11 Painting: Filling, Stroking and Marker Symbols

Contents

• 11.1 Introduction
• 11.2 Specifying paint
• 11.3 Fill Properties
• 11.4 Stroke Properties
• 11.5 Markers
  • 11.5.1 Introduction
  • 11.5.2 The 'marker' element
  • 11.5.3 Marker properties
  • 11.5.4 Details on how markers are rendered
• 11.6 Rendering properties
• 11.7 Inheritance of painting properties
• 11.8 DOM interfaces
  • 11.8.1 Interface SVGICCColor
  • 11.8.2 Interface SVGColor
  • 11.8.3 Interface SVGPaint
  • 11.8.4 Interface SVGMarkerElement

11.1 Introduction

'path' elements, 'text' elements and basic shapes can be filled (which means painting the interior of the object) and stroked (which means painting along the outline of the object). Filling and stroking both can be thought of in more general terms as painting operations.

Certain elements (i.e., 'path', 'polyline', 'polygon' and 'line' elements) can also have marker symbols drawn at their vertices.

With SVG, you can paint (i.e., fill or stroke) with:

• a single color
• a gradient (linear or radial)
• a pattern (vector or image, possibly tiled)
• custom paints available via extensibility

SVG uses the general notion of a paint server. Gradients and patterns are just specific types of paint servers. For example, first you can define a linear gradient by including a 'linearGradient' element within a 'defs', assign an ID to that 'linearGradient' element, and then reference that ID in a 'fill' or 'stroke' property:

<?xml version="1.0" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG December 1999//EN" 
  "http://www.w3.org/Graphics/SVG/SVG-19991203.dtd">
<svg width="4in" height="3in">
  <desc>Linear gradient example
  </desc>
  <g>
    <defs>
      <linearGradient id="MyGradient">
        <stop offset="0%" style="color:#F60"/>
        <stop offset="70%" style="color:#FF6"/>
      </linearGradient>
    </defs>
    <rect style="fill: url(#MyGradient)" width="20" height="15.8"/>
  </g>
</svg>

Download this example

11.2 Specifying paint

Properties 'fill' and 'stroke' take on a value of type <paint>, which is specified as follows:

none

Indicates that the object has no fill (i.e., the interior is transparent).

currentColor

Indicates that the object is. filled with the color specified by the 'color' property. This mechanism is provided to facilitate sharing of color attributes between parent grammars such as other (non-SVG) XML. This mechanism allows you to define a style in your HTML which sets the 'color' property and then pass that style to the SVG user agent so that your SVG text will draw in the same color.

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

<color> is the explicit color (in the sRGB [SRGB] color space) to be used to fill the current object. SVG supports all of CSS2's <color> specifications. If an optional ICC color specification is provided, then the user agent searches the color profile description database for an @color-profile entry whose name descriptor matches <name> and uses the last matching entry that is found. (If no match is found, then the ICC color specification is ignored.) The list of <icccolorvalue>'s is a set of ICC-profile-specific color values, expressed as <number>s. On platforms which support ICC-based color management, the icc-color gets precedence over the <color> (which is in the sRGB color space). Percentages are not allowed on <icccolorvalue>'s. For more on ICC-based colors, refer to Color.

<uri>
   [ none |
      currentColor |
      <color> [icc-color(<name>,<icccolorvalue>[,<icccolorvalue>]*)]]

The <uri> is how you identify a fancy paint style such as a gradient, a pattern or a custom paint from extensibility. The <uri> provides. the ID of the paint server (e.g., a gradient or a pattern) to be used to paint the current object. If the URI reference is not valid (e.g., it points to an object that doesn't exist or the object is not a valid paint server), then the paint method following the <uri> (i.e., none | currentColor |
   <color>
   [icc-color(<name>,<icccolorvalue>[,<icccolorvalue>]*)]|
   inherit) is used if provided; otherwise, the document is in error (see Error processing).

11.3 Fill Properties

Note that graphical objects that are not closed (e.g., a 'path' without a closepath at the end or a 'polyline') still can be filled. The fill operation automatically closes all open subpaths by connecting the last point of the subpath with the first point of the subpath before painting the fill.

evenodd

nonzero

'fill-opacity' specifies the opacity of the painting operation used to paint the interior the current object. (See Painting shapes and text.)

