SVG 2 – 11 February 2014 TopContentsPreviousNextElementsAttributesProperties

# Chapter 14: Paint Servers: Solid Colors, Gradients, Patterns, and Hatches

## 14.1. Introduction

This section covers Paint Servers, a method which allows the ‘fill’ or ‘stroke’ of an object to be defined by a resource found elsewhere. It allows resources to be reused throughout a document. See the section Painting: Filling and Stroking for a general discussion of filling and stroking objects.

SVG defines several types of paint servers:

SVG1.1 refers to "built-in" paint servers. Is there any other kind?

SVG 2 Requirement: Arbitrary fills for shapes. SVG 2 shall support filling and stroking from arbitrary elements. To allow for example videos or images to be used as a fill source. Alex? (no action)

Paint servers are used by including an IRI reference in a ‘fill’ or ‘stroke’ property (i.e. fill="url(#MyLightPurple)").

Properties inherit into a paintserver element from its ancestors; properties do not inherit from the element referencing the paintserver element.

Paintserver elements are never rendered directly (with the exception of which may be rendered in a non-paintserver mode); their only usage is as something that can be referenced using the ‘fill’ and ‘stroke’ properties. The ‘display’ property does not apply to a paintserver element; thus, paintserver elements are not directly rendered even if the ‘display’ property is set to a value other than none, and paintserver elements are available for referencing even when the ‘display’ property on the paintserver element or any of its ancestors is set to none.

## 14.2. Solid colors

Solid Colors are new in SVG 2 (ported from SVG 1.2 Tiny).

SVG 2 Requirement: Support named colors. Will add ‘solidColor’ element to SVG 2. To provide an easy mechanism for creating named colors and palettes. Also useful for animation. Tav (no action)

The 'solidColor' element is a paint server that provides a single color with opacity. It can be referenced any place a single color can be used. The 'solidColor' element allows a palette to be defined and used consistently throughout a document. It is also useful as away of animating a palette colors. (See the chapter Color for a more general discussion of color in SVG.)

Solid colors are defined by a element.

solidColor
Categories:
Paint server element
Content model:
Any number of the following elements, in any order:
animate, script, set
Attributes:
DOM Interfaces:

### 14.2.1. Properties

solid-color

The ‘solid-color’ property specifies the color of the . The keyword currentColor and ICC colors can be specified in the same manner as within a <paint> specification for the ‘fill’ and ‘stroke’ properties.

Value
currentColor | <color> <icccolor>
Initial
black
Applies to
solid-color’ elements
Inherited
no
Percentages
N/A
Media
visual
Animatable
yes
solid-opacity

The ‘solid-opacity’ property defines the opacity of the .

Value
<opacity-value>
Initial
1
Applies to
solid-color’ elements
Inherited
no
Percentages
N/A
Media
visual
Animatable
yes
<opacity-value>
The opacity of the 'solidColor'. Any values outside the range 0.0 (fully transparent) to 1.0 (fully opaque) must be clamped to this range. The value of 'solid-opacity' is independent of the opacity used to render the paint via ‘fill’ or ‘stroke’.
<?xml version="1.0" standalone="no"?>
<svg xmlns="http://www.w3.org/2000/svg"
version="2.0"
viewBox="0 0 300 100" >

<title>Example solidColor</title>
<desc>Fill objects using a solidColor paint server.</desc>

<defs>
<solidColor id="MyLightPurple" solid-color="#a080ff" solid-opacity="0.5"/>
</defs>

<!-- The shapes are filled using a solidColor paint server -->
<circle fill="url(#MyLightPurple)" cx="50" cy="50" r="40"/>
<rect   fill="url(#MyLightPurple)" x="110" y="10" width="80" height="80"/>
<path   fill="url(#MyLightPurple)" d="m 250 10 l 40 80 -80 0 z"/>
</svg>

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

Gradients consist of smooth color transitions between points on a drawing surface. SVG provides for three types of gradients:

Once a gradient is defined, a graphics element can be filled or stroked with the gradient by setting the ‘fill’ or ‘stroke’ properties to reference the gradient.

Color transitions for linear and radial gradients are defined by a series of color stops along a gradient vector. A gradient normal defines how the colors in a vector are painted to the surface. For a linear gradient, the normal corresponds to lines with the same color. It is perpendicular to the vector in an untransformed gradient. When a graphics element references a gradient, conceptually the graphics element should take a copy of the gradient vector and gradient normal and treat it as part of its own geometry. Any transformations applied to the graphics element geometry also apply to the copied gradient vector and gradient normal. Any gradient transforms that are specified on the reference gradient are applied before any graphics element transformations are applied to the gradient.

Would it be better to just refer to the normal as the line where color is constant. In this case, it would be a circle for an untransformed radial gradient.

Alternative figure:

Color transitions for mesh gradients are defined by an array of color stops. The mapping of colors to the drawing surface in this case is done by geometric data located in the stops. This is discussed in detail in the mesh gradients section.

Linear gradients are defined by a element.

