Re: Android port

[Po Lu <luangruo@yahoo.com>]

Mohsen Banan <emacs@mohsen.1.banan.byname.net> writes:

> Hello,
>
> First, thank you very much for your wonderful work.
>
> I have started experimenting with it and have some
> questions that are likely too basic for the
> emacs-devel mailing list.

The appropriate list for these questions is help-gnu-emacs@gnu.org,
which I've copied in.  That list is archived and is also gatewayed into
Usenet, so questions and answers sent there will benefit more people
than those directed to me personally.

> 1) ---------
> Po> I believe the Android port of Emacs is now
> Po> more or less feature complete.
>
> Indeed it is. But the enlarge/zoom gesture did not
> work for me. I like that in termux.
> Has that feature been implemented? Do you plan to
> implement it? In the android environment, I think
> that feature is very valuable.

I've never found it necessary, so patches welcome, I guess.  See
lisp/touch-screen.el.

> 2) -----------
> Po> Follow the instructions in INSTALL.android
> Po> to build and install Emacs for your specific device.
>
> There is no INSTALL.android
> in the clone that I got with:
> git clone git://git.sv.gnu.org/emacs.git -b feature/android
>
> Has there been changes to that?

That document has been moved to `java/INSTALL'.

> 3) ----------
> I experimented with perso-arabic text (e.g.,
> persian tutorial) and the default fonts do not
> support it. Any advice on what font to use and how
> to select it in emacs and in android?
>
> I'll be happy to work with you on this as after
> the font chalenge, there may also be problems with shaping
> (harfbaz, ...)

Font shaping via HarfBuzz has been implemented and is now included in
all prebuilts for 64 bit architectures.  However, Emacs only supports
TrueType fonts, so I suggest installing the TrueType version Noto Sans
Arabic.

The procedure for installing fonts is described in (emacs)Android Fonts.

> 4) ----------
> I want to combine the use of emacs and termux.
> This is something that many would want to do.
> I found:
> https://marek-g.github.io/posts/tips_and_tricks/emacs_on_android/
> but the prebuilt emacs at
> https://github.com/marek-g/emacs-config/releases
> did not work for me.
>
> Would be great, if these two could be integrated
> out of the box.

Emacs is now capable of running subprocesses regardless of system
restrictions, so you should be able to build

  https://github.com/termux/termux-packages/

with the prefix changed to `org.gnu.emacs', and to simply install
the resulting archives in Emacs's home directory.

> ===========
>
> I have not done any Android development in the
> past but if you were willing to guide me a bit, I can
> likely come to speed and I do want to contribute
> towards an out of the box perso-arabic android
> emacs.
>
> Thanks and regards,
>
> ...Mohsen

Thanks for your interest in Emacs.  Fortunately, very little Android
specific knowledge is required to work on the Android port; a good
understanding of C and font scaling should be enough.