<opacity-value>

The opacity of the painting operation used to fill the current object. If a <number> is provided, any values outside the range 0.0 (fully transparent) to 1.0 (fully opaque) will be clamped to this range. If a percentage is provided, any value outside the range of 0% to 100% will be clamped to this range. (See Clamping values which are restricted to a particular range

Related properties: 'stroke-opacity' and 'opacity'.

11.4 Stroke Properties

The following are the properties which affect how an element is stroked.

In all cases, all stroking properties which are affected by directionality, such as those having to do with dash patterns, must be rendered such that the stroke operation starts at the same point at which the graphics element starts. In particular, for 'path' elements, the start of the path is the first point of the initial "moveto" command.

For stroking properties such as dash patterns whose computations are dependent on progress along the outline of the graphics element, distance calculations are required to utilize the SVG user agent's standard Distance along a path algorithms.

When stroking is performed using a complex paint server, such as a gradient or a pattern, the stroke operation must be identical to the result that would have occurred if the geometric shape defined by the geometry of the current graphics element and its associated stroking properties were converted to an equivalent 'path' element and then filled using the given paint server.

<width>

The width of the stroke on the current object, expressed as a <length>. If a percentage is used, the <width> is expressed as a percentage of the current viewport
(See Processing rules for CSS units and percentages.)

'stroke-linecap' specifies the shape to be used at the end of open subpaths when they are stroked.

butt

See drawing below.

round

See drawing below.

square

See drawing below.

'stroke-linejoin' specifies the shape to be used at the corners of paths (or other vector shapes) that are stroked. when they are stroked.

miter

See drawing below.

round

See drawing below.

bevel

See drawing below.

When two line segments meet at a sharp angle and miter joins have been specified for 'stroke-linejoin', it is possible for the miter to extend far beyond the thickness of the line stroking the path. The 'stroke-miterlimit' imposes a limit on the ratio of the miter length to the 'stroke-linewidth'.

<miterlimit>

The limit on the ratio of the miter length to the 'stroke-linewidth'. The value of <miterlimit> must be a number greater than or equal to 1.

'stroke-dasharray' controls the pattern of dashes and gaps used to stroke paths. <dasharray> contains a list of space- or comma-separated numbers that specify the lengths of alternating dashes and gaps in user units. If an odd number of values is provided, then the list of values is repeated to yield an even number of values. Thus, stroke-dasharray: 5 3 2 is equivalent to stroke-dasharray: 5 3 2 5 3 2.

none

Indicates that no dashing is used. If stroked, the line is drawn solid.

<dasharray>

A list of space- or comma-separated <length>'s which can be in user units or in any of the CSS units, including percentages. A percentage represents a distance as a percentage of the current viewport. (See Processing rules for CSS units and percentages.)

'stroke-dashoffset' specifies the distance into the dash pattern to start the dash.

<dashoffset>

A <length>. If a percentage is used, the <width> is expressed as a percentage of the current viewport
(See Processing rules for CSS units and percentages.)

'stroke-opacity' specifies the opacity of the painting operation used to stroke the current object. (See Painting shapes and text.)

<opacity-value>

The opacity of the painting operation used to stroke the current object. If a <number> is provided, any values outside the range 0.0 (fully transparent) to 1.0 (fully opaque) will be clamped to this range. If a percentage is provided, any value outside the range of 0% to 100% will be clamped to this range. (See Clamping values which are restricted to a particular range

Related properties: 'fill-opacity' and 'opacity'.

11.5 Markers

11.5.1 Introduction

To use a marker symbol for arrowheads or polymarkers, you need to define a 'marker' element which defines the marker symbol and then refer to that 'marker' element using the various marker properties (i.e., 'marker-start', 'marker-end', 'marker-mid' or 'marker') on the given 'path' element or vector graphic shape. Here is an example which draws a triangular marker symbol that is drawn as an arrowhead at the end of a path:

<?xml version="1.0" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG December 1999//EN" 
  "http://www.w3.org/Graphics/SVG/SVG-19991203.dtd">
<svg width="4in" height="4in" 
     viewBox="0 0 4000 4000" >
  <defs>
    <marker id="Triangle"
      viewBox="0 0 10 10" refX="0" refY="5" 
      markerWidth="1.25" markerHeight="1.75"
      orient="auto">
      <path d="M 0 0 L 10 5 L 0 10 z" />
    </marker>
  </defs>
  <desc>Placing an arrowhead at the end of a path.
  </desc>
  <path d="M 1000 1000 L 2000 1000 L 3000 2000"
        style="fill:none; stroke:black; stroke-width:100; 
        marker-end:url(#Triangle)" />
</svg>

Download this example

11.5.2 The 'marker' element

The 'marker' element defines the graphics that is to be used for drawing arrowheads or polymarkers on a given 'path' element or vector graphic shape.
 

