Comments on text.texi

Comments on text.texi

[Kim F. Storm]

You have a few open questions in text.texi:

> @item line-spacing
> @kindex line-spacing @r{(text property)}
> A newline can have a @code{line-spacing} text or overlay property
> that controls the height of the corresponding display line.
> @c ???  Which display line is "corresponding"?

The line ended by the newline.

If the line is continued, only the last display continuation line (the
one ended by the newline) is affected.


> @item line-height
> @kindex line-height @r{(text property)}
> A newline can have a @code{line-height} text or overlay property that
> controls the total height of the corresponding display line.
> @c ???  Which display line is "corresponding"?
> We will call the property value @var{line-height}.

Ditto.


> If @var{line-height} is 0, the newline does not contribute to the
> height of the display row; instead the height of the newline glyph is
> reduced.
> @c ??? That is not clear.  Reduced how much?

To the height of the display line without the newline, i.e. to the
max height of any glyph preceding the newline.

> In that case, any @code{line-spacing} property on
> this newline is ignored.  This can be used to tile small images or
> image slices without adding blank areas between the images.
> @c ??? Precisely which of these features does ``this'' mean?

line-heigth = 0

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

Re: Comments on text.texi

[Richard Stallman]

    > @item line-spacing
    > @kindex line-spacing @r{(text property)}
    > A newline can have a @code{line-spacing} text or overlay property
    > that controls the height of the corresponding display line.
    > @c ???  Which display line is "corresponding"?

    The line ended by the newline.

    If the line is continued, only the last display continuation line (the
    one ended by the newline) is affected.

That sounds rather inconsistent to me.  Is this really a useful behavior?

Re: Comments on text.texi

[Kim F. Storm]

Richard Stallman <rms@gnu.org> writes:

>     > @item line-spacing
>     > @kindex line-spacing @r{(text property)}
>     > A newline can have a @code{line-spacing} text or overlay property
>     > that controls the height of the corresponding display line.
>     > @c ???  Which display line is "corresponding"?
>
>     The line ended by the newline.
>
>     If the line is continued, only the last display continuation line (the
>     one ended by the newline) is affected.
>
> That sounds rather inconsistent to me.  Is this really a useful behavior?

Line spacing is really only useful for displaying text (or editing
text in a Word Processor mode).  

Such modes are unlikely to use continued lines, so I think it is quite
sufficient functionality for the intended usage.

Besides, it would be quite difficult to implement this "correctly" so
it can go back and modify the line spacing of display rows with
continued lines.

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

Re: Comments on text.texi

[Richard Stallman]

    Line spacing is really only useful for displaying text (or editing
    text in a Word Processor mode).  

    Such modes are unlikely to use continued lines, so I think it is quite
    sufficient functionality for the intended usage.

Some are proposing that we split a long line at word boundaries at
display time.  This is not identical to the present method of line
continuation, but it is a kind of line continuation.

However, if we handle such line-breaking by adding newlines, there
will be no line-continuation.

    Besides, it would be quite difficult to implement this "correctly" so
    it can go back and modify the line spacing of display rows with
    continued lines.

I see the difficulty.

Anyway, it sounds like my text is accurate, then:

    A newline can have a @code{line-spacing} text or overlay property that
    controls the height of the display line ending with that newline.

Is anything in the text there now not accurate?

Re: Comments on text.texi

[Kim F. Storm]

Richard Stallman <rms@gnu.org> writes:

>     Line spacing is really only useful for displaying text (or editing
>     text in a Word Processor mode).  
>
>     Such modes are unlikely to use continued lines, so I think it is quite
>     sufficient functionality for the intended usage.
>
> Some are proposing that we split a long line at word boundaries at
> display time.  This is not identical to the present method of line
> continuation, but it is a kind of line continuation.

If we do that, we can fix the line-spacing property at the same time.

E.g. if we wrap at word boundary we could look forward for the newline
as see if it has a line-spacing property and use that.

>     Besides, it would be quite difficult to implement this "correctly" so
>     it can go back and modify the line spacing of display rows with
>     continued lines.
>
> I see the difficulty.
>
> Anyway, it sounds like my text is accurate, then:
>
>     A newline can have a @code{line-spacing} text or overlay property that
>     controls the height of the display line ending with that newline.
>
> Is anything in the text there now not accurate?

No.

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