org.libjpegturbo.turbojpeg
Class TJ
java.lang.Object
org.libjpegturbo.turbojpeg.TJ
public final class TJ
- extends java.lang.Object
TurboJPEG utility class (cannot be instantiated)
Field Summary |
static int |
CS_CMYK
CMYK colorspace. |
static int |
CS_GRAY
Grayscale colorspace. |
static int |
CS_RGB
RGB colorspace. |
static int |
CS_YCbCr
YCbCr colorspace. |
static int |
CS_YCCK
YCCK colorspace. |
static int |
FLAG_ACCURATEDCT
Use the most accurate DCT/IDCT algorithm available in the underlying
codec. |
static int |
FLAG_BOTTOMUP
The uncompressed source/destination image is stored in bottom-up (Windows,
OpenGL) order, not top-down (X11) order. |
static int |
FLAG_FASTDCT
Use the fastest DCT/IDCT algorithm available in the underlying codec. |
static int |
FLAG_FASTUPSAMPLE
When decompressing an image that was compressed using chrominance
subsampling, use the fastest chrominance upsampling algorithm available in
the underlying codec. |
static int |
FLAG_FORCEMMX
Deprecated. |
static int |
FLAG_FORCESSE
Deprecated. |
static int |
FLAG_FORCESSE2
Deprecated. |
static int |
FLAG_FORCESSE3
Deprecated. |
static int |
NUMCS
The number of JPEG colorspaces |
static int |
NUMPF
The number of pixel formats |
static int |
NUMSAMP
The number of chrominance subsampling options |
static int |
PF_ABGR
ABGR pixel format. |
static int |
PF_ARGB
ARGB pixel format. |
static int |
PF_BGR
BGR pixel format. |
static int |
PF_BGRA
BGRA pixel format. |
static int |
PF_BGRX
BGRX pixel format. |
static int |
PF_CMYK
CMYK pixel format. |
static int |
PF_GRAY
Grayscale pixel format. |
static int |
PF_RGB
RGB pixel format. |
static int |
PF_RGBA
RGBA pixel format. |
static int |
PF_RGBX
RGBX pixel format. |
static int |
PF_XBGR
XBGR pixel format. |
static int |
PF_XRGB
XRGB pixel format. |
static int |
SAMP_411
4:1:1 chrominance subsampling. |
static int |
SAMP_420
4:2:0 chrominance subsampling. |
static int |
SAMP_422
4:2:2 chrominance subsampling. |
static int |
SAMP_440
4:4:0 chrominance subsampling. |
static int |
SAMP_444
4:4:4 chrominance subsampling (no chrominance subsampling). |
static int |
SAMP_GRAY
Grayscale. |
Method Summary |
static int |
bufSize(int width,
int height,
int jpegSubsamp)
Returns the maximum size of the buffer (in bytes) required to hold a JPEG
image with the given width, height, and level of chrominance subsampling. |
static int |
bufSizeYUV(int width,
int height,
int subsamp)
Deprecated. Use bufSizeYUV(int, int, int, int) instead. |
static int |
bufSizeYUV(int width,
int pad,
int height,
int subsamp)
Returns the size of the buffer (in bytes) required to hold a YUV planar
image with the given width, height, and level of chrominance subsampling. |
static int |
getBlueOffset(int pixelFormat)
For the given pixel format, returns the number of bytes that the blue
component is offset from the start of the pixel. |
static int |
getGreenOffset(int pixelFormat)
For the given pixel format, returns the number of bytes that the green
component is offset from the start of the pixel. |
static int |
getMCUHeight(int subsamp)
Returns the MCU block height for the given level of chrominance
subsampling. |
static int |
getMCUWidth(int subsamp)
Returns the MCU block width for the given level of chrominance
subsampling. |
static int |
getPixelSize(int pixelFormat)
Returns the pixel size (in bytes) for the given pixel format. |
static int |
getRedOffset(int pixelFormat)
For the given pixel format, returns the number of bytes that the red
component is offset from the start of the pixel. |
static TJScalingFactor[] |
getScalingFactors()
Returns a list of fractional scaling factors that the JPEG decompressor in
this implementation of TurboJPEG supports. |
Methods inherited from class java.lang.Object |
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
NUMSAMP
public static final int NUMSAMP
- The number of chrominance subsampling options
- See Also:
- Constant Field Values
SAMP_444
public static final int SAMP_444
- 4:4:4 chrominance subsampling (no chrominance subsampling). The JPEG
or YUV image will contain one chrominance component for every pixel in the
source image.
