SVG is a language for describing two-dimensional graphics in XML [XML11]. SVG allows for three types of graphic objects: vector graphic shapes (e.g., paths consisting of straight lines and curves), multimedia (such as raster images and video) and text. Graphical objects can be grouped, styled, transformed and composited into previously rendered objects.
SVG drawings can be interactive and dynamic. Animations can be defined and triggered either declaratively (i.e., by embedding SVG animation elements in SVG content) or via scripting.
Sophisticated applications of SVG are possible by use of a supplemental scripting language which accesses the SVG Micro Document Object Model (uDOM), which provides complete access to all elements, attributes and properties. A rich set of event handlers can be assigned to any SVG graphical object. Because of its compatibility and leveraging of other Web standards, features like scripting can be done on XHTML and SVG elements simultaneously within the same Web page.
SVG is a language for rich graphical content. For accessibility reasons, if there is an original source document containing higher-level structure and semantics, it is recommended that the higher-level information be made available somehow, either by making the original source document available, or making an alternative version available in a format which conveys the higher-level information, or by using SVG's facilities to include the higher-level information within the SVG content. For suggested techniques in achieving greater accessibility, see Accessibility.
It is believed that this specification is in accordance with the Web Architecture principles as described in Web Architecture [AWWW].
Industry demand, overwhelming support in the SVG working group and requests from the SVG developer community established the need for some form of SVG suited to displaying vector graphics on small devices. Moreover, the mission statement of SVG 1.0 specifically addressed small devices as a target area for vector graphics display. In order to meet these demands the SVG Working Group created a profile specification that was suitable for use on mobile devices as well as on desktops. The SVG Mobile 1.1 specification addressed that requirement and defined two profiles to deal with the variety of mobile devices having different characteristics in terms of CPU speed, memory size, and color support. The SVG Mobile 1.1 specification defined SVG Tiny (SVGT) 1.1, suitable for highly restricted mobile devices; it also defined a second profile, SVG Basic (SVGB) 1.1, targeted for higher level mobile devices. The major difference between SVG Tiny 1.1 and SVG Basic 1.1 was the absence of scripting and styling in SVG 1.1 Tiny, and thus any requirement to maintain a Document Object Model (DOM). This saved a substantial amount of memory in most implementations.
Experience with SVG Tiny 1.1, which was widely adopted in the industry and shipped as standard on a variety of cellphones, indicated that the profile was a little too restrictive in some areas. Features from SVG 1.1 such as gradients and opacity, were seen to have substantial value for creating attractive content, and were shown to be implementable on cellphones. There was also considerable interest in adding audio and video capabilities, building on the SMIL support in SVG Tiny 1.1.
Advances such as DOM Level 3, which introduces namespace support and value normalization, prompted a second look at the use of programming languages and scripting with SVG Tiny. In conjunction with the Java JSR 226 group [JSR226], a lightweight interface called the microDOM, or uDOM, was developed. This could be, but need not be, implemented on top of DOM Level 3. With this advance, lightweight programmatic control of SVG (for example, for games or user interfaces) and use with scripting languages, became feasible on the whole range of platforms from cellphones through to desktops. In consequence, there is only a single Mobile profile for SVG 1.2 - SVG Tiny 1.2
This specification defines the features and syntax for Scalable Vector Graphics (SVG) Tiny 1.2, the core specification and baseline profile of SVG 1.2. Other SVG specifications will extend this baseline functionality to create supersets (for example, SVG 1.2 Full). The SVG Tiny 1.2 specification adds to SVG Tiny 1.1 features requested by SVG authors, implementors and users; SVG Tiny 1.2 is a superset of SVG Tiny 1.1.
This specification describes a collection of abstract modules that provide specific units of functionality. These modules may be combined with each other and with modules defined in other specifications (such as XHTML) to create SVG subset and extension document types that qualify as members of the SVG family of document types. See Conformance for a description of SVG family documents, and [XHTMLplusMathMLplusSVG] for a profile that combines XHTML, MathML and SVG.
Each major section of the SVG specification produces a module named after that section, e.g. "Text Module" or "Structure Module".
Modules define a named collection of either elements or attributes. These collections are used as a shorthand when describing the set of attributes allowed on a particular element (eg. the "Style" attribute collection) or the set of elements allowed as children of a particular element (eg. the "Shape" element collection). All collections have names that begin with an uppercase character.