Categories:
Content model:
Any number of the following elements, in any order:
animate, animateTransform, script, set, stop
Attributes:
DOM Interfaces:

#### 14.3.1.1. Attributes

Defines the coordinate system for attributes x1, y1, x2 and y2.

Value
userSpaceOnUse | objectBoundingBox
lacuna value
objectBoundingBox
Animatable
yes
userSpaceOnUse

If gradientUnits="userSpaceOnUse", x1, y1, x2, and y2 represent values in the coordinate system that results from taking the current user coordinate system in place at the time when the gradient element is referenced (i.e., the user coordinate system for the element referencing the gradient element via a ‘fill’ or ‘stroke’ property) and then applying the transform specified by attribute . Percentages represent values relative to the current viewport.

objectBoundingBox

If gradientUnits="objectBoundingBox", the user coordinate system for attributes x1, y1, x2 and y2 is established using the bounding box of the element to which the gradient is applied (see Object bounding box units) and then applying the transform specified by attribute . Percentages represent values relative to the bounding box for the object.

When gradientUnits="objectBoundingBox" and is the identity matrix, the normal of the linear gradient is perpendicular to the gradient vector in object bounding box space (i.e., the abstract coordinate system where (0,0) is at the top/left of the object bounding box and (1,1) is at the bottom/right of the object bounding box). When the object's bounding box is not square, the gradient normal which is initially perpendicular to the gradient vector within object bounding box space may render non-perpendicular relative to the gradient vector in user space. If the gradient vector is parallel to one of the axes of the bounding box, the gradient normal will remain perpendicular. This transformation is due to application of the non-uniform scaling transformation from bounding box space to user space.

Contains the definition of an optional additional transformation from the gradient coordinate system onto the target coordinate system (i.e., 'userSpaceOnUse' or 'objectBoundingBox'). This allows for things such as skewing the gradient. This additional transformation matrix is post-multiplied to (i.e., inserted to the right of) any previously defined transformations, including the implicit transformation necessary to convert from object bounding box units to user space.

Value
<transform-list>
lacuna value
identity transform
Animatable
yes
x1

x1, y1, x2 and y2 define a gradient vector for the linear gradient. This gradient vector provides starting and ending points onto which the gradient stops are mapped. The values of x1, y1, x2 and y2 can be either numbers or percentages.

Value
<length>
lacuna value
0%
Animatable
yes
y1

See x1.

Value
<length>
lacuna value
0%
Animatable
yes
x2

See x1.

Value
<length>
lacuna value
100%
Animatable
yes
y2

See x1.

Value
<length>
lacuna value
100%
Animatable
yes

SVG 1.1 2nd edition has lacuna value="0%".

Indicates what happens if the gradient starts or ends inside the bounds of the target rectangle.

Value
lacuna value
Animatable
yes
Use the terminal colors of the gradient to fill the remainder of the target region.
reflect
Reflect the gradient pattern start-to-end, end-to-start, start-to-end, etc. continuously until the target rectangle is filled.
repeat
Repeat the gradient pattern start-to-end, start-to-end, start-to-end, etc. continuously until the target region is filled.

An IRI reference to a different or element within the current SVG document fragment. Any attributes which are defined on the referenced element which are not defined on this element are inherited by this element. If this element has no defined gradient stops, and the referenced element does (possibly due to its own attribute), then this element inherits the gradient stop from the referenced element. Inheritance can be indirect to an arbitrary level; thus, if the referenced element inherits attribute or gradient stops due to its own attribute, then the current element can inherit those attributes or gradient stops.

Value
<iri>
lacuna value
empty
Animatable
yes

#### 14.3.1.2. Notes on linear gradients

If x1 = x2 and y1 = y2, then the area to be painted will be painted as a single color using the color and opacity of the last gradient stop.

Example lingrad01 shows how to fill a rectangle by referencing a linear gradient paint server.

<?xml version="1.0" standalone="no"?>
<svg xmlns="http://www.w3.org/2000/svg"
version="1.1"
viewBox="0 0 300 200" >

<title>Example lingrag01</title>
<desc>Fill a rectangle using a linear-gradient paint server.</desc>

<defs>
<stop offset="5%" stop-color="#A8F" />
<stop offset="95%" stop-color="#FDC" />
</defs>

<!-- The rectangle is filled using a linear-gradient paint server -->
stroke="black"
stroke-width="2"
x="25" y="25" width="250" height="150"/>
</svg>

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

Categories:
Content model:
Any number of the following elements, in any order:
animate, animateTransform, script, set, stop
Attributes:
DOM Interfaces:

#### 14.3.2.1. Attributes

Defines the coordinate system for attributes cx, cy, r, fx, fy, and fr.

lacuna value
objectBoundingBox
Animatable
yes
userSpaceOnUse

If gradientUnits="userSpaceOnUse", cx, cy, r, fx, fy, and fr represent values in the coordinate system that results from taking the current user coordinate system in place at the time when the gradient element is referenced (i.e., the user coordinate system for the element referencing the gradient element via a ‘fill’ or ‘stroke’ property) and then applying the transform specified by attribute . Percentages represent values relative to the current viewport.

objectBoundingBox

If gradientUnits="objectBoundingBox", the user coordinate system for attributes cx, cy, r, fx, fr, and fr is established using the bounding box of the element to which the gradient is applied (see Object bounding box units) and then applying the transform specified by attribute . Percentages represent values relative to the bounding box for the object.

