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（翻訳：Adobe Type チーム 山本太郎）
日本語 (Japanese) はこちら
I recently came up with a Variable Font model to handle glyph compression and expansion in horizontal and vertical layout that includes support for characters whose glyphs rotate in vertical layout, such as the glyphs for Western characters, along with TCY (縦中横 tatechūyoko in Japanese, which literally means “horizontal in vertical”) support.
The purpose of this article is to call attention to the open source test font that I developed, along with a description of the model itself, which are intended to be used by developers to implement such support in apps and layout engines.
I spent the last couple of weeks developing a Variable Font version of the infamous Adobe Blank, and the open source project, named Adobe Blank VF & Friends, was released yesterday evening. But, before I detail what makes the Variable Font versions special, besides being Variable Fonts, let’s briefly go over the history of Adobe Blank and Adobe Blank 2.
First released in 2013 as open source, Adobe Blank simply maps all 1,111,998 Unicode code points to non-spacing and non-marking glyphs. What made the project interesting for me was to find the right balance between the number of glyphs and the size of the 'cmap' table. When mapping over a million code points, this becomes a valid concern. After some experimentation, I found that 2,049 glyphs was the sweet spot that resulted in 'CFF ' and 'cmap' tables of a relatively small size.
Adobe Blank 2
Adobe Blank 2, which was first released in 2015, is a two-glyph version of Adobe Blank that includes a Format 13 (Many-to-one range mappings) 'cmap' subtable that maps all 1,111,998 Unicode code points to GID+1. At the time, there was no convenient way to create a Format 13 subtable, so I used ttx, and supplied the actual hex values of the compiled subtable. The current version of ttx can successfully compile a Format 13 subtable by explicitly specifying all 1,111,998 mappings.
That then brings us to the Variable Font versions…
On this date last year, I published the Contextual Spacing GPOS Features article, and this briefer article serves as an update.
This is a brief article to draw readers’ attention to my latest test font, which is a 12-font 65,535-glyph OpenType/CFF Collection that is intended to test how well an app or other font-consuming environment supports language tagging for East Asian text, to include the handling of localized strings, such as those for menu names in the 'name' table, and for named Stylistic Set 'GSUB' features.
The Variable Font Collection test fonts that were made available at the beginning of this month serve this purpose to some extent, but they also require an environment that supports not only Variable Fonts (aka OpenType/CFF2 fonts), but also Variable Font Collections (aka OpenType/CFF2 Collections). The main intent of this OpenType/CFF Collection is to remove the Variable Font baggage from the testing requirement. It also includes support for Macao SAR as a third form of Traditional Chinese, which was described in the previous article.
Please visit the open source Source LOCL Test project for more details, or to download the pre-built OpenType/CFF Collection binary from the Latest Release page.
Macao SAR (SAR stands for Special Administrative Region)—written 澳門特別行政區 or 澳門特區—is in the process of standardizing MSCS (Macao Supplementary Character Set or 澳門增補字符集 in Chinese), which is character set standard that is designed as a supplement to HKSCS (Hong Kong Supplementary Character Set), and by extension, as a supplement to Big Five. One reliable source told me that MSCS can be described as HKSCS plus approximately 150 additional characters.
This is a short article that is simply meant to draw developers’ attention to three OpenType/CFF2 Collections (aka Variable Font Collections) that I built this week, which are now available in the open source Variable Font Collection Test project. As stated in the project, the purpose of these Variable Font Collections is to simulate the Source Han and Noto CJK fonts deployed as Variable Fonts, to help make sure that the infrastructure—OSes, apps, layout engines, libraries, and so on—will support them. Remember that it took several years for Microsoft to support OpenType/CFF Collections (OTCs), which finally happened on 2016-08-02. In other words, this is not trivial.
Something extraordinary happened today.
This extraordinary event provided to me an opportunity to revisit the open source LOCL Test OpenType/CFF test font that I introduced over two years ago. I improved the language declarations in the 'locl' (Localized Forms) GSUB feature definition, and also made other minor tweaks, two of which can be seen in the image above.
The version of Adobe InDesign CC that was released today during Adobe MAX, Version 14.0, now supports language-tagging for a fifth East Asian language: Traditional Chinese for Hong Kong. This new language-tagging option appears as “Chinese: Hong Kong” in the Character Styles and Paragraph Styles panels, and as the same in the Character panel.
