This document describes and prioritises gaps for the support of the Bengali script on the Web and in eBooks. In particular, it is concerned with text layout. It checks that needed features are supported in W3C specifications, such as HTML and CSS and those relating to digital publications. It also checks whether the features have been implemented in browsers and ereaders.
Status of This Document
This section describes the status of this
document at the time of its publication. A list of current W3C
publications and the latest revision of this technical report can be found
in the W3C technical reports index at
https://www.w3.org/TR/.
This document describes and prioritises gaps for the support of the Bengali script on the Web and in eBooks. In particular, it is concerned with text layout. It checks that needed features are supported in W3C specifications, in particular HTML and CSS and those relating to digital publications. It also checks whether the features have been implemented in browsers and ereaders.
It is linked to from the language matrix that tracks Web support for many languages.
Group Draft Notes are not endorsed by
W3C nor its Members.
This is a draft document and may be updated, replaced or obsoleted by other
documents at any time. It is inappropriate to cite this document as other
than work in progress.
The
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does not carry any licensing requirements or commitments on this
document.
The following people contributed information to the gap reports in this document (in alphabetic order): Akshat Joshi, Hai Liang, John Hudson, Vivek Pani.
The W3C needs to make sure that the needs of scripts and languages around the world are built in to technologies such as HTML, CSS, SVG, etc. so that Web pages and eBooks can look and behave as people expect around the world.
This page documents difficulties that people encounter when trying to use languages written in the Bengali script on the Web.
Having identified an issue, it investigates the current status with regards to web specifications and implementations by user agents (browsers, e-readers, etc.), and attempts to prioritise the severity of the issue for web users.
1.3 Prioritization
This document not only describes gaps, it also attempts to prioritise them in terms of the impact on the local user. The prioritisation is indicated by colour.
Key:
It is important to note that these colours do not indicate to what extent a particular feature is broken. They indicate the impact of a broken or missing feature on the content author or end user.
Basic styling is the level that would be generally accepted as sufficient for most Web pages. Advanced level support would include additional features one might expect to include in ebooks or other advanced typographic formats. There may be features of a script or language that are not supported on the Web, but that are not generally regarded as necessary (usually archaic or obscure features). In this case, the feature can be described here, but the status should be marked as OK.
The decision as to what priority level is assigned to a described gap is down to the experts doing the gap analysis. It may not always be straightforward to decide. If a given section in this document refers to more than one feature that is broken, each with different impacts on Web users, the priority for the section should be the lowest denominator.
A cell can be scored as OK if the feature in question is specified in an appropriate specification, and is supported by user agents. A specification that is in CR or later and has two implementations in 'major' browsers will count. This means that the feature may not be supported in all browsers yet. (At some point in the future we may try to distinguish, visually, whether support is available in a specification but still pending in major browsers or applications.)
1.4 Related information
A summary of this report and others can be found as part of the Language Matrix.
See also General page layout & progression for features such as column layout, page turning direction, etc. that are affected by text direction.
2.1 Writing mode
In what direction does text flow along a line and across a page? (See the Bidirectional text section if the basic direction is right-to-left.) If the script uses vertically oriented text, what are the requirements? What about if you mix vertical text with scripts that are normally only horizontal? Do you need a switch to use different characters in vertical vs. horizontal text? Does the browser support short runs of horizontal text in vertical lines (tate-chu-yoko in Japanese) as expected? Is the orientation of characters and the directional ordering of characters supported as needed?
#70 Upright text in vertical lines doesn't segment correctly
This issue is applicable to many Indian languages.
When upright characters appear in vertical lines of text, browsers need to tailor grapheme cluster rules so that full orthographic syllables represented as conjuncts, are kept together.
Gecko appears to segment on grapheme clusters. Blink, and Webkit keep conjuncts together. But all engines have problems with vowel-signs, especially but not only pre-base vowel-signs.
Priority
Marked as advanced, since vertical text is not a common use case. In writing sytems like modern Tamil, it is even less common, since conjuncts are rarely used.
