draft-iab-svg-rfc-02.txt   rfc7996.txt 
Network Working Group N. Brownlee Internet Architecture Board (IAB) N. Brownlee
Internet-Draft The University of Auckland Request for Comments: 7996 The University of Auckland
Intended status: Informational IAB Category: Informational December 2016
Expires: August 29, 2016 February 26, 2016 ISSN: 2070-1721
SVG Drawings for RFCs: SVG 1.2 RFC SVG Drawings for RFCs: SVG 1.2 RFC
draft-iab-svg-rfc-02
Abstract Abstract
. Maybe the text in section This document specifies SVG 1.2 RFC - an This document specifies SVG 1.2 RFC -- an SVG profile for use in
SVG profile for use in diagrams that may appear in RFCs - and diagrams that may appear in RFCs -- and considers some of the issues
considers some of the issues concerning the creation and use of such concerning the creation and use of such diagrams.
diagrams.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This document is not an Internet Standards Track specification; it is
provisions of BCP 78 and BCP 79. published for informational purposes.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Architecture Board (IAB)
and may be updated, replaced, or obsoleted by other documents at any and represents information that the IAB has deemed valuable to
time. It is inappropriate to use Internet-Drafts as reference provide for permanent record. It represents the consensus of the
material or to cite them other than as "work in progress." Internet Architecture Board (IAB). Documents approved for
publication by the IAB are not a candidate for any level of Internet
Standard; see Section 2 of RFC 7841.
This Internet-Draft will expire on August 29, 2016. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7996.
Copyright Notice Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1. Introduction ....................................................2
2. SVG 1.2 RFC: An SVG profile for RFCs . . . . . . . . . . . . 3 2. SVG 1.2 RFC: An SVG Profile for RFCs ............................3
2.1. Elements, properties and attributes allowed in SVG 1.2 2.1. Elements, Properties, and Attributes Allowed in
RFC . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 SVG 1.2 RFC ................................................4
3. How to create SVG drawings . . . . . . . . . . . . . . . . . 6 3. How to Create SVG Drawings ......................................7
4. Accessibility Considerations . . . . . . . . . . . . . . . . 7 4. Accessibility Considerations ....................................7
5. Examples of diagrams common in RFCs . . . . . . . . . . . . . 8 5. Examples of Diagrams Common in RFCs .............................8
5.1. Packet Layout Diagrams . . . . . . . . . . . . . . . . . 8 5.1. Packet Layout Diagrams .....................................8
5.2. Sequence Diagrams (1) . . . . . . . . . . . . . . . . . . 8 5.2. Sequence Diagrams (1) ......................................8
5.3. Sequence Diagrams (2) . . . . . . . . . . . . . . . . . . 8 5.3. Sequence Diagrams (2) ......................................8
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 6. Security Considerations .........................................8
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 7. References ......................................................9
8. Revision History [RFC Editor please delete] . . . . . . . . . 8 7.1. Normative References .......................................9
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 7.2. Informative References .....................................9
9.1. Normative References . . . . . . . . . . . . . . . . . . 10 Appendix A. RELAX NG Compact (RNC) Schema for SVG 1.2 RFC .........11
9.2. Informative References . . . . . . . . . . . . . . . . . 11 IAB Members at the Time of Approval ...............................53
Appendix A. RELAX NG Compact (rnc) Schema for SVG 1.2 RFC . . . 12 Acknowledgements ..................................................53
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 53 Author's Address ..................................................53
1. Introduction 1. Introduction
Over the last few years the RFC Editor has worked with the Internet Over the last few years, the RFC Editor has worked with the Internet
community to develop specifications for changes in the format of community to develop specifications for changes in the format of
RFCs. An outline of the resulting specifications was published as RFCs. An outline of the resulting specifications was published as
[RFC6949] in May 2013. Since then a Design Team has been working [RFC6949] in May 2013. Since then, a Design Team has been working
with the RFC Editor to flesh out those specifications. One aspect of with the RFC Editor to flesh out those specifications. One aspect of
the changes is to allow line drawings in RFCs; [RFC6949] says the changes is to allow line drawings in RFCs; [RFC6949] says
"Graphics may include ASCII art and a more complex form to be Graphics may include ASCII art and a more complex form to be
defined, such as SVG line art [SVG]. Color and grayscale will not defined, such as SVG line art [SVG]. Color and grayscale will not
be accepted. RFCs must correctly display in monochromatic black- be accepted. RFCs must correctly display in monochromatic black-
and-white to allow for monochrome displays, black-and-white and-white to allow for monochrome displays, black-and-white
printing, and support for visual disabilities." printing, and support for visual disabilities.
SVG (Scalable Vector Graphics) has been developed by W3C, the World SVG (Scalable Vector Graphics) has been developed by W3C, the World
Wide Web Consortium; its current standard is SVG 1.1 Full Wide Web Consortium; its current standard is SVG 1.1 Full
[W3C.REC-SVG11-20110816]. This document defines SVG 1.2 RFC, an SVG [W3C.REC-SVG11-20110816]. This document defines SVG 1.2 RFC, an SVG
profile (i.e. a subset of SVG) that is suitable for RFC line profile (i.e., a subset of SVG) that is suitable for RFC line
drawings. drawings.
