1110266 - units that depend on font metrics (such as 'ch') should be derived from horizontal font metrics when writing-mode is vertical but text-orientation is sideways

Status: RESOLVED FIXED

Description

[Jonathan Kew (:jfkthame)]

Compare:

data:text/html;charset=utf-8,
  <div style="font-family:monospace">
    <div style="width:9ch; height:9ch; border:1px solid black">123456789</div>

data:text/html;charset=utf-8,
  <div style="font-family:monospace; writing-mode:vertical-lr; text-orientation:sideways-right">
    <div style="width:9ch; height:9ch; border:1px solid black">123456789</div>

IMO, these should both produce the same size of square <div>, just large enough to fit the line of digits.


Note that it's expected that without text-orientation, as in

data:text/html;charset=utf-8,
  <div style="font-family:monospace; writing-mode:vertical-lr">
    <div style="width:9ch; height:9ch; border:1px solid black">123456789</div>

we get a larger square, because its size will be based on 9 characters of upright vertical text (consider if the ASCII digits were replaced by fullwidth ones).

Webkit appears to behave in this way, too.

Comment 1

[Jonathan Kew (:jfkthame)]

Created attachment 8535084 [details] [diff] [review]
Use horizontal-font metrics as basis for CSS units when text-orientation is sideways

Comment 2

[Simon Montagu :smontagu]

Comment on attachment 8535084 [details] [diff] [review]
Use horizontal-font metrics as basis for CSS units when text-orientation is sideways

Review of attachment 8535084 [details] [diff] [review]:
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Makes sense

Comment 3

[Jonathan Kew (:jfkthame)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/977d6c001d70

Comment 4

[Wes Kocher (:KWierso)]

https://hg.mozilla.org/mozilla-central/rev/977d6c001d70