Wildly OT: pop-up virtual keyboard for Mac or Linux?

[Rustom Mody]

On Wednesday, February 11, 2015 at 11:55:19 AM UTC+5:30, Kushal Kumaran wrote:
> Skip Montanaro  writes:
> 
> > I know this is way off-topic for this group, but I figured if anyone
> > in the online virtual communities I participate in would know the
> > answer, the Pythonistas would... Google has so far not been my friend
> > in this realm.
> >
> > One of the things I really like about my Skype keyboard (and likely
> > other "soft" keyboards on Android) is that when you hold down a "key"
> > for a brief moment, a little mini keyboard pops up, from which you can
> > easily choose various accented variants and other symbols. For
> > instance, If I press and hold the "d" key, I see these choices (ignore
> > the capitalization of the first letter - my mistake sending a text
> > message to myself from my phone, and I can't seem to convert it to
> > lower case):   Đ|¦&dðď
> >
> > While I'm a touch typist, I almost never use auto-repeat, which is the
> > "binding" of held keys in most environments (curse you, IBM and your
> > Selectric!). These days I find my self needing accented characters
> > much more frequently than key repeat (C-u 2 5 - suffices in Emacs to
> > bat out 25 hyphens). Being an American with an American keyboard, I
> > haven't the slightest idea how to type any accented characters or
> > common symbols using the many modifier keys on my keyboard, and no key
> > caps display what the various options are. And I'm getting kind of
> > tired of going to Google and searching for "degree symbol". :-/
> >
> > Is there an X11 or Mac extension/program/app/magic thing which I can
> > install in either environment to get this kind of functionality? I'm
> > thinking that if you hold down a key for the auto-repeat interval,
> > instead of the key repeat thing making all sorts of duplicates, a
> > little window would pop up over/near the insertion point, which I can
> > navigate with the arrow keys, then hit RET to accept or ESC (or
> > similar) to cancel. It need not be perfect. It might (for example)
> > only work in certain environments (Chrome, Emacs, vim, Firefox).
> > Anyplace to start. It need even be written in Python (though that
> > would be cool.) I think that once something like this caught hold, it
> > would fairly quickly take over from the dark lords of auto-repeat.
> >
> 
> For very, very occasional use in emacs, there's C-x 8 RET (insert-char).

For slightly more frequent use (emacs-users)

1. Find a symbol such as ° maybe using google and paste it into emacs
   Does it exist in tex input method? To find out
2. Turn on tex input method (in some buffer) ie
   C-x RET C-\ and give tex (or whatever
3. C-u C-x = will tell info about the char. In particular it says:
   To input type \degree in tex input method

I guess for diacritical marks one could use one of the latin-n input methods

The above applied to á and latin-2-postfix says that á can be input with
a'

M-x describe-input-method will tell you others like

 ------------+---------+----------
  acute      |    '    | a' -> á
  ogonek     |    ,    | a, -> ą
  diaeresis  |    "    | a" -> ä
  circumflex |    ^    | a^ -> â
  breve      |    ~    | a~ -> ă
  cedilla    |    ,    | c, -> ç
  caron      |    ~    | c~ -> č
  dbl. acute |    :    | o: -> ő
  ring       |    .    | u. -> ů
  dot        |    .    | z. -> ż
  stroke     |    /    | d/ -> đ
  others     |    /    | s/ -> ß