[svgwg] Issue: Request for clarification on complex text shaping marked as DoC_accepted

nikosandronikos has just labeled an issue for 
https://github.com/w3c/svgwg as "DoC_accepted":

== Request for clarification on complex text shaping ==
Gecko positions text in individual characters but renders combined 
glyphs (typographic character units[1]) which matches the spec. Blink 
and WebKit position and render individual character glyphs, in 
violation of the spec. I started updating Blink's SVG text layout to 
use HarfBuzz's complex text shaping and match the spec, but I think it
 would be a regression for our users.

Consider the following examples in Gecko vs Blink:
"traffic" vs "transit" with rotation: http://output.jsbin.com/xajice
"traffic" vs "transit" on a curve: http://output.jsbin.com/haqaxi
"yeah!" with diacritics: http://output.jsbin.com/gefuca

These examples look best in OSX10.11.3. Because shaping depends on 
platform-specific fonts, the examples change based on your OS (using 
"serif" instead of "cursive" on ubuntu demonstrates some of these 
issues). This fact seems like very surprising behavior for authors, 
particularly if the content is dynamic.

I don't have an idea of how to make this better but my wishlist 
includes:
1) Replacing "traffic" with "transit" does not wildly change text 
rendering.
2) Arabic is not a second-class citizen in SVG, even with word 
ligatures [2].

[1] https://drafts.csswg.org/css-text-3/#typographic-character-unit
[2] 
https://en.wikipedia.org/wiki/Arabic_script_in_Unicode#Word_ligatures

See https://github.com/w3c/svgwg/issues/65

Received on Monday, 8 August 2016 10:41:04 UTC