[svgwg] UTF-16 code points for addressable characters

r12a has just created a new issue for https://github.com/w3c/svgwg:

== UTF-16 code points for addressable characters ==
11.1.1. Definitions
https://svgwg.org/svg2-draft/text.html#Definitions

> addressable character
>     A character that is addressable by text positioning attributes 
and SVG DOM text methods. Characters discarded during layout such as 
collapsed white space characters are not addressable, neither are 
characters within an element with a value of none for the display 
property. Characters are **addressed by their index measured in UTF-16
 code units**, prior to applying any text-transform conversions, as 
described for the methods in the SVGTextContentElement interface; **as
 a result, a single Unicode character may map to multiple addressable 
characters**. 

We hope that it will not be possible to address a single surrogate 
character, and think that this should be stated in the definition.

We also suggest "a single Unicode code point may map to" to clarify 
the meaning better.

We would actually prefer that accessible characters be defined in 
terms of Unicode code points, rather than UTF-16 code units. 

Addison proposes the following alternative text for "Characters are 
addressed..."

> The address of a given Unicode character (codepoint) is measured in 
UTF-16 code units, prior to applying any text-transform conversions, 
as described for the methods in the SVGTextContentElement interface; 
as a result, a single Unicode code point may be represented by 
multiple UTF-16 code units.

Finally, a quick example of what it means to address a character means
 would probably help readers understand the purpose of an addressable 
character. We struggled with that.

Please view or discuss this issue at 
https://github.com/w3c/svgwg/issues/259 using your GitHub account

Received on Friday, 9 September 2016 12:25:46 UTC