For those who were not aware, OpenType has supported language-tagging for Hong Kong, a flavor of Traditional Chinese, for over 10 years via the three-letter language tag ZHH, which was introduced in Version 1.5 (May 2008) of the OpenType Specification. ZHS is the language tag for Simplified Chinese, and ZHT is the one for Traditional Chinese, but for Taiwan. For Japanese and Korean, JAN and KOR are their language tags, respectively. I am very pleased that Adobe InDesign finally supports all five of these OpenType language tags.
The timing couldn’t have been better…
(After realizing that the retargeting of Adobe-Japan1-7 to include only two glyphs, and with a fairly predictable release date range, exhibited characteristics of a pregnancy, I became inspired to write the text for the Adobe-Japan1-6 is Expecting! article while flying from SJC to ORD on the morning of 2018-07-20. I also prepared the article’s images while in-flight. The passenger sitting next to me was justifiably giving me funny looks. My flight to MSN, which was the final destination to attend my 35th high school class reunion in greater-metropolitan Mount Horeb, was delayed three hours, and this gave me an opportunity to publish the article while still on the ground at ORD.)
What do we know about Japan’s new era name? First and foremost, its announcement is unlikely to occur before 2019-02-25, because doing so would divert attention away from the 30th anniversary of the enthronement, 2019-02-24, but it may occur as late as 2019-05-01, which is the date on which the new era begins. That’s effectively a two-month window of uncertainty.
Interestingly, the date 2019-05-01 takes place not only during UTC #159, which will be hosted by me at Adobe, but also during Japan’s Golden Week (ゴールデンウィーク), which may begin early to prepare for the imperial transition.
Japanese line layout is very complex, and the first attempt to standardize its rules and principles was in the JIS X 4051 standard, which was first issued in 1993 with the title 日本語文書の行組版方法 (Line Composition Rules for Japanese Documents in English). There was a revision issued in 1995, and the latest version was issued in 2004 with the slightly different title 日本語文書の組版方法 (Formatting rules for Japanese documents). Another important document is the W3C Working Group Note JLREQ (Requirements for Japanese Text Layout), which provides much of what is described in JIS X 4051, but covers additional areas, and is tailored toward web technologies. Although still considered working drafts, W3C is also preparing similar documents for Chinese and Korean as CLREQ (Requirements for Chinese Text Layout) and KLREQ (Requirements for Hangul Text Layout and Typography), respectively.
This article is not about these standards per se, which are intended for apps and environments that implement sophisticated line layout. Rather, this article is about harsher “plain text” or comparable environments that generally do not need such treatment, yet still benefit from a modest amount of context-based spacing adjustment, particularly to get rid of unwanted space between full-width brackets and other punctuation whose glyphs generally fill half of the em-box. App menus, app dialogs, and simple text editors are examples of where such adjustments can improve text layout in these modest ways.
Today’s article provides useful details for our relatively small number of customers who author documents with our flagship Creative Cloud apps and make use of CID-keyed OpenType SVG fonts. A rather broadly-deployed CID-keyed OpenType SVG typeface is the open source Source Han Code JP family, whose development details are described in the very first section of this article.
While it is fully possible to build OpenType fonts—CID-keyed or otherwise—that include an 'SVG ' (Scalable Vector Graphics) table, the infrastructure to support them in apps is still maturing. That is the purpose of this article, so please continue reading if the details interest or otherwise affect you.
Per a suggestion by a friend named Leroy, I recently renamed the multiple-style and multiple-family OTCs (OpenType Collections) in this open source repository which includes such OTCs that are based on the Adobe-branded Source Han and Google-branded Noto CJK families. These multiple-style and multiple-family OpenType Collections were described in this article from April of this year. The purpose of this particular article is to introduce better names for them besides Super OTC.
First, some background about Super OTCs…
Shortly after Source Han Sans and Noto Sans CJK were released, I came up with the idea of creating a single OpenType Collection that includes all languages and all weights, and the name Super OTC was coined. This was included in the Version 1.001 update (2014-09-12) as a fourth deployment format for both families, and each one included 28 fonts. These were expanded to 36 fonts when the HW (half-width, ASCII-only) fonts, which covered only the Regular and Bold weights, were added as part of the Version 1.002 update (2015-04-20). Source Han Serif and Noto Serif CJK included a Super OTC in their Version 1.000 release (2017-04-03).
One of my hobbies is apparently to explore various ways to stress-test Adobe products, and the target of today’s article happens to be recent adventures with Adobe InDesign and our Source Han families.
