Sent from the wrong email alias... Begin forwarded message:
> From: [email protected] > Subject: Re: [webkit-dev] Ruby Text Enhancements > Date: September 24, 2010 1:55:19 PM HST > To: [email protected] > > You must be subscribed in order to post to this mailing list. > > > From: Eric Mader <[email protected]> > Subject: Re: [webkit-dev] Ruby Text Enhancements > Date: September 24, 2010 1:55:15 PM HST > To: Roland Steiner <[email protected]> > Cc: David Hyatt <[email protected]>, WebKit Development > <[email protected]>, Yasuo Kida <[email protected]> > > > I have prototyped something that seems to more-or-less work. Here's what I > did: > > 1) Changed RenderRubyRun to subclass these methods: > virtual int marginTop() const; > virtual int marginBottom() const; > virtual int marginLeft() const; > virtual int marginRight() const; > > > 2) added these members to RenderRubyRun: > mutable bool m_haveHorizontalMargins; > mutable int m_leftMargin; > mutable int m_rightMargin; > > 3) Added this private method to RenderRubyRun: > void getHorizontalMargins() const; > > 4) Here's what marginLeft() and MarginRight() look like: > int RenderRubyRun::marginLeft() const > { > getHorizontalMargins(); > > return m_leftMargin; > } > > int RenderRubyRun::marginRight() const > { > getHorizontalMargins(); > > return m_rightMargin; > } > > And here's getHorizontalMargins(): > void RenderRubyRun::getHorizontalMargins() const > { > if (m_haveHorizontalMargins) { > return; > } > > RenderText* rubyRenderText = static_cast<RenderText*> > (rubyText()->firstChild()); > RenderText* baseRenderText = static_cast<RenderText*> > (rubyBase()->firstChild()); > int rubyLength = rubyRenderText->firstTextBox()->width(); > int baseLength = baseRenderText->firstTextBox()->width(); > int leftMargin = RenderBlock::marginLeft(); > int rightMargin = RenderBlock::marginRight(); > > if (baseLength < rubyLength) { > RenderObject* prevSibling = parent()->previousSibling(); > RenderObject* nextSibling = parent()->nextSibling(); > bool prevIsText = prevSibling && prevSibling->isText(); > bool nextIsText = nextSibling && nextSibling->isText(); > > // FIXME: handle odd difference? > if (prevIsText) > leftMargin += (baseLength - rubyLength) / 2; > > if (nextIsText) > rightMargin += (baseLength - rubyLength) / 2; > } > > m_leftMargin = leftMargin; > m_rightMargin = rightMargin; > m_haveHorizontalMargins = true; > > } > > This method makes several assumptions that I'm not 100% sure are always safe: > * That a RenderRuby object holds only 1 RenderRubyRun object. > * That the text for the ruby text and ruby base are always the direct child > of the RenderRubyText and RenderRubyBase object. > * That the neighboring text is always a direct sibling of the RenderRuby > object. > > One enhancement I know is needed is to look at successive neighboring objects > to make sure that there's enough text there that the overhanging part of the > ruby text doesn't overshoot the neighbor(s) as well and bump into something > it can't overlap. > > Does this general approach look right? > > Regards, > Eric Mader > > On Sep 22, 2010, at 12:59 PM, Eric Mader wrote: > >> >> On Sep 21, 2010, at 7:16 PM, Roland Steiner wrote: >> >>> Hi Eric, >>> >>> comments inline: >>> >>> On Wed, Sep 22, 2010 at 6:57 AM, Eric Mader <[email protected]> wrote: >>> >>> On Sep 20, 2010, at 9:52 PM, Roland Steiner wrote: >>>> Oh vey, that's ambituous! :) There's so many corner cases I foresee on >>>> this one that I was just too happy to postpone it when we originally >>>> discussed to leave out CSS3 ruby stuff from the initial implementation, >>>> which is purely based off HTML5 - including supporting multiple base/text >>>> pairs within a single ruby, and line-breaking within the ruby. >>> Yes, it's a bit scary. ;-) I don't think I could implement the whole thing >>> at once, so I'm looking at doing a partial implementation. Maybe the first >>> round would only check to be sure that the neighboring blocks aren't <ruby> >>> blocks. >>> >>> I would actually suggest cutting it down further and at first doing it only >>> where the neighbor is plain text - this should still catch 90% of the cases >>> where you'd want overhang and should vastly reduce the corner cases. You >>> can verify and compute this rather easily when layouting the ruby, and >>> you'd not need to worry about different glyph heights of neighboring inline >>> elements, or about replaced elements interfering. Overhang would be >>> basically be the minimum of: maximum overhang, or length of neighboring >>> text run, or available/remaining space on the line. The latter factor may >>> also cause you to need to break the ruby or move it to the next line >>> altogether. >> >> I'll look at this idea too. What do I need to do to find the neighboring >> inline elements? >> >>> I'm looking at using a RenderOverflow object to implement this. Can you >>> point me at any documentation for this class, other than what's in the >>> code? I'm having some trouble sorting out what all the various rectangles >>> used in conjunction with this object represent. >>> >>> I have to say I'm not personally familiar with RenderOverflow, either >>> (haven't used it with ruby). Just judging from the description it stores >>> overflow rectangles for stuff that is actual content (layout overflow) and >>> stuff that is pure "cosmetic rendering", such as shadows or reflections >>> (visual overflow). For ruby overhang you'd be looking at layout overflow in >>> principle (unless the overhang text also has shadows and stuff, which may >>> add to the visual overflow), AFAICT. But as I said, I'm not really an >>> expert here. >> >> I've been looking at RenderOverflow, and I'm beginning to suspect that it's >> not the best way to proceed. Now I'm thinking that the negative margins are >> the way to go. My guess is that I need to set the margins on either the >> RenderRubyRun object or perhaps the RenderRuby object itself. To compute the >> correct margins, it looks to me like I'll need to access the widths of the >> RenderRubyText and RenderRubyBase objects. So far, I haven't been able to >> work out how to do that. Any clues would be greatly appreciated. >> >>> Cheers, >>> >>> - Roland >> >> Regards, >> Eric >> > > >
_______________________________________________ webkit-dev mailing list [email protected] http://lists.webkit.org/mailman/listinfo.cgi/webkit-dev
