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Chapter 3: Basic Data Types and Interfaces

Contents

3.1. Attribute syntax

In this specification, attributes are defined with an attribute definition table, which looks like this:

Name Value Initial value Animatable
exampleattr <length> | none none yes

In the Value column is a description of the attribute's syntax. There are five methods for describing an attribute's syntax:

  1. Using the CSS Value Definition Syntax [CSS3VALUES]. This is the notation used to define the syntax for most attributes in this specification and is the default.
  2. By reference to an EBNF symbol defined in this or another specification [XML10]. This is indicated by [EBNF] appearing in the Value column.
  3. By reference to an ABNF symbol defined in another specification [STD68]. This is indicated by [ABNF] appearing in the Value column.
  4. As a URL as defined by the URL Standard [URL]. This is indicated by [URL] appearing in the Value column.
  5. In prose, below the attibute definition table. This is indicated by the text "(see below)" appearing in the Value column.

When a presentation attribute defined using the CSS Value Definition Syntax is parsed, this is done as follows:

  1. Let value be the value of the attribute.
  2. Let grammar be the grammar given in the attribute definition table's Value column.
  3. Replace all instances of <length> in grammar with [<length> | <number>].
  4. Replace all instances of <angle> in grammar with [<angle> | <number>].
  5. Return the result of parsing value with grammar.

The insertion of the <number> symbols allows for unitless length and angles to be used in presentation attribute while disallowing them in corresponding property values.

Note that all presentation attributes, since they are defined by reference to their corresponding CSS properties, are defined using the CSS Value Definition Syntax.

When any other attribute defined using the CSS Value Definition Syntax is parsed, this is done by parsing the attribute's value according to the grammar given in attribute definition table.

Note that this allows CSS comments and escapes to be used in such attributes. For example, a value of '10\px/**/' would successfully parse as '10px' in the ‘x’ presentation attribute of the ‘rect’ element.

When an attribute defined as a URL is parsed, this is done by invoking the URL parser with the attribute's value as input and the document's URL as base [URL].

The Initial value column gives the initial value for the attribute. When an attribute fails to parse according to the specified CSS Value Definition Syntax, EBNF or EBNF grammar, or if parsing according to the URL Standard or by the prose describing how to parse the attribute indicates failure, the attribute is assumed to have been specified as the given initial value.

The initial value of a presentation attribute is its corresponding property's initial value. Since the use of an invalid value in a presentation attribute will be treated as if the initial value was specified, this value can override values that come from lower priority style sheet rules, such as those from the user agent style sheet.

For example, although the user agent style sheet sets the value of the ‘overflow’ property to hidden for ‘svg’ elements, specifying an invalid presentation attribute such as overflow="invalid" will result in a rule setting ‘overflow’ to visible, overriding the user agent style sheet value.

The Animatable column indicates whether the attribute can be animated using animation elements; see the Animation chapter for details.

The following common definitions are used for attributes that are defined in terms of an EBNF grammar:

wsp ::= (#x9 | #x20 | #xA | #xC | #xD)
comma-wsp ::= (wsp+ ","? wsp*) | ("," wsp*)

3.2. Real number precision

Unless stated otherwise, numeric values in SVG attributes and in properties that are defined to have an effect on SVG elements must support at least all finite IEEE 754 single-precision values.

It is recommended that higher precision floating point storage and computation be performed on operations such as coordinate system transformations to provide the best possible precision and to prevent round-off errors.

Conforming SVG Viewers are required to perform numerical computation in accordance with their conformance class, as described in Conformance Criteria.

3.3. Basic DOM interfaces

SVG 2 Requirement: Make the SVGList* interfaces a bit more like other lists/arrays.
Resolution: Add array style indexing and .length and .item to svg list types.
Purpose: To align with other array types (e.g. NodeList). Already implemented in Opera and Firefox.
Owner: Erik (ACTION-2975)

We need some explicit wording about attributes being "reflected" using these interfaces.

This should also describe how reflection works for attributes that were promoted to properties, such as ‘transform’. (Some discussion.)

Consider combining the definitions of all the list interfaces; there is a lot of duplicated text currently.

3.3.1. Interface SVGElement

All of the SVG DOM interfaces that correspond directly to elements in the SVG language (such as the SVGPathElement interface for the ‘path’ element) derive from the SVGElement interface.

The CSSOM specification augments SVGElement with a style IDL attribute, so that the ‘style’ attribute can be accessed in the same way as on HTML elements.

interface SVGElement : Element {

  readonly attribute SVGAnimatedString className;

  readonly attribute SVGSVGElement? ownerSVGElement;
  readonly attribute SVGElement? viewportElement;
           attribute long tabIndex;
  void focus();
  void blur();
};

SVGElement implements GlobalEventHandlers;
Attributes:
className (readonly SVGAnimatedString)

This attribute is deprecated and may be removed in a future version of this specification. Authors are advised to use Element.classList intead.

Corresponds to attribute ‘class’ on the given element.

ownerSVGElement (readonly SVGSVGElement)
The nearest ancestor ‘svg’ element. Null if the given element is the outermost svg element.
viewportElement (readonly SVGElement)
The element which established the current viewport. Often, the nearest ancestor ‘svg’ element. Null if the given element is the outermost svg element.
tabIndex (long)
The tabIndex attribute must reflect the value of the tabindex content attribute. Its default value is 0 for elements that are directly focusable, such as through keyboard tabbing in browsers that support that functionality, and −1 for elements that are not focusable without programmatic intervention.
Operations:
void focus()
Focuses the element.