The background is that I produced Unicode-based glyph synopses as part of the Source Han Sans and Source Han Serif releases, but those PDFs show only up to 256 code points per page, and it takes several hundred pages to show their complete Unicode coverage. I also produced single-page PDFs that show all 65,535 glyphs. A Source Han Sans one is available here, and a Source Han Serif one is available here. However, they are not Unicode-based.
At seemingly every opportunity, whether via this blog or during public speaking engagements, I have made it abundantly clear that the Adobe-branded Source Han families share the same glyph set as the corresponding Google-branded Noto CJK families. That is simply because it is true. What requires a bit of explanation, however, is how the two typeface designs—Source Han Sans and Source Han Serif—differ. That is what this particular article is about.
As the Project Architect of these Pan-CJK typeface families, I have my fingers on all of the data that was used during their development, and for preparing each release. I can therefore impart some useful tidbits of information that cannot be found elsewhere.
To take the previous article further—and because I tend to have an urge to stress-test environments—I added two more Super OTCs to the Source Han Super OTC open source project this morning.
The release of Source Han Serif earlier this month, on 2017-04-03, gave me an opportunity to build yet another resource for stress-testing environments, particularly those that consume OpenType/CFF Collections. (This also continues to simplify file management by combining three Super OTCs into a much larger one.)
Perhaps as a continuation of this article from almost a year ago with a clever image, I’d like to use this opportunity to mention that the AFDKO tx tool is about to get a new and improved CFF subroutinizer.
The tx tool has actually had a CFF subroutinizer for quite some time, since late 2008 or so, which is invoked by using the “+S” command-line option in combination with the “-cff” command-line option, and while it was noticeably faster than the AFDKO makeotf tool’s built-in subroutinizer, there were issues that prevented me from using it, such as recursion depth and the inability to limit the number of local and global subroutines.
Based on my testing thus far—using my trusty 2014 Apple MacBook Pro—the tx tool’s new subroutinizer is over three orders of magnitude faster that the makeotf tool’s built-in one. Yes, over one-thousand times faster! CIDFont resources that once took hours to subroutinize now take mere seconds, and with comparable results both in terms of number of subroutines and reduced CFF size. The 65,535-glyph Source Han Sans CIDFont resources take approximately 30 seconds to become subroutinized CFFs, and the 23,058-glyph Kozuka Gothic Pr6N (小塚ゴシック Pr6N) and Kozuka Mincho Pr6N (小塚明朝 Pr6N) ones take less than 10 seconds each.
Anyway, the next release of AFDKO will include a version of the tx tool that includes this new and improved subroutinizer. Of course, the primary beneficiaries of this new version are those who build OpenType/CFF fonts that include thousands or tens of thousands of glyphs, like me.
In closing, I’d like to draw attention to the open source otfcc project on GitHub, which apparently provides similar CFF subroutinization results, in terms of speed and the end result.
I will open this article by stating that OpenType features are almost always GSUB (Glyph SUBstitution) or GPOS (Glyph POSitioning). The former table specifies features that substitute glyphs with other glyphs, usually in a 1:1 fashion, but not always. The latter table specifies features that alter the metrics of glyphs, or the inter-glyph metrics (aka kerning).
The focus of this particular article will be the 'vert' (Vertical Alternates) feature, which substitutes a glyph with the appropriate glyph for vertical writing, and is invoked when in vertical writing mode. In other words, it’s a GSUB feature, and one that needs to be invoked for proper vertical writing. Current implementations that support the 'vert' GSUB feature, which tend to be CJK fonts, substitute glyphs with their vertical forms on a 1:1 basis, though language-tagging may affect the outcome for Pan-CJK fonts, such as the Adobe-branded Source Han Sans and the Google-branded Noto Sans CJK, which support multiple languages.
This article is largely a test, but also serves to start the process of resurrecting L2/14-006 (Proposal to add standardized variation sequences for nine characters) for discussion at UTC #151 in early May.
Liang Hai (梁海) brought up this document for discussion at UTC #150 last week, and while I had an opportunity to have it accepted by the UTC, to be included in Unicode Version 10.0 (June, 2017), I decided that it was prudent to instead prepare a revised proposal that is more complete, mainly because L2/14-006 was submitted and discussed prior to the first release of the Adobe-branded Source Han Sans and Google-branded Noto Sans CJK Pan-CJK typeface families. This functionality was implemented in those typeface families via the 'locl' GSUB feature, which requires the text to be language-tagged. In other words, I learned a lot since L2/14-006 was discussed, and prefer to submit a more complete proposal, even if it means waiting for Unicode Version 11.0 (June, 2018).