[x3d-public] draft X3D 4.1 prose for font files and libraries
Andreas Plesch
andreasplesch at gmail.com
Sat Mar 1 06:45:40 PST 2025
I basically had the same questions as Michalis.
Comments below.
> Date: Sat, 1 Mar 2025 05:52:24 +0100
> From: Michalis Kamburelis <michalis.kambi at gmail.com>
>
> As for FontLibrary,
>
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/components/text.html#FontLibrary
> : I admit I don't understand this proposal (yet).
>
> 1. Where is the FontLibrary actually used? It doesn't seem you can refer to
> a FontLibrary node in any way. It's also not X3DChildNode, so you cannot
> just place it in groups.
>
This is a big missing piece.
After some thought, I think the idea is to give the X3D browser information
on how to render fonts which are referenced in a FontStyle.family field.
One option is to think of it not as a Node but as a Statement describing a
resource available to the X3D browser in general.
Another option is to make it part of WorldInfo as a value for a new
WorldInfo.fonts field ?
The idea came up as an alternative to a FontStyle.url field, so see below.
> 2. The sentence """If present, only the first active font library retrieved
> from the url list shall be used."""" --- What is the meaning of word "used"
> in this sentence? Used for what?
>
What is 'active' ? Probably accessible
"Used": ?
> 3. """Individual font library files can be used by multiple FontStyle nodes
> in a scene.""" -- How? FontStyle does not refer to FontLibrary. And I
> understand in this version, FontStyle would not have its own FontStyle.url
> field.
>
> Did you maybe want to add a field like "SFNode FontLibrary
> fontLibrary" to FontStyle or Text? Or make FontLibrary a X3DChildNode?
>
That was my first thought as well but see above.
A simple way to make a FontLibrary url available to multiple FontStyle
nodes is by DEF/USE.
A FontStyle.fontLibrary field is preferred over a global scope since it
clearly associates a font to a FontStyle/Text.
It is better not to have to rely on the family name to identify a font.
Having to rely on the family name is more error prone for both the author
and the browser.
4. A testcase, preferably many testcase(s), explaining the FontLibrary
> usage (X3D files + intended rendering) would very helpful. (Same goes for
> the previous proposal actually.) Please provide testcases along with spec
> prose -- they make the intention more obvious.
>
Including edge cases if possible.
Overall, so far, I admit FontLibrary is confusing to me, I don't know what
> it means. The previous proposal (extending FontStyle) seems more
> straightforward -- a few people (including me) had feedback, but it seems
> that we all "got the intention" of FontStyle.url correctly, we just pointed
> some things to improve in wording.
>
One advantage of a FontLibrary (or perhaps just 'Font') node would be
DEF/USE.
As mentioned multiple times, the spec. should include language that the
FontStyle.style field may be ignored if a FontLibrary url is accessible as
in most cases that url will only provide data for one specific style..
Regards, -Andreas
> pt., 28 lut 2025 o 19:56 Brutzman, Donald (Don) (CIV) via x3d-public <
> x3d-public at web3d.org> napisa?(a):
>
> > Thanks everyone for responses, implementation improvements, technical
> > details, and many insights.
> >
> > First positive takeaway: WOFF File Format 2.0 is the clear preference to
> > WOFF 1.0.
> >
> > WOFF File Format 2.0, W3C Recommendation, 08 August 2024
> >
> > - "Abstract. Based on experience with WOFF 1.0, which is widely
> > deployed, this specification was developed to provide improved
> compression
> > and thus lower use of network bandwidth, while still allowing fast
> > decompression even on mobile devices. This is achieved by combining a
> > content-aware preprocessing step and improved entropy coding,
> compared to
> > the Flate compression used in WOFF 1.0."
> > - https://www.w3.org/TR/WOFF2
> >
> > Clearly, from recent excellent emails, there are many
> implementer-specific
> > issues and interactions when adding font files that are good to know
> about,
> > but don't necessarily need to be expressed in an X3D model (or the X3D
> > Architecture specification).
> >
> > Dick and I worked further today to assess whether separation of font
> files
> > from FontStyle node into a FontLibrary node was the preferred to
> represent
> > this information in an X3D model. We also repeated WOFF Recommendation's
> > use of term "collection" as part of a *FontLibrary *definition.
> >
> > - The FontLibrary node specifies a collection of one or more font
> > family definitions. A font family may include one or more related font
> > style definitions. FontLibrary provides the ability to selectively
> load
> > font files for use by FontStyle
> > <
> https://outlook.office.com/mail/id/AAkALgAAAAAAHYQDEapmEc2byACqAC%2FEWg0AN5ikByHYYkeveIfklhUi1gAG%2Blh21AAA?nativeVersion=1.2025.219.400#FontStyle>
> and
> > ScreenFontStyle
> > <https://outlook.office.com/mail/id/layout.html#ScreenFontStyle>
> nodes.
