Add Guides Opacity [GDOP] axis

[simoncozens]

Requirements

By ticking the cases (or putting x between the square brackets in text mode), you confirm the following:

• I have inspected the current Axis Registry and there is not a registered custom axis that could be used for the variation purpose on the upcoming font project.
• The metadata fields of the proposed axis meet the Axis Requirements as specified in the Protocol (linked above).

Font project(s) using the axis

This is designed for a color extension to Briem Hand. It can also be applied to the other handwriting primer fonts (Australian Education series, etc).

Short description of what the axis does

Changes the opacity of guidelines running across the glyphs. (If a more general application is required, we could say that it changes the prominence of non-letter portions of the glyph.)

Image

Why is the axis needed

Handwriting primer fonts come in two styles, ruled and unruled. The ruled style is intended for demonstrating the consistent positioning of letter elements based on baseline, ascender, descender, x-height, etc. However, the user benefits from having the ability to control the opacity of the rule to achieve the desired prominence during print. By turning down the rule opacity to zero, the user can switch between ruled and unruled styles in the same font.

Axis metadata fields

(Remove this line and fill out the mock of the data structure of the axis)

# GDLN based on https://github.com/SorkinType/Briem-Hand
tag: "GDLN"
display_name: "Guideline Opacity"
min_value: 0.0
default_value: 0.0
max_value: 1.0
precision: -2
fallback {
  name: "Unruled"
  value: 0.00
}
fallback {
  name: "Ruled"
  value: 1.00
}
fallback_only: false
description: "Adjust opacity of guidelines"

[davelab6]

tag: "GDLN"
display_name: "Guideline Opacity"

I would assume a tag of GDLN would be for more general guidelines, and since this is specifically Guideline Opacity then I think GDLO would be better.

min_value: 0.0
default_value: 0.0
max_value: 1.0
precision: -2

Nit, since precision is -2, I think the values above should be stated as such, so:

min_value: 0.00
default_value: 0.00
max_value: 1.00
precision: -2

I think the 0..1 range makes sense for opacity, 2nd choice would be 0..100 with 0 precision.

[rsheeter]

This seems very specific to Briem Hand; is there a reasonable way to make it more general to increase the odds of it being a reusable axis?

[simoncozens]

It could also potentially be applied to other fonts in the catalogue:

• Edu NSW ACT Foundation
• Edu QLD Beginner
• Edu SA Beginner
• Edu TAS Beginner
• Edu VIC WA NT Beginner

If we need it even more general,

we could say that it changes the prominence of non-letter portions of the glyph.

I'm not sure what that would look like. :-)

[tphinney]

On the one hand, I like a more general “changes the opacity of [markup or other non-essential portions] on/around glyphs”

That is, one could use it for making something fade in, where that something is not critical. Use it for guidelines, for sure, but one could imagine it for other things.

But then again, the same handwriting fonts that display guidelines might also want to display separate and independently controlled markup for showing stroke order and direction. hmmm.

[simoncozens]

If we are going general, I'm not sure I would stick with "opacity". I'm thinking things like the Buffalo Gals "Fringe" axis.

[RosaWagner]

That is indeed useful for any school font. In anticipation of other related guideline axes**, I would dedicate 2 letters pour Guidelines (GL) and 2 letters for the function (OP).

**Not that it won't be necessary implemented but for example:

• Aspect of the line (I often see dotted lines instead of plain to contrast with the letter's outline)
• Thickness of the line
• Number of lines (according to the country or the learning progress it can go from 1 to 4).
• Space between lines (I would see that useful if a "guideline-only" font get released, which will be necessary at some point)

[simoncozens]

Number of lines is one thing we were also thinking about for Briem Hand, so an axis for that might be useful.

I like GLOP.

[vv-monsalve]

We are including just a Default fallback at the axis registry level. Named instances are not yet supported.

I think the 0..1 range makes sense for opacity, 2nd choice would be 0..100 with 0 precision.

Opacity is typically understood in %. So probably better to opt for the latter.

I would dedicate 2 letters pour Guidelines (GL) and 2 letters for the function (OP).

This way is suggested in the protocol after Element Grid, Element Shape experience.

[davelab6]

@RosaWagner great idea! @vv-monsalve proposed on a call now that since the family name particle is Guides for brevity, GD is a better 2-character axis tag handle than GL. So let's go with GDOP.

@evanwadams confirmed GIMP uses 0..100 for opacity in its UI, so let's go with that for the range.

# GDOP based on https://github.com/SorkinType/Briem-Hand
tag: "GDOP"
display_name: "Guides Opacity"
min_value: 0
default_value: 100
max_value: 100
precision: 0
fallback {
  name: "Default"
  value: 100
}
fallback_only: false
description: "Adjust opacity of guides from 100 (fully visible) down to 0 (fully invisible)."

This is now approved to go to registration.