When a structured document is interchanged between an originator and a recipient, the recipient refers to the style specifications that the originator provides to reconstruct the presentation. However, when the recipient does not have sufficient rendering functionality, it may fail to reconstruct the presentation output as the originator expected. In order to preserve presentation output in the course of interchange, the originator and recipient need to negotiate over functionalities referring to the specifications of document rendering systems. To satisfy this requirement, this standard provides the minimum requirements for specifying document rendering systems. The document specification format shall have the same minimum requirements described here.
This International Standard can apply to the document processing environment, where a document is given in a logically structured format which is expressed by a structure markup language, and the visual representation of the document is described by means of the external style and layout specifications which a style and layout specifications language provides. The visual representation of the given document is generated when the style and layout specifications are applied to the logical structure by a document rendering system.
This International Standard provides an abstract list of the features that a rendering system for an authored document may have. The list provides a frame of reference, against which the user and implementor can compare the features of document rendering systems. However, this International Standard does not specify a concrete interchange syntax or direct how each document rendering system shall behave.
This International Standard provides the minimum requirements to specify the features that a document rendering system which transforms formatting objects to rendering output. It may be used as a frame of reference, against which the user, implementer, or software agent may compare the features of a document rendering system. According to these requirements, the user may express what he or she expects of a document rendering system, the implementer may describe the functionality and capability of the document rendering system that he or she implements, and the software agent may negotiate a minimum set of functionality and capability that are shared across different document rendering system implementations.
The output device(s) that the document rendering system supports are described. E.g. Printing systems and browsers.
The document formats, e.g. XML, RTF, etc., which the document rendering system supports to express the logical structure of a given document are described.
The style specification languages, DSSSL and other style specification languages, that the document rendering system supports are described.
The dimension of the rendering media, whether it is paged media or non-paged media, is described here. If the rendering media is paged, supported page sizes are described, e.g. A4, Letter, Legal, etc.
The level of support for colour is described, referring to whether colour is supported by the document rendering system, and if colour is supported, what colour profiles are supported. Colour system, e.g. RGB and CMYK and depth of colour, e.g. 8-bit (256 colours) and 24-bit (16 million colours).
The support for dynamically-generated content, meaning content calculated by and supplied by the stylesheet either as fixed value or conditionally-generated based on the presence or absence of data at rendering time.
Supported coded character standards and encoding schemes are described. E.g. UTF-8, SHIFT_JIS, KS-5601, etc.
The level of support for the composition of combined syllabic characters, whether the document rendering system supports the stacking of combined characters and environmental glyph alteration are supported, is described. E.g. Thai, Arabic, etc.
Support for the inherent directions of the progression of text (from left to right, right to left or top to bottom) and lines (from top to bottom, right to left or left to right) is described.
The interpretation of white-space characters, e.g. tab, space, carriage return and line feed, is described. A string of white-space characters may be collapsed or may be interpreted literally. Additionally, white-space characters may be removed before or after line breaks.
Support for font substitution mechanism, e.g. font substitution based on ISO/IEC 9541-1, is described
Capability of embedding and retrieving a font resource is described. If the document rendering system supports font-resource portability, it can extract an embedded font resource from the document and use it for rendering.
Support for the embedding of non-standard characters and glyphs, e.g. glyphs registered by ISO/IEC 10036, is described.
The attributes, e.g. page width and height, and margin and padding on top, bottom, left and right, of a page that the document rendering system supports are described.
The level of support for columnar pagination, i.e. whether columns are supported, and whether the column gap can be specified, etc. is described.
Basic attributes, e.g. width, height, margin and padding on top, bottom, left and right, and positions in the page, of the regions that the document rendering system can specify are described.
Support for different types of page-geometry sequencing is described. Example types for page-geometry sequencing are single page ordering, repeatable page ordering, and conditional page ordering. Example types for conditional page ordering are page parity and page position.
Support for static content, paginated content and flow maps is described. E.g. document title, page header, page footer, sidebars, multiple flows.