When defining a profile, it is assumed that all the element and attribute collections are defined to be empty. That way, a module can redefine the collection as it is included in the profile, adding elements or attributes to make them available within the profile. Therefore, it is not a mistake to refer to an element or attribute collection from a module that is not included in the profile, it simply means that collection is empty.
This specification defines the baseline language definition for SVG 1.2. The specification is defined in terms of a series of modules, each of which consists of a collection of language features. The modular definition of the language enables alternate profiles of the SVG language.
The Tiny profile of SVG 1.2 consists of all of the features defined within this specification. As a modularized baseline specification, it is possible for: superset profiles (e.g., SVG Full 1.2) which include all of the Tiny profile but add other features to the baseline; subset profiles; and special-purpose profiles which incorporate some modules from this specification in combination with other features as needed to meet particular industry requirements.
When applied to conformance, the term "SVG Tiny 1.2" refers to the Tiny profile of SVG 1.2 defined by this specification. If an implementation does not implement the Tiny profile completely, the UA's conformance claims must state either the profile to which it conforms and/or the specific set of features it implements.
SVG Tiny 1.2 is a backwards compatible upgrade to SVG Tiny 1.1 . Backwards compatible means that conformant SVG Tiny 1.1 content will render the same in conformant SVG Tiny 1.2 User Agents as it did in conformant SVG Tiny 1.1 User Agents. A few key differences from SVG Tiny 1.1 should be noted:
The namespace for SVG Tiny 1.2 is the same as that of SVG 1.0 and 1.1, http://www.w3.org/2000/svg and is mutable [NSState]; names may be added over time by the W3C SVG Working Group by publication in W3C Technical Reports.
Here is an example of an SVG 1.2 file:
<?xml version="1.0"?> <svg xmlns="http://www.w3.org/2000/svg" version="1.2" baseProfile="tiny" viewBox="0 0 30 30"> <desc>Example SVG file</desc> <rect x="10" y="10" width="10" height="10" fill="red"/> </svg>
Here is an example of defining an entity in the internal DTD subset. Note that in XML, there is no requirement to fetch the external DTD subset and so relying on an external subset reduces interoperability. Also note that the SVG Working Group does not provide a normative DTD for SVG Tiny 1.2 but instead provides a normative RelaxNG schema.
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE svg [ <!ENTITY Smile " <rect x='.5' y='.5' width='29' height='39' fill='black' stroke='red'/> <g transform='translate(0, 5)'> <circle cx='15' cy='15' r='10' fill='yellow'/> <circle cx='12' cy='12' r='1.5' fill='black'/> <circle cx='17' cy='12' r='1.5' fill='black'/> <path d='M 10 19 L 15 23 20 19' stroke='black' stroke-width='2'/> </g> "> ]> <svg xmlns="http://www.w3.org/2000/svg" version="1.2" baseProfile="tiny"> <title>Smiley face</title> <desc>This example shows the use of an entity defined in the internal DTD subset. Note that there is no external DTD subset for SVG 1.2, and thus no formal public identifier.</desc> &Smile; </svg>
The MIME type for SVG is "image/svg+xml" (see Media Type registration for image/svg+xml).
It is recommended that SVG files have the extension
".svg"
(all lowercase) on all platforms. It is
recommended that gzip-compressed
SVG files have the extension ".svgz"
(all
lowercase) on all platforms.
It is recommended that SVG files stored on Macintosh HFS
file systems be given a file type of "svg "
(all lowercase, with a space character as the fourth letter).
It is recommended that gzip-compressed
SVG files stored on Macintosh HFS file systems be given a file
type of "svgz"
(all lowercase).
(See Conformance Criteria for more information about gzip-compressed SVG files transmitted over HTTP.)
SVG Tiny 1.2 leverages and integrates with other W3C specifications and standards efforts. By leveraging and conforming to other standards, SVG becomes more powerful and makes it easier for users to learn how to incorporate SVG into their Web sites.
The following describes some of the ways in which SVG maintains compatibility with, leverages and integrates with other W3C efforts:
In environments which support the Document Object Model (DOM) [DOM3].for other XML grammars (e.g., XHTML [XHTML]) and which also support SVG and the SVG DOM, a single scripting approach can be used simultaneously for both XML documents and SVG graphics, in which case interactive and dynamic effects will be possible on multiple XML namespaces using the same set of scripts.
When used in this specification, terms have the meanings assigned in this section.