Note that in RFCs, the text provides normative descriptions of Note that in RFCs, the text provides normative descriptions of
protocols, systems, etc. Diagrams may be used to help explain protocols, systems, etc. Diagrams may be used to help explain
concepts more clearly, but they provide supporting detail, and should concepts more clearly, but they provide supporting details and should
not be considered to be complete specifications in themselves. not be considered to be complete specifications in themselves.
The details (particularly any vocabularies) described in this The details (particularly any vocabularies) described in this
document are expected to change based on experience gained in document are expected to change based on experience gained in
implementing the RFC production center's toolset. Revised documents implementing the new publication toolsets. Revised documents will be
will be published capturing those changes as the toolset is published capturing those changes as the toolsets are completed.
completed. Other implementors must not expect those changes to Other implementers must not expect those changes to remain backwards-
remain backwards-compatible with the details described in this compatible with the details described in this document.
document.
2. SVG 1.2 RFC: An SVG profile for RFCs 2. SVG 1.2 RFC: An SVG Profile for RFCs
As a starting point for SVG 1.2 RFC, the Design Team decided to use As a starting point for SVG 1.2 RFC, the Design Team decided to use
SVG 1.2 Tiny [W3C.REC-SVGTiny12-20081222]. SVG 1.2 Tiny is an SVG SVG Tiny 1.2 (also referred to as "SVG 1.2 Tiny")
subset intended to be implemented on small, mobile devices such as [W3C.REC-SVGTiny12-20081222]. SVG 1.2 Tiny is an SVG subset intended
cellphones and smartphones. That should allow RFCs to be rendered to be implemented on small, mobile devices such as cell phones and
well on such devices, especially those that have small screens. smartphones. That should allow RFCs to be rendered well on such
However, RFCs are self-contained documents that do not change once devices, especially those that have small screens. However, RFCs are
they are published. The use of SVG drawings in RFCs is intended to self-contained documents that do not change once they are published.
allow authors to create drawings that are simple to produce, and The use of SVG drawings in RFCs is intended to allow authors to
easier to understand than our traditional 'ASCII Art' ones. In create drawings that are simple to produce and are easier to
short, we are also trying to improve access to the content in RFCs, understand than our traditional "ASCII art" ones. In short, we are
so SVG drawings need to be kept as simple as possible. also trying to improve access to the content in RFCs, so SVG drawings
need to be kept as simple as possible.
Appendix A (below) provides a complete RELAX NG Compact (rnc) schema Appendix A (below) provides a complete RELAX NG Compact (RNC) schema
for SVG 1.2 RFC. It is derived from the SVG 1.2 schema, and is the [RNG-HOME] for SVG 1.2 RFC. It is derived from the SVG 1.2 schema,
formal definition of SVG 1.2 RFC. The remainder of this section and is the formal definition of SVG 1.2 RFC. The remainder of this
gives a simplified - i.e. easier to read and dunderstand - overview section gives a simplified -- i.e., easier to read and understand --
of SVG 1.2 RFC. overview of SVG 1.2 RFC.
SVG can provide a complete User Interface, but within RFCs, all we SVG can provide a complete User Interface, but within RFCs, all we
need are simple diagrams that do not change once the RFC is need are simple diagrams that do not change once the RFC is
published. Therefore, SVG RFC does not allow anything from the published. Therefore, SVG 1.2 RFC does not allow anything from the
following sections in SVG Tiny 1.2 [W3C.REC-SVGTiny12-20081222]: following sections in SVG Tiny 1.2 [W3C.REC-SVGTiny12-20081222]:
12 Multimedia 12 Multimedia
13 Interactivity 13 Interactivity
15 Scripting 15 Scripting
16 Animation 16 Animation
18 Metadata 18 Metadata
19 Extensibility 19 Extensibility
Note that SVG Tiny 1.2 elements may have many properties or Note that SVG Tiny 1.2 elements may have many properties or
attributes that are needed to support aspects of the above sections. attributes that are needed to support aspects of the above sections.
Those are not allowed in SVG 1.2 RFC. Those are not allowed in SVG 1.2 RFC.
Considering the other sections in SVG Tiny 1.2 We now consider these other sections in SVG Tiny 1.2
[W3C.REC-SVGTiny12-20081222]: [W3C.REC-SVGTiny12-20081222]:
9 Basic Shapes 9 Basic Shapes
10 Text 10 Text
Everything in these sections is allowed in SVG 1.2 RFC. Everything in this section is allowed in SVG 1.2 RFC.
11 Painting: Filling, Stroking, Colors and Paint Servers 11 Painting: Filling, Stroking, Colors and Paint Servers
Anything relating to 'color' is not allowed in SVG 1.2 RFC, Anything relating to 'color' is not allowed in SVG 1.2 RFC;
everything else is allowed. This is a requirement documented in everything else is allowed. This is a requirement documented in
[RFC6949]. [RFC6949].
14 Linking 14 Linking
SVG Tiny 1.2 allows internationalized IRIs in references. In SVG Tiny 1.2 allows Internationalized Resource Identifiers
SVG 1.2 RFC such links must be ASCII only. That should not (IRIs) in references. In SVG 1.2 RFC, such links must be ASCII
cause problems, since one can just use the URI form of any IRI. only. That should not cause problems, since one can just use
Authors should try to use links only to URIs that are long-term the URI form of any IRI. Authors should try to use links only
stable. to URIs that are long-term stable.