<!ENTITY % markerExt "" > <!ELEMENT marker (%descTitleDefs;, (path|text|rect|circle|ellipse|line|polyline|polygon| use|image|svg|g|switch|a %ceExt;%markerExt;)*) > <!ATTLIST marker id ID #IMPLIED xml:lang NMTOKEN #IMPLIED xml:space (default|preserve) #IMPLIED class NMTOKENS #IMPLIED style CDATA #IMPLIED refX CDATA #IMPLIED refY CDATA #IMPLIED viewBox CDATA #IMPLIED preserveAspectRatio CDATA 'xMidYMid meet' markerUnits (stroke-width | userSpace | userSpaceOnUse) "stroke-width" markerWidth CDATA "3" markerHeight CDATA "3" orient CDATA "0" >

Markers are drawn such that their reference point (i.e., attributes ref-x and ref-y) is positioned at the given vertex.

11.5.3 Marker properties

'marker-start' defines the arrowhead or polymarker that shall be drawn at the first vertex of the given 'path' element or vector graphic shape. 'marker-end' defines the arrowhead or polymarker that shall be drawn at the final vertex. 'marker-mid' defines the arrowhead or polymarker that shall be drawn at every other vertex (i.e., every vertex except the first and last).

none

Indicates that no marker symbol shall be drawn at the given vertex (vertices).

<uri>

The <uri> is a URI reference to the ID of a 'marker' element which shall be used as the arrowhead symbol or polymarker at the given vertex (vertices). If the URI reference is not valid (e.g., it points to an object that is undefined or the object is not a 'marker' element), then the marker(s) shall not be drawn.

The 'marker' property specifies the marker symbol that shall be used for all points on the sets the value for all vertices on the given 'path' element or vector graphic shape. It is a short-hand for the three individual marker properties:

11.5.4 Details on how markers are rendered

The following provides details on how markers are rendered:

• Markers are drawn after the given object is filled and stroked.
• Each marker is drawn on the path by first creating a temporary viewport such that the origin of the viewport coordinate system is at the given vertex and the axes are aligned according to the orient attribute on the 'marker' element.
• The width and height of the viewport is established by evaluating the values of <markerUnits>, <markerWidth> and <markerHeight> and calculating temporary values computed-width and computed-height in the user coordinate system of the object referencing the markers. computed-width and computed-height are used to determine the dimensions of the temporary viewport.
• The marker is drawn into the viewport.

For illustrative purposes, we'll repeat the marker example shown earlier:

<?xml version="1.0" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG December 1999//EN" 
  "http://www.w3.org/Graphics/SVG/SVG-19991203.dtd">
<svg width="4in" height="4in" 
     viewBox="0 0 4000 4000" >
  <defs>
    <marker id="Triangle"
      viewBox="0 0 10 10" refX="0" refY="5" 
      markerWidth="1.25" markerHeight="1.75"
      orient="auto">
      <path d="M 0 0 L 10 5 L 0 10 z" />
    </marker>
  </defs>
  <desc>Placing an arrowhead at the end of a path.
  </desc>
  <path d="M 1000 1000 L 2000 1000 L 3000 2000"
        style="fill:none; stroke:black; stroke-width:100; 
        marker-end:url(#Triangle)" />
</svg></svg>

Download this example

The rendering effect of the above file will be visually identical to the following:

