scrolling is slow if window > 100 lines

[GoogleCodeExporter]

When number of lines in the window is more then 100 (e.g. :echo &window)
the text is updated noticeably slower then if the window size is 99 for example.

The font size doesn't make a difference in itself.
The problem really seems to be number of lines (some kind of caching limit?).

I happens in both in the latest binary distribution and in the build I did 
myself directly out of the repository.

the OS is 10.6.8

--------------------------------
:version
VIM - Vi IMproved 7.3 (2010 Aug 15, compiled Sep 16 2011 23:54:11)
MacOS X (unix) version
Included patches: 1-315
Compiled by oflorian@onflbook
Huge version with MacVim GUI.  Features included (+) or not (-):
+arabic +autocmd +balloon_eval +browse ++builtin_terms +byte_offset +cindent 
+clientserver +clipboard +cmdline_compl
+cmdline_hist +cmdline_info +comments +conceal +cryptv +cscope +cursorbind 
+cursorshape +dialog_con_gui +diff +digraphs
 +dnd -ebcdic +emacs_tags +eval +ex_extra +extra_search +farsi +file_in_path +find_in_path +float +folding -footer
+fork() +fullscreen -gettext -hangul_input +iconv +insert_expand +jumplist 
+keymap +langmap +libcall +linebreak
+lispindent +listcmds +localmap -lua +menu +mksession +modify_fname +mouse 
+mouseshape +mouse_dec -mouse_gpm
-mouse_jsbterm +mouse_netterm -mouse_sysmouse +mouse_xterm +multi_byte 
+multi_lang -mzscheme +netbeans_intg +odbeditor
+path_extra +perl +persistent_undo +postscript +printer +profile +python 
-python3 +quickfix +reltime +rightleft -ruby
+scrollbind +signs +smartindent -sniff +startuptime +statusline -sun_workshop 
+syntax +tag_binary +tag_old_static
-tag_any_white -tcl +terminfo +termresponse +textobjects +title +toolbar 
+transparency +user_commands +vertsplit
+virtualedit +visual +visualextra +viminfo +vreplace +wildignore +wildmenu 
+windows +writebackup -X11 -xfontset +xim
-xsmp -xterm_clipboard -xterm_save
   system vimrc file: "$VIM/vimrc"
     user vimrc file: "$HOME/.vimrc"
      user exrc file: "$HOME/.exrc"
  system gvimrc file: "$VIM/gvimrc"
    user gvimrc file: "$HOME/.gvimrc"
    system menu file: "$VIMRUNTIME/menu.vim"
  fall-back for $VIM: "/Applications/MacVim.app/Contents/Resources/vim"
Compilation: gcc -c -I. -Iproto -DHAVE_CONFIG_H -DFEAT_GUI_MACVIM -Wall 
-Wno-unknown-pragmas -pipe  -DMACOS_X_UNIX -no-c
pp-precomp  -g -O2 -D_FORTIFY_SOURCE=1
Linking: gcc   -L/usr/local/lib -o Vim -framework Cocoa -framework Carbon      
-lncurses  -liconv -framework Cocoa    -L
/usr/local/lib  -L/System/Library/Perl/5.8.9/darwin-thread-multi-2level/CORE 
-lperl -lm -lutil -lc -framework Python

Original issue reported on code.google.com by onfl...@gmail.com on 13 Oct 2011 at 2:23

[GoogleCodeExporter]

I've never come across this problem and it seems strange.  Have you gone 
through the troubleshooting guide [1] to rule out that some plugin is causing 
this?

[1] https://github.com/b4winckler/macvim/wiki/Troubleshooting

Original comment by bjorn.winckler@gmail.com on 14 Oct 2011 at 5:02

[GoogleCodeExporter]

Yes, I did that but nothing helps.

I am running it on the 27" LCD, so if I maximize the MacVim, the visible line 
count is about 120.
Scrolling slows down then.
If I make the window smaller, less then 100 lines. The scrolling is fast again.

If I maximize the window BUT make the font larger so that there is less then 
100 visible lines,
everything is fine.

So this looks like it is related to how many visible lines there is, rather 
then 'pixel' size.

---
I can actually reproduce the problem on my other screen (21") when I make the 
font size really small (Mono:h7)

Original comment by onfl...@gmail.com on 14 Oct 2011 at 6:47

[GoogleCodeExporter]

Does it depend on what type of file you are editing?

NB. This does not sound like a MacVim specific issue ... if you want help 
tracking down what's causing Vim to run slow you really should ask on the 
vim_use Google group.

Original comment by bjorn.winckler@gmail.com on 14 Oct 2011 at 7:05

[GoogleCodeExporter]

I forgot to say: be sure to enable the "Experimental renderer" in the Advanced 
preferences -- it is much faster than the original renderer.

Original comment by bjorn.winckler@gmail.com on 14 Oct 2011 at 7:06

[GoogleCodeExporter]

The "Experimental rendered" fixes the problem indeed!

---
BTW: running Vim in the terminal (maximized, small fonts) is OK. The 'original' 
GVim seems OK as well.
I did turn the syntax off and it doesn't matter what kind of file I do load in 
(long lines, short lines), all the same.

So it looks like some kind of issue with the default renderer to me.

Original comment by onfl...@gmail.com on 14 Oct 2011 at 7:18

[GoogleCodeExporter]

Good!

Original comment by bjorn.winckler@gmail.com on 15 Oct 2011 at 11:34

• Changed state: WontFix