This is a refactor extracted from vim-patch 9.0.0067: cannot show virtual text
The logic for inline virtual text is going to be different in nvim than
text property based text in vim, but this refactor is still useful,
as calculation of displayed linesize is going to be stateful in a
similar way.
Problem: The screen.c file is much too big.
Solution: Split it in three parts. (Yegappan Lakshmanan, closesvim/vim#4943)
7528d1f6b5
This is an approximation vim-patch 8.1.2057. Applying the patch directly
isn't feasible since our version of screen.c has diverged too much,
however we still introduce drawscreen.c and drawline.c:
- screen.c is now a much smaller file used for low level screen functions
- drawline.c contains everything needed for win_line()
- drawscreen.c contains everything needed for update_screen()
Co-authored-by: zeertzjq <zeertzjq@outlook.com>
