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15 November 2002

# 19 Animation

### Contents

## 19.1 Introduction

Because the Web is a dynamic medium, SVG supports the ability to change vector graphics over time. SVG content can be animated in the following ways:

- Using SVG's animation elements. SVG document fragments can describe time-based modifications to the document's elements. Using the various animation elements, you can define motion paths, fade-in or fade-out effects, and objects that grow, shrink, spin or change color.
- Using the SVG DOM. The SVG DOM conforms to key aspects of the "Document Object Model (DOM) Level 1" [DOM1] and "Document Object Model (DOM) Level 2" [DOM2] specifications. Every attribute and style sheet setting is accessible to scripting, and SVG offers a set of additional DOM interfaces to support efficient animation via scripting. As a result, virtually any kind of animation can be achieved. The timer facilities in scripting languages such as ECMAScript can be used to start up and control the animations. (See example below.)
- SVG has been designed to allow future versions of SMIL [SMIL1] to use animated or static SVG content as media components.
- In the future, it is expected that future versions of SMIL will be modularized and that components of it could be used in conjunction with SVG and other XML grammars to achieve animation effects.

## 19.2 Animation elements

### 19.2.1 Overview

SVG's animation elements were developed in collaboration with the W3C Synchronized Multimedia (SYMM) Working Group, developers of the Synchronized Multimedia Integration Language (SMIL) 1.0 Specification [SMIL1].

The SYMM Working Group, in collaboration with the SVG Working Group, has authored the SMIL Animation specification [ SMILANIM], which represents a general-purpose XML animation feature set. SVG incorporates the animation features defined in the SMIL Animation specification and provides some SVG-specific extensions.

For an introduction to the approach and features available in any language that supports SMIL Animation, see SMIL Animation overview and SMIL Animation animation model. For the list of animation features which go beyond SMIL Animation, see SVG extensions to SMIL Animation.

### 19.2.2 Relationship to SMIL Animation

SVG is a host language in terms of SMIL Animation and therefore introduces additional constraints and features as permitted by that specification. Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for SVG's animation elements and attributes is the SMIL Animation [ SMILANIM] specification.

SVG supports the following four animation elements which are defined in the SMIL Animation specification:

| 'animate' |  | allows scalar attributes and properties to be assigned different values over time
| 'set' |  | a convenient shorthand for 'animate', which is useful for assigning animation values to non-numeric attributes and properties, such as the 'visibility' property
| 'animateMotion' |  | moves an element along a motion path
| 'animateColor' |  | modifies the color value of particular attributes or properties over time

Additionally, SVG includes the following compatible extensions to SMIL Animation:

| 'animateTransform' |  | modifies one of SVG's transformation attributes over time, such as the transform attribute
| path attribute |  | SVG allows any feature from SVG's path data syntax to be specified in a path attribute to the 'animateMotion' element (SMIL Animation only allows a subset of SVG's path data syntax within a path attribute)
| 'mpath' element |  | SVG allows an 'animateMotion' element to contain a child 'mpath' element which references an SVG 'path' element as the definition of the motion path
| keyPoints attribute |  | SVG adds a keyPoints attribute to the 'animateMotion' to provide precise control of the velocity of motion path animations
| rotate attribute |  | SVG adds a rotate attribute to the 'animateMotion' to control whether an object is automatically rotated so that its x-axis points in the same direction (or opposite direction) as the directional tangent vector of the motion path

For compatibility with other aspects of the language, SVG uses URI references via an xlink:href attribute to identify the elements which are to be targets of the animations.

SMIL Animation requires that the host language define the meaning for document begin and the document end. Since an 'svg' is sometimes the root of the XML document tree and other times can be a component of a parent XML grammar, the document begin for a given SVG document fragment is defined to be the exact time at which the 'svg' element's SVGLoad event is triggered. The document end of an SVG document fragment is the point at which the document fragment has been released and is no longer being processed by the user agent. However, nested 'svg' elements within an SVG document do not constitute document fragments in this sense, and do not define a separate document begin; all times within the nested SVG fragment are relative to the document time defined for the root 'svg' element.

For SVG, the term presentation time indicates the position in the timeline relative to the document begin of a given document fragment.

SVG defines more constrained error processing than is defined in the SMIL Animation [ SMILANIM] specification. SMIL Animation defines error processing behavior where the document continues to run in certain error situations, whereas all animations within an SVG document fragment will stop in the event of any error within the document (see Error processing).

### 19.2.3 Animation elements example

Example anim01 below demonstrates each of SVG's five animation elements.

    <?xml version="1.0" standalone="no"?>
    <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN"
      "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
    <svg width="8cm" height="3cm"  viewBox="0 0 800 300"
         xmlns="http://www.w3.org/2000/svg" version="1.1">
      <desc>Example anim01 - demonstrate animation elements</desc>
      <rect x="1" y="1" width="798" height="298"
            fill="none" stroke="blue" stroke-width="2" />
      <!-- The following illustrates the use of the 'animate' element
            to animate a rectangles x, y, and width attributes so that
            the rectangle grows to ultimately fill the viewport. -->
      <rect id="RectElement" x="300" y="100" width="300" height="100"
            fill="rgb(255,255,0)"  >
        <animate attributeName="x" attributeType="XML"
                 begin="0s" dur="9s" fill="freeze" from="300" to="0" />
        <animate attributeName="y" attributeType="XML"
                 begin="0s" dur="9s" fill="freeze" from="100" to="0" />
        <animate attributeName="width" attributeType="XML"
                 begin="0s" dur="9s" fill="freeze" from="300" to="800" />
        <animate attributeName="height" attributeType="XML"
                 begin="0s" dur="9s" fill="freeze" from="100" to="300" />
      </rect>
      <!-- Set up a new user coordinate system so that
            the text string's origin is at (0,0), allowing
            rotation and scale relative to the new origin -->
      <g transform="translate(100,100)" >
        <!-- The following illustrates the use of the 'set', 'animateMotion',
             'animateColor' and 'animateTransform' elements. The 'text' element
             below starts off hidden (i.e., invisible). At 3 seconds, it:
               * becomes visible
               * continuously moves diagonally across the viewport
               * changes color from blue to dark red
               * rotates from -30 to zero degrees
               * scales by a factor of three. -->
        <text id="TextElement" x="0" y="0"
              font-family="Verdana" font-size="35.27" visibility="hidden"  >
          It's alive!
          <set attributeName="visibility" attributeType="CSS" to="visible"
               begin="3s" dur="6s" fill="freeze" />
          <animateMotion path="M 0 0 L 100 100"
               begin="3s" dur="6s" fill="freeze" />
          <animateColor attributeName="fill" attributeType="CSS"
               from="rgb(0,0,255)" to="rgb(128,0,0)"
               begin="3s" dur="6s" fill="freeze" />
          <animateTransform attributeName="transform" attributeType="XML"
               type="rotate" from="-30" to="0"
               begin="3s" dur="6s" fill="freeze" />
          <animateTransform attributeName="transform" attributeType="XML"
               type="scale" from="1" to="3" additive="sum"
               begin="3s" dur="6s" fill="freeze" />
        </text>
      </g>
    </svg>

Example anim01
At zero seconds |  | At three seconds
At six seconds |  | At nine seconds

View this example as SVG (SVG-enabled browsers only)

The sections below describe the various animation attributes and elements.

### 19.2.4 Attributes to identify the target element for an animation

The following attributes are common to all animation elements and identify the target element for the animation.

    <!ENTITY % SVG.Animation.attrib
        "%SVG.XLink.attrib;
         %SVG.Animation.extra.attrib;"
    >

Attribute definitions:

xlink:href = "<uri>"
  A URI reference to the element which is the target of this animation and which therefore will be modified over time.
  The target element must be part of the current SVG document fragment.
  <uri> must point to exactly one target element which is capable of being the target of the given animation. If <uri> points to multiple target elements, if the given target element is not capable of being a target of the given animation, or if the given target element is not part of the current SVG document fragment, then the document is in error (see Error processing).
  If the xlink:href attribute is not provided, then the target element will be the immediate parent element of the current animation element.
  Refer to the descriptions of the individual animation elements for any restrictions on what types of elements can be targets of particular types of animations.
  Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: Specifying the animation target.

