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git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@1021 632fc199-4ca6-4c93-a231-07263d6284db
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DRC
2013-08-23 06:38:59 +00:00
parent 38cb1ec2a7
commit b2c4745aa3
8 changed files with 118 additions and 76 deletions
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28
java/org/libjpegturbo/turbojpeg/TJCompressor.java
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@@ -155,7 +155,13 @@ public class TJCompressor {
/**
* Set the level of chrominance subsampling for subsequent compress/encode
* operations.
* operations. When pixels are converted from RGB to YCbCr (see
* {@link TJ#CS_YCbCr}) or from CMYK to YCCK (see {@link TJ#CS_YCCK}) 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".
*
* @param newSubsamp the new level of chrominance subsampling (one of
* {@link TJ TJ.SAMP_*})
@@ -351,14 +357,18 @@ public class TJCompressor {
* 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.
*
* @param dstBuf buffer that will receive the YUV planar image. Use
* {@link TJ#bufSizeYUV} to determine the appropriate size for this buffer