CSS Masking (original) (raw)

W3C Working Draft 15 November 2012

This version:

http://www.w3.org/TR/2012/WD-css-masking-20121115/

Latest version:

http://www.w3.org/TR/css-masking/

Editor's draft:

http://dvcs.w3.org/hg/FXTF/raw-file/tip/masking/index.html

Editors:

Dirk Schulze, Adobe Systems, dschulze@adobe.com

Brian Birtles, Mozilla Japan, bbirtles@mozilla.com

Tab Atkins Jr., Google, Inc.

Copyright © 2012 W3C® (MIT, ERCIM,Keio), All Rights Reserved. W3C liability,trademark and document use rules apply.

Abstract

CSS Masking provides two means for partially or fully hiding portions of visual elements: masking and clipping.

Masking describes how to use another graphical element or image as a luminance or alpha mask. Typically, rendering an element via CSS or SVG can conceptually described as if the element, including its children, are drawn into a buffer and then that buffer is composited into the element's parent. Luminance and alpha masks influence the transparency of this buffer before the compositing stage.

Clipping describes the visible region of visual elements. The region can be described by using certain SVG graphics elements or basic shapes. Anything outside of this region is not rendered.

Status of this document

This section describes the status of this document at the time of its publication. Other documents may supersede this document. A list of current W3C publications and the latest revision of this technical report can be found in the W3C technical reports index at http://www.w3.org/TR/.

Publication as a Working Draft does not imply endorsement by the W3C Membership. This is a draft document and may be updated, replaced or obsoleted by other documents at any time. It is inappropriate to cite this document as other than work in progress.

The (archived) public mailing list public-fx@w3.org (seeinstructions) is preferred for discussion of this specification. When sending e-mail, please put the text “css-masking” in the subject, preferably like this: “[css-masking] _…summary of comment…_”

This document was produced by the CSS Working Group (part of the Style Activity) and the SVG Working Group (part of theGraphics Activity).

This document was produced by groups operating under the 5 February 2004 W3C Patent Policy. W3C maintains a public list of any patent disclosures (CSS) and a public list of any patent disclosures (SVG) made in connection with the deliverables of each group; these pages also include instructions for disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains Essential Claim(s) must disclose the information in accordance with section 6 of the W3C Patent Policy.

This is the first public Working Draft of css-masking.

Table of contents

• 1. Introduction
• 2. Module interactions
• 3. Values
• 4. Definitions
• 5. The Mask Rendering Model
  • 5.1. Layering Multiple Mask Images
  • 5.2. Calculating mask values
• 6. Mask
  • 6.1. The ‘mask-image’ property
  • 6.2. The ‘mask-repeat’ property
  • 6.3. The ‘mask-position’ property
  • 6.4. The ‘mask-clip’ property
  • 6.5. The ‘mask-origin’ property
  • 6.6. The ‘mask-size’ property
  • 6.7. The ‘mask’ property
  • 6.8. The ‘mask-type’ property
  • 6.9. The ‘mask’ element
• 7. Mask Box Image
  • 7.1.The ‘mask-box-image-source’ property
  • 7.2.The ‘mask-box-image-slice’ property
  • 7.3.The ‘mask-box-image-width’ property
  • 7.4.The ‘mask-box-image-outset’ property
  • 7.5.The ‘mask-box-image-repeat’ property
  • 7.6. The ‘mask-box-image’ property
  • 7.7.Masking with the mask-box-image
• 8. Clipping paths
  • 8.1. The ‘clip-path’ property
  • 8.2. The ‘clip-rule’ property
  • 8.3. The ‘clip’ property
  • 8.4. The ‘clipPath’ element
  • 8.5. Clipping paths, geometry, and pointer events
• 9. Security
  • 9.1. Origin Restrictions
• 10. DOM interfaces
  • 10.1.Interface SVGClipPathElement
  • 10.2.Interface SVGMaskElement
• References
  • Normative references
  • Other references
• Index
• Property index

1. Introduction

With CSS Masking it is possible to specify another graphics element, shape or file to be used as clipping region or an luminance or alpha mask for compositing the current object into the background.

A mask is applied using the ‘mask’, ‘mask-image’ or ‘mask-box-image’ properties. The mask source may be defined using a ‘mask’ element referenced by the ‘mask’ property. Alternatively, for many simple uses, the ‘mask-image’ property may refer directly to graphical elements or images to be used as mask forgoing the need for an explicit ‘mask’ element. The ‘mask’ property is also a shorthand for other masking properties. ‘mask-box-image’ splits a mask image into 9 pieces. The pieces may be sliced, scaled and stretched in various ways to fit the size of the mask image area.

