Re: NOW: Unicode Font Testing WAS: ayar font and several burmese font issues.

From: David McCreedy (drmccreedy@gmail.com)
Date: Thu Mar 24 2011 - 10:53:17 CST

  • Next message: Philippe Verdy: "Re: NOW: Unicode Font Testing WAS: ayar font and several burmese font issues."

    I too wrote some font test pages for my old website the Gallery of
    Unicode Fonts (http://www.wazu.jp/index.html#test_pages) which is now
    administered by someone else.
    What's being asked for for Myanmar sounds similar to what I did for
    Tamil at http://www.wazu.jp/gallery/Test_Tamil.html except that I
    didn't provide images for font comparison.
    There are no doubt better ways of doing a test page but the layout
    might be useful as a starting point.

    -David McCreedy

    On Thu, Mar 24, 2011 at 10:02 AM, Ed <ed.trager@gmail.com> wrote:
    > Hi, Philippe,
    >
    > For a long time I have had similar ideas.
    >
    > In fact, in an experiment I performed back in September of 2009, I
    > wrote a utility program to produce a set of test cases for Devanagari
    > and also render the test case strings as a set of PNG images which
    > could be used to compare the results of rendering in a browser to the
    > PNG reference rendering. The utility spit out all the resulting PNGs
    > and also an HTML file so that one could quickly review results in a
    > browser window:
    >
    > http://eyegene.ophthy.med.umich.edu/indic/
    >
    > For the draft results for Devanagari shown at the above URL, I believe
    > I used the GPL'ed Chandas font (http://www.sanskritweb.net/cakram/ ;
    > the "glyph ids" shown on the page are obviously specific to the font
    > that was used). The Open Source (Linux) Pango layout engine along
    > with FreeType was used for the renderings shown in the PNG image
    > files.
    >
    > The purpose of the experiment was to test the Pango layout engine,
    > initially against a set of Devanagari OpenType fonts, and to look for
    > bugs which might be present in either Pango or in the fonts
    > themselves.
    >
    > My original idea was to eventually expand my test suite to cover *all*
    > Indic scripts. And not only that, but also to generate equivalent PNG
    > images using Uniscribe and also Apple OSX's rendering pipeline so that
    > one could compare all three OS's text layout engines side-by-side.
    >
    > I quickly realized that such a project would soon consume a lot of my
    > time, as I would need to research and understand better the unique
    > properties of all of the Indic scripts. I inquired with people I knew
    > at one of the major Linux vendors (because one of my primary goals was
    > to ferret out the bugs in Pango) but was told that money was not
    > available for an outside contractor to perform such work. So I
    > stopped.
    >
    > On a related note, for the Open Font Library project
    > (http://openfontlibrary.org/) I had separately written a program
    > called Fontaine ( http://unifont.org/fontaine/ ;
    > http://sourceforge.net/projects/fontaine/ ) which displays key meta
    > information about font files, including but not limited to font name,
    > style, weight, glyph count, character count, copyright, license
    > information and orthographic coverage. At one time, the JSON output
    > from Fontaine was transformed into a very nice report format on the
    > Open Font Library site. I had also written a demonstration web
    > application where a user could upload a font and the app would produce
    > a pretty presentation of Fontaine's report output : for font designers
    > and reviewers of works-in-progress, this output is extremely useful
    > for showing which glyphs are missing for any given orthography, inter
    > alia.
    >
    > Web font technology via the CSS @font-face rules now enjoys broad
    > support among browsers. Using CSS @font-face and well-considered
    > Javascript on the front end --along with tools such as those described
    > above on a server backend-- would make it now possible to create a
    > very comprehensive font testing service as a web application that
    > would be quite useful to designers and users alike. However funding
    > and support from the Unicode Consortium or from one or more commercial
    > members of the Unicode Consortium or other interested vendors might be
    > required to make such a service a reality.
    >
    > - Ed
    >
    > ==================================
    >
    > On Wed, Mar 23, 2011 at 8:50 PM, Philippe Verdy <verdy_p@wanadoo.fr> wrote:
    >> Then there should exist on the Unicode site, a HTML test page showing
    >> correctly encoded Myanmar sample text, with a reference bitmap
    >> rendering built with representative glyphs, and a way to change the
    >> name of the selected font to see if it matches the specs regarding not
    >> only the per character glyphs (those are already in the Unicode
    >> charts), but also for the possible alternate glyphs (if they exist),
    >> the expected reordering, the combinations in significant clusters, the
    >> expected ligatures (when they are mandatory), a non-ligatured
    >> rendering (if it's acceptble as a variant).
    >>
    >> Such test pages should be made for all complex scripts (notably all
    >> Indic scripts). This should even be done independantly of OpenType
    >> specifications (which are more technical and specific to some font
    >> technologies), so that it will not just test the font, but also the
    >> renderer and text layout engine, including in a web browser.
    >>
    >> The PDF given in a prior message also gives some other rendering
    >> constraints, notably for candidate line breaks for line wraps : this
    >> can also be tested in HTML by rendering the text in a narrow text
    >> column (possibly also by allowing the viewing user to rescale the font
    >> size, to make sure that all candidate line breaks effectively become
    >> true line wraps) : the reference image in the test page should then be
    >> shown side-by-side.
    >>
    >> A very basic Javascript would be needed that just adjust some CSS
    >> properties for the tested text (marked up with a simple CSS class that
    >> the Javascript will modify in its stylesheet if the user changes the
    >> selected font name to test and the font size) would be needed, even if
    >> the page content remains mostly static.
    >>
    >> There are some test pages developed in Wikipedia, but they are still
    >> incomplete (and lack the Javascript support for allowing someone to
    >> select another font to test easily). But those pages are pointing
    >> users to a few compatible fonts, even though the tests are still
    >> insufficient due to their limited coverage of the script capabilities
    >> and specificities (even on "rare" letters).
    >>
    >> 2011/3/22 Doug Ewell <doug@ewellic.org>:
    >>> I think there is some confusion here. It looks like Ngwe Tun is saying
    >>> that the Myanmar text on ayarunicodegroup.org is encoded in violation of
    >>> the correct Unicode *ordering conventions* for the script, not that the
    >>> encoding is an ASCII hack or something else other than Unicode (which is
    >>> what "non-Unicode font" and "migrate to Unicode Standards" usually
    >>> imply).
    >>>
    >>> I copied the text from Ayar's home page into BabelPad, a desktop app
    >>> which uses Uniscribe and has no access to any of Ayar's proprietary
    >>> fonts (using Code2000 instead), and didn't see any private-use
    >>> characters. But since I don't read Myanmar, it's entirely possible that
    >>> the text as encoded is complete garbage and needs to be reordered as
    >>> Ngwe Tun says.
    >>>
    >>> --
    >>> Doug Ewell | Thornton, Colorado, USA | http://www.ewellic.org
    >>> RFC 5645, 4645, UTN #14 | ietf-languages @ is dot gd slash 2kf0s
    >>>
    >>>
    >>>
    >>>
    >>>
    >>
    >>
    >>
    >
    >
    >



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