The bounding box is the tightest fitting rectangle aligned with the axes of the applicable element's user coordinate system that entirely encloses the applicable element and its descendants. The bounding box must be computed exclusive of any values for the 'fill', 'stroke', 'stroke-width', 'opacity', or 'visibility' properties. For curved shapes, the bounding box must enclose all portions of the shape, not just end points.
The bounding box must be applicable for any rendering element with positive 'width' or 'height' attributes and with a 'display' property other than 'none', as well as for any container element that may contain such elements. Elements which do not partake in the rendering tree (e.g. elements in the 'defs' element, elements with display='none', etc.), and which have no child elements that partake in the rendering tree (e.g.'g' elements with no children), shall not contribute to the bounding box of the parent element, but may optionally return a bounding box for the sake of calculating their own geometry. Elements which are not found shall have a bounding box with an 'x' and 'y' of '0' and a 'width' and 'height' of '-1'. Elements that do not derive from SVGLocatable do not have a bounding box, and must raise an exception if the bounding box is requested.
For text content elements, for the purposes of the bounding box calculation, each glyph must be treated as a separate graphics element. The calculations must assume that all glyphs occupy the full glyph cell. For example, for horizontal text, the calculations must assume that each glyph extends vertically to the full ascent and descent values for the font. An exception to this is the 'textArea', which uses that element's geometry for the bounding box calculation.
Because declarative or scripted animation can change the shape, size, and position of an element, the bounding box is mutable. Thus, the bounding box for an element shall reflect the current values for the element at the snapshot in time at which the bounding box is requested, whether through a script call or as part of a declarative or linking syntax.
For a formal definition of bounding boxes, see [FOLEY-VANDAM], section 15.2.3, Extents and Bounding Volumes. For further details, see bounding box calculations, the effects of visibility on bounding box, object bounding box units and text elements, and fragment identifiers.
The decorated bounding box follows the definition for bounding box, with the exception that it takes into account not only the geometry, but also all geometry-based drawing operations that are marked in their definitions as contributing to this calculation.
A default value is used when an attribute or property is not specified, or when an attribute or property has an invalid value. This value is to be used for the purposes of rendering, calculating animation values, and when accessing the attribute or property using the TraitAccess interface. Note that, at the XML parser level, SVGT 1.2 does not have default values - they are part of the SVG application layer.
The set of elements being rendered, aurally or visually using the painters model, on an SVG document fragment. The following elements in the fragment:
and their children, are part of the SVG document fragment, but not part of the rendering tree (and thus do not get rendered). Elements with zero opacity, or no 'fill' and no 'stroke', or with the 'visibility' property set to hidden, are still in the rendering tree. The copies of elements referenced by a 'use' element, on the other hand, are not in the SVG document fragment but are in the rendering tree.
The furthest 'svg' ancestor element that does not exit an SVG context.
Note that this definition has been carefully chosen to be applicable not only to SVG Tiny 1.2 (where the rootmost svg element is the only svg element, except when there is an svg element inside a foreignObject) but also for SVG Full 1.2 and SVG that uses sXBL. See also SVG document fragment.
A document fragment where all elements within the fragment must be subject to processing by an SVG user agent according to the rules in this specification.
If SVG content is embedded inline within parent XML (such as XHTML), the SVG context does not include the ancestors above the rootmost svg element. If the SVG content contains any foreignObject elements which in turn contain non-SVG content, the SVG context does not include the contents of the foreignObject elements.
In SVG Tiny 1.2 an SVG context contains one SVG document fragment.
The XML document sub-tree whose rootmost element is an 'svg' element. (i.e. the rootmost svg element.)
An SVG document fragment consists of either a stand-alone SVG document, or a fragment of a parent XML document where the fragment is enclosed by an 'svg' element.
In SVG Tiny 1.2 the SVG document fragment must not contain nested 'svg' elements - nested 'svg' elements are unsupported elements. Note that document conformance is orthogonal to SVG document fragment conformance.
For further details, see the section on Conforming SVG Document Fragments.
Note: When this specification uses the term 'svg' element,
'path' element, or similar reference to
an SVG element defined within this specification, it is
referring to the element whose namespace URI is http://www.w3.org/2000/svg
and whose localname is the string in quotes (e.g., "svg" or "path").
When referencing this specification as a whole or when
referencing a chapter or major section, use the
undated URI, http://www.w3.org/TR/SVGMobile12/
,
where possible. This allows the reference to always indicate
the latest version of this specification.