Link to a definition of what the UA has to do to "focus an element" (e.g reference https://html.spec.whatwg.org/multipage/interaction.html#dom-focus).

void blur()
Unfocuses the element. Use of this method is discouraged. Focus another element instead.

Link to a definition of what the UA has to do to "blur an element" (e.g reference https://html.spec.whatwg.org/multipage/interaction.html#dom-blur).

Do not use this method to hide the focus ring. Do not use any other method that hides the focus ring from keyboard users, in particular do not use a CSS rule to override the ‘outline’ property. Removal of the focus ring leads to serious accessibility issues for users who navigate and interact with interactive content using the keyboard.

3.3.2. Interface SVGAnimatedBoolean

Used for attributes of type boolean which can be animated.

interface SVGAnimatedBoolean {
           attribute boolean baseVal;
  readonly attribute boolean animVal;
};
Attributes:
baseVal (boolean)
The base value of the given attribute before applying any animations.
animVal (readonly boolean)
If the given attribute or property is being animated, contains the current animated value of the attribute or property. If the given attribute or property is not currently being animated, contains the same value as baseVal.

3.3.3. Interface SVGAnimatedString

Used for attributes of type DOMString which can be animated.

interface SVGAnimatedString {
           attribute DOMString baseVal;
  readonly attribute DOMString animVal;
};
Attributes:
baseVal (DOMString)
The base value of the given attribute before applying any animations.
animVal (readonly DOMString)
If the given attribute or property is being animated, contains the current animated value of the attribute or property. If the given attribute or property is not currently being animated, contains the same value as baseVal.

3.3.4. Interface SVGStringList

This interface defines a list of DOMString values.

SVGStringList has the same attributes and methods as other SVGxxxList interfaces.

The supported property indices of an SVGStringList object is all non-negative integers less than the length of the list.

interface SVGStringList {

  readonly attribute unsigned long length;
  readonly attribute unsigned long numberOfItems;

  void clear();
  DOMString initialize(DOMString newItem);
  getter DOMString getItem(unsigned long index);
  DOMString insertItemBefore(DOMString newItem, unsigned long index);
  DOMString replaceItem(DOMString newItem, unsigned long index);
  DOMString removeItem(unsigned long index);
  DOMString appendItem(DOMString newItem);
  setter void (unsigned long index, DOMString newItem);
};
Attributes:
length (readonly unsigned long)
The number of items in the list.
numberOfItems (readonly unsigned long)
The number of items in the list.
Operations:
void clear()
Clears all existing current items from the list, with the result being an empty list.
Exceptions
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the list cannot be modified.
DOMString initialize(DOMString newItem)
Clears all existing current items from the list and re-initializes the list to hold the single item specified by the parameter.
Parameters
  1. DOMString newItem
    The item which should become the only member of the list.
Returns
The item being inserted into the list.
Exceptions
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the list cannot be modified.
DOMString getItem(unsigned long index)
Returns the specified item from the list.
Parameters
  1. unsigned long index
    The index of the item from the list which is to be returned. The first item is number 0.
Returns
The selected item.
Exceptions
DOMException, code INDEX_SIZE_ERR
Raised if the index number is greater than or equal to numberOfItems.
DOMString insertItemBefore(DOMString newItem, unsigned long index)
Inserts a new item into the list at the specified position. The first item is number 0.
Parameters
  1. DOMString newItem
    The item which is to be inserted into the list.
  2. unsigned long index
    The index of the item before which the new item is to be inserted. The first item is number 0. If the index is equal to 0, then the new item is inserted at the front of the list. If the index is greater than or equal to numberOfItems, then the new item is appended to the end of the list.
Returns
The inserted item.
Exceptions
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the list cannot be modified.
DOMString replaceItem(DOMString newItem, unsigned long index)
Replaces an existing item in the list with a new item.
Parameters
  1. DOMString newItem
    The item which is to be inserted into the list.
  2. unsigned long index
    The index of the item which is to be replaced. The first item is number 0.
Returns
The inserted item.
Exceptions
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the list cannot be modified.
DOMException, code INDEX_SIZE_ERR
Raised if the index number is greater than or equal to numberOfItems.
DOMString removeItem(unsigned long index)
Removes an existing item from the list.
Parameters
  1. unsigned long index
    The index of the item which is to be removed. The first item is number 0.
Returns
The removed item.
Exceptions
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the list cannot be modified.
DOMException, code INDEX_SIZE_ERR
Raised if the index number is greater than or equal to numberOfItems.
DOMString appendItem(DOMString newItem)
Inserts a new item at the end of the list.
Parameters
  1. DOMString newItem
    The item which is to be inserted. The first item is number 0.
Returns
The inserted item.
Exceptions
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the list cannot be modified.
setter void (unsigned long index, DOMString newItem)
Replaces the item at index index with newItem.

3.3.5. Interface SVGAnimatedEnumeration

Used for attributes whose value must be a constant from a particular enumeration and which can be animated.

interface SVGAnimatedEnumeration {
           attribute unsigned short baseVal;
  readonly attribute unsigned short animVal;
};
Attributes:
baseVal (unsigned short)
The base value of the given attribute before applying any animations.
animVal (readonly unsigned short)
If the given attribute or property is being animated, contains the current animated value of the attribute or property. If the given attribute or property is not currently being animated, contains the same value as baseVal.

3.3.6. Interface SVGAnimatedInteger

Used for attributes of basic type <integer> which can be animated.

interface SVGAnimatedInteger {
           attribute long baseVal;
  readonly attribute long animVal;
};
Attributes:
baseVal (long)
The base value of the given attribute before applying any animations.
animVal (readonly long)
If the given attribute or property is being animated, contains the current animated value of the attribute or property. If the given attribute or property is not currently being animated, contains the same value as baseVal.

