[x3d-public] text size clarification

[Andreas Plesch]

Here are three browsers for the nist spacing scene:

https://github.com/andreasplesch/x3dom/wiki/Text-sizing

They all look consistent. In particular they all leave some space
above capital letters even for spacing 1 to account for hanging
letters from the line above. But the figure leaving some space in the
spec. says it is for spacing larger than 1.0, not 1 .

I will try to checkout the other text example with the unit square
with other x3d browsers as well.

Not sure why different webbrowsers show the test a bit differently,
Perhaps they differ in how they render text into a canvas. I will try
to reproduce.

-Andreas

On Fri, Oct 25, 2019 at 9:06 AM GPU Group <gpugroup at gmail.com> wrote:
>
> http://dug9.users.sourceforge.net/web3d/tests/Text/Text_size_spacing.x3d
> - nist spacing scene
> http://dug9.users.sourceforge.net/web3d/tests/Text/text_size_spacing.jpg
> - freewrl rendering
>
> On Thu, Oct 24, 2019 at 5:33 PM Brutzman, Donald (Don) (CIV) <brutzman at nps.edu> wrote:
>>
>> Curiously when tested in 2 browsers, X3DOM did not size the inset or layout text equivalently.  Image attached for Internet Explorer and Firefox (Windows 10).
>>
>> On 10/24/2019 3:48 PM, Brutzman, Donald (Don) (CIV) wrote:
>> > On 8/19/2019 6:46 AM, Andreas Plesch wrote:
>> >> https://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/text.html#f-Textsizeandspacingfields
>> >>
>> >> shows how text is sized with the size field.
>> >>
>> >> The example text does not have any letters which reach below the baseline, such as g,j,p, or y, or underscore _. The figure implies that a spacing of 1 would mean that such letters overlap with the line of text below. But this is in conflict with the assumption that as the default value a spacing of 1 should give a readable display for most content.
>> >>
>> >> So should the baseline rather be at the level of the underscore _ ?
>> >> Does a size of 1 mean the letter X is ca. 1 unit tall ?
>> >> Or does it mean that _X in combination is ca. 1 unit tall ?
>> >>
>> >> Here is how dev. x3dom sizes letters. The square is a unit square, centered at the origin:
>> >> https://raw.githack.com/x3dom/x3dom/master/test/regression-suite/test/cases/text/text.html
>> >>
>> >> -Andreas
>> >> --
>> >> Andreas Plesch
>> >> Waltham, MA 02453
>> > Apologies for missing this note 2 months ago (just before flying to Japan for ISO X3D meeting).  Apparently everyone else did too.
>> >
>> > Andreas, might you have suggested prose for a spec revision?
>> >
>> > Also wondering how X_ITE, view3dscene and FreeWrl handle this.
>> >
>> > Also wondering how HTML5.2 handles this.
>> >
>> > Now entered as Mantis issue 1265
>> > https://www.web3d.org/member-only/mantis/view.php?id=1265
>> >
>> > Nicholas, I seem to recall your addressing font spacing as part of IRVE at some point... and so you have good fortune to be assigned issue responsibility (for how everyone will view 3D text, for approximately forever).  Hope that is OK!  8)
>> >
>> > all the best, Don
>> >
>>
>>
>> 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
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-- 
Andreas Plesch
Waltham, MA 02453