SVG contains the following set of basic shape elements:
Mathematically, these shape elements are equivalent to a ‘path’ element that would construct the same shape. The basic shapes may be stroked, filled and used as clip paths. All of the properties available for ‘path’ elements also apply to the basic shapes.
The equivalent path and algorithm to compute the stroke for each shape are defined in the shape sections below.
The ‘rect’ element defines a rectangle which is axis-aligned with the current user coordinate system. Rounded rectangles can be achieved by setting non-zero values for the rx and ry geometric properties.
The x and y coordinates refer to the left and top edges of the rectangle, in the current user coordinate system.
The width and height properties define the overall width and height of the rectangle. A negative value for either property is illegal and must be ignored as a parsing error. A computed value of zero for either dimension disables rendering of the element.
For rounded rectangles,
the computed values of the rx and ry properties define
the x- and y-axis radii of elliptical arcs used to round off the corners of the rectangle.
The arc are always symmetrical along both horizontal and vertical axis; to create a rectangle with uneven corner rounding, define the shape explicitly with a ‘path’.
A negative value for either property is illegal and must be ignored as a parsing error.
A computed value of zero for either dimension,
or a computed value of auto
for both dimensions,
results in a rectangle without corner rounding.
The used values for the x- and y-axis rounded corner radii
may be determined implicitly from the other dimension (using the auto
value),
and are also subject to clamping so that the lengths of
the straight segments of the rectangle are never negative.
The used values for rx and ry are determined
from the computed values by following these steps in order:
auto
(since auto
is the initial value for both properties, this will also occur if neither are specified by the author or if all author-supplied values are invalid),
then the used value of both rx and ry is 0. (This will result in square corners.)auto
,
calculate an absolute length equivalent for rx, resolving percentages against the used width of the rectangle;
the absolute value for ry is the same.auto
,
calculate the absolute length equivalent for ry, resolving percentages against the used height of the rectangle;
the absolute value for rx is the same.Mathematically, a ‘rect’ element is mapped to an equivalent ‘path’ element as follows, after generating absolute used values x, y, width, height, rx, and rx in user units for the user coordinate system, for each of the equivalent geometric properties following the rules specified above and in Units:
Path decomposition resolved during teleconference on June 3rd, 2013.
Example rect01 shows a rectangle with sharp corners. The ‘rect’ element is filled with yellow and stroked with navy.
<?xml version="1.0" standalone="no"?> <svg width="12cm" height="4cm" viewBox="0 0 1200 400" xmlns="http://www.w3.org/2000/svg" version="1.1"> <desc>Example rect01 - rectangle with sharp corners</desc> <!-- Show outline of viewport using 'rect' element --> <rect x="1" y="1" width="1198" height="398" fill="none" stroke="blue" stroke-width="2"/> <rect x="400" y="100" width="400" height="200" fill="yellow" stroke="navy" stroke-width="10" /> </svg>
Example rect01
Example rect02 shows two rounded rectangles. The rx specifies how to round the corners of the rectangles. Note that since no value has been specified for the ry attribute, the used value will be derived from the rx attribute.
<?xml version="1.0" standalone="no"?> <svg width="12cm" height="4cm" viewBox="0 0 1200 400" xmlns="http://www.w3.org/2000/svg" version="1.1"> <desc>Example rect02 - rounded rectangles</desc> <!-- Show outline of viewport using 'rect' element --> <rect x="1" y="1" width="1198" height="398" fill="none" stroke="blue" stroke-width="2"/> <rect x="100" y="100" width="400" height="200" rx="50" fill="green" /> <g transform="translate(700 210) rotate(-30)"> <rect x="0" y="0" width="400" height="200" rx="50" fill="none" stroke="purple" stroke-width="30" /> </g> </svg>
Example rect02
The ‘circle’ element defines a circle based on a center point and a radius.
The cx and cy attributes define the coordinates of the center of the circle.
The r attribute defines the radius of the circle. A negative value for either property is illegal and must be ignored as a parsing error.
Mathematically, a ‘circle’ element is mapped to an equivalent ‘path’ element that consists of four elliptical arc segments, each covering a quarter of the circle. The path begins at the "3 o'clock" point on the radius and proceeds in a clock-wise direction (before any transformations). The rx and ry parameters to the arc commands are both equal to the used value of the r property, after conversion to local user units, while the x-axis-rotation, the large-arc-flag, and the sweep-flag are all set to zero. The coordinates are computed as follows, where cx, cy, and r are the used values of the equivalent properties, converted to user units:
Path decomposition resolved during teleconference on June 3rd, 2013.