If the general inline direction is right-to-left, are there any issues when handling that? Where the inline direction of text is mixed, is this bidirectional text adequately supported? What about numbers and expressions? Do the Unicode bidi controls and HTML markup provide the support needed? Is isolation of directional runs problematic?
3. Glyph shaping & positioning
3.1 Fonts & font styles
Do the standard fallback fonts used in browsers (eg. serif, sans-serif, cursive, etc.) match expectations? Are special font or OpenType features needed for this script that are not available?
3.2 Context-based shaping and positioning
Does the script in question require additional user control features to support alterations to the position or shape of glyphs, for example adjusting the distance between the base text and diacritics, or changing the glyphs used in a systematic way? Do you need to be able to compose/decompose conjuncts, or show characters that are otherwise hidden, etc?
3.3 Letterform slopes, weights, & italics
This covers ways of modifying the glyphs, such as for italicisation, bolding, oblique, etc. Do italic fonts lean in the right direction? Is synthesised italicisation problematic? Are there other problems relating to bolding or italicisation - perhaps relating to generalised assumptions of applicability?
3.4 Cursive text
If this script is cursive (eg. Arabic, N’Ko, Syriac, etc), are there problems or needed features related to the handling of cursive text? Do cursive links break if parts of a word are marked up or styled? Do Unicode joiner and non-joiner characters behave as expected?
This issue is likely to apply to all cursive script text, but also to other scripts that have joins between letters.
When text stroke effects are applied to cursive text, they should not interrupt the cursive flow. For example, the following is problematic.
For more details, see this GitHub issue, which is being used to track this gap. Please add any discussion there, and not to this issue.
3.5 Case & other character transforms
Does your script need special text transforms that are not supported? Does your script convert letters to uppercase, capitalised and lowercase alternatives according to your typographic needs? Do you need to to convert between half-width and full-width presentation forms?
4. Typographic units
4.1 Characters & encoding
Are there any character repertoire issues preventing use of this script on the Web? Do variation selectors need attention? Are there any other encoding-related issues?
4.2 Grapheme/word segmentation & selection
This is about how text is divided into graphemes, words, sentences, etc., and behaviour associated with that. Do Unicode grapheme clusters appropriately segment character units for your script? When you double- or triple-click on the text, is the expected range of characters highlighted? When you move through the text with the cursor, or backspace, etc. do you see the expected behaviour? (Some of the answers to these questions may be picker up in other sections, such as line-breaking, or initial-letter styling.)
#89 Spans around partial orthographic syllables can't be styled
If you try to style part of a syllable by putting a span around the characters you want to style, the overall shape of the syllable is broken.
Here are a number of examples:
Devanagari. If you put a span around the first two characters of the 3-character syllable स्तिठड (eg. in order to color or otherwise style it), the i vowel-sign no longer appears at the start of the word, but looks like it modifies the next character (ठ).
Gujarati. If you put a span around the ન્ડ two characters of the 3-character syllable ન્ડિ in ઇન્ડિય (eg. in order to color or otherwise style it), the i vowel-sign no longer appears at the start of the word, but looks like it modifies the next character (ય).
Bengali. If you put a span around the ব first character of the two character syllable বি in বিভাগের (eg. in order to color or otherwise style it), the vowel-sign no longer appears at the start of the word, but looks like incorrect inputting at the wrong place.
Tamil. If you put a span around the ம first character of the two character syllable மொ in மொழி (eg. in order to color or otherwise style it), the half part of o vowel-sign no longer appears at the start of the word, but looks like incorrect inputting at the wrong place.
Apparently this requirement is a bit difficult to cater to as it requires the knowledge to be transferred by the font to the rendering engine about which part of the glyph is attributed to which code-point in storage. However, if it can be achieved, nothing like it.
#87 Grapheme clusters fail to represent syllabic conjuncts in north Indian scripts
The Unicode concept of 'grapheme cluster' currently fails to represent syllabic conjuncts (plus vowels, etc) in scripts like Devanagari. This means that various editing operations, line breaking algorithms, vertical text, etc. are likely to break text at the wrong point.