17 Fonts 17 Fonts
SVG 1.2 RFC only allows 'serif', 'sans-serif' and 'monospace' SVG 1.2 RFC only allows 'serif', 'sans-serif', and 'monospace'
generic font families from the WebFonts facility, described in generic font families from the WebFonts facility, described in
CSS 2.1, [W3C.REC-CSS2-20110607], section 15, Fonts. In Section 15 ("Fonts") of the W3C Cascading Style Sheets (CSS) 2.1
particular, the SVG 'font' element is not allowed. document [W3C.REC-CSS2-20110607]. In particular, the SVG 'font'
element is not allowed.
2.1. Elements, properties and attributes allowed in SVG 1.2 RFC 2.1. Elements, Properties, and Attributes Allowed in SVG 1.2 RFC
Elements, properties and attributes selected for SVG 1.2 RFC from This section discusses elements, properties, and attributes selected
[W3C.REC-SVGTiny12-20081222]. for SVG 1.2 RFC from [W3C.REC-SVGTiny12-20081222].
In the list below, elements and properties are listed on the In the list below, elements and properties are listed on the
left,and their allowed values are given in parentheses on the left, and their allowed values are given in parentheses on the
right. right.
<color> is the list of allowed colors, a black-and-white <color> is the list of allowed colors, a black-and-white
subset of the SVG color names. subset of the SVG color names.
<style> is a set of CSS attributes that are commonly used (by SVG <style> is a set of CSS attributes that are commonly used (by SVG
drawing applications). They are not part of SVG Tiny 1.2, drawing applications). They are not part of SVG Tiny 1.2
but are included here for compatibility. Note that but are included here for compatibility. Note that
- There is no guarantee that any renderer will implement
all the CSS attributes a drawing application may use.
- Authors will need to consider the compatibility of their
drawings with rendering devices.
Elements: - There is no guarantee that any renderer will implement
all the CSS attributes a drawing application may use.
svg (version=1.2, baseProfile=tiny, width, viewBox, - Authors will need to consider the compatibility of their
preserveAspectRatio, snapshotTime, height, drawings with rendering devices.
id, role)
g (label, class, id, role, fill, <style>, transform)
defs (id, role, fill)
title (id, role)
desc (id, role)
a (id, role, fill, transform)
use (x, y, href, xlink:href, id, role, fill, transform)
rect (x, y, width, height, rx, ry, stroke-miterlimit Elements:
id, role, fill, <style>, transform)
circle (cx, cy, r,
id, role, fill, <style>, transform)
ellipse (cx, cy, rx, ry,
id, role, fill, <style>, transform)
line (x1, y1, x2, y2, id, role, fill, transform)
polyline (points, id, role, fill, transform)
polygon (points, id, role, fill, <style>, transform)
text (x, y, rotate, space, id, role, fill, <style>,
transform)
tspan (x, y, id, role, fill)
textArea (x, y, width, height, auto, id, role, fill,
transform)
tbreak (id, role)
solidColor (id, role, fill) svg (version=1.2, baseProfile=tiny, width, viewBox,
linearGradient (gradientUnits, x1, y1, x2, y2, id, role, fill) preserveAspectRatio, snapshotTime, height,
radialGradient (gradientUnits, cx, cy, r, id, role, fill) id, role)
stop (id, role, fill) g (label, class, id, role, fill, <style>, transform)
path (d, pathLength, stroke-miterlimit, defs (id, role, fill)
id, role, fill, <style>, transform) title (id, role)
desc (id, role)
a (id, role, fill, transform)
use (x, y, href, xlink:href, id, role,
fill, transform)
Properties: (most allow inherit as a value) rect (x, y, width, height, rx, ry, stroke-miterlimit,
id, role, fill, <style>, transform)
circle (cx, cy, r, id, role, fill, <style>, transform)
ellipse (cx, cy, rx, ry, id, role,
fill, <style>, transform)
line (x1, y1, x2, y2, id, role, fill, transform)
polyline (points, id, role, fill, transform)
polygon (points, id, role, fill, <style>, transform)
text (x, y, rotate, space, id, role, fill, <style>,
transform)
tspan (x, y, id, role, fill)
textArea (x, y, width, height, auto, id, role, fill,
transform)
tbreak (id, role)
<style> (font-family, font-weight, font-style, solidColor (id, role, fill)
font-variant, direction, unicode-bidi, linearGradient (gradientUnits, x1, y1, x2, y2, id, role, fill)
text-anchor, fill, fill-rule) radialGradient (gradientUnits, cx, cy, r, id, role, fill)
stop (id, role, fill)
path (d, pathLength, stroke-miterlimit,
id, role, fill, <style>, transform)
<color> (black, white, #000000, #ffffff, #FFFFFF) Properties: (most allow "inherit" as a value)
stroke (<color>, none, currentColor) <style> (font-family, font-weight, font-style,
stroke-width font-variant, direction, unicode-bidi,
stroke-linecap (butt, round, square) text-anchor, fill, fill-rule)
stroke-linejoin (miter, round, bevel)
stroke-mitrelimit <color> (black, white, #000000, #ffffff, #FFFFFF)
stroke-dasharray
stroke-dashoffset stroke (<color>, none, currentColor)
stroke-opacity stroke-width
vector-effect (non-scaling-stroke, none) stroke-linecap (butt, round, square)
viewport-fill (none, currentColor) stroke-linejoin (miter, round, bevel)
viewport-fill-opacity stroke-miterlimit
display (inline, block, list-item, run-in, compact, stroke-dasharray
stroke-dashoffset
