RE: [office] Updated proposal for lines (underlining, crossing-out, overline)

["Paul Langille" <Paul.Langille@corel.com>]

To clarify what I was getting at in the meeting:

The thin/medium/thick entries should be considered 'styles' in my honest
opinion.  Ideally, anyone should be able to add new line styles AT ANY
TIME. The fact that few, if any application supports this at the current
time is a limitation we don't want to have to deal with ever. By putting
this information into 'styles' (including the auto/numbering), we are
properly separating the 'style and formatting' from the document itself.
We are allowing having different styles (i.e. single, double, automatic
single, automatic double), but underlining has no intrinsic semantic
meaning other than 'look at me'. 

I suggest that we have one entry "text-underline-style" that references
a style name at ALL TIMES. Any number (such as used in CSS3) would be
discovered by looking at either: a default "style sheet", or within the
document itself.

Number format(s), and aspects relating to 'automatic font-size matching'
should be held specifically in the underline style description
specifically. The 'thick' style should refer to a underline style that
has the thickness calculatable by: (font-height /
font-to-underline-divisor ) * scale-factor * unit_of_measure_to_pixel
for an example.

As Michael suggests, having some 'defaults' will not be a bad thing. But
we should make it a requirement that before finalizing this
specification, that these defaults are documented within the underline
style section of a 'style file' for use by other applications wanting to
be able to reuse those style types.

If someone wants a 3-pixel underline, for the purposes of the
OpenOfficeXML format, should be created as an underline style that names
this. 



-----Original Message-----
From: Michael Brauer [mailto:michael.brauer@sun.com] 
Sent: Thursday, August 21, 2003 11:05 AM
To: David Faure
Cc: office@lists.oasis-open.org
Subject: Re: [office] Updated proposal for lines (underlining,
crossing-out, overline)


Hi,

David Faure wrote:
> As discussed, here's an updated proposal for the
underlining/crossing-out-overline
> specification, more based on CSS3.
> 
> text-underline-type: none | single | double
> text-underline-style: none | solid | dotted | dashed | long-dash |
dot-dash | dot-dot-dash | wave
> text-underline-width: auto | thick
>    or the full CSS3 spec: auto | <normal> | <number> | <length> |
<percentage> | thin | medium | thick
>    (does any office suite need so much precision on the line widths?)
> text-underline-color already defined (3.10.23)
> text-underline-mode: continuous | skip-white-space
> 
> Notes:
> * text-underline-type isn't in CSS3, I have kept it separated so that
>   "double dotted" is a possible combination, I feel this is more
flexible than
>   the CSS3 mechanism of having "double" in text-underline-style

Compared to adding values like "double-dotted" to text-underline-style, 
this two-attribute approach has the advantage that all double lines are 
interpreted as single lines automatically if text-underline-type is 
ignored. This seems to be reasonable and simplifies transformations to 
CSS3 for all the double line styles that CSS3 does not support. The 
disadvantage of this solutions is that a solid double line will appear 
as single line in CSS3 if text-underline-style is ignored.

If the double line styles are added to text-underline-style, the double 
line would work in CSS3 without any transformation, but all other double

line styles would either disappear in CSS3 or would be displayed as 
single lines probably.

 From the office application view, I personally prefer the two-attribute

solution, but I'm not sure which solution is better from the CSS3 
transformation point of view.


> * the "auto" value for text-underline-width allows "double" underline
to take
>   more space than "single" underline, says the CSS3 specification. I
might be
>   a better naming for the default width. Thick would be what we call
bold.

The "auto" width is also allowed to consider the font size, but "thick" 
unfortunately isn't. In OpenOffice.org and at least one other 
application, a "bold" line considers the font size as well. This means 
that "thick" will be interpreted differently by CSS3 than by (some) 
office applications. For this reason, we from my point of view might 
consider to use the value "thin" instead of "auto" for non bold lines. I

personally do not see requirement for other widths.

> * text-underline-mode would replace fo:score-spaces (3.10.25).
> The reason is that it's IMHO easier to have all settings relating to
underline
> as text-underline-*, and it separates "should I underline spaces" from
> "should I cross out spaces". We have this distinction in KWord
already,
> and at the moment we have to bundle the two into fo:score-spaces. It's
a
> small difference, but I figure we should go for the most flexible
approach.

To replace fo:score-spaces with text-underline-mode seems to be 
reasonable, but makes transformations to XSL-FO more difficult. CSS1/2 
doesn't support score-spaces, so transformations to CSS1/2 wouldn't be 
effected.

> * You can add small-wave to text-underline-style if you see the need
for it.

I think we can/should remove this value.

> * I have added long-dash, it's not in CSS3 (but it's in OO).

It's supported by other applications as well.

> * Given that this comes from CSS (and not from XSLFO), I assume the
proper
> namespace for those attributes is "style:", right? I haven't seen any
"css:"
> namespace, and the possible values for text-underline-style are a
little bit
> different from CSS anyway.

I agree that "style" seems to be the correct namespace. We might 
consider to add a "css" or "css3" namespace, but it seems to me that at 
least for underlining, small differences to the css3 attributes will
exist.

> 
> The same can be used with overline instead of underline, for the lines
over
> the text (IIRC this is possible in OO?).

No, OOo does not support overlining, but we of course can add it to the 
OASIS specification regardless whether OOo supports it or not.

> 
> For crossing out, CSS3 uses the same as above, named
text-line-through-*, 
> but this is only a starting point for us, we need to add the
possibility to 
> cross out with characters, which I'll let Michael look into.
> Tab stop leaders will need something very similar to the crossing out
spec.
> 

Best regards

Michael


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