Java(TM) 2 Platform, Standard Edition, v1.2.2 API Specification: Class Raster - JDK 5 Documentation v1.2.2, Java 2 SDK 英文文档

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java.awt.image
Class Raster

java.lang.Object
  |
  +--java.awt.image.Raster

Direct Known Subclasses:: WritableRaster

public class Raster
extends Object

A class representing a rectangular array of pixels. A Raster encapsulates a DataBuffer that stores the sample values and a SampleModel that describes how to locate a given sample value in a DataBuffer.

A Raster defines values for pixels occupying a particular rectangular area of the plane, not necessarily including (0, 0). The rectangle, known as the Raster's bounding rectangle and available by means of the getBounds method, is defined by minX, minY, width, and height values. The minX and minY values define the coordinate of the upper left corner of the Raster. References to pixels outside of the bounding rectangle may result in an exception being thrown, or may result in references to unintended elements of the Raster's associated DataBuffer. It is the user's responsibility to avoid accessing such pixels.

A SampleModel describes how samples of a Raster are stored in the primitive array elements of a DataBuffer. Samples may be stored one per data element, as in a PixelInterleavedSampleModel or BandedSampleModel, or packed several to an element, as in a SinglePixelPackedSampleModel or MultiPixelPackedSampleModel. The SampleModel is also controls whether samples are sign extended, allowing unsigned data to be stored in signed Java data types such as byte, short, and int.

Although a Raster may live anywhere in the plane, a SampleModel makes use of a simple coordinate system that starts at (0, 0). A Raster therefore contains a translation factor that allows pixel locations to be mapped between the Raster's coordinate system and that of the SampleModel. The translation from the SampleModel coordinate system to that of the Raster may be obtained by the getSampleModelTranslateX and getSampleModelTranslateY methods.

A Raster may share a DataBuffer with another Raster either by explicit construction or by the use of the createChild and createTranslatedChild methods. Rasters created by these methods can return a reference to the Raster they were created from by means of the getParent method. For a Raster that was not constructed by means of a call to createTranslatedChild or createChild, getParent will return null.

The createTranslatedChild method returns a new Raster that shares all of the data of the current Raster, but occupies a bounding rectangle of the same width and height but with a different starting point. For example, if the parent Raster occupied the region (10, 10) to (100, 100), and the translated Raster was defined to start at (50, 50), then pixel (20, 20) of the parent and pixel (60, 60) of the child occupy the same location in the DataBuffer shared by the two Rasters. In the first case, (-10, -10) should be added to a pixel coordinate to obtain the corresponding SampleModel coordinate, and in the second case (-50, -50) should be added.

The translation between a parent and child Raster may be determined by subtracting the child's sampleModelTranslateX and sampleModelTranslateY values from those of the parent.

The createChild method may be used to create a new Raster occupying only a subset of its parent's bounding rectangle (with the same or a translated coordinate system) or with a subset of the bands of its parent.

All constructors are protected. The correct way to create a Raster is to use one of the static create methods defined in this class. These methods create instances of Raster that use the standard Interleaved, Banded, and Packed SampleModels and that may be processed more efficiently than a Raster created by combining an externally generated SampleModel and DataBuffer.

See Also:: DataBuffer, SampleModel, PixelInterleavedSampleModel, BandedSampleModel, SinglePixelPackedSampleModel, MultiPixelPackedSampleModel

Field Summary

protected DataBuffer dataBuffer
          The DataBuffer that stores the image data.

protected int height
          The height of this Raster.

protected int minX
          The X coordinate of the upper-left pixel of this Raster.

protected int minY
          The Y coordinate of the upper-left pixel of this Raster.

protected int numBands
          The number of bands in the Raster.

protected int numDataElements
          The number of DataBuffer data elements per pixel.

protected Raster parent
          The parent of this Raster, or null.

protected SampleModel sampleModel
          The SampleModel that describes how pixels from this Raster are stored in the DataBuffer.

protected int sampleModelTranslateX
          The X translation from the coordinate space of the Raster's SampleModel to that of the Raster.

protected int sampleModelTranslateY
          The Y translation from the coordinate space of the Raster's SampleModel to that of the Raster.

protected int width
          The width of this Raster.

Constructor Summary

protected Raster(SampleModel sampleModel, DataBuffer dataBuffer, Point origin)
          Constructs a Raster with the given SampleModel and DataBuffer.

protected Raster(SampleModel sampleModel, DataBuffer dataBuffer, Rectangle aRegion, Point sampleModelTranslate, Raster parent)
          Constructs a Raster with the given SampleModel, DataBuffer, and parent.

protected Raster(SampleModel sampleModel, Point origin)
          Constructs a Raster with the given SampleModel.