stroke-opacity
vector-effect (non-scaling-stroke, none)
viewport-fill (none, currentColor)
viewport-fill-opacity
display (inline, block, list-item, run-in, compact,
marker, table, inline-table, table-row-group, marker, table, inline-table, table-row-group,
table-header-group, table-footer-group, table-header-group, table-footer-group,
table-row, table-column-group, table-row, table-column-group,
table-column, table-cell, table-caption, table-column, table-cell, table-caption,
none) none)
visibility (visible, hidden, collapse) visibility (visible, hidden, collapse)
color-rendering (auto, optimizeSpeed, optimizeQuality) color-rendering (auto, optimizeSpeed, optimizeQuality)
shape-rendering (auto, optimizeSpeed, crispEdges, shape-rendering (auto, optimizeSpeed, crispEdges,
geometricPrecision) geometricPrecision)
text-rendering (auto, optimizeSpeed, optimizeLegibility, text-rendering (auto, optimizeSpeed, optimizeLegibility,
geometricPrecision) geometricPrecision)
buffered-rendering (auto, dynamic, static) buffered-rendering (auto, dynamic, static)
opacity opacity
solid-opacity solid-opacity
solid-color (currentColor, <color>) solid-color (currentColor, <color>)
color (currentColor, <color>) color (currentColor, <color>)
stop-color (currentColor, <color>) stop-color (currentColor, <color>)
stop-opacity stop-opacity
line-increment (auto) line-increment (auto)
text-align (start,end, center) text-align (start, end, center)
display-align (auto, before, center, after) display-align (auto, before, center, after)
font-size font-size
font-family (serif, sans-serif, monospace) font-family (serif, sans-serif, monospace)
font-weight (normal, bold, bolder, lighter) font-weight (normal, bold, bolder, lighter)
font-style (normal, italic, oblique) font-style (normal, italic, oblique)
font-variant (normal, small-caps) font-variant (normal, small-caps)
direction (ltr, rtl) direction (ltr, rtl)
unicode-bidi (normal, embed, bidi-override) unicode-bidi (normal, embed, bidi-override)
text-anchor (start, middle, end) text-anchor (start, middle, end)
fill (none, <color>) fill (none, <color>)
fill-rule (nonzero, evenodd) fill-rule (nonzero, evenodd)
fill-opacity fill-opacity
3. How to create SVG drawings 3. How to Create SVG Drawings
Many drawing packages can be used to create SVG drawings, for example Many drawing packages can be used to create SVG drawings -- for
Open Source packages Inkscape and Dia. Be aware that such packages example, Open Source packages Inkscape and Dia. Be aware that such
may use SVG elements or attributes that are not allowed in SVG 1.2 packages may use SVG elements or attributes that are not allowed in
RFC. SVG 1.2 RFC.
o For example, the 'marker' attribute is often used to place symbols o For example, the 'marker' attribute is often used to place symbols
such as arrowheads on lines, but 'marker' is not allowed in SVG such as arrowheads on lines, but 'marker' is not allowed in
1.2 Tiny or SVG 1.2 RFC. In such cases one has to draw the SVG 1.2 Tiny or SVG 1.2 RFC. In such cases, one has to draw the
arrowhead in another, simpler way. arrowhead in another, simpler way.
o SVG clip paths are used to define a shape; objects outside that o SVG clip paths are used to define a shape; objects outside that
shape become invisible. The 'clipPath' element is not allowed in shape become invisible. The 'clipPath' element is not allowed in
SVG 1.2 Tiny or SVG 1.2 RFC. SVG 1.2 Tiny or SVG 1.2 RFC.
Diagrams produced with these packages may contain elements, their Diagrams produced with these packages may contain elements, their
attributes or properties, or values of attributes or properties that attributes or properties, or values of attributes or properties that
are not allowed in SVG 1.2 RFC. We will need to provide a tool to are not allowed in SVG 1.2 RFC. We will need to provide a tool to
strip out anything that is not allowed in SVG 1.2 RFC, or to replace either (1) strip out anything that is not allowed in SVG 1.2 RFC or
disallowed values, e.g., 'sans-serif' for 'Sans' as values for 'font- (2) replace disallowed values (e.g., replace 'Sans' with 'sans-serif'
family'. Experience with a simple test version of a tool for this as an allowed value for 'font-family'). Experience with a simple
has shown that such deletion and replacement can be effective for test version of a tool for this has shown that such deletion and
making SVG files from drawing packages conform to SVG 1.2 RFC, replacement can be effective for making SVG files from drawing
without visibly changing the diagrams they produce. packages conform to SVG 1.2 RFC, without visibly changing the
diagrams they produce.
The tool described above can also be used by Authors simply to check The tool described above can also be used by authors simply to check
that their diagrams conform to SVG 1.2 RFC. To help with this, if that their diagrams conform to SVG 1.2 RFC. To help with this, if
visible changes do occur, the tool should produce a list of non- visible changes do occur, the tool should produce a list of
allowed keywords and the context in which they were found. non-allowed keywords and the context in which they were found.