3.3.7. Interface SVGNumber

Used for attributes of basic type <number>.

interface SVGNumber {
  attribute float value;
};
Attributes:
value (float)
The value of the given attribute.

3.3.8. Interface SVGAnimatedNumber

Used for attributes of basic type <number> which can be animated.

interface SVGAnimatedNumber {
           attribute float baseVal;
  readonly attribute float animVal;
};
Attributes:
baseVal (float)
The base value of the given attribute before applying any animations.
animVal (readonly float)
If the given attribute or property is being animated, contains the current animated value of the attribute or property. If the given attribute or property is not currently being animated, contains the same value as baseVal.

3.3.9. Interface SVGNumberList

This interface defines a list of SVGNumber objects.

SVGNumberList has the same attributes and methods as other SVGxxxList interfaces.

The supported property indices of an SVGNumberList object is all non-negative integers less than the length of the list.

An SVGNumberList object can be designated as read only, which means that attempts to modify the object will result in an exception being thrown, as described below.

interface SVGNumberList {

  readonly attribute unsigned long length;
  readonly attribute unsigned long numberOfItems;

  void clear();
  SVGNumber initialize(SVGNumber newItem);
  getter SVGNumber getItem(unsigned long index);
  SVGNumber insertItemBefore(SVGNumber newItem, unsigned long index);
  SVGNumber replaceItem(SVGNumber newItem, unsigned long index);
  SVGNumber removeItem(unsigned long index);
  SVGNumber appendItem(SVGNumber newItem);
  setter void (unsigned long index, SVGNumber newItem);
};
Attributes:
length (readonly unsigned long)
The number of items in the list.
numberOfItems (readonly unsigned long)
The number of items in the list.
Operations:
void clear()
Clears all existing current items from the list, with the result being an empty list.
Exceptions
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the list is read only.
SVGNumber initialize(SVGNumber newItem)
Clears all existing current items from the list and re-initializes the list to hold a single item specified by the parameter. If newItem is in a list, then a new SVGNumber object is created with the same values as newItem and this item is inserted into the list. Otherwise, newItem itself is inserted into the list.
Parameters
  1. SVGNumber newItem
    The item which should become the only member of the list.
Returns
The item being inserted into the list.
Exceptions
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the list is read only.
SVGNumber getItem(unsigned long index)
Returns the specified item from the list. The returned item is the item itself and not a copy. Any changes made to the item are immediately reflected in the list.
Parameters
  1. unsigned long index
    The index of the item from the list which is to be returned. The first item is number 0.
Returns
The selected item.
Exceptions
DOMException, code INDEX_SIZE_ERR
Raised if the index number is greater than or equal to numberOfItems.
SVGNumber insertItemBefore(SVGNumber newItem, unsigned long index)
Inserts a new item into the list at the specified position. The first item is number 0. If newItem is already in a list, then a new SVGNumber object is created with the same values as newItem and this item is inserted into the list. Otherwise, newItem itself is inserted into the list.
Parameters
  1. SVGNumber newItem
    The item which is to be inserted into the list.
  2. unsigned long index
    The index of the item before which the new item is to be inserted. The first item is number 0. If the index is equal to 0, then the new item is inserted at the front of the list. If the index is greater than or equal to numberOfItems, then the new item is appended to the end of the list.
Returns
The inserted item.
Exceptions
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the list is read only.
SVGNumber replaceItem(SVGNumber newItem, unsigned long index)
Replaces an existing item in the list with a new item. If newItem is already in a list, then a new SVGNumber object is created with the same values as newItem and this item is inserted into the list. Otherwise, newItem itself is inserted into the list.
Parameters
  1. SVGNumber newItem
    The item which is to be inserted into the list.
  2. unsigned long index
    The index of the item which is to be replaced. The first item is number 0.
Returns
The inserted item.
Exceptions
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the list is read only.
DOMException, code INDEX_SIZE_ERR
Raised if the index number is greater than or equal to numberOfItems.
SVGNumber removeItem(unsigned long index)
Removes an existing item from the list.
Parameters
  1. unsigned long index
    The index of the item which is to be removed. The first item is number 0.
Returns
The removed item.
Exceptions
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the list cannot be modified.
DOMException, code INDEX_SIZE_ERR
Raised if the index number is greater than or equal to numberOfItems.
SVGNumber appendItem(SVGNumber newItem)
Inserts a new item at the end of the list. If newItem is already in a list, then a new SVGNumber object is created with the same values as newItem and this item is inserted into the list. Otherwise, newItem itself is inserted into the list.
Parameters
  1. SVGNumber newItem
    The item which is to be inserted. The first item is number 0.
Returns
The inserted item.
Exceptions
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the list cannot be modified.
setter void (unsigned long index, SVGNumber newItem)
Replaces the item at index index with newItem. If the list is read only, then a NoModificationAllowedError is thrown.

3.3.10. Interface SVGAnimatedNumberList

Used for attributes which take a list of numbers and which can be animated.

interface SVGAnimatedNumberList {
  readonly attribute SVGNumberList baseVal;
  readonly attribute SVGNumberList animVal;
};
Attributes:
baseVal (readonly SVGNumberList)
The base value of the given attribute before applying any animations.
animVal (readonly SVGNumberList)
A read only SVGNumberList representing the current animated value of the given attribute. If the given attribute is not currently being animated, then the SVGNumberList will have the same contents as baseVal. The object referenced by animVal will always be distinct from the one referenced by baseVal, even when the attribute is not animated.

