the getDataElements and setDataElements methods. The TransferType might or might not be the same as the storage DataType. The TransferType is one of DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, or DataBuffer.TYPE_INT.

Overrides:

getTransferType in class SampleModel

Returns:

the transfertype.

See Also:

SampleModel.getDataElements(int, int, Object, DataBuffer), SampleModel.getDataElements(int, int, int, int, Object, DataBuffer), SampleModel.setDataElements(int, int, Object, DataBuffer), SampleModel.setDataElements(int, int, int, int, Object, DataBuffer), SampleModel.getNumDataElements(), DataBuffer

createSubsetSampleModel

public SampleModel createSubsetSampleModel(int[] bands)

Creates a new MultiPixelPackedSampleModel with a subset of the bands of this MultiPixelPackedSampleModel. Since a MultiPixelPackedSampleModel only has one band, the bands argument must have a length of one and indicate the zeroth band.

Specified by:

createSubsetSampleModel in class SampleModel

Parameters:

bands - the specified bands

Returns:

a new SampleModel with a subset of bands of this MultiPixelPackedSampleModel.

Throws:

RasterFormatException - if the number of bands requested is not one.

IllegalArgumentException - if w or h is not greater than 0

getSample

public int getSample(int x,
                     int y,
                     int b,
                     DataBuffer data)

Returns as int the sample in a specified band for the pixel located at (x, y). An ArrayIndexOutOfBoundsException is thrown if the coordinates are not in bounds.

Specified by:

getSample in class SampleModel

Parameters:

b - the band to return, which is assumed to be 0

data - the DataBuffer containing the image data

x - The X coordinate of the pixel location.

y - The Y coordinate of the pixel location.

Returns:

the specified band containing the sample of the specified pixel.

Throws:

ArrayIndexOutOfBoundException - if the specified coordinates are not in bounds.

See Also:

setSample(int, int, int, int, DataBuffer)

setSample

public void setSample(int x,
                      int y,
                      int b,
                      int s,
                      DataBuffer data)

Sets a sample in the specified band for the pixel located at (x, y) in the DataBuffer using an int for input. An ArrayIndexOutOfBoundsException is thrown if the coordinates are not in bounds.

Specified by:

setSample in class SampleModel

Parameters:

b - the band to return, which is assumed to be 0

s - the input sample as an int

data - the DataBuffer where image data is stored

x - The X coordinate of the pixel location.

y - The Y coordinate of the pixel location.

Throws:

ArrayIndexOutOfBoundsException - if the coordinates are not in bounds.

See Also:

getSample(int, int, int, DataBuffer)

getDataElements

public Object getDataElements(int x,
                              int y,
                              Object obj,
                              DataBuffer data)

Returns data for a single pixel in a primitive array of type TransferType. For a MultiPixelPackedSampleModel, the array has one element, and the type is the smallest of DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, or DataBuffer.TYPE_INT that can hold a single pixel. Generally, obj should be passed in as null, so that the Object is created automatically and is the correct primitive data type.

The following code illustrates transferring data for one pixel from DataBuffer db1, whose storage layout is described by MultiPixelPackedSampleModel mppsm1, to DataBuffer db2, whose storage layout is described by MultiPixelPackedSampleModel mppsm2. The transfer is generally more efficient than using getPixel or setPixel.

 	     MultiPixelPackedSampleModel mppsm1, mppsm2;
	     DataBufferInt db1, db2;
 	     mppsm2.setDataElements(x, y, mppsm1.getDataElements(x, y, null,
                              db1), db2);
 

Using getDataElements or setDataElements to transfer between two DataBuffer/SampleModel pairs is legitimate if the SampleModels have the same number of bands, corresponding bands have the same number of bits per sample, and the TransferTypes are the same.

If obj is not null, it should be a primitive array of type TransferType. Otherwise, a ClassCastException is thrown. An ArrayIndexOutOfBoundsException is thrown if the coordinates are not in bounds, or if obj is not null and is not large enough to hold the pixel data.

Specified by:

getDataElements in class SampleModel

Parameters:

obj - a primitive array in which to return the pixel data or null.

data - the DataBuffer containing the image data.

x - The X coordinate of the pixel location.

y - The Y coordinate of the pixel location.

Returns:

an Object containing data for the specified pixel.

Throws:

ClassCastException - if obj is not a primitive array of type TransferType or is not null

ArrayIndexOutOfBoundsException - if the coordinates are not in bounds, or if obj is not null or not large enough to hold the pixel data

See Also:

setDataElements(int, int, Object, DataBuffer)

getPixel

public int[] getPixel(int x,
                      int y,
                      int[] iArray,
                      DataBuffer data)

Returns the specified single band pixel in the first element of an int array. ArrayIndexOutOfBoundsException is thrown if the coordinates are not in bounds.