To include a diagram into an RFC, the xml2rfc (v3) tool will need to To include a diagram in an RFC, the xml2rfc (v3) tool will need to
provide a way to include SVG drawings in Internet Drafts, as provide a way to include SVG drawings in Internet-Drafts, as
described in [XML2RFCv3] sections 2.5 and 2.67. described in Section 2.5 of [RFC7991].
4. Accessibility Considerations 4. Accessibility Considerations
One of the long-term goals for RFCs is to make them more accessible, One of the long-term goals for RFCs is to make them more accessible,
e.g. to sight-impaired readers. For diagrams, it would be useful for e.g., to sight-impaired readers. For diagrams, it would be useful
authors to provide alternative forms of the diagram, so that voice- for authors to provide alternative forms of the diagram, so that
reading software could be used to 'talk through' the diagram. Simply voice-reading software could be used to "talk through" the diagram.
reading the SVG code for a complex diagram seems unlikely to work. Simply reading the SVG code for a complex diagram seems unlikely
to work.
SVG 1.2 RFC allows SVG's 'title' and 'desc' elements. 'title' SVG 1.2 RFC allows SVG's 'title' and 'desc' elements. 'title'
provides a brief text caption for an SVG object (much like a figure provides a brief text caption for an SVG object (much like a figure
caption), and 'desc' provides a longer text description of what the caption), and 'desc' provides a longer text description of what the
object actually represents. As well, the SVG 'role' attribute can be object actually represents. As well, the SVG 'role' attribute can be
used to indicate to a browser how an SVG object is to be interpreted. used to indicate to a browser how an SVG object is to be interpreted.
Good suggestions on how to use these elements are given in Good suggestions on how to use these elements are given in
[SVG-ACCESS-TIPS]. [SVG-ACCESS-TIPS].
ARIA is a W3C Recommendation for using SVG to create 'Accessible Rich ARIA is a W3C Recommendation for using SVG to create (as the name
Internet Applications.' A helpful introduction to ARIA is provided "ARIA" indicates) "Accessible Rich Internet Applications". A helpful
by [SVG-ARIA-PRIMER], while [SVG-USING-ARIA] gives examples of how to introduction to ARIA is provided by [SVG-ARIA-PRIMER], while
use ARIA to enhance SVG accessibility. [SVG-USING-ARIA] gives examples of how to use ARIA to enhance SVG
accessibility.
5. Examples of diagrams common in RFCs 5. Examples of Diagrams Common in RFCs
Another way to create SVG drawings is to write programs to draw them. Another way to create SVG drawings is to write programs to draw them.
For example, using python and its svgwrite module is a pleasant For example, using Python and its svgwrite module is a pleasant
environment (for those who like writing code); this section presents environment (for those who like writing code); this section presents
a few examples of diagrams created in this way. Note that they are a few examples of diagrams created in this way. Note that they are
merely examples of typical diagrams from RFCs. merely examples of typical diagrams from RFCs.
The SVG diagrams for this section can be seen at The SVG diagrams for this section, along with an HTML version of this
[This-I-D-with-SVG-included] along with an html version of this draft document that includes the SVG diagrams, can be seen at
that includes the SVG diagrams. [NB-SVG-1.2-RFC].
5.1. Packet Layout Diagrams 5.1. Packet Layout Diagrams
Example: Figure 3 from [RFC0793]. Example: Figure 3 from [RFC793].
5.2. Sequence Diagrams (1) 5.2. Sequence Diagrams (1)
Example: Figure 6 from [ExpTrustedProxy]. Example: Figure 6 from [ExpTrustedProxy].
5.3. Sequence Diagrams (2) 5.3. Sequence Diagrams (2)
Example: Figure 3 from [RFC4321]. Example: Figure 3 from [RFC4321].
6. IANA Considerations 6. Security Considerations
This document does not create a new registry nor does it register any
values in existing registries; no IANA action is required.
7. Acknowledgements
Thanks to the RSE and the Design Team members for their helpful
comments and suggestions for SVG 1.2 RFC, as well as from the wider
IETF community.
8. Revision History [RFC Editor please delete]
version -02, 25 Feb 16:
Changed the example metalanguage by removing the metalanguage
code. The svg diagrams remain, as examples of diagrams that have
appeared in earlier RFCs.
version -01, 26 Jan 16:
rnc schema changed to use Joe Hildebrand's version, github:
"rename title element *reference* to svgTitle, in order to allow
combination with XML2RFC schema. Note: XML element name does not
change."
version -00, 6 Jan 16:
Now an IAB draft, changed name to draft-iab-svg-rfc-00.
version -13, 16 Oct 15:
Added Informative Reference to XML2RFC v3 draft on 'how to include
SVG diagrams'.
Added Informative Reference to Nevil's home page for a version of
this I-D with its SVG diagrams included.
Added Informative References to RFC0793 and I-Ds for the example
diagrams.
Changed 'colour' to 'color' so as to be consistent.
Fixed other typos (thanks to Dave Thaler for all these)!
Removed 'grey' color from example diagrams.
version -12, 24 Sep 15:
Appendix A added: a complete relax-ng compact (rnc) schema for
SVG-1.2-RFC.