- See Also:
- Constant Field Values
SAMP_422
public static final int SAMP_422
- 4:2:2 chrominance subsampling. The JPEG or YUV image will contain one
chrominance component for every 2x1 block of pixels in the source image.
- See Also:
- Constant Field Values
SAMP_420
public static final int SAMP_420
- 4:2:0 chrominance subsampling. The JPEG or YUV image will contain one
chrominance component for every 2x2 block of pixels in the source image.
- See Also:
- Constant Field Values
SAMP_GRAY
public static final int SAMP_GRAY
- Grayscale. The JPEG or YUV image will contain no chrominance components.
- See Also:
- Constant Field Values
SAMP_440
public static final int SAMP_440
- 4:4:0 chrominance subsampling. The JPEG or YUV image will contain one
chrominance component for every 1x2 block of pixels in the source image.
Note that 4:4:0 subsampling is not fully accelerated in libjpeg-turbo.
- See Also:
- Constant Field Values
SAMP_411
public static final int SAMP_411
- 4:1:1 chrominance subsampling. The JPEG or YUV image will contain one
chrominance component for every 4x1 block of pixels in the source image.
JPEG images compressed with 4:1:1 subsampling will be almost exactly the
same size as those compressed with 4:2:0 subsampling, and in the
aggregate, both subsampling methods produce approximately the same
perceptual quality. However, 4:1:1 is better able to reproduce sharp
horizontal features. Note that 4:1:1 subsampling is not fully accelerated
in libjpeg-turbo.
- See Also:
- Constant Field Values
NUMPF
public static final int NUMPF
- The number of pixel formats
- See Also:
- Constant Field Values
PF_RGB
public static final int PF_RGB
- RGB pixel format. The red, green, and blue components in the image are
stored in 3-byte pixels in the order R, G, B from lowest to highest byte
address within each pixel.
- See Also:
- Constant Field Values
PF_BGR
public static final int PF_BGR
- BGR pixel format. The red, green, and blue components in the image are
stored in 3-byte pixels in the order B, G, R from lowest to highest byte
address within each pixel.
- See Also:
- Constant Field Values
PF_RGBX
public static final int PF_RGBX
- RGBX pixel format. The red, green, and blue components in the image are
stored in 4-byte pixels in the order R, G, B from lowest to highest byte
address within each pixel. The X component is ignored when compressing
and undefined when decompressing.
- See Also:
- Constant Field Values
PF_BGRX
public static final int PF_BGRX
- BGRX pixel format. The red, green, and blue components in the image are
stored in 4-byte pixels in the order B, G, R from lowest to highest byte
address within each pixel. The X component is ignored when compressing
and undefined when decompressing.
- See Also:
- Constant Field Values
PF_XBGR
public static final int PF_XBGR
- XBGR pixel format. The red, green, and blue components in the image are
stored in 4-byte pixels in the order R, G, B from highest to lowest byte
address within each pixel. The X component is ignored when compressing
and undefined when decompressing.
- See Also:
- Constant Field Values
PF_XRGB
public static final int PF_XRGB
- XRGB pixel format. The red, green, and blue components in the image are
stored in 4-byte pixels in the order B, G, R from highest to lowest byte
address within each pixel. The X component is ignored when compressing
and undefined when decompressing.