Overrides:

getPixel in class SampleModel

Parameters:

iArray - the array containing the pixel to be returned or null

data - the DataBuffer where image data is stored

Returns:

an array containing the specified pixel.

Throws:

ArrayIndexOutOfBoundsException - if the coordinates are not in bounds

See Also:

setPixel(int, int, int[], DataBuffer)

setDataElements

public void setDataElements(int x,
                            int y,
                            Object obj,
                            DataBuffer data)

Sets the data for a single pixel in the specified DataBuffer from a primitive array of type TransferType. For a MultiPixelPackedSampleModel, only the first element of the array holds valid data, and the type must be the smallest of DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, or DataBuffer.TYPE_INT that can hold a single pixel.

The following code illustrates transferring data for one pixel from DataBuffer db1, whose storage layout is described by MultiPixelPackedSampleModel mppsm1, to DataBuffer db2, whose storage layout is described by MultiPixelPackedSampleModel mppsm2. The transfer is generally more efficient than using getPixel or setPixel.

 	     MultiPixelPackedSampleModel mppsm1, mppsm2;
	     DataBufferInt db1, db2;
 	     mppsm2.setDataElements(x, y, mppsm1.getDataElements(x, y, null,
                              db1), db2);
 

Using getDataElements or setDataElements to transfer between two DataBuffer/SampleModel pairs is legitimate if the SampleModel objects have the same number of bands, corresponding bands have the same number of bits per sample, and the TransferTypes are the same.

obj must be a primitive array of type TransferType. Otherwise, a ClassCastException is thrown. An ArrayIndexOutOfBoundsException is thrown if the coordinates are not in bounds, or if obj is not large enough to hold the pixel data.

Specified by:

setDataElements in class SampleModel

Parameters:

obj - a primitive array containing pixel data

data - the DataBuffer containing the image data

x - The X coordinate of the pixel location.

y - The Y coordinate of the pixel location.

See Also:

getDataElements(int, int, Object, DataBuffer)

setPixel

public void setPixel(int x,
                     int y,
                     int[] iArray,
                     DataBuffer data)

Sets a pixel in the DataBuffer using an int array for input. ArrayIndexOutOfBoundsException is thrown if the coordinates are not in bounds.

Overrides:

setPixel in class SampleModel

Parameters:

iArray - the input pixel in an int array

data - the DataBuffer containing the image data

x - The X coordinate of the pixel location.

y - The Y coordinate of the pixel location.

See Also:

getPixel(int, int, int[], DataBuffer)

equals

public boolean equals(Object o)

Description copied from class: Object

Indicates whether some other object is "equal to" this one.

The equals method implements an equivalence relation on non-null object references:

• It is reflexive: for any non-null reference value x, x.equals(x) should return true.
• It is symmetric: for any non-null reference values x and y, x.equals(y) should return true if and only if y.equals(x) returns true.
• It is transitive: for any non-null reference values x, y, and z, if x.equals(y) returns true and y.equals(z) returns true, then x.equals(z) should return true.
• It is consistent: for any non-null reference values x and y, multiple invocations of x.equals(y) consistently return true or consistently return false, provided no information used in equals comparisons on the objects is modified.
• For any non-null reference value x, x.equals(null) should return false.

The equals method for class Object implements the most discriminating possible equivalence relation on objects; that is, for any non-null reference values x and y, this method returns true if and only if x and y refer to the same object (x == y has the value true).

Note that it is generally necessary to override the hashCode method whenever this method is overridden, so as to maintain the general contract for the hashCode method, which states that equal objects must have equal hash codes.

Overrides:

equals in class Object

Parameters:

o - the reference object with which to compare.

Returns:

true if this object is the same as the obj argument; false otherwise.

See Also:

Object.hashCode(), Hashtable

hashCode

public int hashCode()

Description copied from class: Object

Returns a hash code value for the object. This method is supported for the benefit of hashtables such as those provided by java.util.Hashtable.

The general contract of hashCode is:

• Whenever it is invoked on the same object more than once during an execution of a Java application, the hashCode method must consistently return the same integer, provided no information used in equals comparisons on the object is modified. This integer need not remain consistent from one execution of an application to another execution of the same application.
• If two objects are equal according to the equals(Object) method, then calling the hashCode method on each of the two objects must produce the same integer result.
• It is not required that if two objects are unequal according to the Object.equals(java.lang.Object) method, then calling the hashCode method on each of the two objects must produce distinct integer results. However, the programmer should be aware that producing distinct integer results for unequal objects may improve the performance of hashtables.

As much as is reasonably practical, the hashCode method defined by class Object does return distinct integers for distinct objects. (This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the Java^TM programming language.)

Overrides:

hashCode in class Object

Returns:

a hash code value for this object.

See Also:

Object.equals(java.lang.Object), Hashtable