Preliminary Discussions on Additional Font Properties Required for Multilingual Document Interchange

Yushi KOMACHI

<komachi@y-adagio.com>

MLIT-3 (3rd International Symposium on Standardization of Multilingual Information Technology), Hanoi, Vietnum
Oct. 6-7, 1998

Table of Contents

1. Introduction

The internet services, in particular Web and email services have made it possible to interchange documents with inexpensive charge and world wide cover area. Today we can actually interchange our documents without considering any boundary between countries, at least, in the interchange operations. It resulted in a new concept of a logical territory (internet service area) where multiple languages and cultures may be observed.

In the beginning of internet days, email users described their documents defaultly in English language and ASCII coded character set. After recognized as a useful infrastructure, the internet became be expected for document interchange to be performed in creator's or recipient's mother languages.

Corresponding to those requirements, most of today's browsers can support "multilingual". Their "multilingual" functions are, however, provided by selecting an appropriate language on the menu. They should be referred to as multi-localization rather than multilingual. They cannot render such a document as contains different language parts within a page or within the document itself.

The documents interchanged in the internet logical territory are often required to be multilingual mixture, i.e., described using multiple languages within a paragraph, a page or a document. Here we will call those document as real multilingual documents. A typical example is an participant list of online meeting, where each participant should be described his own language/script.

The real multilingual documents must be rendered and represented according to appropriate multilingual formatting[1]. It means that those document should be created and treated with following considerations:

This article focuses on the item (2) and discusses about user requirements on font technology for rendering multilingual mixture and on font properties for multilingual document interchange. Then, some new properties for soft copy presentation[2] are discussed.

Some research regarding those topics was carried out in 1997 by CICC (Center of the International Cooperation for Computerization) and the activities were reported[3].

2. Existing Font Resource Architecture

ISO/IEC JTC1/SC18 (today it is reorganized to be JTC1/SC34) developed several standards for document processing/description languages and font information interchange. They are based on an operational model[4] for document creation and interchange. Its basic concept are:

As far as font is concerned, architecture, interchange format and glyph shape representation of font resource are specified by ISO/IEC 9541 part 1, 2 and 3 respectively[5],[6],[7]. In several countries they are approved as their national standards as they are or translated, e.g., JIS X 4161, 4162 and 4163 respectively.

In general the font standards can support multilingual font treatments. For example it defines several writing modes, alignment lines, typeface design grouping, and other font properties required for multilingual mixed formatting. In actual, however, they are not enough for detailed formatting for non-Latin countries.

There proposed to include some additional font properties and developed Amendment 2 [8] to ISO/IEC 9541-1 with the support of international fonts experts. The status of the document is that DAM had approved and the final text was forwarded to ISO for publication. It can support some Kanji specific formatting. However, the properties defined in the AM2 still insufficient to full support of multilingual mixture.

3. User Requirements for Multilingual and Soft Copy Documents

Before the discussion of font properties, user requirements for multilingual and soft copy documents description are clarified from the font technology's point of view.

4. Additional Font Properties and their Related Values

All the properties defined in this clause are optional and should be used with the required/optional properties of ISO/IEC 9541-1. The properties are described by the extended Backus-Naur Form.

NOTE Those properties should be treated only as a trigger for further discussion, since the discussions within CICC are not yet sufficient.

4.1 Properties for multilingual mixed

4.1.1 Font Resource Combination Name (FONTRESCOMB)

FONTRESNAME is a property-list to specify a font resource combination typically used in formatting the documents which contain several character repertoires. 

  fontrescomb-property ::= fontrescomb-name,
                         fontrescomb-value-property-list
  fontrescomb-name ::= STRUCTURED-NAME
                       -- ISO/IEC 9541-1//FONTRESCOMB
  fontres-value-property-list ::= (fontname-property)+

4.1.2 Alignment Position (ALIGNPOSITION)

ALIGNPOSITION is rel-rationals, defining the position of alignment relative to the height of body size. 

  alignposition-property ::= alignposition-name, alignposition-value
  alignposition-name ::= STRUCTURED-NAME
                       -- ISO/IEC 9541-1//ALIGNPOSITION
  alignposition-value ::= REL-RATIONAL

NOTE This property can only be applied to the writing mode whose WRMODENAME has the value of RIGHT-TO-LEFT or LEFT-TO-RIGHT.

