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);
 

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

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

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.

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.

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.

Overrides:

createCompatibleSampleModel in class SampleModel

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.

Returns:

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

Overrides:

createDataBuffer in class SampleModel

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.

Returns:

the number of data elements.

Overrides:

getNumDataElements in class SampleModel

getSampleSize

public int[] getSampleSize()

Returns the number of bits per sample for all bands.

Returns:

the number of bits per sample.

Overrides:

getSampleSize in class SampleModel

getSampleSize

public int getSampleSize(int band)

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

Parameters:

band - the specified band

Returns:

the number of bits per sample for the specified band.

Overrides:

getSampleSize in class SampleModel

getOffset

public int getOffset(int x,
                     int y)

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

Parameters:

x, y - the specified pixel

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.

Returns:

the transfertype.

Overrides:

getTransferType in class SampleModel

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.

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.

Overrides:

createSubsetSampleModel in class SampleModel

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.

Parameters:

x, y - the coordinates of the specified pixel

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

data - the DataBuffer containing the image data

Returns:

the specified band containing the sample of the specified pixel.

Throws:

ArrayIndexOutOfBoundException - if the specified coordinates are not in bounds.

Overrides:

getSample in class SampleModel

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.

Parameters:

x, y - the coordinates of the specified pixel

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

Throws:

ArrayIndexOutOfBoundsException - if the coordinates are not in bounds.

Overrides:

setSample in class SampleModel

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.

Parameters:

x, y - coordinates of the pixel location.

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

data - the DataBuffer containing the image data.

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

Overrides:

getDataElements in class SampleModel

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.

Parameters:

x, y - the coordinates of the pixel location

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

Overrides:

getPixel in class SampleModel

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.

Parameters:

x, y - the coordinates of the pixel location

obj - a primitive array containing pixel data

data - the DataBuffer containing the image data

Overrides:

setDataElements in class SampleModel

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.

Parameters:

x, y - the coordinates of the pixel location

iArray - the input pixel in an int array

data - the DataBuffer containing the image data

Overrides:

setPixel in class SampleModel