When gradientUnits="objectBoundingBox" and is the identity matrix, then the rings of the radial gradient are circular with respect to the object bounding box space (i.e., the abstract coordinate system where (0,0) is at the top/left of the object bounding box and (1,1) is at the bottom/right of the object bounding box). When the object's bounding box is not square, the rings that are conceptually circular within object bounding box space will render as elliptical due to application of the non-uniform scaling transformation from bounding box space to user space.

Contains the definition of an optional additional transformation from the gradient coordinate system onto the target coordinate system (i.e., 'userSpaceOnUse' or 'objectBoundingBox'). This allows for things such as skewing the gradient. This additional transformation matrix is post-multiplied to (i.e., inserted to the right of) any previously defined transformations, including the implicit transformation necessary to convert from object bounding box units to user space.

lacuna value
identity transform
Animatable
yes
cx = "<length>"

cx, cy and r define the end circle for the radial gradient. The gradient will be drawn such that the 100% gradient stop is mapped to the perimeter of this end circle.

lacuna value
50%
Animatable
yes
cy = "<length>"

See cx.

lacuna value
50%
Animatable
yes
r = "<length>"

See cx.

A negative value is an error (see Error processing).

lacuna value
50%
Animatable
yes
fx = "<length>"

fx, fy, and fr define the start circle for the radial gradient. The gradient will be drawn such that the 0% gradient stop is mapped to the perimeter of this start circle.

lacuna value
see below
Animatable
yes

If attribute fx is not specified, fx will coincide with the presentational value of cx for the element whether the value for 'cx' was inherited or not. If the element references an element that specifies a value for 'fx', then the value of 'fx' is inherited from the referenced element.

fy = "<length>"

See fx.

lacuna value
see below
Animatable
yes

If attribute fy is not specified, fy will coincide with the presentational value of cy for the element whether the value for 'cy' was inherited or not. If the element references an element that specifies a value for 'fy', then the value of 'fy' is inherited from the referenced element.

fr = "<length>"

New in SVG 2. Added to align with Canvas.

fr is the radius of the focal circle. See fx.

A negative value is an error (see Error processing).

lacuna value
0%, see below
Animatable
yes

If the attribute is not specified, the effect is as if a value of '0%' were specified. If the element references an element that specifies a value for 'fr', then the value of 'fr' is inherited from the referenced element.

SVG 2 Requirement: Allow specifying focal circle radius in radial gradients. Add an ‘fr’ attribute to ‘radialGradient’> for SVG 2. To align with Canvas. The zero-offset stop would be along the circle defined by the ‘fx’, ‘fy’ and ‘fr’ attributes. Erik (ACTION-3098)

Indicates what happens if the gradient starts or ends inside the bounds of the object(s) being painted by the gradient. Has the same values and meanings as the attribute on element.

lacuna value
Animatable
yes

An IRI reference to a different or element within the current SVG document fragment. Any attributes which are defined on the referenced element which are not defined on this element are inherited by this element. If this element has no defined gradient stops, and the referenced element does (possibly due to its own attribute), then this element inherits the gradient stop from the referenced element. Inheritance can be indirect to an arbitrary level; thus, if the referenced element inherits attribute or gradient stops due to its own attribute, then the current element can inherit those attributes or gradient stops.

lacuna value
empty
Animatable
yes
SVG 2 Requirement: Clarify radial gradients with focal point on the circle. When the focal point is on the circle edge, with repeat, then the distance between the first and last stop for the repeating colors is 0 and the paint should generate a color that is the average of all the gradient stops. To improve interoperability of radial gradients. Erik (ACTION-3097) SVG 1.1 does not define what to do when the focal point is on the circle edge, with 'repeat'. The distance between the first and last stop for the repeating colors is 0. It was resolved that the paint should generate a color that is the weighted average (by offset) of all the gradient stops.

Changed in SVG 2. SVG 1.1 required that the focal point, if outside the end circle, be moved to be on the end circle. The change was made to align with Canvas.

Allowing the focal point to lie outside the end circle was resolved at the Rigi Kaltbad working group meeting.

If the start circle defined by fx, fy and fr lies outside the end circle defined by cx, cy, and r, effectively a cone is created, touched by the two circles. Areas outside the cone stay untouched by the gradient (transparent black).

If the start circle fully overlaps with the end circle, no gradient is drawn. The area stays untouched (transparent black).

The treatment of the area to the right of the gradient in the right-hand side of the above figure is different from that of Canvas where the area would be transparent black. The difference is to maintain compatibility with SVG 1.1.

The color space for the weighted average is the same as in which the gradient is interpolated. See Rigi Kaltbad working group meeting.

