[Buildroot] [PATCH 2/2] libvncserver: add config option for tightpng encoding support

[Thomas Petazzoni <thomas.petazzoni@free-electrons.com>]

Dear Floris Bos,

On Fri, 26 Dec 2014 01:46:15 +0100, Floris Bos wrote:

> +if BR2_PACKAGE_LIBVNCSERVER
> +
> +config BR2_PACKAGE_LIBVNCSERVER_TIGHTPNG
> +	bool "TightPNG encoding support"
> +	select BR2_PACKAGE_JPEG
> +	select BR2_PACKAGE_LIBPNG
> +	help
> +	  TightPNG encoding speeds up HTML5 based VNC clients like noVNC.
> +
> +	  http://wiki.qemu.org/VNC_Tight_PNG

I've tried to read a bit, but I don't really understand whether JPEG is
absolutely necessary to get TightPNG support. The webpage you mention
says "If the client indicates JPEG support by sending a JPEG
quality pseudo-encoding, then the server can send JPEG, because PNG
will only replace the basic compression type used in normal tight.",
which seems to indicate that the JPEG support is only optional.

> +endif
> diff --git a/package/libvncserver/libvncserver.mk b/package/libvncserver/libvncserver.mk
> index b26d5b9..8479a62 100644
> --- a/package/libvncserver/libvncserver.mk
> +++ b/package/libvncserver/libvncserver.mk
> @@ -56,4 +56,10 @@ else
>  LIBVNCSERVER_CONF_OPTS += --without-zlib
>  endif
>  
> +ifeq ($(BR2_PACKAGE_LIBVNCSERVER_TIGHTPNG),y)
> +LIBVNCSERVER_DEPENDENCIES += libpng

So we don't really need JPEG support after all, since you don't depend
on it?

> +else
> +LIBVNCSERVER_CONF_OPTS += --without-png
> +endif
> +
>  $(eval $(autotools-package))

Thanks,

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com