Section 2.1: Elements/attributes/properties table updated to match
the schema in Appendix A.
version -11, 17 Aug 15:
Section 1: Fixed typo in "Details are expected to change"
paragraph.
version -10, 14 Aug 15:
Section 1: Added "Details are expected to change" paragraph.
version -09, 31 Mar 15:
No changes, version number incremented to keep draft alive
version -08, 29 Sep 14:
Section 1: Changed comment about diagrams 'not being normative' to
'not complete specifications in themselves.
Section 2.1: Added SVG 1.2 Tiny 'id' attribute because most
drawing packages use it in constructing drawings.
Section 2.1: Added SVG 1.2 Tiny 'role' attribute so that ARIA can
use it.
Section 3: added comment about changes to xml2rfc required to
include SVG diagrams.
Section 4: Added reference to svg-aria-primer.
version -07, 3 Jul 14:
Expanded text about Accessibility in 'how to create SVG drawings'
section into 'Accessibility Considerations section. Added two SVG
Accessibility references to support that.
version -06, 26 Jun 14:
Remove trailing / from URL in section 4; the html version on
tools.ietf.org/html assumed the next word was part of that URL.
version -05, 25 Jun 14:
Improved section on 'how to create SVG drawings' By adding some
text about which elements aren't allowed in SVG 1.2 RFC.
Added more text describing the tool for checking, stripping out or
replacing incompatible elements and attributes from an SVG file.
version -04, 30 Apr 14:
Fixed typos, used full references for two of the w3c refs - each
had an author name using UTF8 characters.
Moved the Elements and Attributes appendix up earlier to make it
sub-section 2.1.
Disclaimer added to the Meta-languages section.
version -03, 14 Apr 14:
Added two more example diagrams; a simple packet layout, and a
diagram that uses lots of diagonal lines.
version -02, 12 Feb 14:
Added metalanguage example to make time-sequence drawings.
version -01, 11 Feb 14:
Allow links to 'long-term stable URIs'
Link URIs must be ASCII only
Need for tools to check SVG 1.2 RFC compatibility and to strip
'unnecessary' attributes explicitly stated.
Statement that drawings can't be normative removed; Postscript-
only RFCs already exist.
Added most attributes and elements to the Appendix.
version -00, 29 Jan 14: This document does not introduce any security considerations on
Initial version, using content from Nevil's its own.
emails to the Design Team.
9. References 7. References
9.1. Normative References 7.1. Normative References
[RFC6949] Flanagan, H. and N. Brownlee, "RFC Series Format [RFC6949] Flanagan, H. and N. Brownlee, "RFC Series Format
Requirements and Future Development", RFC 6949, Requirements and Future Development", RFC 6949,
DOI 10.17487/RFC6949, May 2013, DOI 10.17487/RFC6949, May 2013,
<http://www.rfc-editor.org/info/rfc6949>. <http://www.rfc-editor.org/info/rfc6949>.
[W3C.REC-SVGTiny12-20081222] [W3C.REC-SVGTiny12-20081222]
Andersson, O., Berjon, R., Dahlstrom, E., Emmons, A., Andersson, O., Berjon, R., Dahlstrom, E., Emmons, A.,
Ferraiolo, J., Grasso, A., Hardy, V., Hayman, S., Jackson, Ferraiolo, J., Grasso, A., Hardy, V., Hayman, S., Jackson,
D., Lilley, C., McCormack, C., Neumann, A., Northway, C., D., Lilley, C., McCormack, C., Neumann, A., Northway, C.,
Quint, A., Ramani, N., Schepers, D., and A. Shellshear, Quint, A., Ramani, N., Schepers, D., and A. Shellshear,
"Scalable Vector Graphics (SVG) Tiny 1.2 Specification", "Scalable Vector Graphics (SVG) Tiny 1.2 Specification",
World Wide Web Consortium Recommendation REC- World Wide Web Consortium Recommendation
SVGTiny12-20081222, December 2008, REC-SVGTiny12-20081222, December 2008,
<http://www.w3.org/TR/2008/REC-SVGTiny12-20081222>. <http://www.w3.org/TR/2008/REC-SVGTiny12-20081222>.
[W3C.REC-CSS2-20110607] [W3C.REC-CSS2-20110607]
Bos, B., Celik, T., Hickson, I., and H. Lie, "Cascading Bos, B., Celik, T., Hickson, I., and H. Lie, "Cascading
Style Sheets Level 2 Revision 1 (CSS 2.1) Specification", Style Sheets Level 2 Revision 1 (CSS 2.1) Specification",
World Wide Web Consortium Recommendation REC- World Wide Web Consortium Recommendation
CSS2-20110607, June 2011, REC-CSS2-20110607, June 2011,
<http://www.w3.org/TR/2011/REC-CSS2-20110607>. <http://www.w3.org/TR/2011/REC-CSS2-20110607>.
