Axis Tags must be uppercase

[davelab6]

Over in http://typedrawers.com/discussion/comment/25823/#Comment_25823 @PeterCon said,

A bit of feedback on this font -- which also applies to Amstelvar: these are using custom axes, but are not following the spec requirements for custom axis tags:

Like other OpenType tags, axis tags are four unsigned bytes that can equivalently be interpreted as a string of four ASCII characters. Axis tags must begin with a letter (0x41 to 0x5A, 0x61 to 0x7A) and must use only letters, digits (0x30 to 0x39) or space (0x20). Space characters must only occur as trailing characters in tags that have fewer than four letters or digits.

Privately-defined axis tags must begin with an uppercase letter (0x41 to 0x5A), and must use only uppercase letters or digits. Registered axis tags must not use that pattern, but can be any other valid pattern.

https://www.microsoft.com/typography/otspec/fvar.htm has details on axis tag requirements.

I'd like to request that abcA and xyz2 can be changed to ABCA and XYZ2 in order to conform to the spec's requirements.

(This is the same as googlefonts/decovar#2)

[PeterCon]

Thanks, Dave. Upper-casing the tags would bring them into conformance with the spec.

[davelab6]

Here's the ttx dump of the current fvar table:

<?xml version="1.0" encoding="UTF-8"?>
<ttFont ttLibVersion="3.0">

  <fvar>

    <!-- Contrast -->
    <Axis>
      <AxisTag>cntr</AxisTag>
      <MinValue>8.0</MinValue>
      <DefaultValue>100.0</DefaultValue>
      <MaxValue>170.0</MaxValue>
      <NameID>256</NameID>
    </Axis>

    <!-- Grade -->
    <Axis>
      <AxisTag>grad</AxisTag>
      <MinValue>50.0</MinValue>
      <DefaultValue>176.0</DefaultValue>
      <MaxValue>500.0</MaxValue>
      <NameID>257</NameID>
    </Axis>

    <!-- Optical Size -->
    <Axis>
      <AxisTag>opsz</AxisTag>
      <MinValue>10.0</MinValue>
      <DefaultValue>14.0</DefaultValue>
      <MaxValue>72.0</MaxValue>
      <NameID>258</NameID>
    </Axis>

    <!-- ParaWidth -->
    <Axis>
      <AxisTag>prwd</AxisTag>
      <MinValue>84.0</MinValue>
      <DefaultValue>804.0</DefaultValue>
      <MaxValue>804.0</MaxValue>
      <NameID>259</NameID>
    </Axis>

    <!-- ParaWeight -->
    <Axis>
      <AxisTag>prwg</AxisTag>
      <MinValue>10.0</MinValue>
      <DefaultValue>176.0</DefaultValue>
      <MaxValue>1000.0</MaxValue>
      <NameID>260</NameID>
    </Axis>

    <!-- Serif Rise -->
    <Axis>
      <AxisTag>srfr</AxisTag>
      <MinValue>0.0</MinValue>
      <DefaultValue>35.0</DefaultValue>
      <MaxValue>95.0</MaxValue>
      <NameID>261</NameID>
    </Axis>

    <!-- Width -->
    <Axis>
      <AxisTag>wdth</AxisTag>
      <MinValue>120.0</MinValue>
      <DefaultValue>804.0</DefaultValue>
      <MaxValue>804.0</MaxValue>
      <NameID>262</NameID>
    </Axis>

    <!-- Weight -->
    <Axis>
      <AxisTag>wght</AxisTag>
      <MinValue>75.0</MinValue>
      <DefaultValue>176.0</DefaultValue>
      <MaxValue>500.0</MaxValue>
      <NameID>263</NameID>
    </Axis>

    <!-- xHeight -->
    <Axis>
      <AxisTag>xhgt</AxisTag>
      <MinValue>890.0</MinValue>
      <DefaultValue>1000.0</DefaultValue>
      <MaxValue>1200.0</MaxValue>
      <NameID>264</NameID>
    </Axis>
  </fvar>

</ttFont>

[PeterCon]

These changes would make the tags conform to the spec:
"cntr" -> "CNTR"
"grad" -> "GRAD"
"prwd" -> "PRWD"
"prwg" -> "PRWG"
"srfr" -> "SRFR"
"xhgt" -> "XHGT"

Wrt xHeight, could you envisage that becoming a registered axis in the future? (It's an axis I've seen used as an example more than once.) If so, any thoughts on a scale for that axis that would make sense across any fonts using the axis? (E.g., per-mille of em height?) If so, you might use that for your XHGT scale. (Same would be true for other custom axis scales, but I call that out just because I've seen x-height called out so often as a example.)

[dberlow]

Thanks for the suggestions, we are planning to change all the tags in Amstelvar to a different system, where the lowercase and uppercase issues will be resolved. Lowercase x height is part of our "y transparent" axis, which is almost all available in any font's vertical metrics data, so we left it out of Amstelvar, except x ht, because we were changing it.

…

On Fri, Mar 24, 2017 at 4:24 PM, Peter Constable ***@***.***> wrote: These changes would make the tags conform to the spec: "cntr" -> "CNTR" "grad" -> "GRAD" "prwd" -> "PRWD" "prwg" -> "PRWG" "srfr" -> "SRFR" "xhgt" -> "XHGT" Wrt xHeight, could you envisage that becoming a registered axis in the future? (It's an axis I've seen used as an example more than once.) If so, any thoughts on a scale for that axis that would make sense across any fonts using the axis? (E.g., per-mille of em height?) If so, you might use that for your XHGT scale. (Same would be true for other custom axis scales, but I call that out just because I've seen x-height called out so often as a example.) — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#17 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AB3ajp3UoiSSK_QPKazbpLHYI_hzQOtwks5rpCZkgaJpZM4L8qvI> .

[asaumierdemers]

Fixed with commit a879f3f

[dberlow]

Excellent, thanks.

I would rather "AmstelvarAlpha-VF-2017-01-23" not cause any confusion and be in an old fonts folder or something, so just "AmstelvarAlpha-VF" is there?

[davelab6]

I would rather "AmstelvarAlpha-VF-2017-01-23" not cause any confusion and be in an old fonts folder or something, so just "AmstelvarAlpha-VF" is there?

I'll take care of this with git tags

[dberlow]

tag on! thanks.

…

On Mon, Mar 27, 2017 at 4:16 PM, Dave Crossland ***@***.***> wrote: I would rather "AmstelvarAlpha-VF-2017-01-23" not cause any confusion and be in an old fonts folder or something, so just "AmstelvarAlpha-VF" is there? I'll take care of this with git tags — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#17 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AB3ajnKTYm4J4OypQW6FxbvWJeHNq7Utks5rqBkhgaJpZM4L8qvI> .

[davelab6]

https://github.com/TypeNetwork/fb-Amstelvar/releases

#21

[PeterCon]

Thanks! :-)