### 19.2.5 Attributes to identify the target attribute or property for an animation

The following attributes identify the target attribute or property for the given target element whose value changes over time.

    <!ENTITY % SVG.AnimationAttribute.attrib
        "attributeName  CDATA  #REQUIRED
         attributeType  CDATA  #IMPLIED
         %SVG.AnimationAttribute.extra.attrib;"
    >

Attribute definitions:

attributeName = <attributeName>
  Specifies the name of the target attribute. An XMLNS prefix may be used to indicate the XML namespace for the attribute. The prefix will be interpreted in the scope of the current (i.e., the referencing) animation element.
  Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: Specifying the animation target.
attributeType = "CSS | XML | auto"
  Specifies the namespace in which the target attribute and its associated values are defined. The attribute value is one of the following (values are case-sensitive):
  "CSS"
    This specifies that the value of "attributeName" is the name of a CSS property defined as animatable in this specification.
  "XML"
    This specifies that the value of "attributeName" is the name of an XML attribute defined in the default XML namespace for the target element. If the value for `attributeName` has an XMLNS prefix, the implementation must use the associated namespace as defined in the scope of the target element. The attribute must be defined as animatable in this specification.
  "auto"
    The implementation should match the `attributeName` to an attribute for the target element. The implementation must first search through the list of CSS properties for a matching property name, and if none is found, search the default XML namespace for the element.
  The default value is "auto".
  Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: Specifying the animation target.

### 19.2.6 Attributes to control the timing of the animation

The following attributes are common to all animation elements and control the timing of the animation, including what causes the animation to start and end, whether the animation runs repeatedly, and whether to retain the end state the animation once the animation ends.

    <!ENTITY % SVG.AnimationTiming.attrib
        "begin CDATA #IMPLIED
         dur CDATA #IMPLIED
         end CDATA #IMPLIED
         min CDATA #IMPLIED
         max CDATA #IMPLIED
         restart ( always | never | whenNotActive ) 'always'
         repeatCount CDATA #IMPLIED
         repeatDur CDATA #IMPLIED
         fill ( remove | freeze ) 'remove'
         %SVG.AnimationTiming.extra.attrib;"
    >

In the syntax specifications that follow, optional white space is indicated as "S", defined as follows:

    S ::= (#x20 | #x9 | #xD | #xA)*

Attribute definitions:

begin : begin-value-list
  Defines when the element should begin (i.e. become active).
  The attribute value is a semicolon separated list of values.
  begin-value-list ::= begin-value (S? ";" S? begin-value-list )?
    A semicolon separated list of begin values. The interpretation of a list of begin times is detailed in SMIL Animation's section on "Evaluation of begin and end time lists".
  begin-value : ( offset-value | syncbase-value | event-value | repeat-value | accessKey-value | wallclock-sync-value | "indefinite" )
    Describes the element begin.
  offset-value ::= ( S? "+" | "-" S? )? ( Clock-value )
    For SMIL Animation, this describes the element begin as an offset from an implicit syncbase. For SVG, the implicit syncbase begin is defined to be relative to the document begin. Negative begin times are entirely valid and easy to compute, as long as there is a resolved document begin time.
  syncbase-value ::= ( Id-value "." ( "begin" | "end" ) ) ( S? ("+"|"-") S? Clock-value )?
    Describes a syncbase and an optional offset from that syncbase. The element begin is defined relative to the begin or active end of another animation. A syncbase consists of an ID reference to another animation element followed by either `begin` or `end` to identify whether to synchronize with the beginning or active end of the referenced animation element.
  event-value ::= ( Id-value "." )? ( event-ref ) ( S? ("+"|"-") S? Clock-value )?
    Describes an event and an optional offset that determine the element begin. The animation begin is defined relative to the time that the event is raised. The list of event-symbols available for a given event-base element is the list of event attributes available for the given element as defined by the SVG DTD, with the one difference that the leading 'on' is removed from the event name (i.e., the animation event name is 'click', not 'onclick'). A list of all events supported by SVG can be found in Complete list of supported events. Details of event-based timing are described in SMIL Animation: Unifying Event-based and Scheduled Timing.
  repeat-value ::= ( Id-value "." )? "repeat(" integer ")" ( S? ("+"|"-") S? Clock-value )?
    Describes a qualified repeat event. The element begin is defined relative to the time that the repeat event is raised with the specified iteration value.
  accessKey-value ::= "accessKey(" character ")" ( S? ("+"|"-") S? Clock-value )?
    Describes an accessKey that determines the element begin. The element begin is defined relative to the time that the accessKey character is input by the user.
  "wallclock-sync-value : wallclock(" wallclock-value ")"
    Describes the element begin as a real-world clock time. The wallclock time syntax is based upon syntax defined in [ISO8601].
  "indefinite"
    The begin of the animation will be determined by a "beginElement()" method call or a hyperlink targeted to the element.
    The animation DOM methods are described in DOM interfaces.
    Hyperlink-based timing is described in SMIL Animation: Hyperlinks and timing.
  Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'begin' attribute.
dur : Clock-value | "media" | "indefinite"
  Specifies the simple duration.
  The attribute value can be either of the following:
  Clock-value
    Specifies the length of the simple duration in presentation time. Value must be greater than 0.
  "media"
    Specifies the simple duration as the intrinsic media duration. This is only valid for elements that define media.
    (For SVG's animation elements, if "media" is specified, the attribute will be ignored.)
  "indefinite"
    Specifies the simple duration as indefinite.
  If the animation does not have a dur attribute, the simple duration is indefinite. Note that interpolation will not work if the simple duration is indefinite (although this may still be useful for 'set' elements). Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'dur' attribute.
end : end-value-list
  Defines an end value for the animation that can constrain the active duration. The attribute value is a semicolon separated list of values.
  end-value-list ::= end-value (S? ";" S? end-value-list )?
    A semicolon separated list of end values. The interpretation of a list of end times is detailed below.
  end-value : ( offset-value | syncbase-value | event-value | repeat-value | accessKey-value | wallclock-sync-value | "indefinite" )
    Describes the active end of the animation.
  A value of "indefinite" specifies that the end of the animation will be determined by a "endElement()" method call (the animation DOM methods are described in DOM interfaces).
  Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see description of SMIL Animation: 'end' attribute.
min : Clock-value | "media"
  Specifies the minimum value of the active duration.
  The attribute value can be either of the following:
  Clock-value
    Specifies the length of the minimum value of the active duration, measured in local time.
    Value must be greater than 0.
  "media"
    Specifies the minimum value of the active duration as the intrinsic media duration. This is only valid for elements that define media. (For SVG's animation elements, if "media" is specified, the attribute will be ignored.)
  The default value for min is "0". This does not constrain the active duration at all.
  Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'min' attribute.
max : Clock-value | "media"
  Specifies the maximum value of the active duration.
  The attribute value can be either of the following:
  Clock-value
    Specifies the length of the maximum value of the active duration, measured in local time.
    Value must be greater than 0.
  "media"
    Specifies the maximum value of the active duration as the intrinsic media duration. This is only valid for elements that define media. (For SVG's animation elements, if "media" is specified, the attribute will be ignored.)
  There is no default value for max. This does not constrain the active duration at all.
  Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'max' attribute.
restart : "always" | "whenNotActive" | "never"
  always
    The animation can be restarted at any time.
    This is the default value.
  whenNotActive
    The animation can only be restarted when it is not active (i.e. after the active end). Attempts to restart the animation during its active duration are ignored.
  never
    The element cannot be restarted for the remainder of the current simple duration of the parent time container. (In the case of SVG, since the parent time container is the SVG document fragment, then the animation cannot be restarted for the remainder of the document duration.)
  Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'restart' attribute.
repeatCount : numeric value | "indefinite"
  Specifies the number of iterations of the animation function. It can have the following attribute values:
  numeric value
    This is a (base 10) "floating point" numeric value that specifies the number of iterations. It can include partial iterations expressed as fraction values. A fractional value describes a portion of the simple duration. Values must be greater than 0.
  "indefinite"
    The animation is defined to repeat indefinitely (i.e. until the document ends).
  Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'repeatCount' attribute.
repeatDur : Clock-value | "indefinite"
  Specifies the total duration for repeat. It can have the following attribute values:
  Clock-value
    Specifies the duration in presentation time to repeat the animation function `f(t)`.
  "indefinite"
    The animation is defined to repeat indefinitely (i.e. until the document ends).
  Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'repeatDur' attribute.
fill : "freeze" | "remove"
  This attribute can have the following values:
  freeze
    The animation effect F(t) is defined to freeze the effect value at the last value of the active duration. The animation effect is "frozen" for the remainder of the document duration (or until the animation is restarted - see SMIL Animation: Restarting animation ).
  remove
    The animation effect is removed (no longer applied) when the active duration of the animation is over. After the active end of the animation, the animation no longer affects the target (unless the animation is restarted - see SMIL Animation: Restarting animation ).
    This is the default value.
  Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'fill' attribute.

