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Subject: |
Re: How to obtain x/y/hpos/vpos at eol -- excluding overlay 'after-string. |
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Mon, 04 Apr 2016 14:06:08 -0700 |
Thank you, Eli, for taking a look at this particular thread.
There are a couple of applications where this would be useful.
The first application is a common function available interactively called
`posn-at-point` which cannot return the desired `x` and `hpos` when an
'after-string is present at point. For example, line-move-visual in simple.el
has never worked correctly when I have overlay 'after-string at the end of the
line. So, I have been using a workaround with `vertical-motion` to calculate
the desired `temporary-goal-column`. Here is the link to a thread on
emacs.stackexchange.com from about a year ago relating to this issue:
http://emacs.stackexchange.com/questions/7957/calculating-cursor-position-excluding-the-overlay-after-string
The second application is related to feature request 22873 (multiple fake
cursors) and a dormant (yet related) feature request 17684 (drawing a vertical
line the length of the window). I have not been able to accurately predict
programmatically where the fake cursors are located subsequent to the screen
scrolling when overlay 'after-string are present. [I spent a day writing up a
function to calculate the differential of `y` and `vpos` based on previous and
current window-start/end, only to discover that the Little Rascals (fake
cursors) were still somewhere else when scrolling.] The function
`erase_phys_cursor` redraws the character (where the cursor was) based upon (in
part) the values of x/y/hpos/vpos. Until I can figure out how to accurately
predict where those Little Rascals (fake cursors) have gone to when scrolling
occurs, the easiest thing to do is erase/redraw everything along the `x` axis.
`erase_phys_cursor` should not be used, however, when there is no TEXT along
the `x` axis - because that yields strange looking glyphs along the right side
of the screen. Before calling `erase_phys_cursor` (or my custom function
`mc_erase`), I want to check to see where the end of the visual line is --
i.e., x/y/hpos/vpos at the end of each visual line -- and only erase/redraw
characters when the `x` axis is less than the end of the visual line
Keith
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At Mon, 04 Apr 2016 23:30:04 +0300,
Eli Zaretskii wrote:
>
> * * *
>
> Please tell what problem you are trying to solve, and why. Obtaining
> coordinates is a means, but I don't yet see the end, so please help us
> understand that.
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