3.3.11. Interface SVGLength

The SVGLength interface corresponds to the <length> and <percentage> basic data types, and represents a length or percentage that consists of a numerical factor and a unit, where the unit is one of the set of units described in Units (em, ex, px, pt, pc, cm, mm and in), a percentage, a unitless number (user units), or "unknown".

An SVGLength object can be designated as read only, which means that attempts to modify the object will result in an exception being thrown, as described below.

An SVGLength object can be associated with a particular element, as well as being designated with a directionality: horizontal, vertical or unspecified. The associated element and the directionality of the length are used to resolve percentage values to user units. Unless otherwise described, an SVGLength object is not associated with any element and has unspecified directionality.

We need to define the behavior of converting values from/to percentages when the viewport width/height/size is zero. (ACTION-3722 on Cameron.)

The use of numeric length unit type constants is an anti-pattern and new constant values will not be introduced for any other units or length types supported by SVGLength. If other types of lengths are supported and used, the SVGLength uses the SVG_LENGTHTYPE_UNKNOWN unit type. See below for details on how the other properties of an SVGLength operate with these types of lengths.

interface SVGLength {

  // Length Unit Types
  const unsigned short SVG_LENGTHTYPE_UNKNOWN = 0;
  const unsigned short SVG_LENGTHTYPE_NUMBER = 1;
  const unsigned short SVG_LENGTHTYPE_PERCENTAGE = 2;
  const unsigned short SVG_LENGTHTYPE_EMS = 3;
  const unsigned short SVG_LENGTHTYPE_EXS = 4;
  const unsigned short SVG_LENGTHTYPE_PX = 5;
  const unsigned short SVG_LENGTHTYPE_CM = 6;
  const unsigned short SVG_LENGTHTYPE_MM = 7;
  const unsigned short SVG_LENGTHTYPE_IN = 8;
  const unsigned short SVG_LENGTHTYPE_PT = 9;
  const unsigned short SVG_LENGTHTYPE_PC = 10;

  readonly attribute unsigned short unitType;
           attribute float value;
           attribute float valueInSpecifiedUnits;
           attribute DOMString valueAsString;

  void newValueSpecifiedUnits(unsigned short unitType, float valueInSpecifiedUnits);
  void convertToSpecifiedUnits(unsigned short unitType);
};
Constants in group “Length Unit Types”:
SVG_LENGTHTYPE_UNKNOWN (unsigned short)
The unit type is not one of predefined unit types. It is invalid to attempt to define a new value of this type or to attempt to switch an existing value to this type.
SVG_LENGTHTYPE_NUMBER (unsigned short)
No unit type was provided (i.e., a unitless value was specified), which indicates a value in user units.
SVG_LENGTHTYPE_PERCENTAGE (unsigned short)
A percentage value was specified.
SVG_LENGTHTYPE_EMS (unsigned short)
A value was specified using the em units defined in CSS 2.1.
SVG_LENGTHTYPE_EXS (unsigned short)
A value was specified using the ex units defined in CSS 2.1.
SVG_LENGTHTYPE_PX (unsigned short)
A value was specified using the px units defined in CSS 2.1.
SVG_LENGTHTYPE_CM (unsigned short)
A value was specified using the cm units defined in CSS 2.1.
SVG_LENGTHTYPE_MM (unsigned short)
A value was specified using the mm units defined in CSS 2.1.
SVG_LENGTHTYPE_IN (unsigned short)
A value was specified using the in units defined in CSS 2.1.
SVG_LENGTHTYPE_PT (unsigned short)
A value was specified using the pt units defined in CSS 2.1.
SVG_LENGTHTYPE_PC (unsigned short)
A value was specified using the pc units defined in CSS 2.1.
Attributes:
unitType (readonly unsigned short)
The type of the value as specified by one of the SVG_LENGTHTYPE_* constants defined on this interface. The SVG_LENGTHTYPE_UNKNOWN unit type is returned when the length value uses a unit that does not correspond to one of the integer constants, such as ch, or is a non-scalar value, such as a calc() value.
value (float)

The value of the length in user units.

On getting, returns the value converted to user units. If the length cannot be converted to user units, for example because it is a percentage with no basis against which to resolve the percentage, then the value of valueInSpecifiedUnits is returned.

For example, (new SVGLength("10%")).value evalutes to 10, since the SVGLength is not associated with an element and thus has no percentage basis to resolve against.

On setting, sets the numerical factor to the assigned value and the unit type to user units.

Exceptions on setting
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the length is read only.
valueInSpecifiedUnits (float)

The numerical factor of the length value.

On getting, returns the numerical factor if the length is a scalar value (such as '20px' or '50%'), or returns 0 if the length is not a scalar value (such as a calc() value).

On setting, modifies the numerical factor of the length value using the same unit. If the length not a scalar value, then assigning to valueInSpecifiedUnits sets the length to be the specified number of user units.

Exceptions on setting
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the length is read only.
valueAsString (DOMString)

The length value as a string. On getting, returns a string as follows:

  • If the unit type of the length is unknown or user units, the string is simply the numeric factor converted to a string.
  • If the unit type of the length is a percentage, the string is the result of concatenating the numeric factor converted to a string with the string "%".
  • Otherwise, the string is the result of concatenating the numeric factor converted to a string with the CSS length unit in lowercase.

What about serializing non-scalar values, such as calc() values?

On setting, updates the numeric factor and units type of the SVGLength object according to the result of parsing the assigned string as a <length> or <percentage>.