Indic Layout Requirements provides a grammar for indian orthographic syllable boundaries which works for Devanagari, and CSS uses the concept of 'typographic character unit', rather than grapheme cluster, in its specs with the explanation that these cases are beyond the scope of the grapheme cluster concept and that implementations should provide appropriate support. In addition, a modification to the concept of grapheme cluster is currently in development at the Unicode Consortium, which is likely to resolve the problem for a script like Devanagari.
Specs
CSS uses the concept of 'typographic character unit', rather than grapheme cluster, in its specs with the explanation that these cases are beyond the scope of the grapheme cluster concept and that implementations should provide appropriate support.
Are there specific problems related to punctuation or the interaction of the text with punctuation (for example separation of punctuation from previous text, but allowing no line break between)? Are there issues related to handling of abbreviation, ellipsis, or iteration? Are there problems related to bracketing information or demarcating things such as proper nouns, etc?
5.2 Quotations & citations
Are there any issues when dealing with quotations marks, especially when nested? Should block quotes be indented or handled specially?
5.3 Emphasis & highlighting
How are emphasis and highlighting achieved? If lines or marks are drawn alongside, over or through the text, do they need to be a special distance from the text itself? Is it important to skip characters when underlining, etc? How do things change for vertically set text?
5.4 Abbreviation, ellipsis & repetition
What characters or other methods are used to indicate abbreviation, ellipsis & repetition?
5.5 Inline notes & annotations
The ruby spec currently specifies an initial subset of requirements for fine-tuning the typography of phonetic and semantic annotations of East Asian text, including furigana, pinyin and zhuyin fuhao systems. Is is adequate for what it sets out to do? What other controls will be needed in the future? What about other types of inline annotation, such as warichu? (For referent-type notes such as footnotes, see below.)
5.6 Text decoration & other inline features
This is about ways of marking text (see also specific sections dedicated to quotations and inline notes/annotations). Is it possible to express emphasis or highlight content as expected? Bold, italic and under-/over-lines are not always appropriate, and some scripts have their own unique ways of doing things, that are not in the Western tradition at all. Text delimiters mark certain items or sections off from the main text, such as book names in Chinese, quotations, head markers in Tibetan, etc, and often involve the use of punctuation. Is there any behaviour that isn't well supported, such as overlines for numeric digits in Syriac? Are there issues about the positioning or use of underlines? Some aspects related to the drawing of lines alongside or through text involve local typographic considerations. Do underlines need to be broken in special ways for this script? Do you need support for additional line shapes or widths? Does the distance or position of the lines relative to the text need to vary in ways that are not achievable? Are lines correctly drawn relative to vertical text?
#90 Underline and overline need to clear glyph ascenders and descenders
Indian language text has some signs called as Matras which sometimes join above the shirorekha or below the normal baseline.
Applications should ensure that the underline and overline when getting rendered, should adaquetly be taken into consideration. Chrome browser seemed to be perfectly rendering the underline and overline feature by breaking the same where a matra occurs. Internet Explorer also handles it a bit differently by appropriately lowering or heightening the respective lines.
5.7 Data formats & numbers
If the script has its own set of number digits, are there any issues in how they are used? Does the script or language use special format patterns that are problematic (eg. 12,34,000 in India)? What about date/time formats and selection - and are non-Gregorian calendars needed? Do percent signs and other symbols associated with number work correctly, and do numbers need special decorations, (like in Ethiopic or Syriac)? How about the management of personal names, addresses, etc. in web pages: are there issues?
Generally Latin Numerals are acceptable in Devanagari text. Most of the user community identifies with them. However, there could be cases where certain web-pages would prefer to have numerals in Devanagari to cater to mono-lingual (mono-script rather) readers. This is particularly required for input types number and date. It would be useful if the input type values are augmented with the script mnemonics e.g. number_deva or date_deva instead of changing it for entire page through some locale setting. There could be cases where a user may require both kinds of numbering in the same web-page.
