Re: try_cursor_movement not called?

[Po Lu]

Eli Zaretskii <eliz@gnu.org> writes:

> On December 1, 2021 11:54:27 AM GMT+02:00, Po Lu <luangruo@yahoo.com> wrote:
>> I thought that `try_cursor_movement' was the function in charge of
>> updating the cursor in straightforward situations where someone pressed
>> C-f to move forward, and the cursor did not move outside the window.
>> 
>> But if I insert the following text in a buffer:
>> 
>> ABCDEFG
>> 
>> Then move point to A and press C-f, the cursor moves to "B" but
>> try_cursor_movement is not called.
>> 
>> What am I missing?
>> 
>> Thanks.
>> 
>> 
>
> That's redisplay optimizations in action for you: there are optimizations we 
> prefer before try_cursor_movement.
>
> Assuming your Emacs was built with --enable-checking, invoke "M-x
> trace-redisplay" and look up in the code the optimizations it says it
> used.  (You will want to disable blink-cursor-mode and eldoc, to avoid
> too many meaningless trace messages.)

Thanks.  One other question: is it valid to assume w->window_start_valid
is true inside redisplay_internal?