bug#22873: #22873 (multiple fake cursors); and, #17684 (crosshairs).

[Keith David Bershatsky]

The attached draft patch.diff applies to the Emacs 26 branch; bearing last 
commit da94ea92bc3ba6c236b394c00e6bbb725131a149; dated 12/26/2017.

Feature request #17684 (crosshairs) uses the same mechanism as #22873 (multiple 
fake cursors), and the former was actually what inspired me to work on the 
latter.  There is still no support to deal with placing fake cursors on text 
containing fancy overlays, text properties or combined characters.  At this 
time, multiple fake cursors that persist are redrawn each command loop -- which 
can someday be optimized.  Crosshairs are on an idle-timer.

In my own setup, I have incorporated #22873 to work with Magnar's multiple 
cursors library using just a slight modification to a couple of his functions, 
and can provide that if anyone is interested.  In a nutshell, Emacs can draw 
multiple fake cursors using #22873 instead of using the rectangle overlay 
chosen by Magnar.

+-mode is pretty straight forward.  Evaluate or load +-mode.el and type:  M-x 
+-mode

A simple interactive function demonstrating multiple fake cursors is named 
mc-test, which is within +-mode.el

I will continue to work on this project as time goes by -- it is still a work 
in progress ...

Keith

patch.diff
Description: application/diff

+-mode.el
Description: application/el