- See Also:
- Constant Field Values
PF_GRAY
public static final int PF_GRAY
- Grayscale pixel format. Each 1-byte pixel represents a luminance
(brightness) level from 0 to 255.
- See Also:
- Constant Field Values
PF_RGBA
public static final int PF_RGBA
- RGBA pixel format. This is the same as
PF_RGBX
, except that when
decompressing, the X byte is guaranteed to be 0xFF, which can be
interpreted as an opaque alpha channel.
- See Also:
- Constant Field Values
PF_BGRA
public static final int PF_BGRA
- BGRA pixel format. This is the same as
PF_BGRX
, except that when
decompressing, the X byte is guaranteed to be 0xFF, which can be
interpreted as an opaque alpha channel.
- See Also:
- Constant Field Values
PF_ABGR
public static final int PF_ABGR
- ABGR pixel format. This is the same as
PF_XBGR
, except that when
decompressing, the X byte is guaranteed to be 0xFF, which can be
interpreted as an opaque alpha channel.
- See Also:
- Constant Field Values
PF_ARGB
public static final int PF_ARGB
- ARGB pixel format. This is the same as
PF_XRGB
, except that when
decompressing, the X byte is guaranteed to be 0xFF, which can be
interpreted as an opaque alpha channel.
- See Also:
- Constant Field Values
PF_CMYK
public static final int PF_CMYK
- CMYK pixel format. Unlike RGB, which is an additive color model used
primarily for display, CMYK (Cyan/Magenta/Yellow/Key) is a subtractive
color model used primarily for printing. In the CMYK color model, the
value of each color component typically corresponds to an amount of cyan,
magenta, yellow, or black ink that is applied to a white background. In
order to convert between CMYK and RGB, it is necessary to use a color
management system (CMS.) A CMS will attempt to map colors within the
printer's gamut to perceptually similar colors in the display's gamut and
vice versa, but the mapping is typically not 1:1 or reversible, nor can it
be defined with a simple formula. Thus, such a conversion is out of scope
for a codec library. However, the TurboJPEG API allows for compressing
CMYK pixels into a YCCK JPEG image (see
CS_YCCK
) and
decompressing YCCK JPEG images into CMYK pixels.
- See Also:
- Constant Field Values
NUMCS
public static final int NUMCS
- The number of JPEG colorspaces
- See Also:
- Constant Field Values
CS_RGB
public static final int CS_RGB
- RGB colorspace. When compressing the JPEG image, the R, G, and B
components in the source image are reordered into image planes, but no
colorspace conversion or subsampling is performed. RGB JPEG images can be
decompressed to any of the extended RGB pixel formats or grayscale, but
they cannot be decompressed to YUV images.
- See Also:
- Constant Field Values
CS_YCbCr
public static final int CS_YCbCr
- YCbCr colorspace. YCbCr is not an absolute colorspace but rather a
mathematical transformation of RGB designed solely for storage and
transmission. YCbCr images must be converted to RGB before they can
actually be displayed. In the YCbCr colorspace, the Y (luminance)
component represents the black & white portion of the original image, and
the Cb and Cr (chrominance) components represent the color portion of the
original image. Originally, the analog equivalent of this transformation
allowed the same signal to drive both black & white and color televisions,
but JPEG images use YCbCr primarily because it allows the color data to be
optionally subsampled for the purposes of reducing bandwidth or disk
space. YCbCr is the most common JPEG colorspace, and YCbCr JPEG images
can be compressed from and decompressed to any of the extended RGB pixel
formats or grayscale, or they can be decompressed to YUV planar images.
- See Also:
- Constant Field Values
CS_GRAY
public static final int CS_GRAY
- Grayscale colorspace. The JPEG image retains only the luminance data (Y
component), and any color data from the source image is discarded.
Grayscale JPEG images can be compressed from and decompressed to any of
the extended RGB pixel formats or grayscale, or they can be decompressed
to YUV planar images.