6. Line and paragraph layout
6.1 Line breaking & hyphenation
Does the browser capture the rules about the way text in your script wraps when it hits the end of a line? Does line-breaking wrap whole 'words' at a time, or characters, or something else (such as syllables in Tibetan and Javanese)? What characters should not appear at the end or start of a line, and what should be done to prevent that?
6.2 Text alignment & justification
When text in a paragraph needs to have flush lines down both sides, does it follow the rules for your script? Does the script need assistance to conform to a grid pattern? Does your script allow punctuation to hang outside the text box at the start or end of a line? Where adjustments are need to make a line flush, how is that done? Do you shrink/stretch space between words and/or letters? Are word baselines stretched, as in Arabic? What about paragraph indents, or the need for logical alignment keywords, such as start/end, rather than left/right?
6.3 Text spacing
Some scripts create emphasis or other effects by spacing out the words, letters or syllables in a word. Are there requirements for this script/language that are unsupported? (For justification related spacing, see below.)
#118 Browsers apply extraneous spaces when letter-spacing
This issue applies to all languages that use letter-spacing.
Currently browsers that apply letter-spacing do so by adding a space after every letter in the text that is tracked. This results in a superfluous space at the end of the range, which creates an inappropriate gap before the following text. Letter spacing at the end of a line makes the line look misaligned in justified or right-justified text. It also has implications for text that has other styling, such as an outline or a coloured background, at the same time as being stretched.
For more details, see this GitHub issue, which is being used to track this gap. Please add any discussion there, and not to this issue.
This issue is applicable to most languages that form conjuncts from consonant clusters using an invisible virama.
A consonant cluster that uses a conjunct (rather than visible virama) should not be split when letter-spacing is applied.
The GAP
Relying on grapheme clusters as the main segmentation approach fails for many Indic scripts because conjuncts are composed of multiple grapheme clusters, and should be kept together as a unit.
For these situations it is necessary to tailor the segmentation algorithm, so that it recognises the whole consonant cluster plus any attached vowel-signs or combining characters as a single unit.
See also notes on segmentation for the following orthographies relevant to this project: Hindi, Bangla, Punjabi, Tamil.
css-text-3 CSS uses the concept of 'typographic character unit', rather than grapheme cluster, in its specs with the explanation that the cases just described go beyond the scope of the grapheme cluster concept and that implementations should provide appropriate support. The spec doesn't provide details about the support needed for each language.
The Unicode Consortium made some attempts to address this issue, but it has so far not yielded results. CLDR now flags up a few scripts for which conjuncts are common.
Priority
Keeping conjuncts together is a pretty basic requirement. It is not possible to work around this problem.
That said, letter-spacing is not relied on for essential content authoring, therefore the priority was set to advanced.
Gecko: ❌ Most of the half-form conjuncts (which is the large majority of all conjuncts) have space inserted between the glyphs that make up the conjunct (ie. not split into consonants with visible viramas). Vertically-combined glyphs tend not to be split.
Blink: ❌ Same as Gecko.
Webkit: ❌ Same as Gecko.
Action taken
tbd
Outcomes
tbd
#67 Letter-spacing & first-letter selection must keep yo-phola with preceding independent vowels
This topic builds on that for some specific cases in Bengali.
There are two cases in Bengali where hasant (virama) is preceded by an independent vowel, rather than a consonant. These are:
অ্যা [U+0985 BENGALI LETTER A + U+09CD BENGALI SIGN VIRAMA + U+09AF BENGALI LETTER YA + U+09BE BENGALI VOWEL SIGN AA], and
এ্যা [U+098F BENGALI LETTER E + U+09CD BENGALI SIGN VIRAMA + U+09AF BENGALI LETTER YA + U+09BE BENGALI VOWEL SIGN AA]
(In both cases this produces the sound æ, used for non-native words, such as 'application', 'administration' etc.)
This combination should not be split either, even though it doesn't fit the typical CvC structure of a conjunct (where 'v' is the virama).
Specs:css-text-3 CSS uses the concept of 'typographic character unit', rather than grapheme cluster, in its specs with the explanation that the cases just described go beyond the scope of the grapheme cluster concept and that implementations should provide appropriate support. The spec doesn't provide details about the support needed for each language.
