On 16 Feb 2009, at 14:27, Eli Zaretskii wrote:
>
>> Would it be possible to add a termination condition in move_it_to to
>> stop after leaving the window vertically or horizontally (with
>> truncate-lines)?
>
> If we can tolerate an incorrect display, maybe.  The invisible part of
> the line could in principle include characters and faces whose
> presence may have global effects on the rest of the displayed portion,
> such as faces that use larger fonts, to say nothing of inline images.


Are such consequences wanted even if the line continues beyond the  
window vertically (i.e. truncate-lines == nil || word-wrap != nil)?

I can see why you might want to increase line height in case there is  
a high glyph or an inline image, but I could equally see the argument  
for displaying as many lines as possible and only increasing line  
heights when the user scrolls horizontally and the glyph is made  
visible.

If this redisplay issue is all that hinders users from editing such  
files (e.g., XML without newlines), fixing it would be a good idea  
IMHO.   It seems to me that Emacs handles large files quite well  
otherwise - loading and search&replace were blazing fast when I tried  
it.

Also, note that the new word-wrap feature means that users will more  
often deal with long "lines".