Example circle01 consists of a ‘circle’ element that is filled with red and stroked with blue.
<?xml version="1.0" standalone="no"?> <svg width="12cm" height="4cm" viewBox="0 0 1200 400" xmlns="http://www.w3.org/2000/svg" version="1.1"> <desc>Example circle01 - circle filled with red and stroked with blue</desc> <!-- Show outline of viewport using 'rect' element --> <rect x="1" y="1" width="1198" height="398" fill="none" stroke="blue" stroke-width="2"/> <circle cx="600" cy="200" r="100" fill="red" stroke="blue" stroke-width="10" /> </svg>
Example circle01
The ‘ellipse’ element defines an ellipse which is axis-aligned with the current user coordinate system based on a center point and two radii.
The cx and cy coordinates define the center of the ellipse.
The rx and ry properties define the x- and y-axis radii of the
ellipse.
A negative value for either property is illegal and must be ignored as a parsing error.
A computed value of zero for either dimension,
or a computed value of auto
for both dimensions,
disables rendering of the element.
An auto
value for either rx or ry
is converted to a used value, following the rules given above for rectangles
(but without any clamping based on width or height).
Effectively, an auto
value creates a circular shape
whose radius is defined by a value expressed solely in one dimension;
this allows for creating a circle with a radius defined in terms of one of the following:
auto
value for ry.auto
value for rx and a percentage value for ry.
New in SVG 2.
The auto
value for rx and ry was added to allow consistent
parsing of these properties for both ellipses and rectangles.
Previously, if either rx or ry was unspecified,
the ellipse would not render.
Mathematically, an ‘ellipse’ element is mapped to an equivalent ‘path’ element that consists of four elliptical arc segments, each covering a quarter of the ellipse. The path begins at the "3 o'clock" point on the radius and proceeds in a clock-wise direction (before any transformation). The rx and ry parameters to the arc commands are the used values of the equivalent properties after conversion to local user units, while the x-axis-rotation, the large-arc-flag, and the sweep-flag are all set to zero. The coordinates are computed as follows, where cx, cy, rx, and ry are the used values of the equivalent properties, converted to user units:
Path decomposition resolved during teleconference on June 3rd, 2013.
Example ellipse01 below specifies the coordinates of the two ellipses in the user coordinate system established by the ‘viewBox’ attribute on the ‘svg’ element and the transform property on the ‘g’ and ‘ellipse’ elements. Both ellipses use the default values of zero for the cx and cy attributes (the center of the ellipse). The second ellipse is rotated.
<?xml version="1.0" standalone="no"?> <svg width="12cm" height="4cm" viewBox="0 0 1200 400" xmlns="http://www.w3.org/2000/svg" version="1.1"> <desc>Example ellipse01 - examples of ellipses</desc> <!-- Show outline of viewport using 'rect' element --> <rect x="1" y="1" width="1198" height="398" fill="none" stroke="blue" stroke-width="2" /> <g transform="translate(300 200)"> <ellipse rx="250" ry="100" fill="red" /> </g> <ellipse transform="translate(900 200) rotate(-30)" rx="250" ry="100" fill="none" stroke="blue" stroke-width="20" /> </svg>
Example ellipse01
The ‘line’ element defines a line segment that starts at one point and ends at another.
Attribute definitions:
Name | Value | Initial value | Animatable |
---|---|---|---|
x1, y1 | <length-percentage> | <number> | 0 | yes |
Name | Value | Initial value | Animatable |
---|---|---|---|
x2, y2 | <length-percentage> | <number> | 0 | yes |
A future specification may convert the ‘x1’, ‘y1’, ‘x2’, and ‘y2’ attributes to geometric properties. Currently, they can only be specified via element attributes, and not CSS.
Mathematically, a ‘line’ element can be mapped to an equivalent ‘path’ element as follows, after converting coordinates into user coordinate system user units according to Units to generate values x1, y1, x2, and y2:
Because ‘line’ elements are single lines and thus are geometrically one-dimensional, they have no interior; thus, ‘line’ elements are never filled (see the fill property).
Example line01 below specifies the coordinates of the five lines in the user coordinate system established by the ‘viewBox’ attribute on the ‘svg’ element. The lines have different thicknesses.