<?xml version="1.0" standalone="no"?>
<svg xmlns="http://www.w3.org/2000/svg"
version="1.1"
viewBox="0 0 300 200" >

<defs>
cx="150" cy="100"
r="100">
<stop offset="0%"   stop-color="#A8F" />
<stop offset="50%"  stop-color="#FDC" />
<stop offset="100%" stop-color="#A8F" />
</defs>

<!-- The rectangle is filled using a radial gradient paint server -->
stroke="black"
stroke-width="2"
x="25" y="25" width="250" height="150"/>
</svg>

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

New in SVG 2. Added to allow shadings along curved lines. This is needed, for example, in creating life-like drawings.

The mesh gradients in SVG are based on an array of Coons Patches. A Coons Patch is a shading defined by colors place at the corners of an area enclosed by four Bézier curves.

A Coons Patch is equivalent to a bi-cubic Ferguson patch where the distance between a cubic Bézier end point and its nearest control point is one-third the length of the corresponding Ferguson tangent line.

The corner colors are mapped to the patch area with a two step process. First the colors are placed at the corners of a unit square the area inside the square is colored using a bilinear interpolation. Second, the points inside the square are mapped to points inside the patch using the following formula (u, and v are the coordinates inside the unit square):

S = SC + SD − SB, where
SC(u,v) = (1−v)×C1(u) + v×C2(u),
SD(u,v) = (1−u)×D1(v) + u×D2(v), and
SB(u,v) = (1−v)×[(1-u)×C1(0) + u×C1(1)]
+  v×[(1−u)×C2(0) + u×C2(1)].


Finish converting to MATHML.

$S={S}_{C}+{S}_{D}-{S}_{B}$
S = S_C + S_D - S_B_

Come up with better explanation of the mapping with diagram. The subtraction term in the above formula ensures that the boundary conditions are met.

One method of rendering a patch is to "divide and conquer." Check if the four corner colors of the patch are the same within a specified tolerance. If so, paint the patch with the average color using the normal path filling routine. If not, divide the patch into four smaller patches and repeat the color tolerance check. Repeat the process as many times as necessary.

Another way to render a patch is to first divide the patch vertically or horizontally into a series of smaller patches that are each less than one pixel high or wide. Then each resulting patch can be rendered as a path.

For a mesh, the individual patches are placed in an array. There are two reasons for using an array. The first is that an array of meshes is a natural result for most content creation processes (start with a path and then subdivide its area into rows and columns of patches). The second is that the data can be compacted by sharing sides and corners. The array structure is conceptual only. The actual mesh can be distorted in any way possible. The mesh gradient syntax is designed so that it is easy to simulate other types of gradients such as conical gradients or triangle meshes as shown in the examples below.

The structure of a mesh gradient is as follows:

<meshGradient x="100" y="100">
<meshRow>
<meshPatch>
<stop .../>
Up to four stops in first patch. See details below.
</meshPatch>
<meshPatch>
Any number of meshPatches in row.
</meshPatch>
</meshRow>
<meshRow>
Any number of meshRows, each with the same number of meshPatches as in the first row.
</meshRow>

SVG 2 Requirement: Support photorealistic gradients. Mesh gradients are accepted by the WG for SVG 2. To allow more complex gradients such as those found in nature. Tav (ACTION-3121)

Resolution: Rename stop-path to 'd' or 'path' (Coons patch syntax).

Seattle 2011 F2F day 3

Resolution: We will allow just C/c/L/l in mesh path data. We will leave out tensor control points. We will not allow multiple colors at mesh intersections, just use zero size patches instead.

Boston 2011 F2F

Mesh gradients are defined by a element.

Categories:
Content model:
Any number of the following elements, in any order:
animate, animateTransform, meshRow, script, set
Attributes:
DOM Interfaces:

Mesh rows are defined by a meshRow element.

meshRow
Categories:
None
Content model:
Any number of the following elements, in any order:
meshPatch, script
Attributes:
DOM Interfaces:

Mesh patches are defined by a element.

meshPatch
Categories:
None
Content model:
Any number of descriptive elements, script and from one to four stop elements, in any order.
Attributes:
DOM Interfaces:

The vector (linear and radial gradients) or array (mesh gradients) of colors to use in a gradient is defined by the stop elements that are child elements to a , , or element.

In SVG 1.1, the above read: "The ramp of colors..." but "ramp" is used nowhere else in this section.

stop
Categories:
None
Content model:
Any number of the following elements, in any order:
animate, script, set
Attributes:
DOM Interfaces:

#### 14.3.4.1. Attributes

offset

Indicates were the gradient stop is placed. For linear gradients, the offset attribute represents a location along the gradient vector. For radial gradients, it represents a fractional distance from the edge of the innermost/smallest circle to the edge of the outermost/largest circle. This attribute does not apply to mesh gradients.

Value
<number> | <percentage>
lacuna value
see notes below
Animatable
yes
<number>
A number usually ranging from 0 to 1.
<percentage>
A percentage usually ranging from 0% to 100%.
path

Gives the path for one side of a mesh gradient patch. This attribute applies only to mesh gradients.

Value
mesh path data
lacuna value
see notes below
Animatable
yes

A description of mesh path data.