> >
> > FontLibrary node pros (meaning separation of font files from FontStyle
> > node):
> >
> > - Keeps existing (and fairly complex) FontStyle implementations
> > unchanged
> > - Separation of loading and presentation functionality between two
> > nodes
> > - FontLibrary simply adds to the selection of fonts available, and
> > retains emphasis of *family *and *style *fields within a given
> > FontStyle node.
> > - If separate font files redefine a given family (with the same name),
> > then addition of *enabled *field might allow authors to determine
> > which of them is relevant. However *enabled *field can be considered
> > redundant (since changing url has same effect).
> > - Alternative approach to use of an *enabled *field, we might also
> > need to add a sentence such as
> > - "If a font family is redefined by multiple FontLibrary nodes, then
> > the first defined family is used."
> > - (or we can remain silent and let browser implementations sort
> > that out)
> >
> > FontLibrary node cons (meaning bundle all url functionality in
> FontStyle):
> >
> > - Closer coupling of *family *field and font files themselves, recent
> > email dialog indicates that sometimes the font file simply overrides
> the
> > family field...
> > - We do not want to change any defined functionality for *family* and
> *style
> > *fields, they still seem correct in X3D Architecture and no suitable
> > changes yet seen.
> > - No need for *enabled *field.
> >
> > Our current opinion is that FontLibrary provides a superior approach to
> > continued growth of FontStyle node. To facilitate comparison and review,
> > current draft has proposed FontLibrary prose in yellow, and alternate
> > (not accepted) FontStyle alternative in cyan.
> >
> > - X3D 4.1 (draft) Architecture, clause 15 Text component, 15.4.1
> > FontLibrary
> > -
> >
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/components/text.html#FontLibrary
> > X3D Architecture 4.1 draft ? ISO/IEC 19775-1:202x ? 15 Text component
> > <
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD/Part01/components/text.html#FontLibrary
> >
> > 15.2.2.4 Language. The language field specifies the context of the
> > language for the text string in the form of a language and a country
> in
> > which that language is used. Both the language and the country are
> > specified using the language tags defined in which may specify only a
> > country (using the three-character codes defined in ISO 3166) or both
> a
> > language (using the two-character codes ...
> > www.web3d.org
> >
> >
> > Additional questions to ponder, further insights welcome:
> >
> > - Our impression of the term 'webfont' is that it is simply a generic
> > term, not a standard or specification per se, and often employed to
> > reference WOFF. Is that correct?
> >
> > - Font files tend to be large. Might there ever be a use case where
> > an author chooses to define a font as source text in the url field?
> We
> > have some precedent for this in Script url and (sorta) PixelTexture.
> > Nevertheless font definitions are also convoluted and (perhaps
> notoriously)
> > difficult to parse. Of note is that WOFF2 specifically is designed
> for
> > effective binary compression. Our inclination so far is to not
> describe
> > (or encourage) definition of the font within an X3D model. YMMV
> (though we
> > doubt it). Much better authoring approach is to use any of many
> conversion
> > tools that might credibly update a legacy font into WOFF2.
> >
> > Thanks everyone for leaning forward on this, looking ahead to continuing
> > discussion.
> >
> > Have fun with font library collections for X3D models! ?
> >
> >
> > all the best, Don
> >
> > --
> >
> > Don Brutzman Naval Postgraduate School, Code USW/Br
> > brutzman at nps.edu
> >
> > Watkins 270, MOVES Institute, Monterey CA 93943-5000 USA
> > +1.831.656.2149
> >
> > X3D graphics, virtual worlds, navy robotics
> > https://faculty.nps.edu/brutzman
> >
> >
> >
> > ------------------------------
> > *From:* x3d-public <x3d-public-bounces at web3d.org> on behalf of Brutzman,
> > Donald (Don) (CIV) via x3d-public <x3d-public at web3d.org>
> > *Sent:* Wednesday, February 26, 2025 5:39 PM
> > *To:* X3D <x3d-public at web3d.org>
> > *Cc:* Brutzman, Donald (Don) (CIV) <brutzman at nps.edu>
> > *Subject:* Re: [x3d-public] draft X3D 4.1 prose for font files and
> > libraries
> >
> > Dick and I worked on suggested prose for X3D 4.1 with details continuing
> > in Mantis 1490 below.
> >
> > Review request:
> >
> > - X3D 4.1 Architecture (draft), 15 Text component, 15.4.1 FontStyle
> > -
> >
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/components/text.html#FontStyle
> >
> > Improvements:
> >
> > - Include all X3DURLObject fields,
> >
> > SFTime [in,out] autoRefresh 0.0 [0,?)