The SMIL Animation [ SMILANIM] specification defines the detailed processing rules associated with the above attributes. Except for any SVG-specific rules explicitly mentioned in this specification, the SMIL Animation [ SMILANIM] specification is the normative definition of the processing rules for the above attributes.

###### Clock values

Clock values have the same syntax as in SMIL Animation [ SMILANIM], which is repeated here:

    Clock-val         ::= Full-clock-val | Partial-clock-val
                          | Timecount-val
    Full-clock-val    ::= Hours ":" Minutes ":" Seconds ("." Fraction)?
    Partial-clock-val ::= Minutes ":" Seconds ("." Fraction)?
    Timecount-val     ::= Timecount ("." Fraction)? (Metric)?
    Metric            ::= "h" | "min" | "s" | "ms"
    Hours             ::= DIGIT+; any positive number
    Minutes           ::= 2DIGIT; range from 00 to 59
    Seconds           ::= 2DIGIT; range from 00 to 59
    Fraction      ::= DIGIT+
    Timecount         ::= DIGIT+
    2DIGIT        ::= DIGIT DIGIT
    DIGIT         ::= [0-9]

For Timecount values, the default metric suffix is "s" (for seconds). No embedded white space is allowed in clock values, although leading and trailing white space characters will be ignored.

Clock values describe presentation time.

The following are examples of legal clock values:

- Full clock values: `
  02:30:03` = 2 hours, 30 minutes and 3 seconds
  `50:00:10.25` = 50 hours, 10 seconds and 250 milliseconds
- Partial clock value: `
  02:33` = 2 minutes and 33 seconds
  `00:10.5` = 10.5 seconds = 10 seconds and 500 milliseconds
- Timecount values:
  `3.2h` = 3.2 hours = 3 hours and 12 minutes
  `45min` = 45 minutes
  `30s` = 30 seconds
  `5ms` = 5 milliseconds
  `12.467` = 12 seconds and 467 milliseconds

Fractional values are just (base 10) floating point definitions of seconds. Thus:

`00.5s = 500 milliseconds
00:00.005 = 5 milliseconds`

### 19.2.7 Attributes that define animation values over time

The following attributes are common to elements 'animate', 'animateMotion', 'animateColor' and 'animateTransform'. These attributes define the values that are assigned to the target attribute or property over time. The attributes below provide control over the relative timing of keyframes and the interpolation method between discrete values.

    <!ENTITY % SVG.AnimationValue.attrib
        "calcMode ( discrete | linear | paced | spline ) 'linear'
         values CDATA #IMPLIED
         keyTimes CDATA #IMPLIED
         keySplines CDATA #IMPLIED
         from CDATA #IMPLIED
         to CDATA #IMPLIED
         by CDATA #IMPLIED
         %SVG.AnimationValue.extra.attrib;"
    >

Attribute definitions:

`calcMode` = "discrete | linear | paced | spline"
  Specifies the interpolation mode for the animation. This can take any of the following values. The default mode is "linear", however if the attribute does not support linear interpolation (e.g. for strings), the `calcMode` attribute is ignored and discrete interpolation is used.
  `discrete`
    This specifies that the animation function will jump from one value to the next without any interpolation.
  `linear`
    Simple linear interpolation between values is used to calculate the animation function. Except for 'animateMotion', this is the default `calcMode`.
  `paced`
    Defines interpolation to produce an even pace of change across the animation. This is only supported for values that define a linear numeric range, and for which some notion of "distance" between points can be calculated (e.g. position, width, height, etc.). If "`paced`" is specified, any `keyTimes` or `keySplines` will be ignored. For 'animateMotion', this is the default `calcMode`.
  `spline`
    Interpolates from one value in the `values` list to the next according to a time function defined by a cubic Bézier spline. The points of the spline are defined in the `keyTimes` attribute, and the control points for each interval are defined in the `keySplines` attribute.
  Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'calcMode' attribute.
values = "<list>"
  A semicolon-separated list of one or more values. Vector-valued attributes are supported using the vector syntax of the `attributeType` domain. Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'values' attribute.
`keyTimes` = "<list>"
  A semicolon-separated list of time values used to control the pacing of the animation. Each time in the list corresponds to a value in the `values` attribute list, and defines when the value is used in the animation function. Each time value in the `keyTimes` list is specified as a floating point value between 0 and 1 (inclusive), representing a proportional offset into the simple duration of the animation element.
  If a list of `keyTimes` is specified, there must be exactly as many values in the `keyTimes` list as in the `values` list.
  Each successive time value must be greater than or equal to the preceding time value.

  The `keyTimes` list semantics depends upon the interpolation mode:

  - For linear and spline animation, the first time value in the list must be 0, and the last time value in the list must be 1. The `keyTime` associated with each value defines when the value is set; values are interpolated between the `keyTimes`.
  - For discrete animation, the first time value in the list must be 0. The time associated with each value defines when the value is set; the animation function uses that value until the next time defined in `keyTimes`.
  If the interpolation mode is "paced", the `keyTimes` attribute is ignored.
  If there are any errors in the `keyTimes` specification (bad values, too many or too few values), the document fragment is in error (see error processing).
  If the simple duration is indefinite, any `keyTimes` specification will be ignored.
  Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'keyTimes' attribute.
`keySplines` = "<list>"
  A set of Bézier control points associated with the `keyTimes` list, defining a cubic Bézier function that controls interval pacing. The attribute value is a semicolon separated list of control point descriptions. Each control point description is a set of four values: `x1 y1 x2 y2`, describing the Bézier control points for one time segment. The `keyTimes` values that define the associated segment are the Bézier "anchor points", and the `keySplines` values are the control points. Thus, there must be one fewer sets of control points than there are `keyTimes`.
  The values must all be in the range 0 to 1.
  This attribute is ignored unless the `calcMode` is set to "spline".
  If there are any errors in the `keySplines` specification (bad values, too many or too few values), the document fragment is in error (see error processing).
  Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'keySplines' attribute.
from = "<value>"
  Specifies the starting value of the animation.
  Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'from' attribute.
to = "<value>"
  Specifies the ending value of the animation.
  Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'to' attribute.
by = "<value>"
  Specifies a relative offset value for the animation.
  Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'by' attribute.

The SMIL Animation [ SMILANIM] specification defines the detailed processing rules associated with the above attributes. Except for any SVG-specific rules explicitly mentioned in this specification, the SMIL Animation [ SMILANIM] specification is the normative definition of the processing rules for the above attributes.

The animation values specified in the animation element must be legal values for the specified attribute. Leading and trailing white space, and white space before and after semicolon separators, will be ignored.

All values specified must be legal values for the specified attribute (as defined in the associated namespace). If any values are not legal, the document fragment is in error (see error processing).

If a list of values is used, the animation will apply the values in order over the course of the animation. If a list of values is specified, any from, to and by attribute values are ignored.

The processing rules for the variants of from/by/to animations are described in Animation function values.

The following figure illustrates the interpretation of the `keySplines` attribute. Each diagram illustrates the effect of `keySplines` settings for a single interval (i.e. between the associated pairs of values in the `keyTimes` and `values` lists.). The horizontal axis can be thought of as the input value for the unit progress of interpolation within the interval - i.e. the pace with which interpolation proceeds along the given interval. The vertical axis is the resulting value for the unit progress, yielded by the `keySplines` function. Another way of describing this is that the horizontal axis is the input unit time for the interval, and the vertical axis is the output unit time. See also the section Timing and real-world clock times.