Exceptions on setting
DOMException, code SYNTAX_ERR
Raised if the assigned string cannot be parsed as a valid <length> or <percentage>.
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the length is read only.
Operations:
void newValueSpecifiedUnits(unsigned short unitType, float valueInSpecifiedUnits)
Sets the numeric factor of the length value to valueInSpecifiedUnits and the unit type to unitType.
Parameters
  1. unsigned short unitType
    The unit type for the value (e.g., SVG_LENGTHTYPE_MM).
  2. float valueInSpecifiedUnits
    The new value.
Exceptions
DOMException, code NOT_SUPPORTED_ERR
Raised if unitType is SVG_LENGTHTYPE_UNKNOWN or not a valid unit type constant (one of the other SVG_LENGTHTYPE_* constants defined on this interface).
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the length is read only.
void convertToSpecifiedUnits(unsigned short unitType)

Sets the unit type of the length value to the type specified by unitType and sets the numeric factor value such that it represents the same absolute length. For example, if the original value were "0.5cm" and the method was invoked to convert to millimeters, then unitType would return SVG_LENGTHTYPE_MM and valueInSpecifiedUnits would return the numeric value 5.

If the old or new unit type is percentage and the SVGLength object has no associated element, then the percentages are considered to resolve against a length of 100 user units. For example, converting an SVGLength whose value is 20px to a percentage will result in the value being 20%.

Parameters
  1. unsigned short unitType
    The unit type to switch to (e.g., SVG_LENGTHTYPE_MM).
Exceptions
DOMException, code NOT_SUPPORTED_ERR
Raised if unitType is SVG_LENGTHTYPE_UNKNOWN or not a valid unit type constant (one of the other SVG_LENGTHTYPE_* constants defined on this interface).
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the length is read only.

3.3.12. Interface SVGAnimatedLength

Used for attributes of basic type <length> which can be animated.

interface SVGAnimatedLength {
  readonly attribute SVGLength baseVal;
  readonly attribute SVGLength animVal;
};
Attributes:
baseVal (readonly SVGLength)
The base value of the given attribute before applying any animations.
animVal (readonly SVGLength)
A read only SVGLength representing the current animated value of the given attribute. If the given attribute is not currently being animated, then the SVGLength will have the same contents as baseVal. The object referenced by animVal will always be distinct from the one referenced by baseVal, even when the attribute is not animated.

3.3.13. Interface SVGLengthList

This interface defines a list of SVGLength objects.

SVGLengthList has the same attributes and methods as other SVGxxxList interfaces.

The supported property indices of an SVGLengthList object is all non-negative integers less than the length of the list.

An SVGLengthList object can be designated as read only, which means that attempts to modify the object will result in an exception being thrown, as described below.

interface SVGLengthList {

  readonly attribute unsigned long length;
  readonly attribute unsigned long numberOfItems;

  void clear();
  SVGLength initialize(SVGLength newItem);
  getter SVGLength getItem(unsigned long index);
  SVGLength insertItemBefore(SVGLength newItem, unsigned long index);
  SVGLength replaceItem(SVGLength newItem, unsigned long index);
  SVGLength removeItem(unsigned long index);
  SVGLength appendItem(SVGLength newItem);
  setter void (unsigned long index, SVGLength newItem);
};
Attributes:
length (readonly unsigned long)
The number of items in the list.
numberOfItems (readonly unsigned long)
The number of items in the list.
Operations:
void clear()
Clears all existing current items from the list, with the result being an empty list.
Exceptions
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the list is read only.
SVGLength initialize(SVGLength newItem)
Clears all existing current items from the list and re-initializes the list to hold a single item specified by the parameter. If newItem is in a list, then a new SVGLength object is created with the same values as newItem and this item is inserted into the list. Otherwise, newItem itself is inserted into the list.
Parameters
  1. SVGLength newItem
    The item which should become the only member of the list.
Returns
The item being inserted into the list.
Exceptions
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the list is read only.
SVGLength getItem(unsigned long index)
Returns the specified item from the list. The returned item is the item itself and not a copy. Any changes made to the item are immediately reflected in the list.
Parameters
  1. unsigned long index
    The index of the item from the list which is to be returned. The first item is number 0.
Returns
The selected item.
Exceptions
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the list is read only.
SVGLength insertItemBefore(SVGLength newItem, unsigned long index)
Inserts a new item into the list at the specified position. The first item is number 0. If newItem is already in a list, then a new SVGLength object is created with the same values as newItem and this item is inserted into the list. Otherwise, newItem itself is inserted into the list.
Parameters
  1. SVGLength newItem
    The item which is to be inserted into the list.
  2. unsigned long index
    The index of the item before which the new item is to be inserted. The first item is number 0. If the index is equal to 0, then the new item is inserted at the front of the list. If the index is greater than or equal to numberOfItems, then the new item is appended to the end of the list.
Returns
The inserted item.
Exceptions
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the list is read only.
SVGLength replaceItem(SVGLength newItem, unsigned long index)
Replaces an existing item in the list with a new item. If newItem is already in a list, then a new SVGLength object is created with the same values as newItem and this item is inserted into the list. Otherwise, newItem itself is inserted into the list.
Parameters
  1. SVGLength newItem
    The item which is to be inserted into the list.
  2. unsigned long index
    The index of the item which is to be replaced. The first item is number 0.
Returns
The inserted item.
Exceptions
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the list is read only.
DOMException, code INDEX_SIZE_ERR
Raised if the index number is greater than or equal to numberOfItems.
SVGLength removeItem(unsigned long index)
Removes an existing item from the list.
Parameters
  1. unsigned long index
    The index of the item which is to be removed. The first item is number 0.
Returns
The removed item.
Exceptions
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the list is read only.
DOMException, code INDEX_SIZE_ERR
Raised if the index number is greater than or equal to numberOfItems.
SVGLength appendItem(SVGLength newItem)
Inserts a new item at the end of the list. If newItem is already in a list, then a new SVGLength object is created with the same values as newItem and this item is inserted into the list. Otherwise, newItem itself is inserted into the list.
Parameters
  1. SVGLength newItem
    The item which is to be inserted. The first item is number 0.
Returns
The inserted item.
Exceptions
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the list is read only.
setter void (unsigned long index, SVGLength newItem)
Replaces the item at index index with newItem. If the list is read only, then a NoModificationAllowedError is thrown.

