Re: [Gimp-developer] Size on disk vs size reported on status bar

[Elle Stone <ellestone ninedegreesbelow com>]

On 10/03/2017 09:40 PM, Jehan Pagès wrote:
> Hi again!
>
> On Tue, Oct 3, 2017 at 8:18 PM, Elle Stone
> <ellestone ninedegreesbelow com> wrote:
> > On 10/03/2017 01:21 PM, Simon Budig wrote:
> > > The current generation XCF files can contain compressed image data.
> >
> >
> > When I save XCF files I don't use the option in the Save dialog to compress
> > the data. Is there some other compression going on automatically?
>
> Yes, XCF historically uses RLE compression, which is basic hence not
> great, but still enough for a very simple image with a lot of
> identical (i.e. same color) adjacent pixels (as I understand your
> image is).
>
> The option in the save dialog is about activating the newer zlib
> compression instead, which is much more sophisticated and should
> therefore result in even smaller files. But on very simple files,
> simple compression can work great too (sometimes even better than
> complex compression, that's rare but it may happen).

Hi Jehan,

Thanks! for this information. I didn't realize any compression was being 
used if the option in the save dialog wasn't selected.

Saving large files can take a long time. Does anyone know how much time 
percent-wise is literally writing the file out (well, I suppose this 
would partly depend on the type of disk and the file system type), 
versus how much time is spent doing the compression before the file is 
written? How large would the XCF file would be if there were no 
compression at all before writing the file to disk, compared to the 
compressed size?

Best,
Elle