Re: Fringe frame parameters, default values

[Kim F. Storm]

Richard Stallman <address@hidden> writes:

>     Suppose we start with a font whose width is equal to or a little more
>     than the bitmap width, this means that the default setting of the
>     fringe width would be 1.0 for both the left and right fringe.
> 
>     However, if we start with a font which is half the width of the bitmaps,
>     the default ratio for the bitmap widths should be 2.0 (or more) to allow
>     the fringes to be wide enough to show the bitmaps.
> 
> Ok, this argument makes sense.  It suggests that the fringe widths
> should be in pixels.
> 
> But then let's reconsider the default.  Why shouldn't the default
> value be the number of pixels that the fringe bitmaps require?

That makes sense - but that would also mean that we would hard-code
the number 8 as the default fringe width.

> Why make it nil?

All of this started with myself offering to make the fringe bitmaps
customizeable (opening up a can of worms :-).  With that in mind, I
wanted the default to be able to handle the case where one of the
user's bitmaps was wider than the default 8 pixels, i.e. the fringe
widths would automatically adjust to a new bitmap which is, say, 12
pixels wide.

But I agree that nil is a strange value for this (it doesn't
actually have to be nil - any value which is not an integer
will cause the default width to be calculated).

> Whatever special thing nil does, people will probably always want to
> do.

Yes, but I also think it makes sense for a user to know that
to reset the fringe widths to the default setting, he just
set them to nil - rather than having to care about what the
default happens to be.

I've changed frame-parameters to report the actual fringe widths
rather than the configured values.  This doesn't really harm, as a
user (or package) can [and probably will] always set both the left and
right fringe widths to get a desired effect.

I suggest we leave things as they are now.  It works, it has the
maximum amount of flexibility, it will handle different widths of user
customized bitmaps, and it has a `simple' default setting.

-- 
Kim F. Storm <address@hidden> http://www.cua.dk