This subsection provides a list of features that are independent from the layout of the document.
Support for the specification of the z-index depth level of an area is described.
Support for relatively-positioned areas, or floats, for graphics and other objects is described. Treatments available for surrounding text are described. E.g. tight, box and arbitrary shape.
Support for absolutely-positioned areas for graphics and other objects is described. The available bases for the absolute measurements are described. Treatments available for surrounding text are described. E.g. tight, box and arbitrary shape.
Support for footnote, endnote and side note, the note body and the reference to the note is described.
Support for references to cited content that will be replaced at rendering time is described.
Support for content alteration that is triggered by the rendering environment, operator interaction or other conditions is specified.
This subsection provides a list of features that relates to the rendering of tables.
Supported table geometry, e.g. width, height, padding and margin, is described.
Support for table captions is described.
Support for the table header and its behaviour is described. Support for the orientation of headers and iteration of headers after the page break when the table spans across pages, is described.
Support for the table footer and its behaviour is described. Support for the orientation of footers and iteration of footer before the page break when the table spans across pages, is described.
Support for the types of background for a table, e.g. the placement of an image or the colour, is described.
The level of support for complex table compositions is described here, based on the structure set forth in ISO/IEC TR 19758:2002.
This subsection provides a list of features that relates to the rendering of lists.
Support for the geometry of the list, e.g. widths, heights, paddings and margins of the list item label and the list item body, is described here.
Support for the identification of list items is described, including techniques such as enumeration and itemisation, and the types of symbols that can be supplied as list item labels.
This subsection provides a list of features that relates to the rendering of blocks.
Support for the geometry of a block of lines, e.g. width, height, margins, paddings, line leading and line-stacking strategy, is described here.
Support for the wrapping of characters is described, e.g. the wrapping of characters that often takes place for punctuation characters in East Asian scripts, such as Chinese, Japanese and Korean. This is an equivalent feature of Japanese 'Kinsoku'.
Support for the wrapping of words, e.g. whether the last word in a line is wrapped to the next line, or kept in the same, etc, is described. Wrapping of words often takes place in English and other European scripts.
Support for the hyphenation at the line end is described. The principles by which the document rendering system hyphenates and breaks words, e.g. rule-based, dictionary-based and manual.
Support for the wrapping of lines, e.g. controlling widows and orphans, is described.
Support for the wrapping of blocks, e.g. whether a block which only contains a small number of lines, such as a chapter heading, shall be wrapped to the next column or page, is described.
Support for indentation, its values and its use, is described.
The types of content alignment, e.g. lines in a block, areas in the flow, areas in marginalia, etc, are described.
This subsection provides a list of features that relates to the decoration of a document.
Support for the rendering of instream and/or external graphics, e.g. the supported formats, scaling, positioning, etc, is described.
Support for leaders, e.g. the leader length, truncation of the leader, alignment of the leader, etc, is described.
Support for rules, e.g. orientation, length, types of rule, is described.
This subsection provides a list of features that relates to the rendering of inline constructs.
Support for the control of inline areas in a line, e.g. baseline shift, line height, etc, is described.
Support for the override of the inherent directionality of characters is described.
This subsection provides a list of features that relates to the rendering of characters.
Support for the types of spacing between characters, e.g. specified behaviours, automatic behaviours, etc, is described.
Support for the types of spacing between words, e.g. specified behaviours, automatic behaviours, etc, is described.
Support for character variants, e.g. drop initial cap, small caps, etc, is described.
Support for character decorations, e.g. strike-through, underline, overbar, reverse, etc, is described.
Support for selection of fonts, e.g. font family, font style, font weight, etc, is described.
Support for the specification of the association between areas of a document and other areas or external locations, e.g. for operator interaction, is described.
This informative annex offers examples of values one might use when specifying the features of a document rendering system according to this international standard. These values are not meant to be exhaustive but only documentary to give the reader consideration of the kinds of values that might apply for each feature. This international standard explicitly does not standardize the values for specifying the features in order that users of this standard are not constrained by any set of values that might be incomplete. The onus is on the user of this standard to describe a particular feature sufficiently well for the reader of their features to understand the capabilities offered by a document rendering system.