<?xml version="1.0" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG December 1999//EN" 
  "http://www.w3.org/Graphics/SVG/SVG-19991203.dtd">
<svg width="4in" height="4in" 
     viewBox="0 0 4000 4000" >
  <defs>
    <!-- Note: to illustrate the effect of "marker",
      replace "marker" with "symbol" and remove the various 
      marker-specific attributes -->
    <symbol id="Triangle"
      viewBox="0 0 10 10" refX="0" refY="5">
      <path d="M 0 0 L 10 5 L 0 10 z" />
    </symbol>
  </defs>
  <desc>File which produces the same effect
      as the marker example file, but without
      using markers.
  </desc>
  <!-- The path draws as before, but without the marker properties -->
  <path d="M 1000 1000 L 2000 1000 L 3000 2000"
        style="fill:none; stroke:black; stroke-width:100" />

  <!-- The following logic simulates drawing a marker 
       at final vertex of the path. -->

  <!-- First off, move the origin of the user coordinate system
       so that the origin is now aligned with the end point of the path. -->
  <g transform="translate(3000 2000)" >

    <!-- Now, rotate the coordinate system 45 degrees because
         the marker specified orient="auto" and the final segment
         of the path is going in the direction of 45 degrees. -->
    <g transform="rotate(45)" >

      <!-- Establish a new viewport with an <svg> element.
           The width/height of the viewport are 1.25 and 1.75 times
           the current stroke-width, respectively. Since the
           current stroke-width is 100, the viewport's width/height
           is 125 by 175. Apply the viewBox attribute
           from the <marker> element onto this <svg> element.
           Transform the marker symbol to align (refX,refY) with
           the origin of the viewport. -->
      <svg width="125" height="175" 
           viewBox="0 0 10 10"
           transform="translate(0,-5)" >

        <!-- Expand out the contents of the <marker> element. -->
        <path d="M 0 0 L 10 5 L 0 10 z" />
      </svg>
    </g>
  </g>
</svg>

Download this example

11.6 Rendering properties

The SVG user agent performs color interpolations and compositing in the following cases:

• when rendering gradients
• when performing color animations (see 'animateColor')
• when performing alpha blending/compositing of graphics elements into the current background
• when performing various filter effects

The 'color-interpolation' property specifies whether color interpolations and compositing shall be performed in the sRGB [SRGB] color space or in a (light energy linear) linearized RGB color space.

The conversion formulas between sRGB color space and linearized RGB color space is can be found in [SRGB]. The following formula shows the conversion from sRGB to linearized RGB:

  R'[sRGB] = R[sRGB] / 255
  G'[sRGB] = G[sRGB] / 255
  B'[sRGB] = B[sRGB] / 255

If R'[sRGB], G'[sRGB], B'[sRGB] <= 0.04045

  R[linearRGB] = R'[sRGB] / 12.92
  G[linearRGB] = G'[sRGB] / 12.92
  B[linearRGB] = B'[sRGB] / 12.92

else if R'[sRGB], G'[sRGB], B'[sRGB] > 0.04045

  R[linearRGB] = ((R'[sRGB] + 0.055) / 1.055) ^ 2.4
  G[linearRGB] = ((G'[sRGB] + 0.055) / 1.055) ^ 2.4
  B[linearRGB] = ((B'[sRGB] + 0.055) / 1.055) ^ 2.4

Out-of-range color values, if supported by the user agent, also are converted using the above formulas. (See Clamping values which are restricted to a particular range.)

auto

Indicates that the user agent can choose either the sRGB or linearRGBspaces for color interpolation. This option indicates that the author doesn't require that color interpolation occur in a particular color space.

sRGB

Indicates that color interpolation should occur in the sRGB color space.

linearRGB

Indicates that color interpolation should occur in the linearized RGB color space as described above.

The creator of SVG content might want to provide a hint to the implementation about how to make speed vs. quality tradeoffs as it performs color interpolation and compositing. The 'color-rendering' property provides a hint to the SVG user agent about how to optimize its color interpolation and compositing operations:

auto

Indicates that the user agent shall make appropriate tradeoffs to balance speed and quality, but quality shall be given more importance than speed.

optimizeSpeed

Indicates that the user agent shall emphasize rendering speed over quality. For RGB display devices, this option will sometimes cause the user agent to perform color interpolation and compositing in the device RGB color space.

optimizeQuality

Indicates that the user agent shall emphasize quality over rendering speed.