#### 14.3.4.2. Properties

stop-color

The ‘stop-color’ property indicates what color to use at that gradient stop. The keyword currentColor and ICC colors can be specified in the same manner as within a <paint> specification for the ‘fill’ and ‘stroke’ properties.

Value
currentColor | <color> <icccolor>
Initial
black
Applies to
stop elements
Inherited
no
Percentages
N/A
Media
visual
Animatable
yes
stop-opacity

The ‘stop-opacity’ property defines the opacity of a given gradient stop.

Value
<opacity-value>
Initial
1
Applies to
stop elements
Inherited
no
Percentages
N/A
Media
visual
Animatable
yes
<opacity-value>
The opacity of the 'stopColor'. Any values outside the range 0.0 (fully transparent) to 1.0 (fully opaque) must be clamped to this range. The value of 'stop-opacity' is independent of the opacity used to render the paint via ‘fill’ or ‘stroke’.

#### 14.3.4.3. Notes on gradient stops

• Gradient offset values less than 0 (or less than 0%) are rounded up to 0%. Gradient offset values greater than 1 (or greater than 100%) are rounded down to 100%.
• It is necessary that at least two stops defined to have a gradient effect. If no stops are defined, then painting shall occur as if 'none' were specified as the paint style. If one stop is defined, then paint with the solid color fill using the color defined for that gradient stop.
• Each gradient offset value is required to be equal to or greater than the previous gradient stop's offset value. If a given gradient stop's offset value is not equal to or greater than all previous offset values, then the offset value is adjusted to be equal to the largest of all previous offset values.
• If two gradient stops have the same offset value, then the latter gradient stop controls the color value at the overlap point. In particular:

<stop offset="0" stop-color="white"/>
<stop offset=".2" stop-color="red"/>
<stop offset=".2" stop-color="blue"/>
<stop offset="1" stop-color="black"/>


will have approximately the same effect as:

<stop offset="0" stop-color="white"/>
<stop offset=".1999999999" stop-color="red"/>
<stop offset=".2" stop-color="blue"/>
<stop offset="1" stop-color="black"/>


which is a gradient that goes smoothly from white to red, then abruptly shifts from red to blue, and then goes smoothly from blue to black.

## 14.4. Patterns

A pattern is used to ‘fill’ or ‘stroke’ an object using a pre-defined graphic object which can be replicated ("tiled") at fixed intervals in x and y to cover the areas to be painted. Patterns are defined using a pattern element and then referenced by properties ‘fill’ and ‘stroke’ on a given graphics element to indicate that the given element shall be filled or stroked with the pattern.

Attributes x, y, width, height and define a reference rectangle somewhere on the infinite canvas. The reference rectangle has its top/left at (xy) and its bottom/right at (x + widthy + height). The tiling theoretically extends a series of such rectangles to infinity in X and Y (positive and negative), with rectangles starting at (x + m*widthy + n* height) for each possible integer value for m and n.

pattern
Categories:
Container element, paint server element
Content model:
Any number of the following elements, in any order:
a, altGlyphDef, clipPath, cursor, filter, font, font-face, foreignObject, image, marker, mask, script, style, switch, text, view
Attributes:
DOM Interfaces:

### 14.4.1. Attributes

patternUnits

Defines the coordinate system for attributes x, y, width and height.

Value
userSpaceOnUse | objectBoundingBox
lacuna value
objectBoundingBox
Animatable
yes
userSpaceOnUse

If patternUnits="userSpaceOnUse", x, y, width and height represent values in the coordinate system that results from taking the current user coordinate system in place at the time when the pattern element is referenced (i.e., the user coordinate system for the element referencing the pattern element via a ‘fill’ or ‘stroke’ property) and then applying the transform specified by attribute . Percentages represent values relative to the current viewport.

objectBoundingBox

If patternUnits="objectBoundingBox", the user coordinate system for attributes x, y, width and height is established using the bounding box of the element to which the pattern is applied (see Object bounding box units) and then applying the transform specified by attribute . Percentages represent values relative to the bounding box for the object.

patternContentUnits

Defines the coordinate system for the contents of the pattern. Note that this attribute has no effect if attribute viewBox is specified.

Value
userSpaceOnUse | objectBoundingBox
lacuna value
userSpaceOnUse
Animatable
yes
userSpaceOnUse

If patternContentUnits="userSpaceOnUse", the user coordinate system for the contents of the pattern element is the coordinate system that results from taking the current user coordinate system in place at the time when the pattern element is referenced (i.e., the user coordinate system for the element referencing the pattern element via a ‘fill’ or ‘stroke’ property) and then applying the transform specified by attribute .

objectBoundingBox

If patternContentUnits="objectBoundingBox", the user coordinate system for the contents of the pattern element is established using the bounding box of the element to which the pattern is applied (see Object bounding box units) and then applying the transform specified by attribute .

patternTransform

Contains the definition of an optional additional transformation from the pattern coordinate system onto the target coordinate system (i.e., 'userSpaceOnUse' or 'objectBoundingBox'). This allows for things such as skewing the pattern tiles. This additional transformation matrix is post-multiplied to (i.e., inserted to the right of) any previously defined transformations, including the implicit transformation necessary to convert from object bounding box units to user space.