9.2. Informative References 7.2. Informative References
[W3C.REC-SVG11-20110816] [W3C.REC-SVG11-20110816]
Dahlstrom, E., Dengler, P., Grasso, A., Lilley, C., Dahlstrom, E., Dengler, P., Grasso, A., Lilley, C.,
McCormack, C., Schepers, D., Watt, J., Ferraiolo, J., McCormack, C., Schepers, D., Watt, J., Ferraiolo, J.,
Fujisawa, J., and D. Jackson, "Scalable Vector Graphics Fujisawa, J., and D. Jackson, "Scalable Vector Graphics
(SVG) 1.1 (Second Edition)", World Wide Web Consortium (SVG) 1.1 (Second Edition)", World Wide Web Consortium
Recommendation REC-SVG11-20110816, August 2011, Recommendation REC-SVG11-20110816, August 2011,
<http://www.w3.org/TR/2011/REC-SVG11-20110816>. <http://www.w3.org/TR/2011/REC-SVG11-20110816>.
[SVG-ACCESS-TIPS] [SVG-ACCESS-TIPS]
Watson, L., "Tips for Creating Accessible SVG", SitePoint Watson, L., "Tips for Creating Accessible SVG", May 2014,
tips-accessible-svg, May 2014,
<http://www.sitepoint.com/tips-accessible-svg>. <http://www.sitepoint.com/tips-accessible-svg>.
[SVG-ARIA-PRIMER] [SVG-ARIA-PRIMER]
Pappas, L., Schwerdtfeger, R., and M. Cooper, "WAI-ARIA Pappas, L., Schwerdtfeger, R., and M. Cooper,
1.0 Primer", World Wide Web Consortium WD WD-wai-aria- "WAI-ARIA 1.0 Primer", World Wide Web Consortium
primer-20100916, September 2010, Working Draft, September 2010,
<http://www.w3.org/TR/2010/WD-wai-aria-primer-20100916>. <http://www.w3.org/TR/2010/WD-wai-aria-primer-20100916>.
[SVG-USING-ARIA] [SVG-USING-ARIA]
Watson, L., "Using ARIA to enhance SVG accessibility", The Watson, L., "Using ARIA to enhance SVG accessibility",
Paciello Group 2013/12/using-aria-enhance-svg- The Paciello Group, December 2013,
accessibility, December 2013, <https://www.paciellogroup.com/blog/2013/12/
<http://blog.paciellogroup.com/2013/12/ using-aria-enhance-svg-accessibility/>.
using-aria-enhance-svg-accessibility>.
[XML2RFCv3] [RFC7991] Hoffman, P., "The "xml2rfc" Version 3 Vocabulary",
Hoffman, P., "The "xml2rfc" version 3 Vocabulary", draft- RFC 7991, DOI 10.17487/RFC7991, December 2016,
iab-xml2rfc-03 (work in progress), February 2016. <http://www.rfc-editor.org/info/rfc7991>.
[This-I-D-with-SVG-included] [NB-SVG-1.2-RFC]
Brownlee, N., "Example html version of this I-D with its Brownlee, N., "Index of /materials/format/svg",
SVG diagrams included", Nevil's home <https://www.rfc-editor.org/materials/format/svg/>.
page, https://www.cs.auckland.ac.nz/~nevil/SVG_RFC_1.2,
October 16 2015.
[RFC0793] Postel, J., "Transmission Control Protocol", STD 7, [RFC793] Postel, J., "Transmission Control Protocol", STD 7,
RFC 793, DOI 10.17487/RFC0793, September 1981, RFC 793, DOI 10.17487/RFC0793, September 1981,
<http://www.rfc-editor.org/info/rfc793>. <http://www.rfc-editor.org/info/rfc793>.
[ExpTrustedProxy] [ExpTrustedProxy]
Loretto, S., Mattson, J., Skog, R., Spaak, H., Gus, G., Loreto, S., Mattsson, J., Skog, R., Spaak, H., Bourg, G.,
Druta, D., and M. Hafeez, "Explicit Trusted Proxy in Druta, D., and M. Hafeez, "Explicit Trusted Proxy in
HTTP/2.0", Internet Draft draft-loreto-httpbis-trusted- HTTP/2.0", Work in Progress,
proxy20-01, February 2014. draft-loreto-httpbis-trusted-proxy20-01, February 2014.
[RFC4321] Sparks, R., "Problems Identified Associated with the [RFC4321] Sparks, R., "Problems Identified Associated with the
Session Initiation Protocol's (SIP) Non-INVITE Session Initiation Protocol's (SIP) Non-INVITE
Transaction", RFC 4321, DOI 10.17487/RFC4321, January Transaction", RFC 4321, DOI 10.17487/RFC4321,
2006, <http://www.rfc-editor.org/info/rfc4321>. January 2006, <http://www.rfc-editor.org/info/rfc4321>.
Appendix A. RELAX NG Compact (rnc) Schema for SVG 1.2 RFC [RNG-HOME] Murata, M., "RELAX NG home page", February 2014,
<http://www.relaxng.org/>.
The following rnc schema can be used to check whether an svg file Appendix A. RELAX NG Compact (RNC) Schema for SVG 1.2 RFC
The following RNC schema can be used to check whether an SVG file
conforms to SVG 1.2 RFC. For example, if this schema were contained conforms to SVG 1.2 RFC. For example, if this schema were contained
in a file called SVG-1.2-RFC.rnc, the following command will test in a file called SVG-1.2-RFC.rnc, the following command will test
whether svg file diagram.svg is a conformant SVG 1.2 RFC drawing. whether SVG file diagram.svg is a conformant SVG 1.2 RFC drawing.
jing -c SVG-1.2-RFC.rnc diagram.svg jing -c SVG-1.2-RFC.rnc diagram.svg
#--- SVG 1.2 RFC rnc schema; Nevil Brownlee, Thu 26 Jan 2016 (NZST) The RNC schema included below is available on the RFC Editor website
<https://www.rfc-editor.org/materials/format/SVG-1.2-RFC.rnc>. The
website is considered definitive should there be any discrepancies.