Examples of keySplines
| keySplines="0 0 1 1" (the default) |  | keySplines=".5 0 .5 1"
| keySplines="0 .75 .25 1" |  | keySplines="1 0 .25 .25"

To illustrate the calculations, consider the simple example:

    <animate dur="4s" values="10; 20" keyTimes="0; 1"
         calcMode="spline" keySplines={as in table} />

Using the keySplines values for each of the four cases above, the approximate interpolated values as the animation proceeds are:

keySplines values | Initial value | After 1s | After 2s | After 3s | Final value
0 0 1 1 | 10.0 | 12.5 | 15.0 | 17.5 | 20.0
.5 0 .5 1 | 10.0 | 11.0 | 15.0 | 19.0 | 20.0
0 .75 .25 1 | 10.0 | 18.0 | 19.3 | 19.8 | 20.0
1 0 .25 .25 | 10.0 | 10.1 | 10.6 | 16.9 | 20.0

For a formal definition of Bézier spline calculation, see [FOLEY-VANDAM].

### 19.2.8 Attributes that control whether animations are additive

It is frequently useful to define animation as an offset or delta to an attribute's value, rather than as absolute values. A simple "grow" animation can increase the width of an object by 10 pixels:

    <rect width="20px" ...>
      <animate attributeName="width" from="0px" to="10px" dur="10s"
               additive="sum"/>
    </rect>

It is frequently useful for repeated animations to build upon the previous results, accumulating with each interation. The following example causes the rectangle to continue to grow with each repeat of the animation:

    <rect width="20px" ...>
      <animate attributeName="width" from="0px" to="10px" dur="10s"
               additive="sum" accumulate="sum" repeatCount="5"/>
    </rect>

At the end of the first repetition, the rectangle has a width of 30 pixels. At the end of the second repetition, the rectangle has a width of 40 pixels. At the end of the fifth repetition, the rectangle has a width of 70 pixels.

For more information about additive animations, see SMIL Animation: Additive animation. For more information on cumulative animations, see SMIL Animation: Controlling behavior of repeating animation - Cumulative animation.

The following attributes are common to elements 'animate', 'animateMotion', 'animateColor' and 'animateTransform'.

    <!ENTITY % SVG.AnimationAddtion.attrib
        "additive ( replace | sum ) 'replace'
         accumulate ( none | sum ) 'none'
         %SVG.AnimationAddtion.extra.attrib;"
    >

Attribute definitions:

additive = "replace | sum"
  Controls whether or not the animation is additive.
  sum
    Specifies that the animation will add to the underlying value of the attribute and other lower priority animations.
  replace
    Specifies that the animation will override the underlying value of the attribute and other lower priority animations. This is the default, however the behavior is also affected by the animation value attributes `by` and `to`, as described in SMIL Animation: How from, to and by attributes affect additive behavior.
  Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'additive' attribute.
accumulate = "none | sum"
  Controls whether or not the animation is cumulative.
  sum
    Specifies that each repeat iteration after the first builds upon the last value of the previous iteration.
  none
    Specifies that repeat iterations are not cumulative. This is the default.
  This attribute is ignored if the target attribute value does not support addition, or if the animation element does not repeat.
  Cumulative animation is not defined for "to animation".
  This attribute will be ignored if the animation function is specified with only the `to` attribute.
  Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this attribute is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'accumulate' attribute.

### 19.2.9 Inheritance

SVG allows both attributes and properties to be animated. If a given attribute or property is inheritable by descendants, then animations on a parent element such as a 'g' element has the effect of propagating the attribute or property animation values to descendant elements as the animation proceeds; thus, descendant elements can inherit animated attributes and properties from their ancestors.

### 19.2.10 The 'animate' element

The 'animate' element is used to animate a single attribute or property over time. For example, to make a rectangle repeatedly fade away over 5 seconds, you can specify:

    <rect>
      <animate attributeType="CSS" attributeName="opacity"
             from="1" to="0" dur="5s" repeatCount="indefinite" />
    </rect>

Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this element is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'animate' element.

    <!ENTITY % SVG.animate.extra.content "" >
    <!ENTITY % SVG.animate.element "INCLUDE" >
    <![%SVG.animate.element;[
    <!ENTITY % SVG.animate.content
        "( %SVG.Description.class; %SVG.animate.extra.content; )\
    *"
    >
    <!ELEMENT %SVG.animate.qname; %SVG.animate.content; >
    <!-- end of SVG.animate.element -->]]>
    <!ENTITY % SVG.animate.attlist "INCLUDE" >
    <![%SVG.animate.attlist;[
    <!ATTLIST %SVG.animate.qname;
        %SVG.Core.attrib;
        %SVG.Conditional.attrib;
        %SVG.AnimationEvents.attrib;
        %SVG.External.attrib;
        %SVG.Animation.attrib;
        %SVG.AnimationAttribute.attrib;
        %SVG.AnimationTiming.attrib;
        %SVG.AnimationValue.attrib;
        %SVG.AnimationAddtion.attrib;
    >

For a list of attributes and properties that can be animated using the 'animate' element, see Elements, attributes and properties that can be animated.

### 19.2.11 The 'set' element

The 'set' element provides a simple means of just setting the value of an attribute for a specified duration. It supports all attribute types, including those that cannot reasonably be interpolated, such as string and boolean values. The 'set' element is non-additive. The additive and accumulate attributes are not allowed, and will be ignored if specified.

Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this element is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'set' element.

    <!ENTITY % SVG.set.extra.content "" >
    <!ENTITY % SVG.set.element "INCLUDE" >
    <![%SVG.set.element;[
    <!ENTITY % SVG.set.content
        "( %SVG.Description.class; %SVG.set.extra.content; )*"
    >
    <!ELEMENT %SVG.set.qname; %SVG.set.content; >
    <!-- end of SVG.set.element -->]]>
    <!ENTITY % SVG.set.attlist "INCLUDE" >
    <![%SVG.set.attlist;[
    <!ATTLIST %SVG.set.qname;
        %SVG.Core.attrib;
        %SVG.Conditional.attrib;
        %SVG.AnimationEvents.attrib;
        %SVG.External.attrib;
        %SVG.Animation.attrib;
        %SVG.AnimationAttribute.attrib;
        %SVG.AnimationTiming.attrib;
        to CDATA #IMPLIED
    >

Attribute definitions:

to = "<value>"
  Specifies the value for the attribute during the duration of the 'set' element. The argument value must match the attribute type.

For a list of attributes and properties that can be animated using the 'set' element, see Elements, attributes and properties that can be animated.

### 19.2.12 The 'animateMotion' element

The 'animateMotion' element causes a referenced element to move along a motion path.

Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this element is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'animateMotion' element.

    <!ENTITY % SVG.animateMotion.extra.content "" >
    <!ENTITY % SVG.animateMotion.element "INCLUDE" >
    <![%SVG.animateMotion.element;[
    <!ENTITY % SVG.animateMotion.content
        "(( %SVG.Description.class; )*, %SVG.mpath.qname;?
            %SVG.animateMotion.extra.content; )"
    >
    <!ELEMENT %SVG.animateMotion.qname; %SVG.animateMot\
    ion.content; >
    <!-- end of SVG.animateMotion.element -->]]>
    <!ENTITY % SVG.animateMotion.attlist "INCLUDE" >
    <![%SVG.animateMotion.attlist;[
    <!ATTLIST %SVG.animateMotion.qname;
        %SVG.Core.attrib;
        %SVG.Conditional.attrib;
        %SVG.AnimationEvents.attrib;
        %SVG.External.attrib;
        %SVG.Animation.attrib;
        %SVG.AnimationTiming.attrib;
        %SVG.AnimationAddtion.attrib;
        calcMode ( discrete | linear | paced | spline ) 'paced'
        values CDATA #IMPLIED
        keyTimes CDATA #IMPLIED
        keySplines CDATA #IMPLIED
        from CDATA #IMPLIED
        to CDATA #IMPLIED
        by CDATA #IMPLIED
        path CDATA #IMPLIED
        keyPoints CDATA #IMPLIED
        rotate CDATA #IMPLIED
        origin CDATA #IMPLIED
    >

Attribute definitions:

`calcMode` = "discrete | linear | paced | spline"
  Specifies the interpolation mode for the animation. Refer to general description of the calcMode attribute above. The only difference is that the default value for the calcMode for 'animateMotion' is paced. See SMIL Animation: 'calcMode' attribute for 'animateMotion'.
path = "<path-data>"
  The motion path, expressed in the same format and interpreted the same way as the d= attribute on the 'path' element. The effect of a motion path animation is to add a supplemental transformation matrix onto the CTM for the referenced object which causes a translation along the x- and y-axes of the current user coordinate system by the computed X and Y values computed over time.
keyPoints = "<list-of-numbers>"
  keyPoints takes a semicolon-separated list of floating point values between 0 and 1 and indicates how far along the motion path the object shall move at the moment in time specified by corresponding keyTimes value. Distance calculations use the user agent's distance along the path algorithm. Each progress value in the list corresponds to a value in the `keyTimes` attribute list.
  If a list of `keyPoints` is specified, there must be exactly as many values in the `keyPoints` list as in the `keyTimes` list.
  If there are any errors in the `keyPoints` specification (bad values, too many or too few values), then the document is in error (see Error processing).
rotate = "<angle> | auto | auto-reverse"
  auto indicates that the object is rotated over time by the angle of the direction (i.e., directional tangent vector) of the motion path. auto-reverse indicates that the object is rotated over time by the angle of the direction (i.e., directional tangent vector) of the motion path plus 180 degrees. An actual angle value can also be given, which represents an angle relative to the x-axis of current user coordinate system. The rotate attribute adds a supplemental transformation matrix onto the CTM to apply a rotation transformation about the origin of the current user coordinate system. The rotation transformation is applied after the supplemental translation transformation that is computed due to the path attribute. The default value is 0.
origin = "default"
  The origin attribute is defined in the SMIL Animation specification [ SMILANIM-ATTR-ORIGIN]. It has no effect in SVG.

    <!ENTITY % SVG.mpath.extra.content "" >
    <!ENTITY % SVG.mpath.element "INCLUDE" >
    <![%SVG.mpath.element;[
    <!ENTITY % SVG.mpath.content
        "( %SVG.Description.class; %SVG.mpath.extra.content; )*"
    >
    <!ELEMENT %SVG.mpath.qname; %SVG.mpath.content; >
    <!-- end of SVG.mpath.element -->]]>
    <!ENTITY % SVG.mpath.attlist "INCLUDE" >
    <![%SVG.mpath.attlist;[
    <!ATTLIST %SVG.mpath.qname;
        %SVG.Core.attrib;
        %SVG.XLinkRequired.attrib;
        %SVG.External.attrib;
    >

Attribute definitions:

xlink:href = "<uri>"
  A URI reference to the 'path' element which defines the motion path.
  Animatable: no.

For 'animateMotion', the specified values for from, by, to and values consists of x, y coordinate pairs, with a single comma and/or white space separating the x coordinate from the y coordinate. For example, from="33,15" specifies an x coordinate value of 33 and a y coordinate value of 15.

If provided, the values attribute must consists of a list of x, y coordinate pairs. Coordinate values are separated by at least one white space character or a comma. Additional white space around the separator is allowed. For example, values="10,20;30,20;30,40" or values="10mm,20mm;30mm,20mm;30mm,40mm". Each coordinate represents a length. Attributes from, by, to and values specify a shape on the current canvas which represents the motion path.

Two options are available which allow definition of a motion path using any of SVG's path data commands:

- the path attribute defines a motion path directly on 'animateMotion' element using any of SVG's path data commands.
- the 'mpath' sub-element provides the ability to reference an external 'path' element as the definition of the motion path.

Note that SVG's path data commands can only contain values in user space, whereas from, by, to and values can specify coordinates in user space or using unit identifiers. See Units.

The various (x,y) points of the shape provide a supplemental transformation matrix onto the CTM for the referenced object which causes a translation along the x- and y-axes of the current user coordinate system by the (x,y) values of the shape computed over time. Thus, the referenced object is translated over time by the offset of the motion path relative to the origin of the current user coordinate system. The supplemental transformation is applied on top of any transformations due to the target element's transform attribute or any animations on that attribute due to 'animateTransform' elements on the target element.

The additive and accumulate attributes apply to 'animateMotion' elements. Multiple 'animateMotion' elements all simultaneously referencing the same target element can be additive with respect to each other; however, the transformations which result from the 'animateMotion' elements are always supplemental to any transformations due to the target element's transform attribute or any 'animateTransform' elements.

The default calculation mode (calcMode) for animateMotion is "paced". This will produce constant velocity motion along the specified path. Note that while animateMotion elements can be additive, it is important to observe that the addition of two or more "paced" (constant velocity) animations might not result in a combined motion animation with constant velocity.

When a path is combined with "discrete", "linear" or "spline" calcMode settings, and if attribute keyPoints is not provided, the number of values is defined to be the number of points defined by the path, unless there are "move to" commands within the path. A "move to" command within the path (i.e. other than at the beginning of the path description) A "move to" command does not count as an additional point when dividing up the duration, or when associating `keyTimes`, `keySplines` and `keyPoints` values. When a path is combined with a "paced" calcMode setting, all "move to" commands are considered to have 0 length (i.e. they always happen instantaneously), and is not considered in computing the pacing.

For more flexibility in controlling the velocity along the motion path, the keyPoints attribute provides the ability to specify the progress along the motion path for each of the keyTimes specified values. If specified, keyPoints causes keyTimes to apply to the values in keyPoints rather than the points specified in the values attribute array or the points on the path attribute.

The override rules for 'animateMotion are as follows. Regarding the definition of the motion path, the 'mpath' element overrides the the path attribute, which overrides values, which overrides from/by/to. Regarding determining the points which correspond to the keyTimes attributes, the keyPoints attribute overrides path, which overrides values, which overrides from/by/to.

At any time t within a motion path animation of duration dur, the computed coordinate (x,y) along the motion path is determined by finding the point (x,y) which is t/dur distance along the motion path using the user agent's distance along the path algorithm.

The following example demonstrates the supplemental transformation matrices that are computed during a motion path animation.

Example animMotion01 shows a triangle moving along a motion path.

    <?xml version="1.0" standalone="no"?>
    <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN"
      "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
    <svg width="5cm" height="3cm"  viewBox="0 0 500 300"
         xmlns="http://www.w3.org/2000/svg" version="1.1"
         xmlns:xlink="http://www.w3.org/1999/xlink" >
      <desc>Example animMotion01 - demonstrate motion animation computations</desc>
      <rect x="1" y="1" width="498" height="298"
            fill="none" stroke="blue" stroke-width="2" />
      <!-- Draw the outline of the motion path in blue, along
              with three small circles at the start, middle and end. -->
      <path id="path1" d="M100,250 C 100,50 400,50 400,250"
            fill="none" stroke="blue" stroke-width="7.06"  />
      <circle cx="100" cy="250" r="17.64" fill="blue"  />
      <circle cx="250" cy="100" r="17.64" fill="blue"  />
      <circle cx="400" cy="250" r="17.64" fill="blue"  />
      <!-- Here is a triangle which will be moved about the motion path.
           It is defined with an upright orientation with the base of
           the triangle centered horizontally just above the origin. -->
      <path d="M-25,-12.5 L25,-12.5 L 0,-87.5 z"
            fill="yellow" stroke="red" stroke-width="7.06"  >
        <!-- Define the motion path animation -->
        <animateMotion dur="6s" repeatCount="indefinite" rotate="auto" >
           <mpath xlink:href="#path1"/>
        </animateMotion>
      </path>
    </svg>

Example animMotion01
At zero seconds |  | At three seconds |  | At six seconds

View this example as SVG (SVG-enabled browsers only)

The following table shows the supplemental transformation matrices that are applied to achieve the effect of the motion path animation.

| After 0s | After 3s | After 6s
Supplemental transform due to movement along motion path | translate(100,250) | translate(250,100) | translate(400,250)
Supplemental transform due to rotate="auto" | rotate(-90) | rotate(0) | rotate(90)

For a list of elements that can be animated using the 'animateMotion' element, see Elements, attributes and properties that can be animated.

### 19.2.13 The 'animateColor' element

The 'animateColor' element specifies a color transformation over time.

Except for any SVG-specific rules explicitly mentioned in this specification, the normative definition for this element is the SMIL Animation [ SMILANIM] specification. In particular, see SMIL Animation: 'animateColor' element.

