2016-04-04 17:07 GMT+02:00 Igor Stasenko <[email protected]>: > > >> For now, external objects can't extend below the baseline. >> > > Slightly not like that. An external object are bound to concrete position > in text. And layout of a single line are computed based on dimensions of > that object, as well as dimensions of other parts of a line. The text flow > are not affected by the object in terms that there is no capability to > compute wrapping text around it or align it left/right whatever separately > from text. It means that basically external object is like a special kind > of glyph/icon that uses same layout rules as character glyphs, but just > rendered separately. >
I understood as much. I've just seen code that such a "special" glyph can only contribute to text ascent (since, per comment, it is aligned to the baseline). Not very important, just a detail. > >> >> Position inside spans can be ambiguous: last position of a span and first >> position of the next span are the same position. >> >> Well, for some operation the are treated as same, for some - don't. > Since there's nothing can be between two positions at the ends of adjacent > spans, from standpoint of user they represent same position in text. But > from standpoint of model they are different since position are belong to > different spans. > Sure thing, there certain pieces added to avoid problems with such > ambiguity, so that it don't causing problems on user-level. > Ok. Thierry
