java.awt.image

Class DirectColorModel

Contents
  • All Implemented Interfaces:
    Transparency

    public class DirectColorModel
extends PackedColorModel
    The DirectColorModel class is a ColorModel class that works with pixel values that represent RGB color and alpha information as separate samples and that pack all samples for a single pixel into a single int, short, or byte quantity. This class can be used only with ColorSpaces of type ColorSpace.TYPE_RGB. In addition, for each component of the ColorSpace, the minimum normalized component value obtained via the getMinValue() method of ColorSpace must be 0.0, and the maximum value obtained via the getMaxValue() method must be 1.0 (these min/max values are typical for RGB spaces). There must be three color samples in the pixel values and there can be a single alpha sample. For those methods that use a primitive array pixel representation of type transferType, the array length is always one. The transfer types supported are DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, and DataBuffer.TYPE_INT. Color and alpha samples are stored in the single element of the array in bits indicated by bit masks. Each bit mask must be contiguous and masks must not overlap. The same masks apply to the single int pixel representation used by other methods. The correspondence of masks and color/alpha samples is as follows:
    • Masks are identified by indices running from 0 through 2 if no alpha is present, or 3 if an alpha is present.
    • The first three indices refer to color samples; index 0 corresponds to red, index 1 to green, and index 2 to blue.
    • Index 3 corresponds to the alpha sample, if present.

    The translation from pixel values to color/alpha components for display or processing purposes is a one-to-one correspondence of samples to components. A DirectColorModel is typically used with image data which uses masks to define packed samples. For example, a DirectColorModel can be used in conjunction with a SinglePixelPackedSampleModel to construct a BufferedImage. Normally the masks used by the SampleModel and the ColorModel would be the same. However, if they are different, the color interpretation of pixel data will be done according to the masks of the ColorModel.

    A single int pixel representation is valid for all objects of this class, since it is always possible to represent pixel values used with this class in a single int. Therefore, methods which use this representation will not throw an IllegalArgumentException due to an invalid pixel value.

    This color model is similar to an X11 TrueColor visual. The default RGB ColorModel specified by the getRGBdefault method is a DirectColorModel with the following parameters: 

     Number of bits:        32
 Red mask:              0x00ff0000
 Green mask:            0x0000ff00
 Blue mask:             0x000000ff
 Alpha mask:            0xff000000
 Color space:           sRGB
 isAlphaPremultiplied:  False
 Transparency:          Transparency.TRANSLUCENT
 transferType:          DataBuffer.TYPE_INT

    Many of the methods in this class are final. This is because the underlying native graphics code makes assumptions about the layout and operation of this class and those assumptions are reflected in the implementations of the methods here that are marked final. You can subclass this class for other reasons, but you cannot override or modify the behavior of those methods.

    See Also:
    ColorModel, ColorSpace, SinglePixelPackedSampleModel, BufferedImage, ColorModel.getRGBdefault()

    • Constructor Detail

      • DirectColorModel

        public DirectColorModel(int bits,
                int rmask,
                int gmask,
                int bmask)
        Constructs a DirectColorModel from the specified masks that indicate which bits in an int pixel representation contain the red, green and blue color samples. As pixel values do not contain alpha information, all pixels are treated as opaque, which means that alpha = 1.0. All of the bits in each mask must be contiguous and fit in the specified number of least significant bits of an int pixel representation. The ColorSpace is the default sRGB space. The transparency value is Transparency.OPAQUE. The transfer type is the smallest of DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, or DataBuffer.TYPE_INT that can hold a single pixel.
        Parameters:
        bits - the number of bits in the pixel values; for example, the sum of the number of bits in the masks.
        rmask - specifies a mask indicating which bits in an integer pixel contain the red component
        gmask - specifies a mask indicating which bits in an integer pixel contain the green component
        bmask - specifies a mask indicating which bits in an integer pixel contain the blue component