Method Summary

static WritableRaster createBandedRaster(DataBuffer dataBuffer, int w, int h, int scanlineStride, int[] bankIndices, int[] bandOffsets, Point location)
          Creates a Raster based on a BandedSampleModel with the specified DataBuffer, width, height, scanline stride, bank indices, and band offsets.

static WritableRaster createBandedRaster(int dataType, int w, int h, int scanlineStride, int[] bankIndices, int[] bandOffsets, Point location)
          Creates a Raster based on a BandedSampleModel with the specified data type, width, height, scanline stride, bank indices and band offsets.

static WritableRaster createBandedRaster(int dataType, int w, int h, int bands, Point location)
          Creates a Raster based on a BandedSampleModel with the specified data type, width, height, and number of bands.

Raster createChild(int parentX, int parentY, int width, int height, int childMinX, int childMinY, int[] bandList)
          Returns a new Raster which shares all or part of this Raster's DataBuffer.

WritableRaster createCompatibleWritableRaster()
          Create a compatible WritableRaster the same size as this Raster with the same SampleModel and a new initialized DataBuffer.

WritableRaster createCompatibleWritableRaster(int w, int h)
          Create a compatible WritableRaster with the specified size, a new SampleModel, and a new initialized DataBuffer.

WritableRaster createCompatibleWritableRaster(int x, int y, int w, int h)
          Create a compatible WritableRaster with the specified location (minX, minY) and size (width, height), a new SampleModel, and a new initialized DataBuffer.

WritableRaster createCompatibleWritableRaster(Rectangle rect)
          Create a compatible WritableRaster with location (minX, minY) and size (width, height) specified by rect, a new SampleModel, and a new initialized DataBuffer.

static WritableRaster createInterleavedRaster(DataBuffer dataBuffer, int w, int h, int scanlineStride, int pixelStride, int[] bandOffsets, Point location)
          Creates a Raster based on a PixelInterleavedSampleModel with the specified DataBuffer, width, height, scanline stride, pixel stride, and band offsets.

static WritableRaster createInterleavedRaster(int dataType, int w, int h, int scanlineStride, int pixelStride, int[] bandOffsets, Point location)
          Creates a Raster based on a PixelInterleavedSampleModel with the specified data type, width, height, scanline stride, pixel stride, and band offsets.

static WritableRaster createInterleavedRaster(int dataType, int w, int h, int bands, Point location)
          Creates a Raster based on a PixelInterleavedSampleModel with the specified data type, width, height, and number of bands.

static WritableRaster createPackedRaster(DataBuffer dataBuffer, int w, int h, int scanlineStride, int[] bandMasks, Point location)
          Creates a Raster based on a SinglePixelPackedSampleModel with the specified DataBuffer, width, height, scanline stride, and band masks.

static WritableRaster createPackedRaster(DataBuffer dataBuffer, int w, int h, int bitsPerPixel, Point location)
          Creates a Raster based on a MultiPixelPackedSampleModel with the specified DataBuffer, width, height, and bits per pixel.

static WritableRaster createPackedRaster(int dataType, int w, int h, int[] bandMasks, Point location)
          Creates a Raster based on a SinglePixelPackedSampleModel with the specified data type, width, height, and band masks.

static WritableRaster createPackedRaster(int dataType, int w, int h, int bands, int bitsPerBand, Point location)
          Creates a Raster based on a packed SampleModel with the specified data type, width, height, number of bands, and bits per band.

static Raster createRaster(SampleModel sm, DataBuffer db, Point location)
          Creates a Raster with the specified SampleModel and DataBuffer.

Raster createTranslatedChild(int childMinX, int childMinY)
          Create a Raster with the same size, SampleModel and DataBuffer as this one, but with a different location.

static WritableRaster createWritableRaster(SampleModel sm, DataBuffer db, Point location)
          Creates a WritableRaster with the specified SampleModel and DataBuffer.

static WritableRaster createWritableRaster(SampleModel sm, Point location)
          Creates a WritableRaster with the specified SampleModel.

Rectangle getBounds()
          Returns the bounding Rectangle of this Raster.

DataBuffer getDataBuffer()
          Returns the DataBuffer associated with this Raster.

Object getDataElements(int x, int y, int w, int h, Object outData)
          Returns the pixel data for the specified rectangle of pixels in a primitive array of type TransferType.

Object getDataElements(int x, int y, Object outData)
          Returns data for a single pixel in a primitive array of type TransferType.

int getHeight()
          Returns the height in pixels of the Raster.

int getMinX()
          Returns the minimum valid X coordinate of the Raster.

int getMinY()
          Returns the minimum valid Y coordinate of the Raster.

int getNumBands()
          Returns the number of bands (samples per pixel) in this Raster.

int getNumDataElements()
          Returns the number of data elements needed to transfer one pixel via the getDataElements and setDataElements methods.