Tests & results:
Both of the following tests were run with the following pre-installed fonts:
Windows: Shonar Bangla, Arial Unicode MS, Nirmala UI, Vrinda
Mac: Bangla MN, Bangla Sangam MN, Kohinoor Bangla, Tiro Bangla, Baloo Da
Also tested with Noto Sans Bengali and Noto Serif Bengali on the Mac.
Gecko: ✅❌ Windows: works with all fonts. Mac: fails with Bangla MN, Bangla Sangam MN, and Baloo Da, but works with the others. Works with Noto fonts.
Blink: ✅❌ Windows: works with all fonts. Mac: same results as for Gecko.
Webkit: ❌ Mac: failed for all fonts. In fact, letters were all spaced individually, rather than by grapheme cluster. Could not apply Noto fonts.
Gecko, Blink, and Webkit all fail to treat the sequence as a single grapheme, despite the fact that Blink and Webkit actually handle the more usual CvC conjunct arrangement (see this test).
Priority:
Keeping such sequences together is a pretty basic requirement. That said, first-letter selection and letter-spacing are not essential for content authoring, although Bengali content authors should still have equal access to these styling features as Westerners. Content authors could work around the first-letter problem by adding markup (though that's not ideal), but for letter-spacing there is no real alternative, and adding spaces between letters ruins the semantics. The priority was set to advanced.
6.4 Baselines, line-height, etc
Does the browser support requirements for baseline alignment between mixed scripts and in general?
#96 Differences in physical size for fonts affects baseline alignment
This issue is especially applicable to northern Indic scripts with a head line.
By and large, Indian scripts in browsers are rendered with default fonts provided by back-end Operating Systems. If there are major differences in physical size for a particular font size, which most of the times are, it shows the mixed-script text in an un-organized way. This obviously affects all the base-line attributes.
Generally, Indian scripts that have joining line use the joining line as the baseline. Ideally, if a document contains both Devanagari and Gurmukhi text (such as Mahan Khosh), the text should be aligned at the joining line regardless of the script or font.
6.5 Lists, counters, etc.
The CSS Counter Styles specification describes a limited set of simple and complex styles for counters to be used in list numbering, chapter heading numbering, etc.The rules plus more counter styles (totalling around 120 for over 30 scripts) are listed in the document Ready-made Counter Styles. Do these cover your needs? Are the details correct? Are there other aspects related to counters and lists that need to be addressed?
#93 Customised counter styles are unavailable — FIXED !
Customisable counters are needed for many languages.
Many orthographies use native digits or letters for counters, such as those used for list numbering or numbering chapter headings, etc. It needs to be possible to use these local conventions for counters.
Users also need to be able to adapt counter styles for a given context or create new ones where the browser doesn't have baked-in support. Often customisation needs are driven by the need to change the counter suffix for particular contexts, but in some cases the algorithms used for numbering can vary from author to author as well.
The major browser engines support a number of hard-coded counter styles. But when this gap was first reported only Gecko supported user defined counter styling. This meant that native counters were not available for a large number of languages, and the styles could not be tweaked by the author for special uses.
predefined-counter-styles contains templates for counter styles that can be applied by users if the custom counter styles spec is supported.
css-counter-styles-3 explicitly defines a number of local styles, and the other counter styles can be defined by users if the Counter Styles spec's generic mechanism for defining counter styles was implemented.
Priority:
The impact of the lack of support cited here is mitigated by the tendency to use western counters, so the impact could be marked as advanced. However native styles (at least the numeric) are widely used in non-Web content, and these features are likely to be widely used when implemented across all major browsers. Therefore the priority is set to basic.
Tests & results:
I18n test suite, Predefined styles. Contains tests for the styles that are explicitly defined in the Counter Styles spec. Gecko and Blink provide good coverage. Webkit covers most styles with some gaps, but fails for CJK and Ethiopic styles.
I18n test suite, Basic custom counter styles. The spec is essentially done, and Gecko and Blink have implemented it. No support from Webkit.
Fixed ! Blink, WebKit, and Gecko latest browser versions now all support custom counter styles.