      • DirectColorModel

        public DirectColorModel(int bits,
                int rmask,
                int gmask,
                int bmask,
                int amask)
        Constructs a DirectColorModel from the specified masks that indicate which bits in an int pixel representation contain the red, green and blue color samples and the alpha sample, if present. If amask is 0, pixel values do not contain alpha information and all pixels are treated as opaque, which means that alpha = 1.0. All of the bits in each mask must be contiguous and fit in the specified number of least significant bits of an int pixel representation. Alpha, if present, is not premultiplied. The ColorSpace is the default sRGB space. The transparency value is Transparency.OPAQUE if no alpha is present, or Transparency.TRANSLUCENT otherwise. The transfer type is the smallest of DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, or DataBuffer.TYPE_INT that can hold a single pixel.
        Parameters:
        bits - the number of bits in the pixel values; for example, the sum of the number of bits in the masks.
        rmask - specifies a mask indicating which bits in an integer pixel contain the red component
        gmask - specifies a mask indicating which bits in an integer pixel contain the green component
        bmask - specifies a mask indicating which bits in an integer pixel contain the blue component
        amask - specifies a mask indicating which bits in an integer pixel contain the alpha component

      • DirectColorModel

        public DirectColorModel(ColorSpace space,
                int bits,
                int rmask,
                int gmask,
                int bmask,
                int amask,
                boolean isAlphaPremultiplied,
                int transferType)
        Constructs a DirectColorModel from the specified parameters. Color components are in the specified ColorSpace, which must be of type ColorSpace.TYPE_RGB and have minimum normalized component values which are all 0.0 and maximum values which are all 1.0. The masks specify which bits in an int pixel representation contain the red, green and blue color samples and the alpha sample, if present. If amask is 0, pixel values do not contain alpha information and all pixels are treated as opaque, which means that alpha = 1.0. All of the bits in each mask must be contiguous and fit in the specified number of least significant bits of an int pixel representation. If there is alpha, the boolean isAlphaPremultiplied specifies how to interpret color and alpha samples in pixel values. If the boolean is true, color samples are assumed to have been multiplied by the alpha sample. The transparency value is Transparency.OPAQUE, if no alpha is present, or Transparency.TRANSLUCENT otherwise. The transfer type is the type of primitive array used to represent pixel values and must be one of DataBuffer.TYPE_BYTE, DataBuffer.TYPE_USHORT, or DataBuffer.TYPE_INT.
        Parameters:
        space - the specified ColorSpace
        bits - the number of bits in the pixel values; for example, the sum of the number of bits in the masks.
        rmask - specifies a mask indicating which bits in an integer pixel contain the red component
        gmask - specifies a mask indicating which bits in an integer pixel contain the green component
        bmask - specifies a mask indicating which bits in an integer pixel contain the blue component
        amask - specifies a mask indicating which bits in an integer pixel contain the alpha component
        isAlphaPremultiplied - true if color samples are premultiplied by the alpha sample; false otherwise
        transferType - the type of array used to represent pixel values
        Throws:
        IllegalArgumentException - if space is not a TYPE_RGB space or if the min/max normalized component values are not 0.0/1.0.

    • Method Detail

      • getRedMask

        public final int getRedMask()
        Returns the mask indicating which bits in an int pixel representation contain the red color component.
        Returns:
        the mask, which indicates which bits of the int pixel representation contain the red color sample.

      • getGreenMask

        public final int getGreenMask()
        Returns the mask indicating which bits in an int pixel representation contain the green color component.
        Returns:
        the mask, which indicates which bits of the int pixel representation contain the green color sample.

      • getBlueMask

        public final int getBlueMask()
        Returns the mask indicating which bits in an int pixel representation contain the blue color component.
        Returns:
        the mask, which indicates which bits of the int pixel representation contain the blue color sample.

      • getAlphaMask

        public final int getAlphaMask()
        Returns the mask indicating which bits in an int pixel representation contain the alpha component.
        Returns:
        the mask, which indicates which bits of the int pixel representation contain the alpha sample.

