transparency vs. opacity

[Michael Brauer <michael.brauer@sun.com>]

Dear TC members,

below is a list where "transparency" and "opacity" is used in the 
OpenOffice.org XML specification.

transparency
------------
Transparency is used for
a) the <draw:transparency> element, that defines a transparency gradient
b) the "draw:transparency-name" attribute, that applies to a 
transparency gradient to a shape
c) the "draw:transparency" attribute, that specifies a single 
transparency value for a shape or a background image
d) the "draw:shadow-transparency" attribute, that specifies the 
transparency of a shadow
f) as special value "transparent" for the "fo:background-color" and 
"style:text-background-color" that specify the background color for 
paragraphs, text, etc.


opacity
-------
Opacity is used for
g) the "draw:stroke-opacity" attribute that specifies the opacity of a 
stroke


With the expection of f), all usages of transparency are related to 
drawing shapes and graphics, where SVG uses opacity values. f) is taken 
from XSL-FO, that supports "transparent" as special color value. It is 
the only usage of "transparent" or transparency in XSL-FO.

For this reason, I would like to propose to change all transparency 
values to opacity values, with the exception of f). This exception seems 
to be valid, because "transparent" is used here as an attribute value only.


Best regards

Michael