update core media type requirements for picture and img #1247
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Updated prose can be read more easily here: https://raw.githack.com/w3c/publ-epub-revision/0e0781d8c5dacbcbd04b832ba6a542bca7b72230/epub32/spec/epub-contentdocs.html#confreq-resources-cd-fallback-img |
epub32/spec/epub-contentdocs.html
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| <ul> | ||
| <li>it MUST reference Core Media Type Resources from its <code>src</code> and | ||
| <code>srcset</code> attributes, when those attributes are specified;</li> | ||
| <li>any child <a |
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nitpick: "any child source elements" might need to explicit the parent context here, as the main subject is the img element.
We could say "any child source elements of this picture element" (referencing the wording introducing this list item) or "any sibling source elements of the img element".
Note btw that only the preceding source siblings will be used to define the img source set. But we may not need to go to this level of detail…
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Blah, right, "child" was from an earlier drafting. I'll change it to sibling.
epub32/spec/epub-contentdocs.html
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| href="https://www.w3.org/TR/html/semantics-embedded-content.html#the-source-element" | ||
| ><code>source</code> elements</a> also MUST reference Core Media Type | ||
| Resources from their <code>src</code> and <code>srcset</code> attributes unless the | ||
| element specifies that it references a Foreign Resource media type in its |
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nitpick: "specifies that it references a Foreign Resource media type in its type attribute" is understandable but might sound a little odd or hard to parse?
- we never explicitly specify what is a Foreign Resource media type (is it any media type that is not a CMT? or the media type of a Foreign Resource that is correctly declared in the Package Doc?).
- also, a
sourceelement can't be said to "reference a (…) media type" - it doesn't really take into account MIME type parameters, which are allowed in the
typeattribute value.
In HTML/WHATWG lingo, we could say something along the lines of:
unless its
typespecifies a MIME type whose essence is listed as a Core Media Type.
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If we use "essence", everyone has to take a trip to another specification... :)
How about we just keep this in epub parlance by restating it as:
unless it specifies a media type in its
typeattribute that is not a Core Media Type.
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How about we just keep this in epub parlance by restating it as:
unless it specifies a media type in its
typeattribute that is not a Core Media Type.
yes, works for me!
If we use "essence", everyone has to take a trip to another specification... :)
meh, where's the fun when not doing that? 😁🤓
epub32/spec/epub-contentdocs.html
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| </li> | ||
| <li>Otherwise, it MAY reference Foreign Resources in its <code>src</code> and | ||
| <code>srcset</code> attributes provided a <a | ||
| href="epub-packages.html#sec-foreign-restrictions-manifest">manifest fallback</a> |
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s/manifest fallback/manifest fallbacks/ ?
This PR fixes #1237 (again) as described in #1237 (comment):
picturethe only time foreign resources can be referenced is from asourceelement that explicitly identifies that it references a foreign media type in itstypeattributeimgelement requires a core media type fallback whenever itssrcorsrcsetattributes reference foreign resources.@rdeltour please verify that I have this right, and that the spec prose reflects your proposal.