    <!ENTITY % SVG.animateColor.extra.content "" >
    <!ENTITY % SVG.animateColor.element "INCLUDE" >
    <![%SVG.animateColor.element;[
    <!ENTITY % SVG.animateColor.content
        "( %SVG.Description.class; %SVG.animateColor.extra.conte\
    nt; )*"
    >
    <!ELEMENT %SVG.animateColor.qname; %SVG.animateColor\
    .content; >
    <!-- end of SVG.animateColor.element -->]]>
    <!ENTITY % SVG.animateColor.attlist "INCLUDE" >
    <![%SVG.animateColor.attlist;[
    <!ATTLIST %SVG.animateColor.qname;
        %SVG.Core.attrib;
        %SVG.Conditional.attrib;
        %SVG.AnimationEvents.attrib;
        %SVG.External.attrib;
        %SVG.Animation.attrib;
        %SVG.AnimationAttribute.attrib;
        %SVG.AnimationTiming.attrib;
        %SVG.AnimationValue.attrib;
        %SVG.AnimationAddtion.attrib;
    >

The from, by and to attributes take color values, where each color value is expressed using the following syntax (the same syntax as used in SVG's properties that can take color values):

    <color> [icc-color(<name>[,<icccolorvalue>]*)]

The values attribute for the 'animateColor' element consists of a semicolon-separated list of color values, with each color value expressed in the above syntax.

Out of range color values can be provided, but user agent processing will be implementation dependent. User agents should clamp color values to allow color range values as late as possible, but note that system differences might preclude consistent behavior across different systems.

The 'color-interpolation' property applies to color interpolations that result from 'animateColor' animations.

For a list of attributes and properties that can be animated using the 'animateColor' element, see Elements, attributes and properties that can be animated.

### 19.2.14 The 'animateTransform' element

The 'animateTransform' element animates a transformation attribute on a target element, thereby allowing animations to control translation, scaling, rotation and/or skewing.

    <!ENTITY % SVG.animateTransform.extra.content "" >
    <!ENTITY % SVG.animateTransform.element "INCLUDE" >
    <![%SVG.animateTransform.element;[
    <!ENTITY % SVG.animateTransform.content
        "( %SVG.Description.class; %SVG.animateTransform.extra.c\
    ontent; )*"
    >
    <!ELEMENT %SVG.animateTransform.qname; %SVG.anim\
    ateTransform.content; >
    <!-- end of SVG.animateTransform.element -->]]>
    <!ENTITY % SVG.animateTransform.attlist "INCLUDE" >
    <![%SVG.animateTransform.attlist;[
    <!ATTLIST %SVG.animateTransform.qname;
        %SVG.Core.attrib;
        %SVG.Conditional.attrib;
        %SVG.AnimationEvents.attrib;
        %SVG.External.attrib;
        %SVG.Animation.attrib;
        %SVG.AnimationAttribute.attrib;
        %SVG.AnimationTiming.attrib;
        %SVG.AnimationValue.attrib;
       %SVG.AnimationAddtion.attrib;
        type ( translate | scale | rotate | skewX | skewY ) 'translate'
    >

Attribute definitions:

type = "translate | scale | rotate | skewX | skewY"
  Indicates the type of transformation which is to have its values change over time.

The from, by and to attributes take a value expressed using the same syntax that is available for the given transformation type:

- For a type="translate", each individual value is expressed as <tx> [,<ty>].
- For a type="scale", each individual value is expressed as <sx> [,<sy>].
- For a type="rotate", each individual value is expressed as <rotate-angle> [<cx> <cy>].
- For a type="skewX" and type="skewY", each individual value is expressed as <skew-angle>.

(See The transform attribute.)

The values attribute for the 'animateTransform' element consists of a semicolon-separated list of values, where each individual value is expressed as described above for from, by and to.

If calcMode has the value paced, then a total "distance" for each component of the transformation is calculated (e.g., for a translate operation, a total distance is calculated for both tx and ty) consisting of the sum of the absolute values of the differences between each pair of values, and the animation runs to produce a constant distance movement for each individual component.

When an animation is active, the effect of non-additive 'animateTransform' (i.e., additive="replace") is to replace the given attribute's value with the transformation defined by the 'animateTransform'. The effect of additive (i.e., additive="sum") is to post-multiply the transformation matrix corresponding to the transformation defined by this 'animateTransform'. To illustrate:

    <rect transform="skewX(30)"...>
      <animateTransform attributeName="transform" attributeType="XML"
                        type="rotate" from="0" to="90" dur="5s"
                        additive="replace" fill="freeze"/>
      <animateTransform attributeName="transform" attributeType="XML"
                        type="scale" from="1" to="2" dur="5s"
                        additive="replace" fill="freeze"/>
    </rect>

In the code snippet above, because the both animations have additive="replace", the first animation overrides the transformation on the rectangle itself and the second animation overrides the transformation from the first animation; therefore, at time 5 seconds, the visual result of the above two animations would be equivalent to the following static rectangle:

    <rect transform="scale(2)" ... />

whereas in the following example:

    <rect transform="skewX(30)"...>
      <animateTransform attributeName="transform" attributeType="XML"
                        type="rotate" from="0" to="90" dur="5s"
                        additive="sum" fill="freeze"/>
      <animateTransform attributeName="transform" attributeType="XML"
                        type="scale" from="1" to="2" dur="5s"
                        additive="sum" fill="freeze"/>
    </rect>

In this code snippet, because the both animations have additive="sum", the first animation post-multiplies its transformation to any transformations on the rectangle itself and the second animation post-multiplies its transformation to any transformation from the first animation; therefore, at time 5 seconds, the visual result of the above two animations would be equivalent to the following static rectangle:

    <rect transform="skewX(30) rotate(90) scale(2)" ... />

For a list of attributes and properties that can be animated using the 'animateTransform' element, see Elements, attributes and properties that can be animated.

### 19.2.15 Elements, attributes and properties that can be animated

The following lists all of the elements which can be animated by an 'animateMotion' element:

- 'g'
- 'defs'
- 'use'
- 'image'
- 'switch'
- 'path'
- 'rect'
- 'circle'
- 'ellipse'
- 'line'
- 'polyline'
- 'polygon'
- 'text'
- 'clipPath'
- 'mask'
- 'a'
- 'foreignObject'

Each attribute or property within this specification indicates whether or not it can be animated by SVG's animation elements. Animatable attributes and properties are designated as follows:
Animatable: yes.
whereas attributes and properties that cannot be animated are designated:
Animatable: no.

SVG has a defined set of basic data types for its various supported attributes and properties. For those attributes and properties that can be animated, the following table indicates which animation elements can be used to animate each of the basic data types. If a given attribute or property can take values of keywords (which are not additive) or numeric values (which are additive), then additive animations are possible if the subsequent animation uses a numeric value even if the base animation uses a keyword value; however, if the subsequent animation uses a keyword value, additive animation is not possible.

Data type | Additive? | 'animate' | 'set' | 'animate Color' | 'animate Transform' | Notes
--- | --- | --- | --- | --- | --- | ---
<angle> | yes | yes | yes | no | no |
<color> | yes | yes | yes | yes | no | Only RGB color values are additive.
<coordinate> | yes | yes | yes | no | no |
<frequency> | no | no | no | no | no |
<integer> | yes | yes | yes | no | no |
<length> | yes | yes | yes | no | no |
<list of xxx> | no | yes | yes | no | no |
<number> | yes | yes | yes | no | no |
<paint> | yes | yes | yes | yes | no | Only RGB color values are additive.
<percentage> | yes | yes | yes | no | no |
<time> | no | no | no | no | no |
<transform-list> | yes | no | no | no | yes | Additive means that a transformation is post-multiplied to the base set of transformations.
<uri> | no | yes | yes | no | no |
All other data types used in animatable attributes and properties | no | yes | yes | no | no |

Any deviation from the above table or other special note about the animation capabilities of a particular attribute or property is included in the section of the specification where the given attribute or property is defined.

## 19.3 Animation using the SVG DOM

Example dom01 shows a simple animation using the DOM.