Note the convention of suffixing the annex section titles with the corresponding body section titles is for guidance to the normative text associated with an item.
Examples:
Laser printer
Inkjet printer
Dot matrix printer
LCD
CRT
NTSC (TU-R BT.470-6)
PDF/A (ISO 19005:1995-1)
PDF/X-1a (ISO 15930-1:2001)
JPEG file (ISO/IEC 10918-1:1994)
Macintosh PICT (Inside Macintosh: Imaging with QuickDraw, Appendix A)
Examples:
HTML 4.0
ISO/IEC 10180 SPDL
PostScript Level 2
PDF 1.4
PCL 4
Rich Text Format version 1.6
Examples:
CSS 2.1
XSL-FO 1.1
DSSSL (ISO/IEC 10179)
Examples:
paged media
non-paged media
A4
US-letter
US-legal
The colour support describes the native colour space and colour depth that are available on the device correctly. There are several popular standards for display devices that specifies colour space range, colour encoding and colour depth in detail. Simple reference these standards is sufficient description of colour support for display devices.
The available colour space and colour depth for printing devices are not standardized in detail. The printing device may accept the device independent colour specification and render the requested colour by approximated colour for the device. For example, some monochrome printers may accept the colour document data and convert it to monochrome data internally and the output is monochrome. Although it is helpful to describe the acceptable colour spaces and colour matching methods, the description on acceptable colour spaces is not essential. The native colour support or available subset shall be described. Some standards of printing colour chart (e.g. ISO 12642-1 initial set of 182 colours) can be referred as available colour space. If there is no appropriate device-independent standard to describe available colour space, the device dependent colour space families in ISO 10180 may be used for to avoid undefined keywords.
Examples:
IEC 61966-2-1 Default colour space (sRGB, 8bit per R, G, B components)
IEC 61966-2-2 Extended RGB colour space (scRGB, 16bit per R, G, B components)
ISO 12641-1 colours by CMYK inks
ISO/IEC 10180 DeviceCMYK (8bit for C, M, Y components and 10bit for K component)
ISO/IEC 10180 DeviceGray (16bit)
Examples:
table of contents generation
list numbering
figure numbering
example numbering
table numbering
Considering the fact that some character sets are designed for specific character encodings, each character sets provides the list of acceptable encoding schemes. For the specification of multilingual coded character set “ISO/IEC 10646” is not recommended to avoid the unclear coverage. The specification by subsets in ISO/IEC 10646 Annex A is better.
Examples:
ISO/IEC 8859-1 coded by ISO-2022, UTF-8 or UTF-16
ISO/IEC 10646 collection 1 coded by UTF-8
ISO/IEC 10646 collection 1, 2, 3, 4, 30 coded by UTF-8, UTF-16, UTF-32BE
The compositions of combined characters are expected to be described by the character set and encoding schemes to give source characters and the coverage of composed glyph or characters. Considering the fact that the coverage of required composition is not standardized exactly except of Latin, Cyrillic, Greek and IPA characters, it is possible that the coverage of composed glyph or characters are unspecified.
Examples:
ISO/IEC 6937
ISO/IEC 10646 collection 2, 3, 30 composed by ISO/IEC 10646 1, 4 implementation level 3 coded by UTF-8
ISO/IEC 10646 collection 14, 15, 64, 68 implementation level 2 coded by UTF-8 (Arabic)
ISO/IEC 10646 collection 16 implementation level 2 coded by UTF-8 (Devanagari)
ISO/IEC 10646 collection 29, 53 implementation level 3 coded by UTF-8 (Hangul Jamo)
This description is not the direction of text against paper or printing. When each glyph is rendered as isolated graphics, it is possible to line up the glyph for any direction. This description shall provide the information on the control of implicit pen position moving and selection of glyph shape which is appropriate for direction during the rendering of coded text. Most scripts have their default inline direction (direction from a glyph to next logical glyph), and the selection of glyph shape in their default inline direction is required. If the rendering in non-default inline direction is supported, the pair of character set and the method to specify the non-default inline direction shall be described. On many systems, the method to specify the inline direction is different from the method to select the appropriate glyph shape for the specified inline direction. The glyph shape selection for non-default inline direction is strongly dependent with the font resource; it shall be described in 4.1.12 and 4.1.13.
