[x3d-public] text minor alignment - additional enumeration value? designing better test layout?
Don Brutzman
brutzman at nps.edu
Tue Oct 6 06:50:41 PDT 2015
Thanks for the careful thinking Andreas.
Of note is that FontStyle specification is carefully designed to handle various text directions in support of internationalization (i18n). This is really important not to break.
Something else that seems to vary among implementations is that font size can vary for different font types. Further, aside from X3DOM use of Webfonts, there seems to be little browser support for alternate fonts.
Coming up with an example that shows your case below, perhaps in comparison to other FontStyle use cases, may help define the goals more precisely.
Another awkward part of Text in X3D is that things like italics, bold, marked-up paragraphs etc. have to be done with separate nodes... makes it quite hard to compose a typical HTML paragraph.
All this probably deserves further investigation:
a. The X3D Text component is pretty rich, so new extensibility can be considered using existing capabilities. Perhaps we might design some kind of TextLayout prototype that allows more flexibility in markup while producing the corresponding X3D v3.3 Text/FontStyle/Transform combinations needed to render it.
http://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/text.html
b. Alternatively we might consider specifying new HtmlTexture and SvgTexture nodes to simplify such layouts. Further integration of X3D into web pages is a very important area of work.
c. Worth a deep look is efforts by Nicholas Polys on Display Techniques in Information-Rich Virtual Environments (IRVEs),
http://scholar.lib.vt.edu/theses/available/etd-06152006-024611/unrestricted/DisplayTechniquesinIRVEs_final.pdf
and subsequent research papers which evaluate effectiveness of various text display strategies.
d. There are a few practical examples for Text/FontStyle in Chapter 3 of X3D for Web Authors:
http://x3dgraphics.com/examples/X3dForWebAuthors/Chapter02-GeometryPrimitives
http://x3dgraphics.com/slidesets/X3dForWebAuthors/Chapter02-GeometryPrimitives.pdf
e. Specified but not yet widely used: X3D ScreenFontStyle node.
http://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/layout.html#ScreenFontStyle
f. Somewhat speculative but most examples are pretty simple: 3D extruded text. Based on what's been done to date, am thinking that if we keep 2D text layouts then occasional alternatives using 3D fonts are workable as well.
hmmmm....
On 9/11/2015 6:02 AM, Andreas Plesch wrote:
> This is getting a bit off topic but there is related question I would like get feedback on. Currently, perhaps for some historic reason, x3dom centers all text at the local origin by default, like justify='"MIDDLE" "MIDDLE"' for single line text. It does that also for left aligned multi-line text, eg. it centers the bounding box of the complete text box at the origin.
>
> I believe that kind of alignment cannot be represented with a justify value although it seems actually what may be expected not unreasonably by some as a default positioning. '"MIDDLE" "MIDDLE"' for multi-line text would center the box at the origin but at the same time also center all lines for a middle alignment. Currently this positioning can only be achieved by using a transform around the text and routing x-offsets into it. Even some scripting is required for the simple math involved.
>
> What this means is that perhaps a third value for the MFString justify field would be needed,dealing with 'absolute' positioning of the major (x) axis, similar to minor alignment. There may be a way to make this backwards compatible as well.
>
> Andreas
>
>
>
>
> On Fri, Sep 11, 2015 at 8:26 AM, Andreas Plesch <andreasplesch at gmail.com <mailto:andreasplesch at gmail.com>> wrote:
>
> Hello,
>
> as I looked into the 'length' and 'maxExtent' fields of the text node, I noticed similar issues with snapshots for the NIST conformance example scenes. For those fields it turns out that they are not widely supported in players, sofar only BS Contact seems to have support while freeWrl, view3dscene and InstantPlayer do not.
>
> I think both 'length' and 'maxExtent' could be implemented for x3dom due to the way it renders text. 'length' is very similar to the maxWidth parameter of ctx.fillText() for canvas, and maxExtent is defining a texture mapping.
>
> Andreas
>
>
> On Wed, Sep 9, 2015 at 5:07 PM, Roy Walmsley <roy.walmsley at ntlworld.com <mailto:roy.walmsley at ntlworld.com>> wrote:
>
> Andreas,____
>
> __ __
>
> Thanks for the update. Perhaps all it needs is for the snapshot to be regenerated, and also the first slide in the show.____
>
> __ __
>
> Roy____
>
> __ __
>
> *From:*Andreas Plesch [mailto:andreasplesch at gmail.com <mailto:andreasplesch at gmail.com>]
> *Sent:* 09 September 2015 21:43
> *To:* Roy Walmsley
> *Cc:* X3D Graphics public mailing list
> *Subject:* Re: [x3d-public] text minor alignment____
>
> __ __
>
> Hello Roy,____
>
> thanks for reviewing this issue. In the mean time I had opportunity to view the scene with freeWrl and InstantPlayer. Both render the scene as expected, eg. with the first line above the x-axis while its baseline just touches it. So I think something was a bit off when the snapshot on the archive web site was generated.____
>
> Andreas____
>
> __ __
>
> __ __
>
> On Wed, Sep 9, 2015 at 8:14 AM, Roy Walmsley <roy.walmsley at ntlworld.com <mailto:roy.walmsley at ntlworld.com>> wrote:____
>
> Andreas,____
>
> ____
>
> I have reviewed your comments below and find that I am in agreement with you.____
>
> ____
>
> You are correct in saying that the default for the /justify/ field is [“BEGIN” “FIRST”]. This is quite clearly stated in 15.2.2.3 of the 19775-1 specification.____
>
> ____
>
> Then, when /horizontal/ is TRUE and /topToBottom/ is TRUE, which both are by default, Table 15.4 in the 19775-1 specification states that when the minor alignment is “FIRST” the baseline of the first line shall be aligned with the origin.____
>
> ____
>
> The inevitable conclusion is that the figure displaying the NIST Conformance for the default field settings is incorrect. I will raise this issue for discussion at the next available opportunity. Please keep us informed of any further findings.____
>
> ____
>
> Great catch. Thank you.____
>
> ____
>
> Regards,____
>
> ____
>
> Roy
>
>
> ____
>
> ____
>
> -- ____
>
> Andreas Plesch
> 39 Barbara Rd.
> Waltham, MA 02453____
>
>
>
>
>
> --
> Andreas Plesch
> 39 Barbara Rd.
> Waltham, MA 02453
>
>
> _______________________________________________
> x3d-public mailing list
> x3d-public at web3d.org
> http://web3d.org/mailman/listinfo/x3d-public_web3d.org
>
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 http://faculty.nps.edu/brutzman
More information about the x3d-public
mailing list