    <?xml version="1.0" standalone="no"?>
    <!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN"
      "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
    <svg width="4cm" height="2cm" viewBox="0 0 400 200"
         xmlns="http://www.w3.org/2000/svg"
         onload="StartAnimation(evt)" version="1.1">
      <script type="text/ecmascript"><![CDATA[
        var timevalue = 0;
        var timer_increment = 50;
        var max_time = 5000;
        var text_element;
        function StartAnimation(evt) {
          text_element = evt.target.ownerDocument.getElementById("TextElement");
          ShowAndGrowElement();
        }
        function ShowAndGrowElement() {
          timevalue = timevalue + timer_increment;
          if (timevalue > max_time)
            return;
          // Scale the text string gradually until it is 20 times larger
          scalefactor = (timevalue * 20.) / max_time;
          text_element.setAttribute("transform", "scale(" + scalefactor + ")");
          // Make the string more opaque
          opacityfactor = timevalue / max_time;
          text_element.setAttribute("opacity", opacityfactor);
          // Call ShowAndGrowElement again <timer_increment> milliseconds later.
          setTimeout("ShowAndGrowElement()", timer_increment)
        }
        window.ShowAndGrowElement = ShowAndGrowElement
      ]]></script>
      <rect x="1" y="1" width="398" height="198"
            fill="none" stroke="blue" stroke-width="2"/>
      <g transform="translate(50,150)" fill="red" font-size="7">
        <text id="TextElement">SVG</text>
      </g>
    </svg>

Example dom01
At zero seconds |  | At 2.5 seconds |  | At five seconds

View this example as SVG (SVG-enabled browsers only)

The above SVG file contains a single graphics element, a text string that says "SVG". The animation loops for 5 seconds. The text string starts out small and transparent and grows to be large and opaque. Here is an explanation of how this example works:

- The `onload="StartAnimation(evt)"` attribute indicates that, once the document has been fully loaded and processed, invoke ECMAScript function `StartAnimation`.
- The 'script' element defines the ECMAScript which makes the animation happen. The `StartAnimation()` function is only called once to give a value to global variable `text_element` and to make the initial call to `ShowAndGrowElement()`. `ShowAndGrowElement()` is called every 50 milliseconds and resets the `transform` and `style` attributes on the text element to new values each time it is called. At the end of `ShowAndGrowElement`, the function tells the ECMAScript engine to call itself again after 50 more milliseconds.
- The 'g' element shifts the coordinate system so that the origin is shifted toward the lower-left of the viewing area. It also defines the fill color and font-size to use when drawing the text string.
- The 'text' element contains the text string and is the element whose attributes get changed during the animation.

If scripts are modifying the same attributes or properties that are being animated by SVG's animation elements, the scripts modify the base value for the animation. If a base value is modified while an animation element is animating the corresponding attribute or property, the animations are required to adjust dynamically to the new base value.

If a script is modifying a property on the override style sheet at the same time that an animation element is animating that property, the result is implementation-dependent; thus, it is recommended that this be avoided.

## 19.4 Animation Module

Elements | Attributes | Content Model
--- | --- | ---
animate | Core.attrib, Conditional.attrib, External.attrib, AnimationEvents.attrib, Animation.attrib, AnimationAttribute.attrib, AnimationTiming.attrib, AnimationValue.attrib, AnimationAddtion.attrib | (Description.class)
set | Core.attrib, Conditional.attrib, External.attrib, AnimationEvents.attrib, Animation.attrib, AnimationAttribute.attrib, AnimationTiming.attrib, to | (Description.class)
animateMotion | Core.attrib, Conditional.attrib, External.attrib, AnimationEvents.attrib, Animation.attrib, AnimationTiming.attrib, AnimationAddtion.attrib, AnimationValue.attrib, path, keyPoints, rotate, origin | (Description.class | mpath)
animateTransform | Core.attrib, Conditional.attrib, External.attrib, AnimationEvents.attrib, Animation.attrib, AnimationAttribute.attrib, AnimationTiming.attrib, AnimationValue.attrib, AnimationAddtion.attrib, type | (Description.class)
animateColor | Core.attrib, Conditional.attrib, External.attrib, AnimationEvents.attrib, Animation.attrib, AnimationAttribute.attrib, AnimationTiming.attrib, AnimationValue.attrib, AnimationAddtion.attrib | (Description.class)
mpath | Core.attrib, XLinkRequired.attrib, External.attrib | (Description.class)

### 19.4.1 Animation Content Set

The Animation Module defines the Animation.class content set.

Content Set Name | Elements in Content Set
--- | ---
Animation.class | animate, animateColor, animateTransform, animateMotion, set

### 19.4.2 Animation Attribute Sets

The Animation Module defines the Animation.attrib, AnimationAttribute.attrib, AnimationTiming.attrib, AnimationValue.attrib and AnimationAddtion.attrib attribute sets.

Collection Name | Attributes in Collection
--- | ---
Animation.attrib | XLink.attrib
AnimationAttribute.attrib | attributeName, attributeType
AnimationTiming.attrib | begin, dur, end, min, max, restart, repeatCount, repeatDur, fill
AnimationValue.attrib | calcMode, values, keyTimes, keySplines, from, to, by
AnimationAddtion.attrib | additive, accumulate

##

## 19.5 DOM interfaces

The following two interfaces are from SMIL Animation. They are included here for easy reference:

### Interface ElementTimeControl

The ElementTimeControl interface, part of the org.w3c.dom.smil module and defined in SMIL Animation: Supported interfaces, defines common methods for elements which define animation behaviors compatible with SMIL Animation.

Calling `beginElement()` causes the animation to begin in the same way that an animation with event-based begin timing begins. The effective begin time is the current presentation time at the time of the DOM method call. Note that `beginElement()` is subject to the `restart` attribute in the same manner that event-based begin timing is. If an animation is specified to disallow restarting at a given point, `beginElement()` methods calls must fail. Refer also to the section Restarting animation.

Calling `beginElementAt(seconds)` has the same behavior as `beginElement()`, except that the effective begin time is offset from the current presentation time by an amount specified as a parameter. Passing a negative value for the offset causes the element to begin as for `beginElement()`, but has the effect that the element begins at the specified offset into its active duration. The `beginElementAt()` method must also respect the `restart` attribute. The restart semantics for a `beginElementAt()` method call are evaluated at the time of the method call, and not at the effective begin time specified by the offset parameter.

Calling `endElement()` causes an animation to end the active duration, just as `end` does. Depending upon the value of the `fill` attribute, the animation effect may no longer be applied, or it may be frozen at the current effect. Refer also to the section Freezing animations. If an animation is not currently active (i.e. if it has not yet begun or if it is frozen), the `endElement()` method will fail.

Calling `endElementAt()` causes an animation to end the active duration, just as `endElement()` does, but allows the caller to specify a positive offset, to cause the element to end at a point in the future. Other than delaying when the end actually happens, the semantics are identical to those for `endElement()`. If `endElementAt()` is called more than once while an element is active, the end time specified by the last method call will determine the end behavior.

IDL Definition

      interface ElementTimeControl {
        boolean beginElement (  )
                        raises( DOMException );
        boolean beginElementAt ( in float offset )
                        raises( DOMException );
        boolean endElement (  )
                        raises( DOMException );
        boolean endElementAt ( in float offset )
                        raises( DOMException );
      };

Methods
  beginElement

    Causes this element to begin the local timeline (subject to restart constraints).

    No Parameters
    Return value

      boolean |  | `true` if the method call was successful and the element was begun. `false` if the method call failed. Possible reasons for failure include: The element is already active and cannot be restarted when it is active. The `restart` attribute is set to `"whenNotActive"`. The element is active or has been active and cannot be restarted. The `restart` attribute is set to `"never"`.

    Exceptions

      DOMException |  | SYNTAX_ERR: The element was not defined with the appropriate syntax to allow `beginElement` calls.

  beginElementAt

    Causes this element to begin the local timeline (subject to restart constraints), at the passed offset from the current time when the method is called. If the offset is >= 0, the semantics are equivalent to an event-base begin with the specified offset. If the offset is < 0, the semantics are equivalent to beginElement(), but the element active duration is evaluated as though the element had begun at the passed (negative) offset from the current time when the method is called.

    Parameters

      in float offset |  | The offset in seconds at which to begin the element.