The effect of applying a mask is as if the mask images or mask source elements are rendered into an off-screen image which has been initialized to transparent black. The graphical object to which the mask is applied will be painted onto the background through the mask, thus completely or partially masking out parts of the graphical object.

Clipping defines a visible region of a visual element. The region can be specified with SVG graphics element or basic shapes. Everything outside of a region does not get rendered.

A luminance mask (middle) is applied on a shape filled with a gradient (left). This results in a masked shape (right).

2. Module interactions

This specification defines a set of CSS properties that affect the visual rendering of elements to which those properties are applied; these effects are applied after elements have been sized and positioned according to the Visual formatting model from [CSS21]. Some values of these properties result in the creation of a containing block, and/or the creation of a stacking context.

Definitions of CSS properties and values in this specification comply with CSS Backgrounds and Borders [CSS3BG].

Some property and element definitions in this specification require an SVG 1.1 implementation [SVG11]. UAs without support for SVG must not implement the ‘mask-type’ and ‘clip-rule’ properties as well as the ‘mask’ and ‘clipPath’ elements. Furthermore, the ‘mask’ and ‘clip-path’ properties must not support references to ‘mask’ and ‘clipPath’ elements.

3. Values

This specification follows the CSS property definition conventions from [CSS21]. Value types not defined in this specification are defined in CSS Level 2 Revision 1 [CSS21].

In addition to the property-specific values listed in their definitions, all properties defined in this specification also accept theinherit keyword as their property value. For readability it has not been repeated explicitly.

4. Definitions

When used in this specification, terms have the meanings assigned in this section.

bounding client rect

The union of all border boxes for the element that has an associated CSS layout box and is not in the http://www.w3.org/2000/svg namespace and it's descendant elements. Or the object bounding box [SVG11], if the element does not have an associated CSS layout box and is in thehttp://www.w3.org/2000/svg namespace (See getBoundingClientRect [CSSOM-VIEW]).

local coordinate system

In general, a coordinate system defines locations and distances on the current canvas. The current local coordinate system (also user coordinate system) is the coordinate system that is currently active and which is used to define how coordinates and lengths are located and computed, respectively, on the current canvas [CSS3-TRANSFORMS].

For elements that have an associated CSS layout box, the current user coordinate system has its origin at the top-left corner of the bounding client rect and one unit equals one CSS pixel. The viewport for resolving percentage values is defined by the width and height of the bounding client rect.

If the element does not have an associated CSS layout box and is in the http://www.w3.org/2000/svg namespace, the current local coordinate system has its origin at the top-left corner of the element's nearest viewport.

user coordinate system

See definition of local coordinate system.

object bounding box units

The bounding client rect defines the coordinate system in which to resolve values, as defined in object bounding box units [SVG11].

mask

An off-screen image which has been initialized to transparent black. The graphical object to which the mask is applied will be painted onto the background through the mask, thus completely or partially masking out parts of the graphical object.

mask source

A mask defined by a ‘mask’ element.

clipping path

A combination of the SVG elements ‘path’, ‘text’ and basic shapes which serve as the outline of a (in the absence of anti-aliasing) 1-bit mask, where everything on the "inside" of the outline is allowed to show through but everything on the outside is masked out. See ‘clip-path’.

5. The Mask Rendering Model

The application of the ‘clip-path’, ‘mask’ or ‘mask-image’ properties to an element formatted with the CSS box model establishes a stacking context the same way that CSS ‘opacity’ does, and all the element's descendants are rendered together as a group with the masking applied to the group as a whole.

The ‘mask’ and ‘mask-image’ properties have no effect on the geometry of the target element's CSS boxes.

The compositing model follows the SVG compositing model [SVG11]: first any filter effect is applied, then any clipping, masking and opacity. These effects all apply after any other CSS effects such as ‘border’. As per SVG, the application of ‘mask’ or ‘mask-image’ has no effect on hit-testing.

5.1. Layering Multiple Mask Images

The mask of a box can have multiple layers. The number of layers is determined by the number of comma-separated values in the ‘mask-image’ property. Note that a value of ‘none’ still creates a layer.

Each of the images is sized, positioned, and tiled according to the corresponding value in the other mask properties. The lists are matched up from the first value: excess values at the end are not used. If a property doesn't have enough comma-separated values to match the number of layers, the UA must calculate its used value by repeating the list of values until there are enough.

For example, this set of declarations:

mask-image: url(flower.png), url(ball.png), url(grass.png); mask-position: center center, 20% 80%, top left, bottom right; mask-origin: border-box, content-box; mask-repeat: no-repeat;

has exactly the same effect as this set with the extra position dropped and the missing values for ‘mask-origin’ and ‘mask-repeat’ filled in (emphasized for clarity):

mask-image: url(flower.png), url(ball.png), url(grass1.png); mask-position: center center, 20% 80%, top left; mask-origin: border-box, content-box**, border-box**; mask-repeat: no-repeat**, no-repeat, no-repeat**;

The first image in the list is the layer closest to the user, the next one is painted behind the first, and so on. All mask images are transformed to alpha masks (if necessary) and combined by compositing on the mask.

