Hi,

On Tue, Feb 13, 2018 at 10:23:09AM +0100, Guillermo Rodriguez Garcia wrote:
> I need to use libjpeg-turbo for some apps that rely on specific
> libjpeg-turbo extensions that are not available in the standard (IJG's)
> libjpeg library. So I started to create a set of ptxdist rules for
> libjpeg-turbo.
>
> libjpeg-turbo is supposed to provide a drop-in replacement for the standard
> IJG's libjpeg, and in fact many Linux distributions have already switched
> to it. So most packages that currently depend on LIBJPEG should be able to
> use libjpeg-turbo as well without any changes.
>
> Example: gst-plugins-good1.in currently does the following:
>
> select LIBJPEG if GST_PLUGINS_GOOD1_JPEG
>
> However, gst-plugins-good1 should work just fine with libjpeg-turbo as
> well. In fact the upstream gst-plugins already switched to libjpeg-turbo
> some time ago (see the Cerbero scripts)
>
> So, what is the recommended way to approach this in ptxdist? I can imagine
> some options:
>
> 1. Provide a separate set of .in/.make files for libjpeg-turbo and a
> separate LIBJPEG_TURBO package. So new packages that want to use
> libjpeg-turbo would need to explicitly select LIBJPEG_TURBO (instead of
> LIBJPEG). But this means that packages that currently use libjpeg would not
> be able to benefit from the performance improvements in libjpeg-turbo. Also
> I am not sure whether these two libraries (libjpeg and libjpeg-turbo) can
> actually coexist in the same system.

No.

> 2. Modify the LIBJPEG rules to provide an option to select between the
> standard (IJG) libjpeg, or libjpeg-turbo. This would be similar to what is
> done in alsa.in/alsa.make to select between the "full" and "light" versions
> of the library.

Either this ...

> 3. Other?

... or change the libjpeg rule to always build libjpeg-turbo instead.

I would prefer to avoid an option. But I'm not sure
1. if there are use-cases where libjpeg is preferable
2. if there are packages that fail to build with libjpeg-turbo

I have some libjpeg-turbo stuff lying around here somewhere. It was just
never finished. I've just dumped it in my test BSP so see if anythings
fails to build. I'll report the result later.