Raster getParent()
          Returns the parent Raster (if any) of this Raster, or else null.

double[] getPixel(int x, int y, double[] dArray)
          Returns the samples in an array of double for the specified pixel.

float[] getPixel(int x, int y, float[] fArray)
          Returns the samples in an array of float for the specified pixel.

int[] getPixel(int x, int y, int[] iArray)
          Returns the samples in an array of int for the specified pixel.

double[] getPixels(int x, int y, int w, int h, double[] dArray)
          Returns a double array containing all samples for a rectangle of pixels, one sample per array element.

float[] getPixels(int x, int y, int w, int h, float[] fArray)
          Returns a float array containing all samples for a rectangle of pixels, one sample per array element.

int[] getPixels(int x, int y, int w, int h, int[] iArray)
          Returns an int array containing all samples for a rectangle of pixels, one sample per array element.

int getSample(int x, int y, int b)
          Returns the sample in a specified band for the pixel located at (x,y) as an int.

double getSampleDouble(int x, int y, int b)
          Returns the sample in a specified band for a pixel located at (x,y) as a double.

float getSampleFloat(int x, int y, int b)
          Returns the sample in a specified band for the pixel located at (x,y) as a float.

SampleModel getSampleModel()
          Returns the SampleModel that describes the layout of the image data.

int getSampleModelTranslateX()
          Returns the X translation from the coordinate system of the SampleModel to that of the Raster.

int getSampleModelTranslateY()
          Returns the Y translation from the coordinate system of the SampleModel to that of the Raster.

double[] getSamples(int x, int y, int w, int h, int b, double[] dArray)
          Returns the samples for a specified band for a specified rectangle of pixels in a double array, one sample per array element.

float[] getSamples(int x, int y, int w, int h, int b, float[] fArray)
          Returns the samples for a specified band for the specified rectangle of pixels in a float array, one sample per array element.

int[] getSamples(int x, int y, int w, int h, int b, int[] iArray)
          Returns the samples for a specified band for the specified rectangle of pixels in an int array, one sample per array element.

int getTransferType()
          Returns the TransferType used to transfer pixels via the getDataElements and setDataElements methods.

int getWidth()
          Returns the width in pixels of the Raster.

Methods inherited from class java.lang.Object

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

Field Detail

sampleModel

protected SampleModel sampleModel

The SampleModel that describes how pixels from this Raster are stored in the DataBuffer.

dataBuffer

protected DataBuffer dataBuffer

The DataBuffer that stores the image data.

minX

protected int minX

The X coordinate of the upper-left pixel of this Raster.

minY

protected int minY

The Y coordinate of the upper-left pixel of this Raster.

width

protected int width

The width of this Raster.

height

protected int height

The height of this Raster.

sampleModelTranslateX

protected int sampleModelTranslateX

The X translation from the coordinate space of the Raster's SampleModel to that of the Raster.

sampleModelTranslateY

protected int sampleModelTranslateY

The Y translation from the coordinate space of the Raster's SampleModel to that of the Raster.

numBands

protected int numBands

The number of bands in the Raster.

numDataElements

protected int numDataElements

The number of DataBuffer data elements per pixel.

parent

protected Raster parent

The parent of this Raster, or null.

Constructor Detail

Raster

protected Raster(SampleModel sampleModel,
                 Point origin)

Constructs a Raster with the given SampleModel. The Raster's upper left corner is origin and it is the same size as the SampleModel. A DataBuffer large enough to describe the Raster is automatically created.

Parameters:: sampleModel - The SampleModel that specifies the layout.; origin - The Point that specified the origin.

Raster

protected Raster(SampleModel sampleModel,
                 DataBuffer dataBuffer,
                 Point origin)

Constructs a Raster with the given SampleModel and DataBuffer. The Raster's upper left corner is origin and it is the same size as the SampleModel. The DataBuffer is not initialized and must be compatible with SampleModel.

Parameters:: sampleModel - The SampleModel that specifies the layout.; dataBuffer - The DataBuffer that contains the image data.; origin - The Point that specifies the origin.

Raster

protected Raster(SampleModel sampleModel,
                 DataBuffer dataBuffer,
                 Rectangle aRegion,
                 Point sampleModelTranslate,
                 Raster parent)

Constructs a Raster with the given SampleModel, DataBuffer, and parent. aRegion specifies the bounding rectangle of the new Raster. When translated into the base Raster's coordinate system, aRegion must be contained by the base Raster. (The base Raster is the Raster's ancestor which has no parent.) sampleModelTranslate specifies the sampleModelTranslateX and sampleModelTranslateY values of the new Raster. Note that this constructor should generally be called by other constructors or create methods, it should not be used directly.

Parameters:: sampleModel - The SampleModel that specifies the layout.; dataBuffer - The DataBuffer that contains the image data.; aRegion - The Rectangle that specifies the image area.; sampleModelTranslate - The Point that specifies the translation from SampleModel to Raster coordinates.; parent - The parent (if any) of this raster.

Method Detail

createInterleavedRaster

public static WritableRaster createInterleavedRaster(int dataType,
                                                     int w,
                                                     int h,
                                                     int bands,
                                                     Point location)

Creates a Raster based on a PixelInterleavedSampleModel with the specified data type, width, height, and number of bands.

The upper left corner of the Raster is given by the location argument. If location is null, (0, 0) will be used. The dataType parameter should be one of the enumerated values defined in the DataBuffer class.