      • getRed

        public final int getRed(int pixel)
        Returns the red color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB. A color conversion is done if necessary. The pixel value is specified as an int. The returned value is a non pre-multiplied value. Thus, if the alpha is premultiplied, this method divides it out before returning the value. If the alpha value is 0, for example, the red value is 0.
        Specified by:
        getRed in class ColorModel
        Parameters:
        pixel - the specified pixel
        Returns:
        the red color component for the specified pixel, from 0 to 255 in the sRGB ColorSpace.

      • getGreen

        public final int getGreen(int pixel)
        Returns the green color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB. A color conversion is done if necessary. The pixel value is specified as an int. The returned value is a non pre-multiplied value. Thus, if the alpha is premultiplied, this method divides it out before returning the value. If the alpha value is 0, for example, the green value is 0.
        Specified by:
        getGreen in class ColorModel
        Parameters:
        pixel - the specified pixel
        Returns:
        the green color component for the specified pixel, from 0 to 255 in the sRGB ColorSpace.

      • getBlue

        public final int getBlue(int pixel)
        Returns the blue color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB. A color conversion is done if necessary. The pixel value is specified as an int. The returned value is a non pre-multiplied value. Thus, if the alpha is premultiplied, this method divides it out before returning the value. If the alpha value is 0, for example, the blue value is 0.
        Specified by:
        getBlue in class ColorModel
        Parameters:
        pixel - the specified pixel
        Returns:
        the blue color component for the specified pixel, from 0 to 255 in the sRGB ColorSpace.

      • getAlpha

        public final int getAlpha(int pixel)
        Returns the alpha component for the specified pixel, scaled from 0 to 255. The pixel value is specified as an int.
        Specified by:
        getAlpha in class ColorModel
        Parameters:
        pixel - the specified pixel
        Returns:
        the value of the alpha component of pixel from 0 to 255.

      • getRGB

        public final int getRGB(int pixel)
        Returns the color/alpha components of the pixel in the default RGB color model format. A color conversion is done if necessary. The pixel value is specified as an int. The returned value is in a non pre-multiplied format. Thus, if the alpha is premultiplied, this method divides it out of the color components. If the alpha value is 0, for example, the color values are each 0.
        Overrides:
        getRGB in class ColorModel
        Parameters:
        pixel - the specified pixel
        Returns:
        the RGB value of the color/alpha components of the specified pixel.
        See Also:
        ColorModel.getRGBdefault()

      • getRed

        public int getRed(Object inData)
        Returns the red color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB. A color conversion is done if necessary. The pixel value is specified by an array of data elements of type transferType passed in as an object reference. The returned value is a non pre-multiplied value. Thus, if the alpha is premultiplied, this method divides it out before returning the value. If the alpha value is 0, for example, the red value is 0. If inData is not a primitive array of type transferType, a ClassCastException is thrown. An ArrayIndexOutOfBoundsException is thrown if inData is not large enough to hold a pixel value for this ColorModel. Since DirectColorModel can be subclassed, subclasses inherit the implementation of this method and if they don't override it then they throw an exception if they use an unsupported transferType. An UnsupportedOperationException is thrown if this transferType is not supported by this ColorModel.
        Overrides:
        getRed in class ColorModel
        Parameters:
        inData - the array containing the pixel value
        Returns:
        the value of the red component of the specified pixel.
        Throws:
        ArrayIndexOutOfBoundsException - if inData is not large enough to hold a pixel value for this color model
        ClassCastException - if inData is not a primitive array of type transferType
        UnsupportedOperationException - if this transferType is not supported by this color model