> > SFTime [in,out] autoRefreshTimeLimit 3600.0 [0,?)
> > SFString [in,out] description ""
> > SFBool [in,out] load TRUE
> > MFString [in,out] url [] [URI]
> >
> > - Decided to NOT overload functionality of *family * field by adding
> > file names (sorry Holger! adjusting your implementation will likely
> be
> > simple in comparison)
> >
> > - New prose:
> >
> > The *url* field is optional and can refer to a relative or online address
> > for a font library that contains one or more font definitions. An empty
> > *url* list indicates that the default set of fonts provided by the
> > browser are used. If present, only the first active font library
> retrieved
> > from the *url* list shall be used. Individual font library files can be
> > used by multiple FontStyle nodes in a scene. Each font file only needs to
> > be loaded once per session.
> > X3D browsers shall support WOFF (MIME type application/x-font-woff) (see
> W3C
> > WOFF File Format
> > <
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/references.html#W3C_WOFF
> >).
> > Support for the OpenType file format (MIME type
> > application/x-font-opentype) (see OpenType Specification
> > <
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/bibliography.html#OPENTYPE
> >)
> > and TrueType file format (MIME type application/x-font-truetype) (see
> ISO/IEC
> > 14496-22 Open Font Format
> > <
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/references.html#I14496_22
> >)
> > is also recommended.
> > Security, licensing, and copyright/usage permissions are handled via the
> > exposure of a font file itself.
> > Support for the *autoRefresh*, *autoRefreshTimeLimit*, and *load* fields
> is
> > optional.
> > More details on the *autoRefresh*, *autoRefreshTimeLimit*, *description*,
> > *load*, and *url* fields are contained in 9.2.1 URLs, URNs and URIs
> > <
> https://www.web3d.org/specifications/X3Dv4Draft/ISO-IEC19775-1v4.1-CD//Part01/components/networking.html#URLs
> >
> > .
> > Looking it over, adding more functionality to FontStyle node seems to be
> > unwise. Dick has an excellent proposal:
> > TODO alternative approach: move all new functionality into a separate
> > *FontLibrary* node to avoid complicating FontStyle further. This also
> > offers the ability to succinctly load multiple font libraries in a given
> > scene. The expense of defining a new node for X3D is offset by clearer
> > distinction between X3D 4.0 and 4.1, also simplifying model content
> > significantly.
> > Feedback is welcome.
> > Leaving existing FontStyle implementations alone probably avoids many
> > unintended side effects. First law of engineering: "If it ain't broke,
> > don't fix it."
> >
> > Thanks for all review. It feels like we are finally converging on a
> > straightforward approach to valuable future capabilities.
> >
> > Have fun with X3D fonts! ?
> >
> >
> > all the best, Don
> >
> > --
> >
> > Don Brutzman Naval Postgraduate School, Code USW/Br
> > brutzman at nps.edu
> >
> > Watkins 270, MOVES Institute, Monterey CA 93943-5000 USA
> > +1.831.656.2149
> >
> > X3D graphics, virtual worlds, navy robotics
> > https://faculty.nps.edu/brutzman
> >
> >
> >
> > ------------------------------
> > *From:* Brutzman, Donald (Don) (CIV) <brutzman at nps.edu>
> > *Sent:* Monday, February 24, 2025 9:32 AM
> > *To:* X3D <x3d-public at web3d.org>
> > *Cc:* Holger Seelig <holger.seelig at yahoo.de>
> > *Subject:* Re: [x3d-public] Open dyslexic and/or (unfortunately)
> > comicsans fonts; draft X3D 4.1 prose for font files and libraries
> >
> > Wow, really super Holger! ?
> >
> > There was a conversation about this on x3d-public a few years back... We
> > committed to adding it in X3D 4.1 and (if I recall correctly) also noted
> > that adding a url field might enable usage of larger font files.
> >
> > I've attempted to capture this candidate specification change in a Mantis
> > issue. All review, feedback, and improvements are always welcome.
> >
> > - Mantis 1490 FontStyle handling of font files and font libraries
> > - https://mantis.web3d.org/view.php?id=1490
> >
> > Description.
> > A goal for X3D 4.1 is use of font files in FontStyle (see Mantis 0001464
> > <https://mantis.web3d.org/view.php?id=1464>).
> >
> > Addition of individual-font files might be accomplished by listing the
> > font file name in the FontStyle 'family' field.
> >
> > Referencing different fonts in a single combined font library file may
> > require an additional field, for example 'url'. In general the use of a
> > font library may be preferred, but repeatedly run-time retrieval of a
> font
> > library is not desirable, since the file might be quite large and rarely
> > changing. This might be noted in the specification prose, e.g.