3.3.14. Interface SVGAnimatedLengthList

Used for attributes of type SVGLengthList which can be animated.

interface SVGAnimatedLengthList {
  readonly attribute SVGLengthList baseVal;
  readonly attribute SVGLengthList animVal;
};
Attributes:
baseVal (readonly SVGLengthList)
The base value of the given attribute before applying any animations.
animVal (readonly SVGLengthList)
A read only SVGLengthList representing the current animated value of the given attribute. If the given attribute is not currently being animated, then the SVGLengthList will have the same contents as baseVal. The object referenced by animVal will always be distinct from the one referenced by baseVal, even when the attribute is not animated.

3.3.15. Interface SVGAngle

The SVGAngle interface corresponds to the <angle> basic data type, and represents an angle that consists of a numerical factor and a unit, where the unit is degrees, radians, grads, unitless numbers or "unknown".

An SVGAngle object can be designated as read only, which means that attempts to modify the object will result in an exception being thrown, as described below.

The use of numeric angle unit type constants is an anti-pattern and new constant values will not be introduced for any other units or angle types supported by SVGAngle. If other types of angles are supported and used, the SVGAngle uses the SVG_ANGLETYPE_UNKNOWN unit type. See below for details on how the other properties of an SVGAngle operate with these types of angles.

interface SVGAngle {

  // Angle Unit Types
  const unsigned short SVG_ANGLETYPE_UNKNOWN = 0;
  const unsigned short SVG_ANGLETYPE_UNSPECIFIED = 1;
  const unsigned short SVG_ANGLETYPE_DEG = 2;
  const unsigned short SVG_ANGLETYPE_RAD = 3;
  const unsigned short SVG_ANGLETYPE_GRAD = 4;

  readonly attribute unsigned short unitType;
           attribute float value;
           attribute float valueInSpecifiedUnits;
           attribute DOMString valueAsString;

  void newValueSpecifiedUnits(unsigned short unitType, float valueInSpecifiedUnits);
  void convertToSpecifiedUnits(unsigned short unitType);
};
Constants in group “Angle Unit Types”:
SVG_ANGLETYPE_UNKNOWN (unsigned short)
The unit type is not one of predefined unit types. It is invalid to attempt to define a new value of this type or to attempt to switch an existing value to this type.
SVG_ANGLETYPE_UNSPECIFIED (unsigned short)
No unit type was provided (i.e., a unitless value was specified). For angles, a unitless value is treated the same as if degrees were specified.
SVG_ANGLETYPE_DEG (unsigned short)
The unit type was explicitly set to degrees.
SVG_ANGLETYPE_RAD (unsigned short)
The unit type is radians.
SVG_ANGLETYPE_GRAD (unsigned short)
The unit type is grads.
Attributes:
unitType (readonly unsigned short)
The type of the value as specified by one of the SVG_ANGLETYPE_* constants defined on this interface. The SVG_ANGLETYPE_UNKNOWN unit type is returned when the length value uses a unit that does not correspond to one of the integer constants, such as turn.
value (float)
The value of the angle in degrees. On getting, returns the value converted to degrees. If the type of the SVGAngle is unknown, the numerical factor of the angle is returned. On setting, sets the numerical factor to the assigned value and the unit type to unitless numbers.
Exceptions on setting
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the angle is read only.
valueInSpecifiedUnits (float)
The numerical factor of the angle value.
Exceptions on setting
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the angle is read only.
valueAsString (DOMString)

The angle value as a string. On getting, returns a string as follows:

  • If the unit type of the angle is unknown or unitless numbers, the string is simply the numeric factor converted to a string.
  • Otherwise, the string is the result of concatenating the numeric factor converted to a string with the CSS angle unit in lowercase.

On setting, updates the numeric factor and units type of the SVGAngle object according to the result of parsing the assigned string as an <angle>.

Exceptions on setting
DOMException, code SYNTAX_ERR
Raised if the assigned string cannot be parsed as a valid <angle>.
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the angle is read only.
Operations:
void newValueSpecifiedUnits(unsigned short unitType, float valueInSpecifiedUnits)
Sets the numeric factor of the angle value to valueInSpecifiedUnits and the unit type to unitType.
Parameters
  1. unsigned short unitType
    The unit type for the value (e.g., SVG_ANGLETYPE_DEG).
  2. float valueInSpecifiedUnits
    The new value.
Exceptions
DOMException, code NOT_SUPPORTED_ERR
Raised if unitType is SVG_ANGLETYPE_UNKNOWN or not a valid unit type constant (one of the other SVG_ANGLETYPE_* constants defined on this interface).
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the angle is read only.
void convertToSpecifiedUnits(unsigned short unitType)

Sets the unit type of the angle value to the type specified by unitType and sets the numeric factor value such that it represents the same absolute angle. For example, if the original value were "180deg" and the method was invoked to convert to radians, then unitType would return SVG_ANGLETYPE_RAD and valueInSpecifiedUnits would return the numeric value π.

