Hinted size of Roboto has decreased between v1 and v2

[jamesgk]

Although the height of the various letters have not changed between Roboto version 1 and version 2, the hinted size of the letters has visibly changed between version 1 and version 2.

This is most visible in 12px, 14px, and 16px sizes, where the 1-pixel height difference between Roboto v1 is most visible.

For example, here is the hinted height of the letter 'x', which is 1082 units in both Roboto v1 and Roboto v2:
12px: v1=7px v2=6px
14px: v1=8px v2=7px
16px: v1=9px v2=8px

Capital letters also change, although not dramatically. In 16px, the height of 'A' changes from 12px to 11px, although it's 1456 units in both Roboto v1 and v2.

Internal bug b/19127020
/cc @roozbehp @christianrobertson @davelab6 @jungshik

[roozbehp]

IIRC, this was supposed to be fixed in their latest delivery. So it may have been fixed by now. (Anyway, even if it's fixed, a unit test should be created to check for it so we don't regress.)

[jungshik]

@roozbehp What's the latest delivery date of hinted Roboto ? I just pulled and the latest in the repo seems to be that of March 30. Do we have a newer delivery? If so, I want to use them on CrOS.

[jungshik]

This is also an issue reported against CrOS ( http://crbug.com/462015 ) . Internal bug : https://b/19127020

For the record, this bug was moved from https://code.google.com/a/google.com/p/roboto/issues/detail?id=148

[jungshik]

/cc @xiangye

[jungshik]

I think it's fixed in the latest delivery (2015-06-25) which @jamesgk just checked in.

In the image below, the top is the latest Roboto and the bottom is Roboto (as of 2014-12-09). Both were taken with ftview (Freetype 2.5.5 with LCD aa with horizontal RGB).

I counted the vertical pixels (of 'x' and 's' @12, 14, 16 ppem and of 'A' @16ppem) and confirmt that they match those of Roboto v1 (as reported by @roozbehp in comment 0) in the latest Roboto (top) while it has issues raised in this bug in 2014-12-09 snapshot (bottom).

I also did the same with grey-scale aa and got the same count. (btw, somehow, ftview and ftdiff in FT 2.6 and trunk always use grey-scale aa even when I selected LCD subpixel aa).

[davelab6]

I think it's fixed in the latest delivery (2015-06-25) which @jamesgk just checked in.

I notice a few changes when comparing TTXs of the version currently in https://github.com/google/fonts/tree/master/apache/roboto and https://github.com/google/roboto/tree/master/hinted

• The glyphorder has changed
• The vertical metrics also changed, eg in the Condensed Bold from

    <sTypoAscender value="1536"/>
    <sTypoDescender value="-512"/>
    <sTypoLineGap value="102"/>
    <usWinAscent value="1946"/>
    <usWinDescent value="512"/>
    <ascent value="1900"/>
    <descent value="-500"/>

to

    <sTypoAscender value="2146"/>
    <sTypoDescender value="-555"/>
    <sTypoLineGap value="0"/>
    <usWinAscent value="2146"/>
    <usWinDescent value="555"/>
    <ascent value="2146"/>
    <descent value="-555"/>

• Name IDs with platformID="1" were reintroduced.
• The POST table regressed from v3 to v2, adding PSNames

[jungshik]

• The glyphorder has changed : Under normal circumstances, users of a font should never worry about this. It's a bug on the side of a font user/a downstream program to rely on the stable glyph order.

The following two issues are not regressions. They're supposed to be (and they're) taken care of by building 'web' target:

• The POST table regressed from v3 to v2, adding PSNames
• The vertical metrics also changed,

This one we may consider cleaning up.

• Name IDs with platformID="1" were reintroduced.

[davelab6]

Under normal circumstances, users of a font should never worry about this. It's a bug on the side of a font user/a downstream program to rely on the stable glyph order.

I agree, although it is worth noting :)

The following two issues are not regressions. They're supposed to be (and they're) taken care of by building 'web' target

I'm sorry, 'regression' is not the right word, I didn't intend its implications; I should have said 'decremented' (from v3 to v2) or just 'changed' :)

I'm curious why the POST table v2 is preferable for web fonts.

I also wonder if you could explain the vertical metrics change. I guess that this could be as disruptive for users as changing the hinted x height again, so I'd like to understand it :)

[jungshik]

I also wonder if you could explain the vertical metrics change

It's NOT a change. Roboto has had what you called 'new metrics' for ages on Android (perhaps since J if not earlier).

I'm actually turning the table to you. Why in the world does Roboto in Google Fonts have different metrics than Roboto as shipped on Android and Chrome OS?

This issue is not a good place to discuss this issue. I'm filing an internal bug on this discrepancy.

[jungshik]

I agree, although it is worth noting :)

I don't think it's worth noting. It's a non-event. ;-p.

[davelab6]

Why in the world does Roboto in Google Fonts have different metrics than Roboto as shipped on Android and Chrome OS?

I actually don't think I really understand why. I'd be grateful if you could explain :)