Examples:
ISO/IEC 8859-1 (left-to-right)
ISO-IR 127 (right-to-left)
ISO/IEC 10646 collection 1, 2, 3, 4, 7, 14, 15, 64, 68 (left-to-right, right-to-left by ISO/IEC 10646 collection 202)
ISO/IEC 10646 collection 93, 94, 95, 96 (left-to-right, bottom-to-top by XSL writing-mode property)
ISO/IEC 10646 collection 380 (top-to-bottom, right-to-left by XSL writing-mode property)
There are two groups of white-space characters. One group is the characters that the white-space with fixed size is inserted (e.g. ISO-8859-1 0x20 space, ISO-6429 0x09 horizontal tab, ISO 10646 U+3000 ideographic space, etc). Another group is the control characters that the rendering system cannot reflect the designed features and displayed by white-space (e.g. ISO-6429 0x0A line feed, 0x0B vertical tab, etc). The white-space characters in the first group are often repeated to adjust the text layout. The rendering system acting as simple typewriter displays the repeated white spaces literally, but some intelligent rendering system collapses the repeated white-space to single space (e.g. HTML). The collapse of repeated white-space may be restricted to the white-spaces before new line sequence, because the effect of collapse is expected to be negligible in many cases.
Examples:
ISO/IEC 10646 U+3000: always rendered in literal.
ISO/IEC 10646 U+0020: collapsed before new line sequence.
ISO/IEC 10646 U+0009: 8 times width of U+0020, collapsed before new line sequence.
ISO/IEC 10646 U+000A: always collapsed and displayed by single ISO 10646 U+0020 space.
The font properties for matching are defined in several standards (ISO/IEC 9541-1, ISO/IEC 14496-22 4.2.7 OS/2 table, ISO/IEC 14496-22 4.6.6 PCLT table, CSS 2.1, XSL 1.1), but some of them are missing the definition of matching algorithm. If the algorithm used in the device is not standardized and difficult to described, the list of referred properties is helpful. This entry does not describe the coverage of supported font format. For example, a rendering system can substitute all ISO/IEC 14496-22 OFF objects in the document by system internal bitmap fonts selected by the described substitution rule.
Examples:
CSS 2.1 font matching algorithm
ISO/IEC 10180 FontReference::MatchRules::SameIfSpecified matched by FontReference::Satisfaction::NameOrProps
ISO/IEC 14496-22 Annex B. Font Class parameter
ISO/IEC 14496-22 4.2.7.17 Panose
This entry provides the information on the methods to collect the fonts required in rendering. If the input document format is designed to include embedded font resources in various formats, it is recommended to list acceptable formats. For example, CSS 3 web fonts have the tags to indicate the font formats used in CSS, some of them are unpublished format. Also the method of retrieval and the supported font formats shall be described. This entry does not describe the font embedding feature of device output. For example, this entry does not describe if the rendering system generates ISO 19905 PDF/A data with embedded font or all texts are rendered as graphics. The font-resource portability can be described as a collection of the entries.
Examples:
ISO/IEC 19005 PDF/A embedded Type1 font and Type42 font
CSS 3 web fonts (ISO/IEC 9541-3 Type1 font and ISO/IEC 16500-6 TrueDoc PFR) retrieved by URI via file and http protocol
This description gives information on the method to embed non-standard glyph identifier in the coded text: a glyph cannot be specified by character code (e.g. CJK ideographic variant, glyph of punctuations in specific inline direction), a ligature or combining character coded by multiple character code points. Except of glyph identifier, the description on glyph selection mechanism is helpful to guide the access of non-standard characters and glyphs. ISO/IEC 14496-22 Open Font Format is a standard of a font format including the predefined glyph substitution table, although the specification does not guarantee the availability of required glyphs.
