Previously, a screen cell would occupy 28+4=32 bytes per cell
as we always made space for up to MAX_MCO+1 codepoints in a cell.
As an example, even a pretty modest 50*80 screen would consume
50*80*2*32 = 256000, i e a quarter megabyte
With the factor of two due to the TUI side buffer, and even more when
using msg_grid and/or ext_multigrid.
This instead stores a 4-byte union of either:
- a valid UTF-8 sequence up to 4 bytes
- an escape char which is invalid UTF-8 (0xFF) plus a 24-bit index to a
glyph cache
This avoids allocating space for huge composed glyphs _upfront_, while
still keeping rendering such glyphs reasonably fast (1 hash table lookup
+ one plain index lookup). If the same large glyphs are using repeatedly
on the screen, this is still a net reduction of memory/cache
consumption. The only case which really gets worse is if you blast
the screen full with crazy emojis and zalgo text and even this case
only leads to 4 extra bytes per char.
When only <= 4-byte glyphs are used, plus the 4-byte attribute code,
i e 8 bytes in total there is a factor of four reduction of memory use.
Memory which will be quite hot in cache as the screen buffer is scanned
over in win_line() buffer text drawing
A slight complication is that the representation depends on host byte
order. I've tested this manually by compling and running this
in qemu-s390x and it works fine. We might add a qemu based solution
to CI at some point.
Problem: Wrong cursor position when clicking after concealed text
with 'virtualedit'.
Solution: Store virtual columns in ScreenCols[] instead of text
columns, and always use coladvance() when clicking.
This also fixes incorrect curswant when clicking on a TAB, so now
Test_normal_click_on_ctrl_char() asserts the same results as the ones
before patch 9.0.0048.
closes: vim/vim#12808e500ae8e29
Remove the mouse_adjust_click() function.
There is a difference in behavior with the old mouse_adjust_click()
approach: when clicking on the character immediately after concealed
text that is completely hidden, cursor is put on the clicked character
rather than at the start of the concealed text. The new behavior is
better, but it causes unnecessary scrolling in a functional test (which
is an existing issue unrelated to these patches), so adjust the test.
Now fully merged:
vim-patch:9.0.0177: cursor position wrong with 'virtualedit' and mouse click
Allow Include What You Use to remove unnecessary includes and only
include what is necessary. This helps with reducing compilation times
and makes it easier to visualise which dependencies are actually
required.
Work on https://github.com/neovim/neovim/issues/549, but doesn't close
it since this only works fully for .c files and not headers.
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>
