Re: The display margin

[David Kastrup <dak@gnu.org>]

storm@cua.dk (Kim F. Storm) writes:

> David Kastrup <dak@gnu.org> writes:
> 
> > storm@cua.dk (Kim F. Storm) writes:
> > 
> > > But of course, if that image is showing text, a text cursor may
> > > still make sense...
> > 
> > In general, a change of cursor is an indicator that the behavior of
> > clicking will change.  Since different cursors might indicate
> > different behaviors, it certainly makes sense to have this as a
> > separate property.
> 
> I will add both a generic 'pointer' text property, and a specific
> image :pointer property.  
> 
> Maybe also an image :keymap property, but that will require more
> work, so I will have to investigate further before doing so.

I've been using keymaps on images for years already (via the display
property or so).  It was the only way to make an image clickable
since you could not enquire whether a click position was on an image
or on text beside it (at least for images on zero-width overlays).

> > > or newer would do...  But if you want something which really
> > > narrows down when this was introduced, (fboundp
> > > 'posn-object-x-y) will do.
> > 
> > This has such an _indirect_ flavor to it.  Let's hope that nobody
> > does a branch having one but not the other feature.
> 
> Sure.  Maybe (boundp 'void-text-area-pointer) will be better as it's
> in the C code [will be when my current fixes are committed in a few
> days].

Guess we'll find something.

> > > I was just asking in the context of "required information in
> > > mouse click events".  Your answer seems to be "nothing further".
> > 
> > Actually, given that we now have a pixel-accurate position within
> > the object (maybe this is generalizable in some manner also for
> > text?), it would be nice having a way of knowing the
> > pixel-accurate size of a displayed object in the first place so
> > that one can calculate the relative position in the image easily,
> > too.
> 
> I'll look into adding this info as well ... at least for images.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum