V4 metadata - Initial

[dbolack-ab]

Description

Adds new frontmatter brew metadata fields per discussion.

Uses defaults:

bleed:
  top: .125in
  bottom: .125in
  outer: .125in
  inner: .125in
safetySpace:
  top: .25in
  bottom: .25in
  outer: .25in
  inner: .5in
trimSize:
  width: 8.5in
  height: 11in
columns: 2
columnGutter: .125in
license: None
legalAuthors: 

NOTE The safe space and bleed have been adjusted to inner and outer from left and right to better represent print realities. Template writers will be responsible for handling the left vs right binding side.

DTRPG also recommends additional safe space for text, but I think we should leave that to the template writers.

Related Issues or Discussions

#4709

QA Instructions, Screenshots, Recordings

Ensure all necessary tests are in place

[Gazook89]

Can this metadata be added now, in v3, but just not exposed via the interface at all? Is there any risk to that? I'm just thinking that if we can get this worked out and merged then it is one less thing that has to happen "all at once" with v4.

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One thing I was unsure about was "safetySpace", because I was thinking it was the same as "margin". It's not, and for reference in case anyone is curious, here is a link. Basically, the space between the paper edge and the main content is the margin, and the space between paper edge and any critical graphic element (which might not be the main "content") is the "safe zone"-- meaning, don't put important stuff in that zone.

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Should columns: 2 be the default, or just a single column, and otherwise leave it to the templates/theme?

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Do you prefer this PR be narrowly focused on Page Layout related metadata, rather than ballooning it to include any other additions or deletions that may come about?

[dbolack-ab]

Can this metadata be added now, in v3, but just not exposed via the interface at all? Is there any risk to that? I'm just thinking that if we can get this worked out and merged then it is one less thing that has to happen "all at once" with v4.

I don't see a reason not to do so, other than demarcation. But I see that as a valid reason.

One thing I was unsure about was "safetySpace", because I was thinking it was the same as "margin". It's not, and for reference in case anyone is curious, here is a link. Basically, the space between the paper edge and the main content is the margin, and the space between paper edge and any critical graphic element (which might not be the main "content") is the "safe zone"-- meaning, don't put important stuff in that zone.

Safety space is the margin of error for the trim blades when the raw paper is cut.

Should columns: 2 be the default, or just a single column, and otherwise leave it to the templates/theme?

I think all of these values should default to being inherited from the theme, and we'll need a mechanism for that, overriding, and resetting to the template.

Do you prefer this PR be narrowly focused on Page Layout related metadata, rather than ballooning it to include any other additions or deletions that may come about?

Trying to bite-size as much as possible. :")