Parameters
  1. unsigned short unitType
    The unit type to switch to (e.g., SVG_ANGLETYPE_DEG).
Exceptions
DOMException, code NOT_SUPPORTED_ERR
Raised if unitType is SVG_ANGLETYPE_UNKNOWN or not a valid unit type constant (one of the other SVG_ANGLETYPE_* constants defined on this interface).
DOMException, code NO_MODIFICATION_ALLOWED_ERR
Raised when the angle is read only.

3.3.16. Interface SVGAnimatedAngle

Used for attributes of basic data type <angle> that can be animated.

interface SVGAnimatedAngle {
  readonly attribute SVGAngle baseVal;
  readonly attribute SVGAngle animVal;
};
Attributes:
baseVal (readonly SVGAngle)
The base value of the given attribute before applying any animations.
animVal (readonly SVGAngle)
A read only SVGAngle representing the current animated value of the given attribute. If the given attribute is not currently being animated, then the SVGAngle will have the same contents as baseVal. The object referenced by animVal will always be distinct from the one referenced by baseVal, even when the attribute is not animated.

3.3.17. Interface SVGAnimatedRect

Used for attributes of type DOMRect which can be animated.

interface SVGAnimatedRect {
  readonly attribute DOMRectReadOnly baseVal;
  readonly attribute DOMRectReadOnly animVal;
};
Attributes:
baseVal (readonly DOMRectReadOnly)
The base value of the given attribute before applying any animations.
animVal (readonly DOMRectReadOnly)
A DOMRectReadOnly representing the current animated value of the given attribute. If the given attribute is not currently being animated, then the DOMRectReadOnly will have the same contents as baseVal. The object referenced by animVal will always be distinct from the one referenced by baseVal, even when the attribute is not animated.

3.3.18. Interface SVGUnitTypes

The SVGUnitTypes interface defines a commonly used set of constants and is a base interface used by SVGGradientElement, SVGPatternElement, SVGClipPathElement, SVGMaskElement and SVGFilterElement.

[NoInterfaceObject]
interface SVGUnitTypes {
  // Unit Types
  const unsigned short SVG_UNIT_TYPE_UNKNOWN = 0;
  const unsigned short SVG_UNIT_TYPE_USERSPACEONUSE = 1;
  const unsigned short SVG_UNIT_TYPE_OBJECTBOUNDINGBOX = 2;
};
Constants in group “Unit Types”:
SVG_UNIT_TYPE_UNKNOWN (unsigned short)
The type is not one of predefined types. It is invalid to attempt to define a new value of this type or to attempt to switch an existing value to this type.
SVG_UNIT_TYPE_USERSPACEONUSE (unsigned short)
Corresponds to value 'userSpaceOnUse'.
SVG_UNIT_TYPE_OBJECTBOUNDINGBOX (unsigned short)
Corresponds to value 'objectBoundingBox'.

3.3.19. Interface SVGGraphicsElement

SVG 2 Requirement: Detect if a mouse event is on the fill or stroke of a shape.
Resolution: SVG 2 will make it easier to detect if an mouse event is on the stroke or fill of an element.
Purpose: To allow authors to discriminate between pointer events on the fill and stroke of an element without having to duplicate the element
Owner: Cameron (ACTION-3279)

Interface SVGGraphicsElement represents SVG elements whose primary purpose is to directly render graphics into a group. The ‘transform’ property applies to all SVGGraphicsElement. All SVGGraphicsElement have a bounding box in current local coordinate system.

dictionary SVGBoundingBoxOptions {
  boolean fill = true;
  boolean stroke = false;
  boolean markers = false;
  boolean clipped = false;
};

interface SVGGraphicsElement : SVGElement {
  readonly attribute SVGAnimatedTransformList transform;

  DOMRect getBBox(optional SVGBoundingBoxOptions options);
  DOMMatrix? getCTM();
  DOMMatrix? getScreenCTM();
  DOMMatrix getTransformToElement(SVGGraphicsElement element);
};

SVGGraphicsElement implements SVGTests;
Attributes:
transform (readonly SVGAnimatedTransformList)
Corresponds to attribute ‘transform’ on the given element.

This needs to be updated to reflect the value of the ‘transform’ property.

Operations:
DOMRect getBBox(optional SVGBoundingBoxOptions options)

Returns the result of invoking the bounding box algorithm for the element, with fill, stroke, markers and clipped members of the options dictionary argument used to control which parts of the element are included in the bounding box, using the element's local coordinate system as the coordinate system to return the bounding box in.

Returns
An DOMRect object that defines the bounding box.
DOMMatrix? getCTM()
Returns the transformation matrix from current user units (i.e., after application of the ‘transform’ property) to the viewport coordinate system for the nearest viewport element (CTM). Note that null is returned if this element is not hooked into the document tree.

What is the expected result if you call getCTM on an ‘svg’ element? See thread. Also see example. (ACTION-3724 on Dirk.)

Returns
An DOMMatrix object that defines the CTM.
DOMMatrix? getScreenCTM()
Returns the transformation matrix from current user units (i.e., after application of the ‘transform’ property) to the parent user agent's notion of a "pixel". For display devices, ideally this represents a physical screen pixel. For other devices or environments where physical pixel sizes are not known, then an algorithm similar to the CSS 2.1 definition of a "pixel" can be used instead. Note that null is returned if this element is not hooked into the document tree. This method would have been more aptly named as getClientCTM, but the name getScreenCTM is kept for historical reasons.

Should this take into account the 'transform' on the ‘svg’ element itself? See example. Chrome/Opera/IE: returns the identity matrix for this example, Firefox: difference between transform style and attribute, and is not an identity matrix.

