[TxMt] Re: TextMate freezes when lines are super long

[Allan Odgaard]

On 8 Dec 2013, at 3:30, Walter Lee Davis wrote:

> FWIW, I believe this happens because of the regular expression 
> scanning going on to effect syntax highlighting. If you can set this 
> particular file type to .txt or another non-highlighted format first, 
> you may find that opening it goes faster.

I believe the main issue is text layout. This is pretty expensive and 
it’s hard to break up a single line partly due to unicode rules partly 
because we need the width of the full line (which requires the full line 
to go through layout).

Enabling soft wrap should improve performance significantly since here 
we do break up the line (on spaces) and only the stuff that is visible 
will actually go through layout, so smaller chunks are given to 
CoreText.

It’s a known issue, but how to fix it is challenging, as effectively 
we need to pass less to CoreText, and to do that properly we need to 
partially replicate unicode rules in TextMate (instead of leaving that 
to the system) and also need to estimate glyph widths to have some 
estimates to use before we get real values from CoreText.