Er, um, oops.
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.
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.)
Early last August, I celebrated the release of Microsoft’s Windows 10 Anniversary Update (Version 1607, and also known as Redstone 1 or RS1), mainly because it represented the very first version of Windows OS to support OpenType/CFF Collections (aka OTCs). Alas, my favorite Source Han Sans—and now Source Han Serif—deployment format, the Super OTC that packs all of the fonts into a single and easy-to-manage font resource, could not be installed.
Besides being the world’s first open source serif-style Pan-CJK typeface families, the Adobe-branded Source Han Serif and the Google-branded Noto Serif CJK also represent the first broad deployment of two highly-complex and related ideographs that are in the process of being encoded. Their glyphs are shown above in all seven weights. Although it may be hard to believe, the fourth line illustrates the simplified version.
Or, perhaps more accurately, the project that has been keeping me busy for the past couple of years.
The Adobe-branded Source Han Serif (named 源ノ明朝 in Japanese, 본명조 in Korean, 思源宋体 in Simplified Chinese, and 思源宋體 in Traditional Chinese) and Google-branded Noto Serif CJK open source Pan-CJK typeface families, which represent the serif-style counterparts to the similarly-named and also open source Source Han Sans and Noto Sans CJK Pan-CJK typeface families, were released on 2017-04-03. You can read more about the Source Han Serif release here (日本語—한국어—简体中文—繁體中文), which includes a six-minute promotional video.
This article provides information that you would not expect to find in the official announcements for Source Han Serif or Noto Serif CJK, mainly because such information is intended for a completely different audience, which is primarily comprised of font developers.
Unless noted otherwise, all further references to Source Han Serif or Source Han Sans will apply to Noto Serif CJK or Noto Sans CJK, respectively.
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.
The IVD (Ideographic Variation Database) is all about ideograph variants. Up until earlier this year, its scope was limited to CJK Unified Ideographs, per UTS #37 (Unicode Ideographic Variation Database). Its scope now includes characters with the Ideographic property that are not canonically nor compatibly decomposable, which still excludes CJK Compatibility Ideographs.
In an ideal world, a particular glyph—whether it’s considered the standard (aka encoded) form or an unencoded variant of the standard form—would be associated with a single registered IVS (Ideographic Variation Sequence) within an IVD collection. However, we do not live in a perfect world, and several real-world conditions can lead to duplicate sequence identifiers within an IVD collection.
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).
As recorded on the very first page of Adobe Tech Note #5078, Adobe-Japan1-6 was released on 2004-03-05, and one of the glyphs that was added was CID+20958. According to the Adobe-Japan1-6 ordering file, its glyph name is freedial, and is assigned to the Dingbats FDArray element for the purpose of hinting. Of course, if you look for CID+20958 in Adobe Tech Note #5078, you can find it on the bottom of page 54, immediately to the right of CID+20957 that maps from U+26BD ⚽ SOCCER BALL, though it is blank. This is simply because Adobe does not have the rights to use NTT’s trademarked FreeDial mark. CID+20958 was included in Adobe-Japan1-6 for the benefit of font developers who do have the rights to use this mark, and can thus include the glyph in their fonts.
Again. I arrived on the afternoon of 2016-10-16.
This month provided to me yet another opportunity to visit Japan, the Land of the Rising Sun and my wife’s home country, thanks to IRG #47 (Ideographic Rapporteur Group Meeting #47) being hosted there. This trip was also the first time for me to visit an island of Japan other than Honshū (本州), specifically Shikoku (四国).
As a follow on to our seven-year-old May of 2009 article of the same name, several things have happened with the Adobe Clean family that have yet to be reported, and which have CJK implications. Hence the reason for spending my Sunday morning writing this article.