Returns
An DOMMatrix object that defines the given transformation matrix.
DOMMatrix getTransformToElement(SVGGraphicsElement element)
Returns the transformation matrix from the user coordinate system on the current element (after application of the ‘transform’ property) to the user coordinate system on parameter element (after application of its ‘transform’ property).

If the passed in element is in another document, what should happen? Measurements. Proposal to limit this to the same fragment if not removeable.

Parameters
  1. SVGElement element
    The target element.
Returns
An DOMMatrix object that defines the transformation.
Exceptions
InvalidStateError
Raised if the currently defined transformation matrices make it impossible to compute the given matrix (e.g., because one of the transformations is singular).

3.3.20. Interface SVGGeometryElement

Interface SVGGeometryElement represents SVG elements whose rendering is defined by geometry and which can be filled and stroked. This includes paths, text and the basic shapes.

interface SVGGeometryElement : SVGGraphicsElement {
  boolean isPointInFill(DOMPoint point);
  boolean isPointInStroke(DOMPoint point);
};
Operations:
boolean isPointInFill(DOMPoint point)
Returns whether the specified point is within the fill of the element. Normal hit testing rules apply; the value of the ‘pointer-events’ property on the element determines whether a point is considered to be within the fill.
Parameters
  1. DOMPoint point
    The point to check for intersection with the fill of this element. The DOMPoint is interpreted as a as a point in the local coordinate system of this element.
Returns
true if the point is within the fill of this shape, or false otherwise.
boolean isPointInStroke(DOMPoint point)
Returns whether the specified point is within the stroke of the element. Normal hit testing rules apply; the value of the ‘pointer-events’ property on the element determines whether a point is considered to be within the stroke.
Parameters
  1. DOMPoint point
    The point to check for intersection with the stroke of this element. The DOMPoint is interpreted as a as a point in the local coordinate system of this element.
Returns
true if the point is within the stroke of this shape, or false otherwise.

3.3.21. Interface SVGTests

Interface SVGTests defines an interface which applies to all elements which have attributes ‘requiredExtensions’ and ‘systemLanguage’.

[NoInterfaceObject]
interface SVGTests {

  readonly attribute SVGStringList requiredExtensions;
  readonly attribute SVGStringList systemLanguage;
};
Attributes:
requiredExtensions (readonly SVGStringList)
Corresponds to attribute ‘requiredExtensions’ on the given element.
systemLanguage (readonly SVGStringList)
Corresponds to attribute ‘systemLanguage’ on the given element.

3.3.22. Interface SVGFitToViewBox

Interface SVGFitToViewBox defines DOM attributes that apply to elements which have XML attributes ‘viewBox’ and ‘preserveAspectRatio’.

[NoInterfaceObject]
interface SVGFitToViewBox {
  readonly attribute SVGAnimatedRect viewBox;
  readonly attribute SVGAnimatedPreserveAspectRatio preserveAspectRatio;
};
Attributes:
viewBox (readonly SVGAnimatedRect)
Corresponds to attribute ‘viewBox’ on the given element.
preserveAspectRatio (readonly SVGAnimatedPreserveAspectRatio)
Corresponds to attribute ‘preserveAspectRatio’ on the given element.

3.3.23. Interface SVGZoomAndPan

The SVGZoomAndPan interface defines attribute zoomAndPan and associated constants.

[NoInterfaceObject]
interface SVGZoomAndPan {

  // Zoom and Pan Types
  const unsigned short SVG_ZOOMANDPAN_UNKNOWN = 0;
  const unsigned short SVG_ZOOMANDPAN_DISABLE = 1;
  const unsigned short SVG_ZOOMANDPAN_MAGNIFY = 2;

  attribute unsigned short zoomAndPan;
};
Constants in group “Zoom and Pan Types”:
SVG_ZOOMANDPAN_UNKNOWN (unsigned short)
The enumeration was set to a value that is not one of predefined types. It is invalid to attempt to define a new value of this type or to attempt to switch an existing value to this type.
SVG_ZOOMANDPAN_DISABLE (unsigned short)
Corresponds to value 'disable'.
SVG_ZOOMANDPAN_MAGNIFY (unsigned short)
Corresponds to value 'magnify'.
Attributes:
zoomAndPan (unsigned short)
Corresponds to attribute ‘zoomAndPan’ on the given element. The value must be one of the SVG_ZOOMANDPAN_* constants defined on this interface.

3.3.24. Interface SVGURIReference

Interface SVGURIReference defines an interface which applies to all elements which have an ‘href’ attribute.

[NoInterfaceObject]
interface SVGURIReference {
  readonly attribute SVGAnimatedString href;
};
Attributes:
href (readonly SVGAnimatedString)

Corresponds to the ‘href’ attribute. If the element also supports the deprecated ‘xlink:href’ attribute, the resulting SVGAnimatedString object will correspond to the ‘xlink:href’ attribute in the XLink namespace if, and only if, all of the following conditions are true at the time when the href IDL attribute is accessed:

  • There is no ‘href’ attribute without a namespace specified on the element, and
  • There is no animation element whose target element is this element and whose ‘attributeName’ is the string ‘href’ (that is, without an XMLNS prefix), and
  • There is an ‘href’ attribute in the XLink namespace on the element, or there is an animation element whose target element is this element and whose ‘attributeName’ references the ‘href’ attribute in the XLink namespace.

If any of the above conditions does not hold at the time when the the href IDL attribute is accessed, the returned attribute will correspond to the ‘href’ attribute without a namespace.

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