It's time to look more closely at how we're dealing with baselines in vertical text. Cases with mixed upright and sideways text are liable to end up with irregular baselines in vertical-rl mode. (The same example in vertical-lr are less likely to look bad, but selecting the text shows similar irregularities in the extent of the highlighted area.) The attached testcase shows an example of baseline irregularity when vertical-rl writing mode is selected, at least on OS X (it's possible the exact results may depend on system fonts).

And here's a reftest to go with it.

(In reply to Jonathan Kew (:jfkthame) from comment #0) > (The same example in > vertical-lr are less likely to look bad, but selecting the text shows > similar irregularities in the extent of the highlighted area.) The patch doesn't address the vertical-lr case, correct? I'm not necessarily saying that this is a bad thing - selecting the text in horizontal-tb seems to show similar irregularities - but I'm still not completely clear how we define "baseline" in vertical-lr and rl.

(In reply to Simon Montagu :smontagu from comment #3) > (In reply to Jonathan Kew (:jfkthame) from comment #0) > > (The same example in > > vertical-lr are less likely to look bad, but selecting the text shows > > similar irregularities in the extent of the highlighted area.) > > The patch doesn't address the vertical-lr case, correct? I'm not necessarily > saying that this is a bad thing - selecting the text in horizontal-tb seems > to show similar irregularities - but I'm still not completely clear how we > define "baseline" in vertical-lr and rl. Right, this doesn't address that; and since I wrote that original comment, I realized the same thing applies horizontally, and we probably shouldn't be worrying about it. As for what "baseline" means in vertical mode, it's not entirely clear to me, but the new patch in bug 1084370 (on top of this fix) should make things substantially better.

Minor fix to make the reftest more reliable across platforms.

https://hg.mozilla.org/integration/mozilla-inbound/rev/9f4207643d30 https://hg.mozilla.org/integration/mozilla-inbound/rev/72894fb00f25

https://hg.mozilla.org/mozilla-central/rev/9f4207643d30 https://hg.mozilla.org/mozilla-central/rev/72894fb00f25