<?xml version="1.0" standalone="no"?> <svg width="12cm" height="4cm" viewBox="0 0 1200 400" xmlns="http://www.w3.org/2000/svg" version="1.1"> <desc>Example line01 - lines expressed in user coordinates</desc> <!-- Show outline of viewport using 'rect' element --> <rect x="1" y="1" width="1198" height="398" fill="none" stroke="blue" stroke-width="2" /> <g stroke="green" > <line x1="100" y1="300" x2="300" y2="100" stroke-width="5" /> <line x1="300" y1="300" x2="500" y2="100" stroke-width="10" /> <line x1="500" y1="300" x2="700" y2="100" stroke-width="15" /> <line x1="700" y1="300" x2="900" y2="100" stroke-width="20" /> <line x1="900" y1="300" x2="1100" y2="100" stroke-width="25" /> </g> </svg>
Example line01
The ‘polyline’ element defines a set of connected straight line segments. Typically, ‘polyline’ elements define open shapes.
Attribute definitions:
Name | Value | Initial value | Animatable |
---|---|---|---|
points | <points> | (none) | yes |
where:
The points that make up the polyline. All coordinate values are in the user coordinate system.
If an odd number of coordinates is provided, then the element is in error, with the same user agent behavior as occurs with an incorrectly specified ‘path’ element. In such error cases the user agent will drop the last, odd coordinate and otherwise render the shape.
The initial value, (none), indicates that the polyline element is valid but does not render.
A future specification may convert the ‘points’ attribute to a geometric property. Currently, it can only be specified via an element attribute, and not CSS.
Mathematically, a ‘polyline’ element can be mapped to an equivalent ‘path’ element as follows:
Example polyline01 below specifies a polyline in the user coordinate system established by the ‘viewBox’ attribute on the ‘svg’ element.
<?xml version="1.0" standalone="no"?> <svg width="12cm" height="4cm" viewBox="0 0 1200 400" xmlns="http://www.w3.org/2000/svg" version="1.1"> <desc>Example polyline01 - increasingly larger bars</desc> <!-- Show outline of viewport using 'rect' element --> <rect x="1" y="1" width="1198" height="398" fill="none" stroke="blue" stroke-width="2" /> <polyline fill="none" stroke="blue" stroke-width="10" points="50,375 150,375 150,325 250,325 250,375 350,375 350,250 450,250 450,375 550,375 550,175 650,175 650,375 750,375 750,100 850,100 850,375 950,375 950,25 1050,25 1050,375 1150,375" /> </svg>
Example polyline01
The ‘polygon’ element defines a closed shape consisting of a set of connected straight line segments.
Attribute definitions:
Name | Value | Initial value | Animatable |
---|---|---|---|
points | <points> | (none) | yes |
The points that make up the polygon. All coordinate values are in the user coordinate system.
If an odd number of coordinates is provided, then the element is in error, with the same user agent behavior as occurs with an incorrectly specified ‘path’ element.
The initial value, (none), indicates that the polygon element is valid, but does not render.
A future specification may convert the ‘points’ attribute to a geometric property. Currently, it can only be specified via an element attribute, and not CSS.
Mathematically, a ‘polygon’ element can be mapped to an equivalent ‘path’ element as follows:
Example polygon01 below specifies two polygons (a star and a hexagon) in the user coordinate system established by the ‘viewBox’ attribute on the ‘svg’ element.
<?xml version="1.0" standalone="no"?> <svg width="12cm" height="4cm" viewBox="0 0 1200 400" xmlns="http://www.w3.org/2000/svg" version="1.1"> <desc>Example polygon01 - star and hexagon</desc> <!-- Show outline of viewport using 'rect' element --> <rect x="1" y="1" width="1198" height="398" fill="none" stroke="blue" stroke-width="2" /> <polygon fill="red" stroke="blue" stroke-width="10" points="350,75 379,161 469,161 397,215 423,301 350,250 277,301 303,215 231,161 321,161" /> <polygon fill="lime" stroke="blue" stroke-width="10" points="850,75 958,137.5 958,262.5 850,325 742,262.6 742,137.5" /> </svg>
Example polygon01
An SVGRectElement object represents a ‘rect’ element in the DOM.
[Exposed=Window] interface SVGRectElement : SVGGeometryElement { [SameObject] readonly attribute SVGAnimatedLength x; [SameObject] readonly attribute SVGAnimatedLength y; [SameObject] readonly attribute SVGAnimatedLength width; [SameObject] readonly attribute SVGAnimatedLength height; [SameObject] readonly attribute SVGAnimatedLength rx; [SameObject] readonly attribute SVGAnimatedLength ry; };
The x, y, width, height, rx and ry IDL attributes reflect the computed values of the x, y, width, height, rx and ry properties and their corresponding presentation attributes, respectively.
