Default values of attributes and child elements of <style:style> elements

[Regina Henschel <regina.henschel@libreoffice.org>]

Hi members,

Chapter 20 contains attributes and elements of <style:*-properties> 
elements. These are child elements of the <style:style> element. As such 
they are subject of the inheritance described in section 16.2. If an 
attribute does not exist in the <style:style> element, which is 
referenced from the element, which is to be formatted, the value is 
used, which you get by the inheritance algorithm. The last level in the 
inheritance chain is described as “If there is no value specified in 
that default style, an implementation-dependent value is used.“

But some of the items in chapter 20 have wordings like “The default 
value is 90deg.” (20.2 chart:angle-offset) or “The default value is true 
if svg:width and svg:height attributes are not specified.” (20.4 
chart:auto-size) or “By default, the step count is automatically 
calculated based on the size and resolution of the filled area.” (20.130 
draw:gradient-step-count)

What does “default” mean in context of inheritance?

It might mean, that the “default” is used, if the <style:style> element, 
which is referenced by the element, has no formatting information for 
this formatting aspect. But that would contradict the  desired inheritance.

Or it might mean, that on the last level of inheritance the “default” 
value is used. But that would contradict “an implementation-dependent 
value is used”.

To solve this problem I suggest:

1. If it is appropriate for the single formatting aspect:
Add a special value for the default value or default behavior of the 
formatting aspect, so that you can get the “default” even if the parent 
has a different value set. This is already done for some items by using 
“auto”, “none” or “-1”.
For example in case of draw:gradient-step-count (20.130) solve it to:
“A value of 0 means that the step count is automatically calculated 
based on the size and resolution of the filled area.”

2. Describe the last level of the inheritance algorithm in section 16.2 
more precisely and add inheritance to section 20.1:
“If there is no value specified in that default style, but this 
specification defines a default value, than this default value is used. 
In all remaining cases an implementation-dependent value is used.“ (for 
16.2)
“For the formatting specified in this chapter the inheritance algorithm 
described in section 16.2. is in use.” (for 20.1)

What do you think? I would write the needed issues then.

Kind regards
Regina