Value
<transform-list>
lacuna value
identity transform
Animatable
yes
x

x, y, width and height indicate how the pattern tiles are placed and spaced. These attributes represent coordinates and values in the coordinate space specified by the combination of attributes and .

Value
<length>
lacuna value
0
Animatable
yes
y

See x.

Value
<length>
lacuna value
0
Animatable
yes
width

See x.

Value
<length>
lacuna value
0
Animatable
yes

A negative value is an error (see Error processing). A value of zero disables rendering of the element (i.e., no paint is applied).

height

See x.

Value
<length>
lacuna value
0
Animatable
yes

A negative value is an error (see Error processing). A value of zero disables rendering of the element (i.e., no paint is applied).

An IRI reference to a different pattern element within the current SVG document fragment. Any attributes which are defined on the referenced element which are not defined on this element are inherited by this element. If this element has no children, and the referenced element does (possibly due to its own attribute), then this element inherits the children from the referenced element. Inheritance can be indirect to an arbitrary level; thus, if the referenced element inherits attributes or children due to its own attribute, then the current element can inherit those attributes or children.

Value
<iri>
lacuna value
empty
Animatable
yes
preserveAspectRatio

See .

Value
[defer] <align> [<meetOrSlice>]
lacuna value
xMidYMid meet
Animatable
yes

### 14.4.2. Notes on patterns

SVG's user agent style sheet sets the ‘overflow’ property for pattern elements to hidden, which causes a rectangular clipping path to be created at the bounds of the pattern tile. Unless the ‘overflow’ property is overridden, any graphics within the pattern which goes outside of the pattern rectangle will be clipped. Note that if the ‘overflow’ property is set to visible the rendering behavior for the pattern is undefined. Example pattern01 below shows the effect of clipping to the pattern tile.

The contents of the pattern are relative to a new coordinate system. If there is a viewBox attribute, then the new coordinate system is fitted into the region defined by the x, y, width, height and attributes on the pattern element using the standard rules for viewBox and . If there is no viewBox attribute, then the new coordinate system has its origin at (xy), where x is established by the x attribute on the pattern element, and y is established by the y attribute on the pattern element. Thus, in the following example:

<pattern x="10" y="10" width="20" height="20">
<rect x="5" y="5" width="10" height="10"/>
</pattern>


the rectangle has its top/left located 5 units to the right and 5 units down from the origin of the pattern tile.

The viewBox attribute introduces a supplemental transformation which is applied on top of any transformations necessary to create a new pattern coordinate system due to attributes x, y, width, height and .

Event attributes and event listeners attached to the contents of a pattern element are not processed; only the rendering aspects of pattern elements are processed.

Example pattern01 shows how to fill a rectangle by referencing a pattern paint server. Note how the blue stroke of each triangle has been slightly clipped at the top and the left. This is due to SVG's user agent style sheet setting the ‘overflow’ property for pattern elements to hidden, which causes the pattern to be clipped to the bounds of the pattern tile.

<?xml version="1.0" standalone="no"?>
<svg xmlns="http://www.w3.org/2000/svg"
version="1.1"
viewBox="0 0 300 200" >

<title>Example pattern01</title>
<desc>Fill an ellipse using a pattern paint server.</desc>

<defs>
<pattern id="TrianglePattern"
patternUnits="userSpaceOnUse"
x="0" y="0" width="50" height="50"
viewBox="0 0 10 10" >
<path d="M 0 0 L 7 0 L 3.5 7 z"
fill="plum"
stroke="blue" />
</pattern>
</defs>

<!-- The ellipse is filled using a triangle pattern paint server -->
<ellipse fill="url(#TrianglePattern)"
stroke="black"
stroke-width="2"
cx="150" cy="100" rx="125" ry="75" />
</svg>

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

## 14.5. Hatches

Hatches are new in SVG 2. They were added to allow the kinds of patterns required for mapping, engraving, etc. where continuous lines are needed.

SVG 2 Requirement: Support hatches. SVG 2 should support hatchings without the artifacts that patterns currently impose. To allow the kinds of patterns required for mapping, engraving, etc. where continuous lines are required. Tav (no action)

A hatch is used to ‘fill’ or ‘stroke’ an object using one or more pre-defined paths that are repeated at fixed intervals in a specified direction to cover the areas to be painted. Hatches are defined using a hatch element and then referenced by properties ‘fill’ and ‘stroke’ on a given graphics element to indicate that the given element shall be filled or stroked with the hatch. Paths are defined by elements.

Attributes x, y, pitch, rotate, and define an infinitely long reference strip on the infinite canvas. The strip has one edge at (xy) and its other edge at a distance of pitch in the direction defined by rotate. This one-dimension tiling theoretically extends a series of such strips in the direction of 'rotate' to infinity (positive and negative), with strips starting at (x + m*pitch*cos(rotate), y + m*pitch*sin(rotate) for each possible integer value of m.

hatch
Categories:
Paint server element
Content model:
Any number of the following elements, in any order:
hatchPath, script
Attributes:
DOM Interfaces:

Review content model.

