Synthesizing advance of upright glyphs in vertical flow |
||||
Issue descriptionIn a web developer meetup in Japan, I've got a feedback that, when Latin characters are set to upright in vertical flow, it should synthesize advances from the bounding box. Currently, WebKit and Blink on Mac does this, while Blink on Windows synthesize from font's height, leaving a space when, for instance, "x" is rendered. CSS spec says, in case the font doesn't have vertical advance, the behavior is UA dependent.
,
Mar 11 2016
After reviewing our code, #0 was incorrect. Blink always uses height. Probably the diff the authors were seeing is because the used fonts were different.
,
Mar 11 2016
The fix, if any, should be done in hb_font_funcs_t implementations, right? Now, I'm a bit skeptical of using bounding boxes alone, as that will leave no space between adjacent glyphs. No one will do that for horizontal layout for example. This is only relevant for cases where the font does NOT have a vmtx table, correct?
,
Mar 11 2016
> The fix, if any, should be done in hb_font_funcs_t implementations, right? Yes, I guess the call back to get the vertical advance is the one to fix, correct? > Now, I'm a bit skeptical of using bounding boxes alone, as that will leave no space between adjacent glyphs. No one will do that for horizontal layout for example. Agreed, I'll consult with WebKit code (if they do any in code, IIRC they had before for their Mac/iOS platform code) or Ken to see appropriate method before working on this. > This is only relevant for cases where the font does NOT have a vmtx table, correct? Yes. As far as I'm aware of, most Latin fonts don't have the table. I discussed with Ken that ideally all fonts in all scripts should have the table, but it hasn't happened yet.
,
Mar 11 2016
Sounds right. Ken Lunde's input is appreciated. Thanks!
,
Mar 13 2017
This issue has been available for more than 365 days, and should be re-evaluated. Please re-triage this issue. The Hotlist-Recharge-Cold label is applied for tracking purposes, and should not be removed after re-triaging the issue. For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot
,
Mar 13 2017
Did you get a chance to discuss this with Ken, Koji? Thanks.
,
Mar 13 2017
No...and I've been forgotten for a year, and no stars mean this is probably we could revisit if we hear more from authors. Closing.
,
Mar 16 2017
This should happen in HarfBuzz, not Blink. |
||||
►
Sign in to add a comment |
||||
Comment 1 by kojii@chromium.org
, Mar 11 2016