> >
> > - "MFString [in,out] url [] [URI]"
> > - "The family field may list a specific font file. A font listed in the
> > family field may be provided by a corresponding font library."
> > - "The url field may refer to a font library. Font libraries can be used
> > by multiple FontStyle nodes in a scene and need only be loaded once per
> > session."
> >
> > Support levels: add "Level 2, FontStyle, support for font files in family
> > field and support for font libraries via url field ."
> >
> > Security, licensing, and copyright/usage issues are handled via the
> > exposure of the font file itself. If retrievable (locally or online) then
> > proper access is presumably handled separately.
> >
> > Additional information.
> > - X3D 4.1 (draft) Architecture, 15 Text component, 15.4.1 FontStyle
> > -
> >
> https://www.web3d.org/specifications/X3Dv4/ISO-IEC19775-1v4-IS/Part01/components/text.html#FontStyle
> >
> > - X3D 4.1 (draft) Architecture, 15 Text component, 15.4.2 Text
> > -
> >
> https://www.web3d.org/specifications/X3Dv4/ISO-IEC19775-1v4-IS/Part01/components/text.html#Text
> >
> > - X3D 4.1 (draft) Architecture, 15 Text component, 15.5 Support levels
> > -
> >
> https://www.web3d.org/specifications/X3Dv4/ISO-IEC19775-1v4-IS/Part01/components/text.html#SupportlLevels
> >
> > Have fun with X3D Text! :)
> >
> >
> > all the best, Don
> >
> > --
> >
> > Don Brutzman Naval Postgraduate School, Code USW/Br
> > brutzman at nps.edu
> >
> > Watkins 270, MOVES Institute, Monterey CA 93943-5000 USA
> > +1.831.656.2149
> >
> > X3D graphics, virtual worlds, navy robotics
> > https://faculty.nps.edu/brutzman
> >
> >
> >
> > ------------------------------
> > *From:* x3d-public <x3d-public-bounces at web3d.org> on behalf of Holger
> > Seelig via x3d-public <x3d-public at web3d.org>
> > *Sent:* Monday, February 24, 2025 2:48 AM
> > *To:* X3D <x3d-public at web3d.org>
> > *Cc:* Holger Seelig <holger.seelig at yahoo.de>
> > *Subject:* Re: [x3d-public] Open dyslexic and/or (unfortunately)
> > comicsans fonts
> >
> > With X_ITE you can use a URL in the family field of a FontStyle node to
> > specify a path to a custom font file. Provided you have one of these
> fonts,
> > it should be very easy:
> >
> > <?xml version="1.0" encoding="UTF-8"?>
> > <!DOCTYPE X3D PUBLIC "ISO//Web3D//DTD X3D 4.0//EN" "
> > https://www.web3d.org/specifications/x3d-4.0.dtd">
> > <X3D profile='Interchange' version='4.0' xmlns:xsd='
> > http://www.w3.org/2001/XMLSchema-instance'
> xsd:noNamespaceSchemaLocation='
> > https://www.web3d.org/specifications/x3d-4.0.xsd'>
> > <head>
> > <component name='Text' level='1'/>
> > </head>
> > <Scene>
> > <Transform DEF='Text'>
> > <Shape>
> > <Appearance>
> > <Material/>
> > </Appearance>
> > <Text
> > string='"3D Text"'>
> > <FontStyle
> > family='"path/to/your/font.otf", "SERIF"'/>
> > </Text>
> > </Shape>
> > </Transform>
> > </Scene>
> > </X3D>
> >
> > Supported File Formats:
> >
> >
> https://create3000.github.io/x_ite/components/text/fontstyle/#supported-file-formats
> >
> > Best regards,
> > Holger
> >
> > --
> > Holger Seelig
> > Leipzig, Germany
> >
> > holger.seelig at yahoo.de
> > https://create3000.github.io/x_ite/
> >
> > Am 24.02.2025 um 11:09 schrieb John Carlson via x3d-public <
> > x3d-public at web3d.org>:
> >
> > If someone knows how change the fonts of the standards to OpenDyslexic or
> > ComicSans, that might be a great accessibility experiment.
> > _______________________________________________
> > x3d-public mailing list
> > x3d-public at web3d.org
> > http://web3d.org/mailman/listinfo/x3d-public_web3d.org
> >
> >
> > _______________________________________________
> > x3d-public mailing list
> > x3d-public at web3d.org
> > http://web3d.org/mailman/listinfo/x3d-public_web3d.org
> >
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--
Andreas Plesch
Waltham, MA 02453
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