The creator of SVG content might want to provide a hint to the implementation about what tradeoffs to make as it renders vector graphics elements such as 'path' elements and basic shapes such as circles and rectangles. The 'shape-rendering' property provides these hints.

auto

Indicates that the user agent shall make appropriate tradeoffs to balance speed, crisp edges and geometric precision, but with geometric precision given more importance than speed and crisp edges.

optimizeSpeed

Indicates that the user agent shall emphasize rendering speed over geometric precision and crisp edges. This option will sometimes cause the user agent to turn off shape anti-aliasing.

crispEdges

Indicates that the user agent shall attempt to emphasize the contrast between clean edges of artwork over rendering speed and geometric precision. To achieve crisp edges, the user agent might turn off anti-aliasing for all lines and curves or possibly just for straight lines which are close to vertical or horizontal. Also, the user agent might adjust line positions and line widths to align edges with device pixels.

geometricPrecision

Indicates that the user agent shall emphasize geometric precision over speed and crisp edges.

The creator of SVG content might want to provide a hint to the implementation about what tradeoffs to make as it renders text. The 'text-rendering' property provides these hints.

auto

Indicates that the user agent shall make appropriate tradeoffs to balance speed, legibility and geometric precision, but with legibility given more importance than speed and geometric precision.

optimizeSpeed

Indicates that the user agent shall emphasize rendering speed over legibility and geometric precision. This option will sometimes cause the user agent to turn off text anti-aliasing.

optimizeLegibility

Indicates that the user agent shall emphasize legibility over rendering speed and geometric precision. The user agent will often choose whether to apply anti-aliasing techniques, built-in font hinting or both to produce the most legible text.

geometricPrecision

Indicates that the user agent shall emphasize geometric precision over legibility and rendering speed. This option will usually cause the user agent to suspend the use of hinting so that glyph outlines are drawn with comparable geometric precision to the rendering of path data.

The creator of SVG content might want to provide a hint to the implementation about how to make speed vs. quality tradeoffs as it performs image processing. The 'image-rendering' property provides a hint to the SVG user agent about how to optimize its image rendering.:

auto

Indicates that the user agent shall make appropriate tradeoffs to balance speed and quality, but quality shall be given more importance than speed.

optimizeSpeed

Indicates that the user agent shall emphasize rendering speed over quality. This option will sometimes cause the user agent to use a bilinear image resampling algorithm.

optimizeQuality

Indicates that the user agent shall emphasize quality over rendering speed. This option will sometimes cause the user agent to use a bicubic image resampling algorithm.

The 'visibility' indicates whether a given object shall be rendered at all.

visible

The current object is drawn.

hidden

The current object is not drawn.

11.7 Inheritance of painting properties

The values of any of the painting properties described in this chapter can be inherited from a given object's parent. Painting, however, is always done on each leaf-node individually, never at the 'g' level. Thus, for the following SVG, two distinct gradients are painted (one for each rectangle):

<?xml version="1.0" standalone="no"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG December 1999//EN" 
  "http://www.w3.org/Graphics/SVG/SVG-19991203.dtd">
<svg width="4in" height="3in">
  <desc>Gradients apply to leaf nodes
  </desc>
  <g>
    <defs>
      <linearGradient id="MyGradient">
        <stop offset="0%" style="color:#F60"/>
        <stop offset="70%" style="color:#FF6"/>
      </linearGradient>
    </defs>
    <g style="fill: url(#MyGradient)">
      <rect width="20" height="15.8"/>
      <rect width="35" height="8"/>
   </g>
  </g>
</svg>

Download this example

11.8 DOM interfaces

11.8.1 Interface SVGICCColor

The SVGICCColor expresses an ICC-based color specification and is a base class for interface SVGColor

interface SVGICCColor  {
  readonly attribute  unsigned long numberOfColorValues;
  float      getColorValue(in unsigned long index);

  void           clear(); // Clear all entries, giving an empty list
  float      insertBefore(in float colorValue,
                                           in unsigned long index)
                                           raises(DOMException);
  float      replace(in float colorValue,
                                      in unsigned long index)
                                      raises(DOMException);
  float      remove(in unsigned long index)
                                     raises(DOMException);
  float      append(in float colorValue)
                                     raises(DOMException);

11.8.2 Interface SVGColor

The SVGColor corresponds to color value definition for the 'stop-color' property and is a base class for interface SVGPaint. It incorporates SVG's extended notion of color, which incorporates ICC-based color specifications.