      • getGreen

        public int getGreen(Object inData)
        Returns the green color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB. A color conversion is done if necessary. The pixel value is specified by an array of data elements of type transferType passed in as an object reference. The returned value is a non pre-multiplied value. Thus, if the alpha is premultiplied, this method divides it out before returning the value. If the alpha value is 0, for example, the green value is 0. If inData is not a primitive array of type transferType, a ClassCastException is thrown. An ArrayIndexOutOfBoundsException is thrown if inData is not large enough to hold a pixel value for this ColorModel. Since DirectColorModel can be subclassed, subclasses inherit the implementation of this method and if they don't override it then they throw an exception if they use an unsupported transferType. An UnsupportedOperationException is thrown if this transferType is not supported by this ColorModel.
        Overrides:
        getGreen in class ColorModel
        Parameters:
        inData - the array containing the pixel value
        Returns:
        the value of the green component of the specified pixel.
        Throws:
        ArrayIndexOutOfBoundsException - if inData is not large enough to hold a pixel value for this color model
        ClassCastException - if inData is not a primitive array of type transferType
        UnsupportedOperationException - if this transferType is not supported by this color model

      • getBlue

        public int getBlue(Object inData)
        Returns the blue color component for the specified pixel, scaled from 0 to 255 in the default RGB ColorSpace, sRGB. A color conversion is done if necessary. The pixel value is specified by an array of data elements of type transferType passed in as an object reference. The returned value is a non pre-multiplied value. Thus, if the alpha is premultiplied, this method divides it out before returning the value. If the alpha value is 0, for example, the blue value is 0. If inData is not a primitive array of type transferType, a ClassCastException is thrown. An ArrayIndexOutOfBoundsException is thrown if inData is not large enough to hold a pixel value for this ColorModel. Since DirectColorModel can be subclassed, subclasses inherit the implementation of this method and if they don't override it then they throw an exception if they use an unsupported transferType. An UnsupportedOperationException is thrown if this transferType is not supported by this ColorModel.
        Overrides:
        getBlue in class ColorModel
        Parameters:
        inData - the array containing the pixel value
        Returns:
        the value of the blue component of the specified pixel.
        Throws:
        ArrayIndexOutOfBoundsException - if inData is not large enough to hold a pixel value for this color model
        ClassCastException - if inData is not a primitive array of type transferType
        UnsupportedOperationException - if this transferType is not supported by this color model

      • getAlpha

        public int getAlpha(Object inData)
        Returns the alpha component for the specified pixel, scaled from 0 to 255. The pixel value is specified by an array of data elements of type transferType passed in as an object reference. If inData is not a primitive array of type transferType, a ClassCastException is thrown. An ArrayIndexOutOfBoundsException is thrown if inData is not large enough to hold a pixel value for this ColorModel. Since DirectColorModel can be subclassed, subclasses inherit the implementation of this method and if they don't override it then they throw an exception if they use an unsupported transferType. If this transferType is not supported, an UnsupportedOperationException is thrown.
        Overrides:
        getAlpha in class ColorModel
        Parameters:
        inData - the specified pixel
        Returns:
        the alpha component of the specified pixel, scaled from 0 to 255.
        Throws:
        ClassCastException - if inData is not a primitive array of type transferType
        ArrayIndexOutOfBoundsException - if inData is not large enough to hold a pixel value for this ColorModel
        UnsupportedOperationException - if this tranferType is not supported by this ColorModel

      • getRGB

        public int getRGB(Object inData)
        Returns the color/alpha components for the specified pixel in the default RGB color model format. A color conversion is done if necessary. The pixel value is specified by an array of data elements of type transferType passed in as an object reference. If inData is not a primitive array of type transferType, a ClassCastException is thrown. An ArrayIndexOutOfBoundsException is thrown if inData is not large enough to hold a pixel value for this ColorModel. The returned value is in a non pre-multiplied format. Thus, if the alpha is premultiplied, this method divides it out of the color components. If the alpha value is 0, for example, the color values is 0. Since DirectColorModel can be subclassed, subclasses inherit the implementation of this method and if they don't override it then they throw an exception if they use an unsupported transferType.
        Overrides:
        getRGB in class ColorModel
        Parameters:
        inData - the specified pixel
        Returns:
        the color and alpha components of the specified pixel.
        Throws:
        UnsupportedOperationException - if this transferType is not supported by this ColorModel
        See Also:
        ColorModel.getRGBdefault()