This description does not provide information on the data format which embeds font files of these glyphs into the document. It shall be described in 4.1.12.
Examples:
ISO/IEC 10036 glyph identifier
Unicode IVD Adobe-Japan1
ISO/IEC 14496-22 OFFS, glyph substitution by vert and vrt2 for hani scripts.
Examples:
physical page dimensions
logical region placement
logical region orientation
logical region dimensions
padding
margin
Examples:
evenly-sized columns
eqaully-spaced columns
arbitrarily-sized columns
arbitrarily-spaced columns
arbitrary column flow
simple serpentine columns
Examples:
region placement
region dimensions
region margins
region padding
region identification
Examples:
single page
repeating page
conditional page
page parity
page position
page blankness
Examples:
flowed paginating content
static repeating content
content associated with named regions
multiple flows of paginating content
Examples:
layering of content coincident on a page
Examples:
floating graphics
tight text flow
box text flow
arbitrary-shape text flow
Examples:
floating graphics
tight text flow
box text flow
arbitrary-shape text flow
Examples:
footnotes
endnotes
Examples:
footnote citation
title citation
citing arbitrary content
Examples:
operator-directed alteration
alterations triggered by formatting conditions
Examples:
table dimensions
table margins
padding
Examples:
caption content
caption positioning
Examples:
header orientation
header iteration
header suppression
header annotation
Examples:
footer orientation
footer iteration
footer suppression
Examples:
Colour in table background
image in table background
repetition of image in table background
anchoring of image in table background
scaling of image in table background
Examples:
Complex table compositions by TR 19758:2002
Examples:
List label width
List label height
List label padding
List label margin
List body width
List body height
List body padding
List body margin
Examples:
item identification by itemization
item identification by use of symbols
resumption of list item identification
Examples:
block width
block height
block margin
block padding
line leading
fixed size line stacking
accomodating size line stacking
Examples:
Wrapping of characters
Wrapping of characters by JIS X 4051-1995
Examples:
engaging wrapping of text to new lines
disengaging wrapping of text to new lines
adjustable count of words being wrapped on last line of a block
Examples:
Hyphenation by rules
Hyphenation by dictionary
Examples:
engaging wrapping of lines to new columns or pages
disengaging wrapping of lines to new columns or pages
adjustable count of lines at start of columns or pages
adjustable count of lines at end of columns or pages
Examples:
engaging wrapping of entire blocks of lines to new columns or pages
disengaging wrapping of entire blocks of lines to new columns or pages
adjustable count of blocks at end or start of columns or pages
Examples:
indentation of the first line of a block
indentation of the last line of a block
indentation control in the presence of side floats
Examples:
alignment of lines in a block
separate alignment the last line in a block
alignment of marginalia marks with flowed content
alignment of areas in parallel pagination flows
Examples:
rendering of external graphic images
rendering of internally-specified graphic images
query of properties of graphic images
support of view port
scaling of view port
positioning of view port
specifying of view port dimensions
Examples:
elastic leader
inelastic leader
leader style
leader content
leader alignment
Examples:
rule orientation
rule dimension
rule style
Examples:
line height
baseline shift
embedded containers of lines with arbitrary orientation and flow control
Examples:
automatic respect of inherent Unicode directionality of characters in use
specified override of directionality
specified containment of sequences of characters to prevent undue influence of characters with strong directions
Examples:
inter-character spacing
automatic character spacing behaviours and any available overrides
Examples:
inter-word spacing
automatic word spacing behaviours and any available overrides
Examples:
drop initial caps
small caps
Examples:
strike-through
underline
overbar
reverse
Examples:
font family
font style or posture
Examples:
unidirectional links
bidirectional links
types of operator interaction
links within the document
links outside of the document
support for external link-bases