PackedColorModel
Class PackedColorModel
- java.lang.Object
-
- java-awt-image-ColorModel
-
- java.awt.image.PackedColorModel
- All Implemented Interfaces:
- Transparency
- Direct Known Subclasses:
- DirectColorModel
public abstract class PackedColorModel extends ColorModel
The PackedColorModel
class is an abstract ColorModel
class that works with pixel values which represent color and alpha information as separate samples and which pack all samples for a single pixel into a single int, short, or byte quantity- This class can be used with an arbitrary ColorSpace
. The number of color samples in the pixel values must be the same as the number of color components in the ColorSpace
. There can be a single alpha sample. The array length is always 1 for those methods that use a primitive array pixel representation of type transferType
. 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
getNumComponents
- 1. - The first
getNumColorComponents
indices refer to color samples. - If an alpha sample is present, it corresponds the last index.
- The order of the color indices is specified by the
ColorSpace
. Typically, this reflects the name of the color space type (for example, TYPE_RGB), index 0 corresponds to red, index 1 to green, and index 2 to blue.
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 PackedColorModel
is typically used with image data that uses masks to define packed samples. For example, a PackedColorModel
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 is 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 that use this representation do not throw an IllegalArgumentException
due to an invalid pixel value.
A subclass of PackedColorModel
is DirectColorModel
, which is similar to an X11 TrueColor visual.
Fields
Fields inherited from class java.awt.image.ColorModel
pixel_bits, transferType
Fields inherited from interface java.awt.Transparency
BITMASK, OPAQUE, TRANSLUCENT
Constructors
PackedColorModel
public PackedColorModel(ColorSpace space, int bits, int[] colorMaskArray, int alphaMask, boolean isAlphaPremultiplied, int trans, int transferType)
Constructs a PackedColorModel
from a color mask array, which specifies which bits in an int
pixel representation contain each of the color samples, and an alpha mask. Color components are in the specified ColorSpace
. The length of colorMaskArray
should be the number of components in the ColorSpace
. 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 the alphaMask
is 0, there is no alpha. 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, trans
, specifies what alpha values can be represented by this color model. The transfer type is the type of primitive array used to represent pixel values.
- Parameters:
-
space
- the specifiedColorSpace
-
bits
- the number of bits in the pixel values -
colorMaskArray
- array that specifies the masks representing the bits of the pixel values that represent the color components -
alphaMask
- specifies the mask representing the bits of the pixel values that represent the alpha component -
isAlphaPremultiplied
-true
if color samples are premultiplied by the alpha sample;false
otherwise -
trans
- specifies the alpha value that can be represented by this color model -
transferType
- the type of array used to represent pixel values - Throws:
-
IllegalArgumentException
- ifbits
is less than 1 or greater than 32
PackedColorModel
public PackedColorModel(ColorSpace space, int bits, int rmask, int gmask, int bmask, int amask, boolean isAlphaPremultiplied, int trans, int transferType)
Constructs a PackedColorModel
from the specified masks which indicate which bits in an int
pixel representation contain the alpha, red, green and blue color samples. Color components are in the specified ColorSpace
, which must be of type ColorSpace.TYPE_RGB. 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 amask
is 0, there is no alpha. 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, trans
, specifies what alpha values can be represented by this color model. The transfer type is the type of primitive array used to represent pixel values.
- Parameters:
-
space
- the specifiedColorSpace
-
bits
- the number of bits in the pixel values -
rmask
- specifies the mask representing the bits of the pixel values that represent the red color component -
gmask
- specifies the mask representing the bits of the pixel values that represent the green color component -
bmask
- specifies the mask representing the bits of the pixel values that represent the blue color component -
amask
- specifies the mask representing the bits of the pixel values that represent the alpha component -
isAlphaPremultiplied
-true
if color samples are premultiplied by the alpha sample;false
otherwise -
trans
- specifies the alpha value that can be represented by this color model -
transferType
- the type of array used to represent pixel values - Throws:
-
IllegalArgumentException
- ifspace
is not a TYPE_RGB space - See Also:
ColorSpace
Methods
getMask
public final int getMask(int index)
Returns the mask indicating which bits in a pixel contain the specified color/alpha sample. For color samples, index
corresponds to the placement of color sample names in the color space. Thus, an index
equal to 0 for a CMYK ColorSpace would correspond to Cyan and an index
equal to 1 would correspond to Magenta. If there is alpha, the alpha index
would be:
alphaIndex = numComponents() - 1;
- Parameters:
-
index
- the specified color or alpha sample - Returns:
- the mask, which indicates which bits of the
int
pixel representation contain the color or alpha sample specified byindex
. - Throws:
-
ArrayIndexOutOfBoundsException
- ifindex
is greater than the number of components minus 1 in thisPackedColorModel
or ifindex
is less than zero
getMasks
public final int[] getMasks()
Returns a mask array indicating which bits in a pixel contain the color and alpha samples.
- Returns:
- the mask array , which indicates which bits of the
int
pixel representation contain the color or alpha samples.
createCompatibleSampleModel
public SampleModel createCompatibleSampleModel(int w, int h)
Creates a SampleModel
with the specified width and height that has a data layout compatible with this ColorModel
.
- Overrides:
-
createCompatibleSampleModel
in classColorModel
- Parameters:
-
w
- the width (in pixels) of the region of the image data described -
h
- the height (in pixels) of the region of the image data described - Returns:
- the newly created
SampleModel
- - Throws:
-
IllegalArgumentException
- ifw
orh
is not greater than 0 - See Also:
SampleModel
isCompatibleSampleModel
public boolean isCompatibleSampleModel(SampleModel sm)
Checks if the specified SampleModel
is compatible with this ColorModel
. If sm
is null
, this method returns false
.
- Overrides:
-
isCompatibleSampleModel
in classColorModel
- Parameters:
-
sm
- the specifiedSampleModel
, ornull
- Returns:
-
true
if the specifiedSampleModel
is compatible with thisColorModel
;false
otherwise- - See Also:
SampleModel
getAlphaRaster
public WritableRaster getAlphaRaster(WritableRaster raster)
Returns a WritableRaster
representing the alpha channel of an image, extracted from the input WritableRaster
. This method assumes that WritableRaster
objects associated with this ColorModel
store the alpha band, if present, as the last band of image data. Returns null
if there is no separate spatial alpha channel associated with this ColorModel
. This method creates a new WritableRaster
, but shares the data array.
- Overrides:
-
getAlphaRaster
in classColorModel
- Parameters:
-
raster
- aWritableRaster
containing an image - Returns:
- a
WritableRaster
that represents the alpha channel of the image contained inraster
-
equals
public boolean equals(Object obj)
Tests if the specified Object
is an instance of PackedColorModel
and equals this PackedColorModel
.
- Overrides:
-
equals
in classColorModel
- Parameters:
-
obj
- theObject
to test for equality - Returns:
-
true
if the specifiedObject
is an instance ofPackedColorModel
and equals thisPackedColorModel
;false
otherwise- - See Also:
-
Object.hashCode()
,HashMap
© 1993–2017, Oracle and/or its affiliates. All rights reserved.
Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.