      • getDataElements

        public Object getDataElements(int rgb,
                     Object pixel)
        Returns a data element array representation of a pixel in this ColorModel, given an integer pixel representation in the default RGB color model. This array can then be passed to the setDataElements method of a WritableRaster object. If the pixel variable is null, a new array is allocated. If pixel is not null, it must be a primitive array of type transferType; otherwise, a ClassCastException is thrown. An ArrayIndexOutOfBoundsException is thrown if pixel is not large enough to hold a pixel value for this ColorModel. The pixel array is returned. Since DirectColorModel can be subclassed, subclasses inherit the implementation of this method and if they don't override it then they throw an exception if they use an unsupported transferType.
        Overrides:
        getDataElements in class ColorModel
        Parameters:
        rgb - the integer pixel representation in the default RGB color model
        pixel - the specified pixel
        Returns:
        an array representation of the specified pixel in this ColorModel
        Throws:
        ClassCastException - if pixel is not a primitive array of type transferType
        ArrayIndexOutOfBoundsException - if pixel is not large enough to hold a pixel value for this ColorModel
        UnsupportedOperationException - if this transferType is not supported by this ColorModel
        See Also:
        WritableRaster.setDataElements(int, int, java.lang.Object), SampleModel.setDataElements(int, int, java.lang.Object, java.awt.image.DataBuffer)

      • getComponents

        public final int[] getComponents(int pixel,
                  int[] components,
                  int offset)
        Returns an array of unnormalized color/alpha components given a pixel in this ColorModel. The pixel value is specified as an int. If the components array is null, a new array is allocated. The components array is returned. Color/alpha components are stored in the components array starting at offset, even if the array is allocated by this method. An ArrayIndexOutOfBoundsException is thrown if the components array is not null and is not large enough to hold all the color and alpha components, starting at offset.
        Overrides:
        getComponents in class ColorModel
        Parameters:
        pixel - the specified pixel
        components - the array to receive the color and alpha components of the specified pixel
        offset - the offset into the components array at which to start storing the color and alpha components
        Returns:
        an array containing the color and alpha components of the specified pixel starting at the specified offset.

      • getComponents

        public final int[] getComponents(Object pixel,
                  int[] components,
                  int offset)
        Returns an array of unnormalized color/alpha components given a pixel in this ColorModel. The pixel value is specified by an array of data elements of type transferType passed in as an object reference. If pixel is not a primitive array of type transferType, a ClassCastException is thrown. An ArrayIndexOutOfBoundsException is thrown if pixel is not large enough to hold a pixel value for this ColorModel. If the components array is null, a new array is allocated. The components array is returned. Color/alpha components are stored in the components array starting at offset, even if the array is allocated by this method. An ArrayIndexOutOfBoundsException is thrown if the components array is not null and is not large enough to hold all the color and alpha components, starting at offset. Since DirectColorModel can be subclassed, subclasses inherit the implementation of this method and if they don't override it then they throw an exception if they use an unsupported transferType.
        Overrides:
        getComponents in class ColorModel
        Parameters:
        pixel - the specified pixel
        components - the array to receive the color and alpha components of the specified pixel
        offset - the offset into the components array at which to start storing the color and alpha components
        Returns:
        an array containing the color and alpha components of the specified pixel starting at the specified offset.
        Throws:
        ClassCastException - if pixel is not a primitive array of type transferType
        ArrayIndexOutOfBoundsException - if pixel is not large enough to hold a pixel value for this ColorModel, or if components is not null and is not large enough to hold all the color and alpha components, starting at offset
        UnsupportedOperationException - if this transferType is not supported by this color model

      • createCompatibleWritableRaster

        public final WritableRaster createCompatibleWritableRaster(int w,
                                            int h)
        Creates a WritableRaster with the specified width and height that has a data layout (SampleModel) compatible with this ColorModel.
        Overrides:
        createCompatibleWritableRaster in class ColorModel
        Parameters:
        w - the width to apply to the new WritableRaster
        h - the height to apply to the new WritableRaster
        Returns:
        a WritableRaster object with the specified width and height.
        Throws:
        IllegalArgumentException - if w or h is less than or equal to zero
        See Also:
        WritableRaster, SampleModel