### 14.5.1. Attributes

hatchUnits

Defines the coordinate system for attributes x, y, pitch and rotate.

Value
userSpaceOnUse | objectBoundingBox
lacuna value
objectBoundingBox
Animatable
yes
userSpaceOnUse

If hatchUnits="userSpaceOnUse", x, y, pitch, and rotate represent values in the coordinate system that results from taking the current user coordinate system in place at the time when the hatch element is referenced (i.e., the user coordinate system for the element referencing the hatch element via a ‘fill’ or ‘stroke’ property) and then applying the transform specified by attribute . Percentages represent values relative to the current viewport.

objectBoundingBox

If hatchUnits="objectBoundingBox", the user coordinate system for attributes x, y, pitch, and rotate is established using the bounding box of the element to which the hatch is applied (see Object bounding box units) and then applying the transform specified by attribute . Percentages represent values relative to the bounding box for the object.

hatchContentUnits

Defines the coordinate system for the contents of the hatch.

Value
userSpaceOnUse | objectBoundingBox
lacuna value
userSpaceOnUse
Animatable
yes
userSpaceOnUse

If hatchContentUnits="userSpaceOnUse", the user coordinate system for the contents of the hatch element is the coordinate system that results from taking the current user coordinate system in place at the time when the hatch element is referenced (i.e., the user coordinate system for the element referencing the hatch element via a ‘fill’ or ‘stroke’ property) and then applying the transform specified by attribute .

objectBoundingBox

If hatchContentUnits="objectBoundingBox", the user coordinate system for the contents of the hatch element is established using the bounding box of the element to which the hatch is applied (see Object bounding box units) and then applying the transform specified by attribute .

hatchTransform

Contains the definition of an optional additional transformation from the hatch coordinate system onto the target coordinate system (i.e., 'userSpaceOnUse' or 'objectBoundingBox'). This allows for things such as skewing the hatch strips. This additional transformation matrix is post-multiplied to (i.e., inserted to the right of) any previously defined transformations, including the implicit transformation necessary to convert from object bounding box units to user space.

Value
<transform-list>
lacuna value
identity transform
Animatable
yes
x

x, y, pitch and rotate indicate how the hatch strips are placed and spaced. These attributes represent coordinates and values in the coordinate space specified by the combination of attributes and .

Value
<length>
lacuna value
0
Animatable
yes
y

See x.

Value
<length>
lacuna value
0
Animatable
yes
pitch

See x.

Value
<length>
lacuna value
0
Animatable
yes

A negative value is an error (see Error processing). A value of zero disables rendering of the element (i.e., no paint is applied).

rotate

See x.

Value
<angle>
lacuna value
0
Animatable
yes

Changed name from 'angle' to 'rotate' at Tokyo F2F.

An IRI reference to a different hatch element within the current SVG document fragment. Any attributes which are defined on the referenced element which are not defined on this element are inherited by this element. If this element has no children, and the referenced element does (possibly due to its own attribute), then this element inherits the children from the referenced element. Inheritance can be indirect to an arbitrary level; thus, if the referenced element inherits attributes or children due to its own attribute, then the current element can inherit those attributes or children.

Value
<iri>
lacuna value
empty
Animatable
yes

### 14.5.2. Notes on hatches

SVG's user agent style sheet sets the ‘overflow’ property for hatch elements to hidden, which causes an infinite strip clipping path to be created at the bounds of the hatch strip. Unless the ‘overflow’ property is overridden, any graphics within the hatch which goes outside of the hatch strip will be clipped. Note that if the ‘overflow’ property is set to visible the area outside must be rendered (NB this is different from a pattern element). Strips with higher x (larger m) values must be rendered after strips with lower x (lower m) values.

The contents of the hatch are relative to a new coordinate system. The new coordinate system has its origin at (xy), where x is established by the x attribute on the hatch element, and y is established by the y attribute on the hatch element. The coordinate system is rotated around the origin by the angle given by the rotate attribute.

The viewBox and preserveAspectRatio attributes are not useful and have been removed (as compared to the pattern element).

Event attributes and event listeners attached to the contents of a hatch element are not processed; only the rendering aspects of hatch elements are processed.

The following illustrates a very simple hatch fill:

<hatch pitch="5" rotate="135">
<hatchPath stroke="#a080ff" stroke-width="2"/>
</hatch>


Proper examples with links to the SVG need to be given.

### 14.5.3. Hatch paths

Hatch paths are defined by a element.

hatchPath
Categories:
None
Content model:
Any number of the following elements, in any order:
script
Attributes:
DOM Interfaces:

#### 14.5.3.1. Attributes

d

Defines a single path in the hatch.

Value
Path data
lacuna value
An infinite line, see below
Animatable
yes
offset

Defines the point along the reference line where a path begins.

Value
<length>
lacuna value
0
Animatable
yes

#### 14.5.3.2. Notes on hatch paths

Hatch paths are defined with the same Path data used in the d attribute of the path element. The path is defined relative to the origin of each strip translated in the x direction by the offset (the y direction is aligned along the infinite axis of the strip).