#--- SVG 1.2 RFC RNC schema; Nevil Brownlee, Thu 26 Jan 2016 (NZST)
default namespace = "http://www.w3.org/2000/svg" default namespace = "http://www.w3.org/2000/svg"
namespace ns1 = "http://www.w3.org/1999/xlink" namespace ns1 = "http://www.w3.org/1999/xlink"
rfc-color = ( # SVG-1.2-RFC doesn't allow "color or grey-scale" rfc-color = ( # SVG-1.2-RFC doesn't allow color or grayscale
"black" | "white" | "#000000" | "#FFFFFF" | "#ffffff" | "inherit" ) "black" | "white" | "#000000" | "#FFFFFF" | "#ffffff" | "inherit" )
start = svg start = svg
svg = svg =
element svg { element svg {
((attribute fill-opacity { "inherit" | xsd:string }?, ((attribute fill-opacity { "inherit" | xsd:string }?,
attribute stroke-opacity { "inherit" | xsd:string }?) attribute stroke-opacity { "inherit" | xsd:string }?)
& (attribute fill { "none" | rfc-color }?, & (attribute fill { "none" | rfc-color }?,
attribute fill-rule { "inherit" | "nonzero" | "evenodd" }?, attribute fill-rule { "inherit" | "nonzero" | "evenodd" }?,
attribute stroke { rfc-color }?, attribute stroke { rfc-color }?,
attribute stroke-dasharray { "inherit" | "none" | xsd:string }?, attribute stroke-dasharray { "inherit" | "none" | xsd:string }?,
skipping to change at page 13, line 44 skipping to change at page 12, line 28
}?, }?,
attribute font-variant { "normal" | "small-caps" | "inherit" }?, attribute font-variant { "normal" | "small-caps" | "inherit" }?,
attribute font-weight { attribute font-weight {
"normal" "normal"
| "bold" | "bold"
| "bolder" | "bolder"
| "lighter" | "lighter"
}?, }?,
attribute text-anchor { attribute text-anchor {
"start" | "middle" | "end" | "inherit" "start" | "middle" | "end" | "inherit"
}?,
}?,
attribute text-align { attribute text-align {
"start" | "center" | "end" | "inherit" "start" | "center" | "end" | "inherit"
}?)), }?)),
(attribute id { xsd:NCName } (attribute id { xsd:NCName }
| attribute xml:id { xsd:NCName })?, | attribute xml:id { xsd:NCName })?,
attribute xml:base { xsd:anyURI | xsd:string }?, attribute xml:base { xsd:anyURI | xsd:string }?,
attribute xml:lang { xsd:language? }?, attribute xml:lang { xsd:language? }?,
attribute class { xsd:NMTOKENS }?, attribute class { xsd:NMTOKENS }?,
attribute role { xsd:string }?, attribute role { xsd:string }?,
attribute rel { xsd:string }?, attribute rel { xsd:string }?,
attribute rev { xsd:string }?, attribute rev { xsd:string }?,
attribute typeof { xsd:string }?, attribute typeof { xsd:string }?,
attribute content { xsd:string }?, attribute content { xsd:string }?,
attribute datatype { xsd:string }?, attribute datatype { xsd:string }?,
attribute resource { xsd:string }?, attribute resource { xsd:string }?,
skipping to change at page 53, line 39 skipping to change at page 52, line 19
attribute about { xsd:string }?, attribute about { xsd:string }?,
attribute property { xsd:string }?, attribute property { xsd:string }?,
attribute xml:space { "default" | "preserve" }?, attribute xml:space { "default" | "preserve" }?,
attribute requiredFeatures { xsd:string }?, attribute requiredFeatures { xsd:string }?,
attribute requiredExtensions { xsd:string }?, attribute requiredExtensions { xsd:string }?,
attribute requiredFormats { xsd:string }?, attribute requiredFormats { xsd:string }?,
attribute requiredFonts { xsd:string }?, attribute requiredFonts { xsd:string }?,
attribute systemLanguage { xsd:string }? attribute systemLanguage { xsd:string }?
} }
#--- End of SVG 1.2 RFC rnc schema #--- End of SVG 1.2 RFC RNC schema
IAB Members at the Time of Approval
Authors' Addresses The IAB members at the time this memo was approved were
(in alphabetical order):
Jari Arkko
Ralph Droms
Ted Hardie
Joe Hildebrand
Russ Housley
Lee Howard
Erik Nordmark
Robert Sparks
Andrew Sullivan
Dave Thaler
Martin Thomson
Brian Trammell
Suzanne Woolf
Acknowledgements
Thanks to the RSE and the Design Team members for their helpful
comments and suggestions for SVG 1.2 RFC. Thanks also to the wider
IETF community for their input.
Author's Address
Nevil Brownlee Nevil Brownlee
The University of Auckland The University of Auckland
Email: n.brownlee@auckland.ac.nz Email: n.brownlee@auckland.ac.nz
Internet Architecture Board
Email: iab@iab.org
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