- See Also:
- Constant Field Values
CS_CMYK
public static final int CS_CMYK
- CMYK colorspace. When compressing the JPEG image, the C, M, Y, and K
components in the source image are reordered into image planes, but no
colorspace conversion or subsampling is performed. CMYK JPEG images can
only be decompressed to CMYK pixels.
- See Also:
- Constant Field Values
CS_YCCK
public static final int CS_YCCK
- YCCK colorspace. YCCK (AKA "YCbCrK") is not an absolute colorspace but
rather a mathematical transformation of CMYK designed solely for storage
and transmission. It is to CMYK as YCbCr is to RGB. CMYK pixels can be
reversibly transformed into YCCK, and as with YCbCr, the chrominance
components in the YCCK pixels can be subsampled without incurring major
perceptual loss. YCCK JPEG images can only be compressed from and
decompressed to CMYK pixels.
- See Also:
- Constant Field Values
FLAG_BOTTOMUP
public static final int FLAG_BOTTOMUP
- The uncompressed source/destination image is stored in bottom-up (Windows,
OpenGL) order, not top-down (X11) order.
- See Also:
- Constant Field Values
FLAG_FORCEMMX
@Deprecated
public static final int FLAG_FORCEMMX
- Deprecated.
- See Also:
- Constant Field Values
FLAG_FORCESSE
@Deprecated
public static final int FLAG_FORCESSE
- Deprecated.
- See Also:
- Constant Field Values
FLAG_FORCESSE2
@Deprecated
public static final int FLAG_FORCESSE2
- Deprecated.
- See Also:
- Constant Field Values
FLAG_FORCESSE3
@Deprecated
public static final int FLAG_FORCESSE3
- Deprecated.
- See Also:
- Constant Field Values
FLAG_FASTUPSAMPLE
public static final int FLAG_FASTUPSAMPLE
- When decompressing an image that was compressed using chrominance
subsampling, use the fastest chrominance upsampling algorithm available in
the underlying codec. The default is to use smooth upsampling, which
creates a smooth transition between neighboring chrominance components in
order to reduce upsampling artifacts in the decompressed image.
- See Also:
- Constant Field Values
FLAG_FASTDCT
public static final int FLAG_FASTDCT
- Use the fastest DCT/IDCT algorithm available in the underlying codec. The
default if this flag is not specified is implementation-specific. For
example, the implementation of TurboJPEG for libjpeg[-turbo] uses the fast
algorithm by default when compressing, because this has been shown to have
only a very slight effect on accuracy, but it uses the accurate algorithm
when decompressing, because this has been shown to have a larger effect.
- See Also:
- Constant Field Values
FLAG_ACCURATEDCT
public static final int FLAG_ACCURATEDCT
- Use the most accurate DCT/IDCT algorithm available in the underlying
codec. The default if this flag is not specified is
implementation-specific. For example, the implementation of TurboJPEG for
libjpeg[-turbo] uses the fast algorithm by default when compressing,
because this has been shown to have only a very slight effect on accuracy,
but it uses the accurate algorithm when decompressing, because this has
been shown to have a larger effect.
- See Also:
- Constant Field Values
TJ
public TJ()
getMCUWidth
public static int getMCUWidth(int subsamp)
throws java.lang.Exception
- Returns the MCU block width for the given level of chrominance
subsampling.
- Parameters:
subsamp
- the level of chrominance subsampling (one of
SAMP_*
)
- Returns:
- the MCU block width for the given level of chrominance subsampling
- Throws:
java.lang.Exception
getMCUHeight
public static int getMCUHeight(int subsamp)
throws java.lang.Exception
- Returns the MCU block height for the given level of chrominance
subsampling.
- Parameters:
subsamp
- the level of chrominance subsampling (one of
SAMP_*
)
- Returns:
- the MCU block height for the given level of chrominance
subsampling
- Throws:
java.lang.Exception
getPixelSize
public static int getPixelSize(int pixelFormat)
throws java.lang.Exception
- Returns the pixel size (in bytes) for the given pixel format.
