Re: Lossless jpeg cropping

[Anders Bo Rasmussen <fuzz fuzz dk>]

On Mon, May 15, 2006 at 01:20:41PM +0200, Stephane Delcroix wrote:
> Hi all,
> 
> I've worked on this during my honeymoon: adding lossless cropping for
> jpeg in f-spot.
> 
> Get the patches from http://bugzilla.gnome.org/show_bug.cgi?id=339081
> 
> The first patch (libs and API) is ok and works well. The second one is
> only a way to show and test that new functionality.
> 
> I don't want to make a clear and neat UI binding before having some
> feedbacks on lossless jpeg cropping from the list:
> 
>  * Do you think it is useful ?

This is for me the most important missing feature. At the moment I have
to start a program in Wine to do it (I only do it for small posters
since it is too time consuming).

>  * The X and Y offsets must be aligned with jpeg blocks (i.e. multiple
> of 8). The user should know whether the results of his cropping will be
> as requested. What about breaking aspect ratio constraints ?

First of all I don't think the user selects the excat pixel where he
wants to cut. Digital cameras has more pixels than a screen.

What happens if it is not on a multiple of 8? Do the image only loose
quality in the blocks that is next to a border? If so I think it would
suffice if it was possible to set the image quality of these blocks to
100. If that is not possible with this library, it is probably too much
work, to not work around it.

I can se the following solution, if the above is not possible:

If the user has selected that he wants lossless cropping, the UI
could restrain the selection to allowed places. So when the user draws
the box he wants to cut it will only appear where it is possible to cut. 


Regards

  Anders