6.6 Styling initials
Does the browser or ereader correctly handle special styling of the initial letter of a line or paragraph, such as for drop caps or similar? How about the size relationship between the large letter and the lines alongide? where does the large letter anchor relative to the lines alongside? is it normal to include initial quote marks in the large letter? is the large letter really a syllable? etc. Are all of these things working as expected?
#115 Consonant clusters with a visible virama should only have the first consonant+virama highlighted
This issue is applicable to most languages that form conjuncts from consonant clusters using a visible virama.
When the start of a line contains a 2-consonant cluster that uses a visible virama, ::first-letter should highlight only the first consonant+virama. This corresponds to a grapheme cluster, as defined by Unicode.
Specs:css-text-3 CSS uses the concept of 'typographic character unit', which defaults to a grapheme cluster. The spec doesn't provide details about the support needed for each language.
The Unicode Consortium defines grapheme clusters to, by default, stop after the first virama in a cluster.
Priority:This choice needs to be discussed. If a cluster is rendered as a conjunct, it should be selected as a single unit. If, instead, the virama is displayed (ie. it is not a conjunct) then only the initial part of the cluster should be selected. Since the underlying code points are identical if a cluster is displayed as a conjunct or instead with visible viramas, it's not possible to distinguish one situation from another by working with the code points. In the absence of a technical solution that examines what the font used does when rendering, this is a difficult problem to solve. This priority rating says that, in the absence of a perfect solution, it is better to select a whole non-conjunct cluster than to break a conjunct. So it is labelled advanced, rather than basic.
#94 Conjuncts are not selected as a single unit when styling initials
This issue is applicable to most languages that form conjuncts from consonant clusters using an invisible virama.
When the start of a line contains a consonant cluster that uses a conjunct (rather than visible virama), ::first-letter should highlight the whole cluster.
Consonant clusters that form conjuncts using an invisible virama between the component letters need to be selected as a unit. This doesn't work well if segmentation relies on Unicode grapheme clusters, since a conjunct with two consonants will be parsed as two grapheme clusters (the first ending after the virama, and the second starting with the second consonant and including any following vowel-signs or other combining characters).
For these situations it is necessary to tailor the segmentation algorithm, so that it recognises the whole consonant cluster plus any attached vowel-signs or combining characters as a single unit.
css-text-3 CSS uses the concept of 'typographic character unit', rather than grapheme cluster, in its specs with the explanation that the cases just described go beyond the scope of the grapheme cluster concept and that implementations should provide appropriate support. The spec doesn't provide details about the support needed for each language.
The Unicode Consortium made some attempts to address this issue, but it has so far not yielded results. CLDR now flags up a few scripts for which conjuncts are common.
Gecko: ✅❌ Most of the half-form conjuncts fail (which is the large majority of all conjuncts in Devanagari), and are broken into an initial consonant with visible virama and a following consonant.
Priority:
Keeping conjuncts together is a pretty basic requirement. Without a fix for this, authors need to manually mark up text to apply initial letter styling, but that isn't a very useful workaround.
#84 initial-letter positioning is not widely available
Having selected the correct text for highlighting, it is important to ensure proper alignment of the baseline and height of the initial letter highlight relative to the other lines of text. This doesn't work well without help from the dedicated CSS properties, initial-letters and the initial-letters-align. Unfortunately, only Safari supports the first property, and it requires the -webkit prefix, so this is still an immature feature.
Safari aligns the alphabetic baseline of the highlighted text with that on the specified number of lines. The relationship between the highlighted letters and the first line of the paragraph appears to be based on cap height, but is not clear. The requirements for that relationship are not yet really clear, despite the information in Indian Layout Requirements.
The impact here is advanced, since it is mainly needed for advanced layouts.
#67 Letter-spacing & first-letter selection must keep yo-phola with preceding independent vowels
This topic builds on that for some specific cases in Bengali.
