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DRC
2011-03-15 19:33:43 +00:00
parent 4a0cf492f4
commit 4c5eae3bd0
1 changed files with 17 additions and 15 deletions
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32
turbojpeg.h
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@@ -84,9 +84,9 @@ TJXFORM_VFLIP, /* Flip (mirror) image vertically. This transform is
bottom edge. */
TJXFORM_TRANSPOSE, /* Transpose image (flip/mirror along upper left to lower
right axis.) This transform is always perfect. */
TJXFORM_TRANSVERSE, /* Transpose image (flip/mirror along upper right to lower
left axis.) This transform is imperfect if there are
any partial MCU blocks in the image. */
TJXFORM_TRANSVERSE, /* Transverse transpose image (flip/mirror along upper
right to lower left axis.) This transform is imperfect
if there are any partial MCU blocks in the image. */
TJXFORM_ROT90, /* Rotate image clockwise by 90 degrees. This transform
is imperfect if there are any partial MCU blocks on the
bottom edge. */
@@ -184,19 +184,21 @@ DLLEXPORT tjhandle DLLCALL tjInitCompress(void);
bytes) of the JPEG image
[INPUT] jpegsubsamp = Specifies the level of chrominance subsampling. When
the image is converted from the RGB to YCbCr colorspace as part of the
JPEG compression process, every other Cb and Cr (chrominance) pixel can be
discarded to produce a smaller image with little perceptible loss of image
clarity (the human eye is more sensitive to small changes in brightness
than small changes in color.)
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 small changes in color.)
TJ_420: 4:2:0 subsampling. Discards every other Cb, Cr pixel in both
horizontal and vertical directions
TJ_422: 4:2:2 subsampling. Discards every other Cb, Cr pixel only in
the horizontal direction
TJ_440: 4:4:0 subsampling. Discards every other Cb, Cr pixel only in
the vertical direction
TJ_444: no subsampling
TJ_GRAYSCALE: Generate grayscale JPEG image
TJ_420: 4:2:0 subsampling. The JPEG image will contain one chrominance
component for every 2x2 block of pixels in the source image.
TJ_422: 4:2:2 subsampling. The JPEG image will contain one chrominance
component for every 2x1 block of pixels in the source image.
TJ_440: 4:4:0 subsampling. The JPEG image will contain one chrominance
component for every 1x2 block of pixels in the source image.
TJ_444: no subsampling. The JPEG image will contain one chrominance
component for every pixel in the source image.
TJ_GRAYSCALE: Generate grayscale JPEG image. The JPEG image will contain
no chrominance components.
[INPUT] jpegqual = JPEG quality (an integer between 0 and 100 inclusive)
[INPUT] flags = the bitwise OR of one or more of the flags described in the