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Document the new scaling factors

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git-svn-id: svn+ssh://svn.code.sf.net/p/libjpeg-turbo/code/trunk@756 632fc199-4ca6-4c93-a231-07263d6284db
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DRC
2012-01-28 06:49:22 +00:00
parent ea1ca03b75
commit 84d37a09b6
1 changed files with 8 additions and 4 deletions
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12
README-turbo.txt
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@@ -303,6 +303,14 @@ Fully supported:
-- rdjpgcom: locale awareness -- rdjpgcom: locale awareness
Partially supported:
-- libjpeg: IDCT scaling extensions in decompressor
libjpeg-turbo supports IDCT scaling with scaling factors of 1/8, 1/4, 3/8,
1/2, 5/8, 3/4, 7/8, 9/8, 5/4, 11/8, 3/2, 13/8, 7/4, 15/8, and 2/1, but only
1/4 and 1/2 are SIMD-accelerated.
Fully supported when using libjpeg v7/v8 emulation: Fully supported when using libjpeg v7/v8 emulation:
-- libjpeg: In-memory source and destination managers -- libjpeg: In-memory source and destination managers
@@ -313,10 +321,6 @@ Not supported:
-- libjpeg: DCT scaling in compressor -- libjpeg: DCT scaling in compressor
cinfo.scale_num and cinfo.scale_denom are silently ignored. cinfo.scale_num and cinfo.scale_denom are silently ignored.
-- libjpeg: IDCT scaling extensions in decompressor
libjpeg-turbo still supports IDCT scaling with scaling factors of 1/2, 1/4,
and 1/8 (same as libjpeg v6b.)
-- libjpeg: Fancy downsampling in compressor -- libjpeg: Fancy downsampling in compressor
cinfo.do_fancy_downsampling is silently ignored. cinfo.do_fancy_downsampling is silently ignored.