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DRC
2013-08-23 06:38:59 +00:00
parent 0fb3247f9a
commit ff3d754f29
8 changed files with 118 additions and 76 deletions
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25
java/doc/org/libjpegturbo/turbojpeg/TJ.html
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@@ -807,18 +807,19 @@ PF_CMYK</H3>
<PRE>
public static final int <B>PF_CMYK</B></PRE>
<DL>
<DD>CMYK pixel format. Unlike RGB, which is a display colorspace,
CMYK (Cyan/Magenta/Yellow/Key) is a print colorspace in which the
value of each color component corresponds to the 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 <A HREF="../../../org/libjpegturbo/turbojpeg/TJ.html#CS_YCCK"><CODE>CS_YCCK</CODE></A>) and decompressing YCCK JPEG
images into CMYK pixels.
<DD>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 <A HREF="../../../org/libjpegturbo/turbojpeg/TJ.html#CS_YCCK"><CODE>CS_YCCK</CODE></A>) and
decompressing YCCK JPEG images into CMYK pixels.
<P>
<DL>
<DT><B>See Also:</B><DD><A HREF="../../../constant-values.html#org.libjpegturbo.turbojpeg.TJ.PF_CMYK">Constant Field Values</A></DL>

28
java/doc/org/libjpegturbo/turbojpeg/TJCompressor.html
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@@ -469,7 +469,13 @@ public void <B>setSubsamp</B>(int&nbsp;newSubsamp)
throws java.lang.Exception</PRE>
<DL>
<DD>Set the level of chrominance subsampling for subsequent compress/encode
operations.
operations. When pixels are converted from RGB to YCbCr (see
<A HREF="../../../org/libjpegturbo/turbojpeg/TJ.html#CS_YCbCr"><CODE>TJ.CS_YCbCr</CODE></A>) or from CMYK to YCCK (see <A HREF="../../../org/libjpegturbo/turbojpeg/TJ.html#CS_YCCK"><CODE>TJ.CS_YCCK</CODE></A>) as part
of the JPEG compression process, some of the Cb and Cr (chrominance)
components can be discarded or averaged together to produce a smaller
image with little perceptible loss of image clarity (the human eye is more
sensitive to small changes in brightness than to small changes in color.)
This is called "chrominance subsampling".
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>newSubsamp</CODE> - the new level of chrominance subsampling (one of
@@ -609,14 +615,18 @@ public void <B>encodeYUV</B>(byte[]&nbsp;dstBuf,
instance and output a YUV planar image to the given destination buffer.
This method uses the accelerated color conversion routines in TurboJPEG's
underlying codec but does not execute any of the other steps in the JPEG
compression process. The Y, U, and V image planes are stored sequentially
into the destination buffer, and the size of each plane is determined by
the width and height of the source image, as well as the specified padding
and level of chrominance subsampling. If the chrominance components are
subsampled along the horizontal dimension, then the width of the luminance
plane is padded to the nearest multiple of 2 in the output image (same
goes for the height of the luminance plane, if the chrominance components
are subsampled along the vertical dimension.)
compression process. The Y, U (Cb), and V (Cr) image planes are stored
sequentially into the destination buffer, and the size of each plane is
determined by the width and height of the source image, as well as the
specified padding and level of chrominance subsampling. If the
chrominance components are subsampled along the horizontal dimension, then
the width of the luminance plane is padded to the nearest multiple of 2 in
the output image (same goes for the height of the luminance plane, if the
chrominance components are subsampled along the vertical dimension.)
<p>
NOTE: Technically, the JPEG format uses the YCbCr colorspace, but per the
convention of the digital video community, the TurboJPEG API uses "YUV" to
refer to an image format consisting of Y, Cb, and Cr image planes.
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>dstBuf</CODE> - buffer that will receive the YUV planar image. Use

4
java/doc/org/libjpegturbo/turbojpeg/TJDecompressor.html
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@@ -887,6 +887,10 @@ public void <B>decompressToYUV</B>(byte[]&nbsp;dstBuf,
that, if the width or height of the image is not an even multiple of the
MCU block size (see <A HREF="../../../org/libjpegturbo/turbojpeg/TJ.html#getMCUWidth(int)"><CODE>TJ.getMCUWidth(int)</CODE></A> and <A HREF="../../../org/libjpegturbo/turbojpeg/TJ.html#getMCUHeight(int)"><CODE>TJ.getMCUHeight(int)</CODE></A>),
then an intermediate buffer copy will be performed within TurboJPEG.
<p>
NOTE: Technically, the JPEG format uses the YCbCr colorspace, but per the
convention of the digital video community, the TurboJPEG API uses "YUV" to
refer to an image format consisting of Y, Cb, and Cr image planes.
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>dstBuf</CODE> - buffer that will receive the YUV planar image. Use