4.1.3 Property-value Lists

For an actual font substitution, some property values should be listed for typical font resources. The list should includes the values of:

The property-value list should be specified as an informative annex of font resource architecture standards.

4.2 Properties for interlinear formatting

The properties of interlinear objects are basically the issue of formatting rather than font. In some systems, however, font properties for formatting hinting are effective. From this point of view, the ISO/IEC 9541-1 introduced such formatting hinting properties as Scores.

4.2.1 Ruby (RUBY)

RUBY is a property-list, specifying sub-line description to associates the pronounciation or the explanation with words and phrases which in most cases consist of Kanji characters. 

  ruby-property ::= ruby-name, ruby-value-property-list
  ruby-name ::= STRUCTURED-NAME
              -- ISO/IEC 9541-1//RUBY
  ruby-value-property-list ::= 
(ruby-glyph-complement-property|ruby-font-size-property|ruby-formatting-type
-property|ruby-typeface-property|ruby-horizontal-writing-direction-alignment
-property|ruby-writing-vertical-direction-alignment-property|ruby-line-progr
ession-direction-offset-property)+

  ruby-glyph-complement-property ::= ruby-glyph-complement-name, 
                                   ruby-glyph-complement-value
  ruby-glyph-complement-name ::= STRUCTURED-NAME
             -- ISO/IEC 9541-1//RUBYCOMP
  ruby-glyph-complement-value ::= "HIRAGANA-RUBY" | "KATAKANA-RUBY" |
                                  "DEFAULT"

  ruby-font-size-property ::= ruby-font-size-name, ruby-font-size-value
  ruby-font-size-name ::= STRUCTURED-NAME
             -- ISO/IEC 9541-1//RUBYSIZE
  ruby-font-size-value ::= "HALF"|"ONE-THIRD"
                         -- 1/2 | 1/3

  ruby-formatting-type-property ::= ruby-formatting-type-name, 
  ruby-formatting-type-value
  ruby-formatting-type-name ::= STRUCTURED-NAME
            -- ISO/IEC 9541-1//RUBYTYPE
  ruby-formatting-type-value ::= "2-CHARS-RUBY"|"3-CHARS-RUBY"

  ruby-typeface-property ::= ruby-typeface-name, ruby-typeface-value
  ruby-typeface-name ::= STRUCTURED-NAME
            -- ISO/IEC 9541-1//RUBYTYPEFACE
  ruby-typeface-value ::= STRUCTURED-NAME

  ruby-horizontal-writing-direction-alignment-property ::= 
                  ruby-horizontal-writing-direction-alignment-name, 
                  ruby-horizontal-writing-direction-alignment-value
  ruby-horizontal-writing-direction-alignment-name ::= STRUCTURED-NAME
            -- ISO/IEC 9541-1//RUBYHORALIGN
  ruby-horizontal-writing-direction-alignment-value ::= 
                 "TOP"|"CENTER"|"JUSTIFICATION"

  ruby-vertical-writing-direction-alignment-property ::= 
                 ruby-vertical-writing-direction-alignment-name, 
                 ruby-vertical-writing-direction-alignment-value
  ruby-vertical-writing-direction-alignment-name ::= STRUCTURED-NAME
            -- ISO/IEC 9541-1//RYBYVERALIGN
  ruby-vertical-writing-direction-alignment-value ::= 
                 "CENTER"|"JUSTIFICATION"

  ruby-line-progression-direction-offset-property ::= 
                    ruby-line-progression-direction-offset-name, 
                    ruby-line-progression-direction-offset-value
  ruby-line-progression-direction-offset-name ::= STRUCTURED-NAME
            -- ISO/IEC 9541-1//RUBYOFFSET
  ruby-line-progression-direction-offset-value ::= REL-RATIONAL

