Re: [Boost-users] [GIL] rotated90cw_view - jpeg lossless rotation

Subject: Re: [Boost-users] [GIL] rotated90cw_view - jpeg lossless rotation
From: Jose (jmalv04_at_[hidden])
Date: 2009-12-06 12:22:52

On Sun, Dec 6, 2009 at 5:13 PM, Sebastian Redl
<sebastian.redl_at_[hidden]> wrote:

>> I think libjpeg has a way of applying lossless transformations while
>> reading it. Is that correct, or am I mistaken here?
>>
>
> JPEG lossless transformation is a trick performed on the compressed JPEG
> data (IIUC, you basically shuffle the values in each block), and can
> therefore not be achieved by using a generic image library that provides a
> JPEG reader and writer. You need specialized functions that operate on the
> compressed JPEG data.
>
> Sebastian
>

Maybe. Then it would make sense to support this by wrapping the jpeg7
function jtransform_perfect_transform