    Return value

      boolean |  | `true` if the method call was successful and the element was begun. `false` if the method call failed. Possible reasons for failure include: The element is already active and cannot be restarted when it is active. The `restart` attribute is set to `"whenNotActive"`. The element is active or has been active and cannot be restarted. The `restart` attribute is set to `"never"`.

    Exceptions

      DOMException |  | SYNTAX_ERR: The element was not defined with the appropriate syntax to allow `beginElementAt` calls.

  endElement
    Causes this element to end the local timeline.
    No Parameters
    Return value

      boolean |  | `true` if the method call was successful and the element was ended. `false` if method call failed. Possible reasons for failure include: The element is not active.

    Exceptions

      DOMException |  | SYNTAX_ERR: The element was not defined with the appropriate syntax to allow `endElement` calls.

  endElementAt

    Causes this element to end the local timeline at the specified offset from the current time when the method is called.

    Parameters

      in float offset |  | The offset in seconds at which to end the element. Must be >= 0.

    Return value

      boolean |  | `true` if the method call was successful and the element was ended. `false` if the method call failed. Possible reasons for failure include: The element is not active.

    Exceptions

      DOMException |  | SYNTAX_ERR: The element was not defined with the appropriate syntax to allow `endElementAt` calls.

The corresponding Java binding:

    package org.w3c.dom.svg;
    import org.w3c.dom.DOMException;
    public interface ElementTimeControl {
      boolean beginElement (  )
                      throws DOMException;
      boolean beginElementAt ( float offset )
                      throws DOMException;
      boolean endElement (  )
                      throws DOMException;
      boolean endElementAt ( float offset )
                      throws DOMException;
    }

### Interface TimeEvent

The TimeEvent interface, defined in SMIL Animation: Supported interfaces defined in SMIL Animation: Supported interfaces, provides specific contextual information associated with Time events.

The different types of events that can occur are:

beginEvent
  This event is raised when the element local timeline begins to play. It will be raised each time the element begins the active duration (i.e. when it restarts, but not when it repeats). It may be raised both in the course of normal (i.e. scheduled or interactive) timeline play, as well as in the case that the element was begun with the `beginElement()` or `beginElementAt()` methods. Note that if an element is restarted while it is currently playing, the element will raise an end event and another begin event, as the element restarts.
  - Bubbles: No
  - Cancelable: No
  - Context Info: None
endEvent
  This event is raised at the active end of the element. Note that this event is not raised at the simple end of each repeat. This event may be raised both in the course of normal (i.e. scheduled or interactive) timeline play, as well as in the case that the element was ended with the `endElement()` or `endElementAt()` methods. Note that if an element is restarted while it is currently playing, the element will raise an end event and another begin event, as the element restarts.
  - Bubbles: No
  - Cancelable: No
  - Context Info: None
repeatEvent
  This event is raised when an element local timeline repeats. It will be raised each time the element repeats, after the first iteration.
  The event provides a numerical indication of which repeat iteration is beginning. The value is a 0-based integer, but the repeat event is not raised for the first iteration and so the observed values of the detail attribute will be >= 1.
  - Bubbles: No
  - Cancelable: No
  - Context Info: detail (current iteration)

IDL Definition

      interface TimeEvent : events::Event {
        readonly attribute views::AbstractView view;
        readonly attribute long                detail;
        void initTimeEvent ( in DOMString typeArg, in views::AbstractView viewArg, in long detailArg );
      };

Attributes
  readonly views::AbstractView view
    The `view` attribute identifies the AbstractView [DOM2-VIEWS] from which the event was generated.
  readonly long detail
    Specifies some detail information about the Event, depending on the type of the event. For this event type, indicates the repeat number for the animation.
Methods
  initTimeEvent
    The initTimeEvent method is used to initialize the value of a TimeEvent created through the DocumentEvent interface. This method may only be called before the TimeEvent has been dispatched via the dispatchEvent method, though it may be called multiple times during that phase if necessary. If called multiple times, the final invocation takes precedence.
    Parameters

      in DOMString typeArg |  | Specifies the event type.
      in views::AbstractView viewArg |  | Specifies the Event's AbstractView.
      in long detailArg |  | Specifies the Event's detail.

    No Return Value
    No Exceptions

The corresponding Java binding:

    package org.w3c.dom.svg;
    import org.w3c.dom.events.Event;
    import org.w3c.dom.views.AbstractView;
    public interface TimeEvent extends
                   Event {
      public AbstractView getView( );
      public int          getDetail( );
      void initTimeEvent ( String typeArg, AbstractView viewArg, int detailArg );
    }

The following interfaces are defined below: SVGAnimationElement, SVGAnimateElement, SVGSetElement, SVGAnimateMotionElement, SVGMPathElement, SVGAnimateColorElement, SVGAnimateTransformElement.

### Interface SVGAnimationElement

The SVGAnimationElement interface is the base interface for all of the animation element interfaces: SVGAnimateElement, SVGSetElement, SVGAnimateColorElement, SVGAnimateMotionElement and SVGAnimateTransformElement.

Unlike other SVG DOM interfaces, the SVG DOM does not specify convenience DOM properties corresponding to the various language attributes on SVG's animation elements. Specification of these convenience properties in a way that will be compatible with future versions of SMIL Animation is expected in a future version of SVG. The current method for accessing and modifying the attributes on the animation elements is to use the standard `getAttribute`, `setAttribute`, `getAttributeNS` and `setAttributeNS` defined in DOM2.

IDL Definition

      interface SVGAnimationElement :
                      SVGElement,
                      SVGTests,
                      SVGExternalResourcesRequired,
                      smil::ElementTimeControl,
                      events::EventTarget {
        readonly attribute SVGElement targetElement;
        float getStartTime (  );
        float getCurrentTime (  );
        float getSimpleDuration (  )
                        raises( DOMException );
      };

Attributes
  readonly SVGElement targetElement
    The element which is being animated.
Methods
  getStartTime

    Returns the start time in seconds for this animation.

    No Parameters
    Return value

      float |  | The start time in seconds for this animation relative to the start time of the time container.

    No Exceptions
  getCurrentTime

    Returns the current time in seconds relative to time zero for the given time container.

    No Parameters
    Return value

      float |  | The current time in seconds relative to time zero for the given time container.

    No Exceptions
  getSimpleDuration

    Returns the number of seconds for the simple duration for this animation. If the simple duration is undefined (e.g., the end time is indefinite), then an exception is raised.

    No Parameters
    Return value

      float |  | The number of seconds for the simple duration for this animation.

    Exceptions

      DOMException |  | NOT_SUPPORTED_ERR: The simple duration is not determined on the given element.

### Interface SVGAnimateElement

The SVGAnimateElement interface corresponds to the 'animate' element.

Object-oriented access to the attributes of the 'animate' element via the SVG DOM is not available.

IDL Definition

      interface SVGAnimateElement : SVGAnimationElement {};

### Interface SVGSetElement

The SVGSetElement interface corresponds to the 'set' element.

Object-oriented access to the attributes of the 'set' element via the SVG DOM is not available.

IDL Definition

      interface SVGSetElement : SVGAnimationElement {};

### Interface SVGAnimateMotionElement

The SVGAnimateMotionElement interface corresponds to the 'animateMotion' element.

Object-oriented access to the attributes of the 'animateMotion' element via the SVG DOM is not available.

IDL Definition

      interface SVGAnimateMotionElement : SVGAnimationElement {};

### Interface SVGMPathElement

The SVGMPathElement interface corresponds to the 'mpath' element.

IDL Definition

      interface SVGMPathElement :
                      SVGElement,
                      SVGURIReference,
                      SVGExternalResourcesRequired {};

### Interface SVGAnimateColorElement

The SVGAnimateColorElement interface corresponds to the 'animateColor' element.

Object-oriented access to the attributes of the 'animateColor' element via the SVG DOM is not available.

IDL Definition

      interface SVGAnimateColorElement : SVGAnimationElement {};

### Interface SVGAnimateTransformElement

The SVGAnimateTransformElement interface corresponds to the 'animateTransform' element.

Object-oriented access to the attributes of the 'animateTransform' element via the SVG DOM is not available.

IDL Definition

      interface SVGAnimateTransformElement : SVGAnimationElement {};

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