If a d attribute is not provided, the path defaults to an infinitely long line aligned with the y-axis of the reference strip and passing through a point offset distance in the x direction from the strip origin (see above).

If a d attribute is given, the hatch path is constructed by repeating the d data, each time with an offset along the y-axis determined by the y value of the last path data point. (The offset must be positive, a negative or zero offset value results in the hatch path not being rendered.) A hatch path need not start with a "moveto" path instruction. If missing, the first path instruction uses for its current point a value of (x,0) where x is the x value of the last data point given in the path. If the first path command is not a "moveto" and the last not a "closepath", the last point of each repeating section is joined to the first point of the next repeating section with the current value of ‘stroke-linejoin’.

A hatch path can have any of the stroke style properties applied to it, however only solid color paint servers are allowed for the ‘stroke’ property.

Limiting 'stroke' to solid paint servers was resolved at the Tokyo F2F.

<hatch  hatchUnits="userSpaceOnUse" pitch="6">
<hatchPath stroke-width="1" d="c 0,4 8,6 8,10 8,14 0,16 0,20"/>
</hatch>
<hatch  hatchUnits="userSpaceOnUse" pitch="20">
<hatchPath stroke-width="2" d="L 0,0 10,50"/>
</hatch>
<hatch  hatchUnits="userSpaceOnUse" pitch="20">
<hatchPath stroke-width="2" d="M 0,0 10,50"/>
</hatch>
<hatch  hatchUnits="userSpaceOnUse" pitch="20">
<hatchPath stroke-width="2"/>
<hatchPath stroke-width="2" offset="5" stroke-dasharray="10 4 2 4"/>
</hatch>

## 14.6. DOM interfaces

### 14.6.1. Interface SVGSolidColorElement

IDL needs to be added for SVGSolidColorElement.

interface SVGGradientElement : SVGElement {

const unsigned short SVG_SPREADMETHOD_UNKNOWN = 0;
const unsigned short SVG_SPREADMETHOD_REFLECT = 2;
const unsigned short SVG_SPREADMETHOD_REPEAT = 3;

};

SVGGradientElement implements SVGUnitTypes;
Constants in group “Spread Method Types”:
The type is not one of predefined types. It is invalid to attempt to define a new value of this type or to attempt to switch an existing value to this type.
Corresponds to value 'reflect'.
Corresponds to value 'repeat'.
Attributes:
Corresponds to attribute ‘gradientUnits’ on the given element. Takes one of the constants defined in SVGUnitTypes.
Corresponds to attribute ‘gradientTransform’ on the given element.
Corresponds to attribute ‘spreadMethod’ on the given element. One of the Spread Method Types defined on this interface.

The SVGLinearGradientElement interface corresponds to the element.
interface SVGLinearGradientElement : SVGGradientElement {
};
Attributes:
Corresponds to attribute x1 on the given element.
Corresponds to attribute y1 on the given element.
Corresponds to attribute x2 on the given element.
Corresponds to attribute y2 on the given element.

interface SVGRadialGradientElement : SVGGradientElement {
};
Attributes:
Corresponds to attribute cx on the given element.
Corresponds to attribute cy on the given element.
Corresponds to attribute r on the given element.
Corresponds to attribute fx on the given element.
Corresponds to attribute fy on the given element.
Corresponds to attribute fr on the given element.

The SVGMeshGradientElement interface corresponds to the element.
interface SVGMeshGradientElement : SVGGradientElement {
};
Attributes:
Corresponds to attribute x on the given element.
Corresponds to attribute y on the given element.

### 14.6.6. Interface SVGMeshRowElement

interface SVGMeshRowElement : SVGElement {
};

### 14.6.7. Interface SVGMeshPatchElement

interface SVGMeshPatchElement : SVGElement {
};

### 14.6.8. Interface SVGStopElement

The SVGStopElement interface corresponds to the stop element.
interface SVGStopElement : SVGElement {
};
Attributes:
Corresponds to attribute offset on the given stop element.

### 14.6.9. Interface SVGPatternElement

The SVGPatternElement interface corresponds to the pattern element.
interface SVGPatternElement : SVGElement {
};

SVGPatternElement implements SVGFitToViewBox;
SVGPatternElement implements SVGURIReference;
SVGPatternElement implements SVGUnitTypes;
Attributes:
Corresponds to attribute on the given pattern element. Takes one of the constants defined in SVGUnitTypes.
Corresponds to attribute on the given pattern element. Takes one of the constants defined in SVGUnitTypes.
Corresponds to attribute on the given pattern element.
Corresponds to attribute x on the given pattern element.
Corresponds to attribute y on the given pattern element.
Corresponds to attribute width on the given pattern element.
Corresponds to attribute height on the given pattern element.

### 14.6.10. Interface SVGSolidHatchElement

IDL needs to be added for SVGHatchElement.

### 14.6.11. Interface SVGSolidHatchPathElement

IDL needs to be added for SVGHatchPathElement.

SVG 2 – 11 February 2014 TopContentsPreviousNextElementsAttributesProperties