An SVGCircleElement object represents a ‘circle’ element in the DOM.
[Exposed=Window] interface SVGCircleElement : SVGGeometryElement { [SameObject] readonly attribute SVGAnimatedLength cx; [SameObject] readonly attribute SVGAnimatedLength cy; [SameObject] readonly attribute SVGAnimatedLength r; };
The cx, cy and r IDL attributes reflect the computed values of the cx, cy and y properties and their corresponding presentation attributes, respectively.
An SVGEllipseElement object represents a ‘ellipse’ element in the DOM.
[Exposed=Window] interface SVGEllipseElement : SVGGeometryElement { [SameObject] readonly attribute SVGAnimatedLength cx; [SameObject] readonly attribute SVGAnimatedLength cy; [SameObject] readonly attribute SVGAnimatedLength rx; [SameObject] readonly attribute SVGAnimatedLength ry; };
The cx, cy, rx and ry IDL attributes reflect the computed values of the cx, cy, rx and ry properties and their corresponding presentation attributes, respectively.
[Exposed=Window] interface SVGLineElement : SVGGeometryElement { [SameObject] readonly attribute SVGAnimatedLength x1; [SameObject] readonly attribute SVGAnimatedLength y1; [SameObject] readonly attribute SVGAnimatedLength x2; [SameObject] readonly attribute SVGAnimatedLength y2; };
The x1, y1, x2 and y2 IDL attributes reflect the ‘x1’, ‘y1’, ‘x2’ and ‘y2’ content attributes, respectively
The SVGAnimatedPoints interface is used to reflect a ‘points’ attribute on a ‘polygon’ or ‘polyline’ element. It is mixed in to the SVGPolygonElement and SVGPolylineElement interfaces.
Note: In SVG 1.1 SE, the animatedPoints attribute represented the current animated value. In this version of SVG, it is simply an alias for points.
interface mixin SVGAnimatedPoints { [SameObject] readonly attribute SVGPointList points; [SameObject] readonly attribute SVGPointList animatedPoints; };
The points and animatedPoints IDL attributes represent the current non-animated value of the reflected attribute. On getting points or animatedPoints, an SVGPointList object is returned that reflects the base value of the reflected attribute.
The SVGPointList interface is a list interface whose elements are DOMPoint objects. An SVGPointList object represents a list of points.
[Exposed=Window] interface SVGPointList { readonly attribute unsigned long length; readonly attribute unsigned long numberOfItems; void clear(); DOMPoint initialize(DOMPoint newItem); getter DOMPoint getItem(unsigned long index); DOMPoint insertItemBefore(DOMPoint newItem, unsigned long index); DOMPoint replaceItem(DOMPoint newItem, unsigned long index); DOMPoint removeItem(unsigned long index); DOMPoint appendItem(DOMPoint newItem); setter void (unsigned long index, DOMPoint newItem); };
The behavior of all of the interface members of SVGPointList are defined in List interfaces.
This specification imposes additional requirements on the behaviour of DOMPoint objects beyond those described in the Geometry Interfaces specification, so that they can be used to reflect ‘points’ attributes.
Every DOMPoint object operates in one of three modes. It can:
A DOMPoint object can be associated with a particular element. The associated element is used to determine which element's content attribute to update if the object reflects an attribute. Unless otherwise described, a DOMPoint object is not associated with any element.
A DOMPoint object can be designated as read only, which means that attempts to modify the object will result in an exception being thrown. When assigning to a read only DOMPoint's x, y, w or z IDL attribute, a NoModificationAllowedError must be thrown instead of updating the internal coordinate value.
Note that this applies only to the read-write DOMPoint interface; the DOMPointReadOnly interface, which is not used for reflecting the ‘points’ attribute, will already throw an exception if an attempt is made to modify it.
When assigning to a writable DOMPoint's x, y, w or z IDL attribute, the following steps are run after updating the internal coordinate value:
An SVGPolylineElement object represents a ‘polyline’ element in the DOM.
[Exposed=Window] interface SVGPolylineElement : SVGGeometryElement { }; SVGPolylineElement includes SVGAnimatedPoints;
An SVGPolygonElement object represents a ‘polygon’ element in the DOM.
[Exposed=Window] interface SVGPolygonElement : SVGGeometryElement { }; SVGPolygonElement includes SVGAnimatedPoints;