In the following year, 2010, I developed and deployed a Japanese version of Adobe Clean named Ryo Clean PlusN (りょう Clean PlusN in Japanese), and then in 2015, I developed and deployed a Pan-CJK version named Adobe Clean Han (Adobe Clean 黑体 in Simplified Chinese, Adobe Clean 黑體 in Traditional Chinese, Adobe Clean 角ゴシック in Japanese, and Adobe Clean 고딕 in Korean). These typeface families are Adobe corporate fonts that are meant to be used for product literature, for serving to Adobe websites, and for use by Adobe apps. They are not meant to be used by our customers, but I suspect that the readership of this blog may be interested in some of the development details. If this interests you, please continue reading.
Attention, students! Class is in session.
In my experience, the following two statements about standards are seemingly conflicting yet accurate:
On one hand, developing products, such as typeface designs and their fonts, depends on standards.
On the other hand, standards themselves are developed by humans, meaning that they are prone to error, especially when they happen to be character set or glyph standards that include thousands or tens of thousands of representative glyphs.
August 2, 2016 is the official release date for Microsoft’s Windows 10 Anniversary Update (aka Redstone or RS1). Although I do not use Windows OS, I am jumping for joy, for the benefit of those who do use this modern and world-class OS.
Thanks to our friends at Microsoft, the DirectWrite that ships with the Windows 10 Anniversary Update supports OpenType/CFF Collections (aka OTCs), such as those deployed as part of the Adobe-branded Source Han Sans and Google-branded Noto Sans CJK open source projects, to include their all-inclusive “one font to rule them all” Super OTCs.
This will be a short, sweet, and to-the-point article. Sorry, no graphics nor photos.
When developing name-keyed fonts, glyph names matter. They matter a lot. When developing new fonts, the glyph names should either be explicitly listed in AGLFN (Adobe Glyph List For New Fonts) or derivable via the AGL Specification. Glyph names that adhere to AGLFN or the AGL Specification result in fonts with well-formed 'cmap' tables, which means that their glyphs will behave better in a broader range of environments. I cannot stress the importance of this.
CIDs (Character IDs), on the other hand, represent a completely different beast. If a font is genuinely CID-keyed, it means that there are absolutely no glyph names, regardless of whether the source font or fonts that were used to build the CID-keyed font were named-keyed. Once a font resource becomes CID-keyed, the original glyph names are literally jettisoned, and the only way in which to map Unicode values to glyphs is via the 'cmap' table, which is usually done using a UTF-32 CMap resource. In other words, when developing fonts that are intended to be deployed in a CID-keyed fashion, the source glyph names play absolutely no role in how such fonts are processed.
Anyway, there are two messages that are being conveyed in today’s article.
The first message is short and sweet, and meant to be strong: Adobe advises against including XUID arrays in all new and updated font-related resources, meaning fonts themselves and their corresponding CMap resources. The good news is that omitting the XUID array represents one less thing to worry about during font development.
The second message is longer, meant to provide some background information, and describes why Adobe advises against including XUID arrays in font-related resources.
One of my more popular open source fonts is Adobe Blank, and to a less extent the related Adobe Blank 2 because it uses a 'cmap' table format, Format 13, that is not broadly supported. Actually, Adobe Blank provides absolutely nothing, because it maps all 1,111,998 Unicode code points to a range of 2,048 non-spacing and non-marking glyphs, yet such a font is useful for particular scenarios, such as addressing the FOUT (Flash Of Unstyled Text) problem.
Allow me to introduce Adobe NotDef, which is modeled after Adobe Blank in that it covers all of Unicode and maps to a range of 2,048 glyphs, but differs in that the functional glyphs are spacing and marking. The original suggestion for Adobe NotDef came from Dave Crossland. The glyphs match the shape and advance width of the standard Adobe .notdef glyph that is invoked in environments that do not support font fallback when the selected font does not include a glyph for a particular character, and as Dave wrote, Adobe NotDef is useful for font fallback purposes in that it can be used to prevent the display of non-standard .notdef glyphs that may be present in some fonts in the font fallback chain.