Interface SVGColor does not correspond to the <color> basic data type. For the <color> basic data type, the applicable DOM interfaces are defined in [DOM2-CSS]; in particular, see the [DOM2-CSS-RGBCOLOR].

interface SVGColor  {
  // Paint Types
  const unsigned short kSVG_COLORTYPE_UNKNOWN           = 0; // invalid, must be retrieved as a string
  const unsigned short kSVG_COLORTYPE_RGBCOLOR          = 1;
  const unsigned short kSVG_COLORTYPE_RGBCOLOR_ICCCOLOR = 2;
  readonly attribute  unsigned short colorType;

  readonly attribute RGBColor rgbColor;
  readonly attribute SVGICCColor iccColor;

  void setRGBColor(in RGBColor rgbColor);
  void setRGBColorICCColor(in RGBColor rgbColor, in SVGICCColor iccColor);

  // Convenience creation routines.
  RGBColor      createRGBColor();      // Returns RGBColor=black
  SVGICCColor   createSVGICCColor();   // Returns empty unattached list

  // If this property currently is being animated, these properties
  // reflect the current animated value.
  // Otherwise, they reflect the static document properties.
  readonly attribute  unsigned short animatedColorType;
  readonly attribute RGBColor animatedRgbColor;
  readonly attribute SVGICCColor animatedIccColor;
}

11.8.3 Interface SVGPaint

The SVGPaint interface corresponds to basic type <paint> and represents the values of properties 'fill' and 'stroke'.

interface SVGPaint : SVGColor  {
  // Paint Types
  // First three match SVGColor's colorTypes.
  const unsigned short kSVG_PAINTTYPE_UNKNOWN    = 0; // invalid, must be retrieved as a string
  const unsigned short kSVG_PAINTTYPE_RGBCOLOR              = 1;
  const unsigned short kSVG_PAINTTYPE_RGBCOLOR_ICCCOLOR     = 2;
  const unsigned short kSVG_PAINTTYPE_NONE                  = 101;
  const unsigned short kSVG_PAINTTYPE_CURRENTCOLOR          = 102;
  const unsigned short kSVG_PAINTTYPE_URI_NONE              = 103;
  const unsigned short kSVG_PAINTTYPE_URI_CURRENTCOLOR      = 104;
  const unsigned short kSVG_PAINTTYPE_URI_RGBCOLOR          = 105;
  const unsigned short kSVG_PAINTTYPE_URI_RGBCOLOR_ICCCOLOR = 106;
  readonly attribute  unsigned short paintType;

  readonly attribute DOMString uri;

  void setUri(in DOMString uri);
  void setPaint(in unsigned short paintType, 
                in DOMString uri, 
                in RGBColor rgbColor, 
                in SVGICCColor iccColor);

  // If this property currently is being animated, these properties
  // reflect the current animated value.
  // Otherwise, they reflect the static document properties.
  readonly attribute  unsigned short animatedPaintType;
  readonly attribute DOMString animatedUri;
};

11.8.4 Interface SVGMarkerElement

The SVGMarkerElement interface corresponds to the 'marker' element.

interface SVGMarkerElement : SVGStyledElement {
  // markerUnit Types
  const unsigned short kSVG_MARKERUNITS_UNKNOWN           = 0;
  const unsigned short kSVG_MARKERUNITS_USERSPACE         = 1;
  const unsigned short kSVG_MARKERUNITS_USERSPACEONUSE    = 2;
  const unsigned short kSVG_MARKERUNITS_STROKEWIDTH       = 3;
  attribute  unsigned short markerUnits;

  attribute SVGLength refX;
  attribute SVGLength refY;
  attribute SVGRect viewBox;
  attribute SVGPreserveAspectRatio preserveAspectRatio;
  attribute SVGLength markerWidth;
  attribute SVGLength markerHeight;

  // orient Types
  const unsigned short kSVG_MARKER_ORIENT_UNKNOWN = 0;
  const unsigned short kSVG_MARKER_ORIENT_AUTO    = 1;
  const unsigned short kSVG_MARKER_ORIENT_ANGLE   = 2;
  readonly attribute SVGAngle orientAngle;

  void setOrientToAuto();
  void setOrientToAngle(SVGAngle angle);
};