4.2.2 Return Mark (RETMARK)

RETMARK is a property-list, specifying sub-line description to indicate the reading sequence for Japanese interpretation of old Chinese documents. 

  return-mark-property ::= return-mark-name, return-mark-property-list
  return-mark-name ::= STRUCTURED-NAME
           -- ISO/IEC 9541-1//RETMARK
  return-mark-property-list ::= (return-mark-offset-x-property| 
                       return-mark-offset-y-property)*

  return-mark-offset-x-property ::= return-mark-offset-x-name, 
                                    return-mark-offset-x-value
  return-mark-offset-x-name ::= STRUCTURED-NAME
            -- ISO/IEC 9541-1//RETMARKXOFFSET
  return-mark-offset-x-value ::= REL-RATIONAL

  return-mark-offset-y-property ::= return-mark-offset-y-name, 
                                    return-mark-offset-y-value
  return-mark-offset-y-name ::= STRUCTURED-NAME
            -- ISO/IEC 9541-1//RETMARKYOFFSET
  return-mark-offset-y-value ::= REL-RATIONAL

4.2.3 Added Kana (ADDEDKANA)

ADDEDKANA is a property-list, specifying sub-line description to complement the pronunciation of Kanji for Japanese interpretation of old Chinese documents. 

  added-kana-property ::= added-kana-name, added-kana-property-list
  added-kana-name ::= STRUCTURED-NAME
                    -- ISO/IEC 9541-1//ADDEDKANA
  added-kana-property-list ::= 
      (added-kana-font-size-property|added-kana-typeface-property|
       added-kana-offset-x-property|added-kana-offset-y-property)*

  added-kana-font-size-property ::= added-kana-font-size-name, 
           added-kana-font-size-value-type, added-kana-font-size-value
  added-kana-font-size-name ::= STRUCTURED-NAME
                    -- ISO/IEC 9541-1//ADDEDKANASIZE
  added-kana-font-size-value-type ::= "ABS" | "RELATIVE"
  added-kana-font-size-value ::= REL-RATIONAL

  added-kana-typeface-property ::= added-kana-typeface-name, 
                                   added-kana-typeface-value
  added-kana-typeface-name ::= STRUCTURED-NAME
                    -- ISO/IEC 9541-1//ADDEDKANATYPEFACE
  added-kana-typeface-value ::= STRUCTURED-NAME

  added-kana-offset-x-property ::= added-kana-offset-x-name, 
                                   added-kana-offset-x-value
  added-kana-offset-x-name ::= STRUCTURED-NAME
                    -- ISO/IEC 9541-1//ADDEDKANAXOFFSET
  added-kana-offset-x-value ::= REL-RATIONAL

  added-kana-offset-y-property ::= added-kana-offset-y-name, 
                                   added-kana-offset-y-value
  added-kana-offset-y-name ::= STRUCTURED-NAME
                    -- ISO/IEC 9541-1//ADDEDKANAYOFFSET
  added-kana-offset-y-value ::= REL-RATIONAL

4.3 Properties for color formatting

NOTE For color formatting, there should be more discussions, in particular, on font resource specific issues.

4.3.1 Design Color (DSNCOLOR)

DSNCOLOR is a structured-name, the recommended color at which the font resource is designed to be displayed, according to the judgment of the design source (DSNSOURCE). 

  dsncolor-property ::= dsncolor-name, dsncolor-value
  dsncolor-name ::= STRUCTUREDE-NAME
               -- ISO/IEC 9541-1//DSNCOLOR
  dsncolor-value ::= STRUCTURED-NAME

5. Standardizing Strategy

The properties are strongly requested to be approved as an international standard for open interchange of multilingual documents. For international standardizing, the following strategies are suggested:

6. Conclusion

New font properties for multilingual mixtiure and web documents are proposed to satisfy the user requirements for open interchange of multimingual documents in an internet environment. Since they are expected to be authorized as an international standard, some procedures and strategy are suggested.

Proposals and comments on font technology, in particular, regarding country stecific font properties, are welcomed and appreciated.

References