      • getDataElement

        public int getDataElement(int[] components,
                 int offset)
        Returns a pixel value represented as an int in this ColorModel, given an array of unnormalized color/alpha components. An ArrayIndexOutOfBoundsException is thrown if the components array is not large enough to hold all the color and alpha components, starting at offset.
        Overrides:
        getDataElement in class ColorModel
        Parameters:
        components - an array of unnormalized color and alpha components
        offset - the index into components at which to begin retrieving the color and alpha components
        Returns:
        an int pixel value in this ColorModel corresponding to the specified components.
        Throws:
        ArrayIndexOutOfBoundsException - if the components array is not large enough to hold all of the color and alpha components starting at offset

      • getDataElements

        public Object getDataElements(int[] components,
                     int offset,
                     Object obj)
        Returns a data element array representation of a pixel in this ColorModel, given an array of unnormalized color/alpha components. This array can then be passed to the setDataElements method of a WritableRaster object. An ArrayIndexOutOfBoundsException is thrown if the components array is not large enough to hold all the color and alpha components, starting at offset. If the obj variable is null, a new array is allocated. If obj is not null, it must be a primitive array of type transferType; otherwise, a ClassCastException is thrown. An ArrayIndexOutOfBoundsException is thrown if obj is not large enough to hold a pixel value for this ColorModel. Since DirectColorModel can be subclassed, subclasses inherit the implementation of this method and if they don't override it then they throw an exception if they use an unsupported transferType.
        Overrides:
        getDataElements in class ColorModel
        Parameters:
        components - an array of unnormalized color and alpha components
        offset - the index into components at which to begin retrieving color and alpha components
        obj - the Object representing an array of color and alpha components
        Returns:
        an Object representing an array of color and alpha components.
        Throws:
        ClassCastException - if obj is not a primitive array of type transferType
        ArrayIndexOutOfBoundsException - if obj is not large enough to hold a pixel value for this ColorModel or the components array is not large enough to hold all of the color and alpha components starting at offset
        UnsupportedOperationException - if this transferType is not supported by this color model
        See Also:
        WritableRaster.setDataElements(int, int, java.lang.Object), SampleModel.setDataElements(int, int, java.lang.Object, java.awt.image.DataBuffer)

      • coerceData

        public final ColorModel coerceData(WritableRaster raster,
                    boolean isAlphaPremultiplied)
        Forces the raster data to match the state specified in the isAlphaPremultiplied variable, assuming the data is currently correctly described by this ColorModel. It may multiply or divide the color raster data by alpha, or do nothing if the data is in the correct state. If the data needs to be coerced, this method will also return an instance of this ColorModel with the isAlphaPremultiplied flag set appropriately. This method will throw a UnsupportedOperationException if this transferType is not supported by this ColorModel. Since ColorModel can be subclassed, subclasses inherit the implementation of this method and if they don't override it then they throw an exception if they use an unsupported transferType.
        Overrides:
        coerceData in class ColorModel
        Parameters:
        raster - the WritableRaster data
        isAlphaPremultiplied - true if the alpha is premultiplied; false otherwise
        Returns:
        a ColorModel object that represents the coerced data.
        Throws:
        UnsupportedOperationException - if this transferType is not supported by this color model

      • isCompatibleRaster

        public boolean isCompatibleRaster(Raster raster)
        Returns true if raster is compatible with this ColorModel and false if it is not.
        Overrides:
        isCompatibleRaster in class ColorModel
        Parameters:
        raster - the Raster object to test for compatibility
        Returns:
        true if raster is compatible with this ColorModel; false otherwise.

      • toString

        public String toString()
        Returns a String that represents this DirectColorModel.
        Overrides:
        toString in class ColorModel
        Returns:
        a String representing this DirectColorModel.

Document created the 11/06/2005, last modified the 04/03/2020
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