kc3-lang/libjpeg-turbo

2024-10-24T13:25:10

Allow disabling prog/opt/lossless if prev. enabled - Due to an oversight, a113506d175d03ae0e40965c3d3d21a5d561e119 (libjpeg-turbo 1.4 beta1) effectively made the call to std_huff_tables() in jpeg_set_defaults() a no-op if the Huffman tables were previously defined, which made it impossible to disable Huffman table optimization or progressive mode if they were previously enabled in the same API instance. std_huff_tables() retains its previous behavior for decompression instances, but it now force-enables the standard (baseline) Huffman tables for compression instances. - Due to another oversight, there was no way to disable lossless mode if it was previously enabled in a particular API instance. jpeg_set_defaults() now accomplishes this, which makes TJ*PARAM_LOSSLESS behave as intended/documented. - Due to yet another oversight, setCompDefaults() in the TurboJPEG API library permanently modified the value of TJ*PARAM_SUBSAMP when generating a lossless JPEG image, which affected subsequent lossy compression operations. This issue was hidden by the issue above and thus does not need to be publicly documented. Fixes #792