There are two cases in Bengali where hasant (virama) is preceded by an independent vowel, rather than a consonant. These are:
অ্যা [U+0985 BENGALI LETTER A + U+09CD BENGALI SIGN VIRAMA + U+09AF BENGALI LETTER YA + U+09BE BENGALI VOWEL SIGN AA], and
এ্যা [U+098F BENGALI LETTER E + U+09CD BENGALI SIGN VIRAMA + U+09AF BENGALI LETTER YA + U+09BE BENGALI VOWEL SIGN AA]
(In both cases this produces the sound æ, used for non-native words, such as 'application', 'administration' etc.)
This combination should not be split either, even though it doesn't fit the typical CvC structure of a conjunct (where 'v' is the virama).
Specs:css-text-3 CSS uses the concept of 'typographic character unit', rather than grapheme cluster, in its specs with the explanation that the cases just described go beyond the scope of the grapheme cluster concept and that implementations should provide appropriate support. The spec doesn't provide details about the support needed for each language.
Tests & results:
Both of the following tests were run with the following pre-installed fonts:
Windows: Shonar Bangla, Arial Unicode MS, Nirmala UI, Vrinda
Mac: Bangla MN, Bangla Sangam MN, Kohinoor Bangla, Tiro Bangla, Baloo Da
Also tested with Noto Sans Bengali and Noto Serif Bengali on the Mac.
Gecko: ✅❌ Windows: works with all fonts. Mac: fails with Bangla MN, Bangla Sangam MN, and Baloo Da, but works with the others. Works with Noto fonts.
Blink: ✅❌ Windows: works with all fonts. Mac: same results as for Gecko.
Webkit: ❌ Mac: failed for all fonts. In fact, letters were all spaced individually, rather than by grapheme cluster. Could not apply Noto fonts.
Gecko, Blink, and Webkit all fail to treat the sequence as a single grapheme, despite the fact that Blink and Webkit actually handle the more usual CvC conjunct arrangement (see this test).
Priority:
Keeping such sequences together is a pretty basic requirement. That said, first-letter selection and letter-spacing are not essential for content authoring, although Bengali content authors should still have equal access to these styling features as Westerners. Content authors could work around the first-letter problem by adding markup (though that's not ideal), but for letter-spacing there is no real alternative, and adding spaces between letters ruins the semantics. The priority was set to advanced.
7. Page & book layout
7.1 General page layout & progression
How are the main text area and ancilliary areas positioned and defined? Are there any special requirements here, such as dimensions in characters for the Japanese kihon hanmen? The book cover for scripts that are read right-to-left scripts is on the right of the spine, rather than the left. Is that provided for? When content can flow vertically and to the left or right, how do you specify the location of objects, text, etc. relative to the flow? For example, keywords 'left' and 'right' are likely to need to be reversed for pages written in English and page written in Arabic. Do tables and grid layouts work as expected? How do columns work in vertical text? Can you mix block of vertical and horizontal text correctly? Does text scroll in the expected direction? Other topics that belong here include any local requirements for things such as printer marks, tables of contents and indexes.
7.2 Grids & tables
Does the script have special requirements for character grids or tables?
7.3 Footnotes, endnotes, etc.
Does your script have special requirements for footnotes, endnotes or other necessary annotations of this kind in the way needed for your culture? (There is a section above for purely inline annotations, such as ruby or warichu. This section is more about annotation systems that separate the reference marks and the content of the notes.)
7.4 Page headers, footers, etc.
Are there special conventions for page numbering, or the way that running headers and the like are handled?
7.5 Forms & user interaction
Are vertical form controls well supported? In right-to-left scripts, is it possible to set the base direction for a form field? Is the scroll bar on the correct side? etc.
8. Other
8.1 Culture-specific features
Sometimes a script or language does things that are not common outside of its sphere of influence. This is a loose bag of additional items that weren't previously mentioned. This section may also be relevant for observations related to locale formats (such as number, date, currency, format support).
8.2 What else?
There are many other CSS modules which may need review for script-specific requirements, not to mention the SVG, HTML, Speech, MathML and other specifications. What else is likely to cause problems for worldwide deployment of the Web, and what requirements need to be addressed to make the Web function well locally?