- Parameters:
pixelFormat
- the pixel format (one of PF_*
)
- Returns:
- the pixel size (in bytes) for the given pixel format
- Throws:
java.lang.Exception
getRedOffset
public static int getRedOffset(int pixelFormat)
throws java.lang.Exception
- For the given pixel format, returns the number of bytes that the red
component is offset from the start of the pixel. For instance, if a pixel
of format
TJ.PF_BGRX
is stored in char pixel[]
,
then the red component will be
pixel[TJ.getRedOffset(TJ.PF_BGRX)]
.
- Parameters:
pixelFormat
- the pixel format (one of PF_*
)
- Returns:
- the red offset for the given pixel format
- Throws:
java.lang.Exception
getGreenOffset
public static int getGreenOffset(int pixelFormat)
throws java.lang.Exception
- For the given pixel format, returns the number of bytes that the green
component is offset from the start of the pixel. For instance, if a pixel
of format
TJ.PF_BGRX
is stored in char pixel[]
,
then the green component will be
pixel[TJ.getGreenOffset(TJ.PF_BGRX)]
.
- Parameters:
pixelFormat
- the pixel format (one of PF_*
)
- Returns:
- the green offset for the given pixel format
- Throws:
java.lang.Exception
getBlueOffset
public static int getBlueOffset(int pixelFormat)
throws java.lang.Exception
- For the given pixel format, returns the number of bytes that the blue
component is offset from the start of the pixel. For instance, if a pixel
of format
TJ.PF_BGRX
is stored in char pixel[]
,
then the blue component will be
pixel[TJ.getBlueOffset(TJ.PF_BGRX)]
.
- Parameters:
pixelFormat
- the pixel format (one of PF_*
)
- Returns:
- the blue offset for the given pixel format
- Throws:
java.lang.Exception
bufSize
public static int bufSize(int width,
int height,
int jpegSubsamp)
throws java.lang.Exception
- Returns the maximum size of the buffer (in bytes) required to hold a JPEG
image with the given width, height, and level of chrominance subsampling.
- Parameters:
width
- the width (in pixels) of the JPEG imageheight
- the height (in pixels) of the JPEG imagejpegSubsamp
- the level of chrominance subsampling to be used when
generating the JPEG image (one of TJ.SAMP_*
)
- Returns:
- the maximum size of the buffer (in bytes) required to hold a JPEG
image with the given width, height, and level of chrominance subsampling
- Throws:
java.lang.Exception
bufSizeYUV
public static int bufSizeYUV(int width,
int pad,
int height,
int subsamp)
throws java.lang.Exception
- Returns the size of the buffer (in bytes) required to hold a YUV planar
image with the given width, height, and level of chrominance subsampling.
- Parameters:
width
- the width (in pixels) of the YUV imagepad
- the width of each line in each plane of the image is padded to
the nearest multiple of this number of bytes (must be a power of
2.)height
- the height (in pixels) of the YUV imagesubsamp
- the level of chrominance subsampling used in the YUV
image (one of TJ.SAMP_*
)
- Returns:
- the size of the buffer (in bytes) required to hold a YUV planar
image with the given width, height, and level of chrominance subsampling
- Throws:
java.lang.Exception
bufSizeYUV
@Deprecated
public static int bufSizeYUV(int width,
int height,
int subsamp)
throws java.lang.Exception
- Deprecated. Use
bufSizeYUV(int, int, int, int)
instead.
- Throws:
java.lang.Exception
getScalingFactors
public static TJScalingFactor[] getScalingFactors()
throws java.lang.Exception
- Returns a list of fractional scaling factors that the JPEG decompressor in
this implementation of TurboJPEG supports.
- Returns:
- a list of fractional scaling factors that the JPEG decompressor in
this implementation of TurboJPEG supports
- Throws:
java.lang.Exception