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Abstract

This document describes and prioritises gaps for the support of the Gujarati 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.

This document was created by Richard Ishida.

See also the GitHub contributors list for the Indian Language Enablement project, and the discussions related to the Gujarati script.

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 Gujarati 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.

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.)

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?

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.)

GitHub issue #89

Languages: hi bn ta gu pa 2

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.

GitHub issue #88

Languages: hi gu 1

When the Devanagari phrase separator । U+0964 DEVANAGARI DANDA (called purna viram in Hindi) or ॥ U+0965 DEVANAGARI DOUBLE DANDA (deergh viram in Hindi) are used, some browsers select them with the preceding word on double-click, while in other browsers they are selected separately.

The properties of purna viram and deergh viram should be the same as the properties of FullStop or other punctuation marks, and a new line should not begin with purna viram and deergh viram.

GitHub issue #87

Languages: hi bn gu 1

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.

See requirements at: Indic Layout Requirements

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.

Tests

Selectors 3, first-letter
...

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?

Are there any issues when dealing with quotations marks, especially when nested? Should block quotes be indented or handled specially?

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?

What characters or other methods are used to indicate abbreviation, ellipsis & repetition?

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.)

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?

GitHub issue #90

Languages: hi bn ta gu pa 1

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.

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?

GitHub issue #91

Languages: hi bn ta gu pa 2

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.

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?

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?

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.)

GitHub issue #118

Languages: hi bn ta gu pa 2

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.

GitHub issue #117

Languages: hi bn ta gu 2

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.

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.

For examples see Typographic character units in complex scripts.

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.

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.

Interactive test, When letter-spacing is applied to Devanagari the browser will not split conjuncts
Interactive test, When letter-spacing is applied to Bengali the browser will not split conjuncts

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.

tbd

Does the browser support requirements for baseline alignment between mixed scripts and in general?

GitHub issue #96

Languages: hi bn gu pa 2

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.

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?

GitHub issue #110

Languages: gu 3

Customisable counters are needed for many languages.

There is no way for users to create local counter styles that are not built in to the browser, and users also often want to tweak the counter style in some way (esp. the prefix/suffix).

A gujarati (numeric) counter style is supported by the 3 main browser engines, so there appear to be no issues here. However, the only prefix/suffix supported by browsers is the full stop. Others should be allowed, where the user wants.

This gap is now fixed. 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.

GitHub issue #93

Languages: hi bn ta gu pa ks mr as mni 3

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.

These are just a few examples out of many.

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.

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.

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.

Blink (Fixed) • WebKit

Fixed ! Blink, WebKit, and Gecko latest browser versions now all support custom counter styles.

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?

GitHub issue #111

Languages: gu 1

This issue is applicable to most languages that form conjuncts from consonant clusters using an invisible virama.

Because of the problems associated with grapheme cluster boundaries (see above), first-letter selection in CSS doesn't work well for conjuncts. For example, chrome fails to style the whole conjunct in પ્રૌદ્યોગીકી when using ::first-letter in a selector, and styles only the પ્ instead of પ્રૌ. Similar is the case of Internet Explorer, it only styles પ. This is problematic for many words in a script such as Gujarati, and forces the content author to use explicit spans rather than the proper mechanism for selecting initial letter.

Indian Layout Requirements provides a grammar for indian orthographic syllable boundaries which works for Gujarati, 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 Gujarati.

In addition, the alignment of styled initial-letter character glyphs with the rest of the text is not clearly specified or implemented.

For more details, see this GitHub issue, which is being used to track this gap.

GitHub issue #84

Languages: hi bn ta gu pa 2

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.

Gujarati Gap Analysis

Abstract

Status of This Document

1. Introduction

1.1 Contributors

1.2 About this document

1.3 Prioritization

1.4 Related information

2. Text direction

2.1 Vertical text

#70 Upright text in vertical lines doesn't segment correctly

The GAP

Priority

Tests

Action taken

Outcomes

2.2 Bidirectional text

3. Glyph shaping & positioning

3.1 Fonts & font styles

3.2 Context-based shaping and positioning

3.3 Letterform slopes, weights, & italics

3.4 Cursive text

3.5 Case & other character transforms

4. Typographic units

4.1 Characters & encoding

4.2 Grapheme/word segmentation & selection

#89 Spans around partial orthographic syllables can't be styled

#88 Dandas are wrapped alone to the beginning of a line

#87 Grapheme clusters fail to represent syllabic conjuncts in north Indian scripts

5. Punctuation & inline features

5.1 Phrase & section boundaries

5.2 Quotations & citations

5.3 Emphasis & highlighting

5.4 Abbreviation, ellipsis & repetition

5.5 Inline notes & annotations

5.6 Text decoration & other inline features

#90 Underline and overline need to clear glyph ascenders and descenders

5.7 Data formats & numbers

#91 Data formats need to be controllable by users

6. Line and paragraph layout

6.1 Line breaking & hyphenation

6.2 Text alignment & justification

6.3 Text spacing

#118 Browsers apply extraneous spaces when letter-spacing

#117 Letter-spacing splits conjuncts

The GAP

Priority

Tests & results

Action taken

Outcomes

6.4 Baselines, line-height, etc

#96 Differences in physical size for fonts affects baseline alignment

6.5 Lists, counters, etc.

#110 User-defined counters needed — FIXED !

FIXED !

#93 Customised counter styles are unavailable — FIXED !

The GAP

Priority:

Tests & results:

Action taken

Outcomes

6.6 Styling initials

#111 Conjuncts are not selected as a single unit when styling initials

#84 initial-letter positioning is not widely available

7. Page & book layout

7.1 General page layout & progression

7.2 Grids & tables

7.3 Footnotes, endnotes, etc.

7.4 Page headers, footers, etc.

7.5 Forms & user interaction

8. Other

8.1 Culture-specific features

8.2 What else?