[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

bug#18493: 24.3.93; posn-col-row should take text-scale-mode into accoun

From: Dmitry Gutov
Subject: bug#18493: 24.3.93; posn-col-row should take text-scale-mode into account
Date: Fri, 19 Sep 2014 00:55:06 +0400
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.1

On 09/18/2014 06:58 PM, Eli Zaretskii wrote:

That's the intended behavior: posn-col-row is documented to return the
coordinates of its argument in canonical character units.  And that is
what it does here.  There's no bug here.

Fair enough. Maybe define an alternative function, which does take text zoom into account?

Or otherwise, I'd be fine with precise algorithm how to convert one into the other, if it's relatively simple and unlikely to change.

Calculate what, exactly?  The results of this function _are_ reliable.
You just cannot in general use them as the logical (a.k.a. "physical")
column and row number, i.e. the ordinal number of a character from the
line beginning and its line number relative to window-start.  You can
only use them as the real column and row if your text uses the default
face.  But once variable-size fonts, stretch glyphs, images, and other
display atrocities come into play, there's no meaningful way of
talking about "columns" and "rows" that can be used as indices into
the text.

Text zoom is different from all the other features you enumerate here, though. In programming language buffers, I usually have no images or proportional fonts, but zooming the text is something that happens once in a while.

So the answer to your question depends on what you intend to do with
the value.

All the recent display engine issues I've been creating are for the same package and feature: company-mode and its overlay-based popup, which I'd like to polish up a bit before trying other methods of popup rendering, because they won't be available to users of Emacs 24.4 and older versions, and it'll likely be quite some time until the next release.

IOW, please explain what is it that "you'd like".

The "current column" obtained from the return value of this function, is used to position each line of the popup in the display string of the overlay that spans the next few lines. So naturally, the return value should not depend on the zoom level. And I'm using `posn-col-row' for this because it became the consensus in the several discussions I've had with you recently on this subject.

reply via email to

[Prev in Thread] Current Thread [Next in Thread]