5.2. Calculating mask values

A mask may be interpreted using one of two different methods with regards to calculating the mask values that will be multiplied with the target alpha values.

The first and simplest method of calculating the mask values is to use the alpha channel of the mask source. In this case the mask value at a given point is simply the value of the alpha channel at that point. The color channels do not contribute to the mask value.

The second method of calculating the mask values is to use the luminance of the mask source. In this case the mask value at a given point is computed from the color channel values and alpha channel value using the following procedure.

1. Compute a luminance value from the color channel values.
   • If the computed value of ‘color-interpolation’ on the ‘mask’ element is ‘linearRGB’, convert the original image color values (potentially in the sRGB color space) to the linear RGB color space.
   • Then, using non-premultiplied RGB color values, apply the luminance-to-alpha coefficients (as defined in the ‘feColorMatrix’ filter primitive [SVG11]) to convert the RGB color values to luminance values.
2. Multiply the computed luminance value by the corresponding alpha value to produce the mask value.

Regardless of the method used, the procedure for calculating mask values assumes the content of the mask is a four-channel RGBA graphics object. For other types of graphics objects, special handling is required as follows.

For a three-channel RGB graphics object that is used in a mask (e.g., when referencing a three-channel image file), the effect is as if the object were converted into a four-channel RGBA image with the alpha channel uniformly set to 1.

For a single-channel image that is used in a mask (e.g., when referencing a single-channel grayscale image file), the effect is as if the object were converted into a four-channel RGBA image, where the single channel from the referenced object is used to compute the three color channels and the alpha channel is uniformly set to 1. Note that when referencing a grayscale image file, the transfer curve relating the encoded grayscale values to linear light values must be taken into account when computing the color channels.

Note that SVG graphics elements (e.g., ‘circle’ or ‘text’) are all treated as four-channel RGBA images for the purposes of masking operations.

The effect of a mask is identical to what would have happened if there were no mask but instead the alpha channel of the given object were multiplied with the mask's resulting mask values.

6. Mask

6.1. The ‘mask-image’ property

This property sets the mask image(s) of an element. Images are drawn with the first specified one on top (closest to the user) and each subsequent image behind the previous one. Where:

= [ [ alpha | luminance ]? ] | none

A 2D image. (See [CSS3-IMAGES].)

‘alpha’

A value of ‘alpha’ indicates that the alpha values of the mask image should be used as the mask values. See Calculating mask values.

‘luminance’

A value of ‘luminance’ indicates that the luminance values of the mask image should be used as the mask values. See Calculating mask values.

‘none’

A value of ‘none’ counts as an image layer but does not mask the element.

If neither ‘luminance’ or ‘alpha’ is specified, a value of ‘alpha’ is used.

A mask image that is empty (zero width or zero height), that fails to download, is non-existent, or that cannot be displayed (e.g. because it is not in a supported image format) is ignored. No masking is applied.

See the section “Layering multiple mask images” for how ‘mask-image’ interacts with other comma-separated mask properties to form each mask image layer.

Media fragments can be used to use a portion of an image as a mask. The CSS Images module will provide fallback syntax for image formats and include additional controls for image display.

Some examples specifying mask images:

body { mask-image: linear-gradient(black 0%, transparent 100%) } p { mask-image: none } div { mask-image: url(tl.png), url(tr.png) }

6.2. The ‘mask-repeat’ property

Specifies how mask images are tiled after they have been sized and positioned. Where

= repeat-x | repeat-y | [repeat | space | round | no-repeat]{1,2}

Single values for have the following meanings:

‘repeat-x’

Computes to ‘repeat no-repeat’.

‘repeat-y’

Computes to ‘no-repeat repeat’.

‘repeat’

Computes to ‘repeat repeat’.

‘space’

Computes to ‘space space’

‘round’

Computes to ‘round round’

‘no-repeat’

Computes to ‘no-repeat no-repeat’

If a value has two keywords, the first one is for the horizontal direction, the second for the vertical one, as follows:

‘repeat’

The image is repeated in this direction as often as needed to cover the mask painting area.

‘space’

The image is repeated as often as will fit within the mask painting area without being clipped and then the images are spaced out to fill the area. The first and last images touch the edges of the area. If the mask painting area is larger than the mask positioning area, then the pattern repeats to fill the mask painting area. The value of ‘mask-position’ for this direction is ignored, unless there is not enough space for two copies of the image in this direction, in which case only one image is placed and ‘mask-position’ determines its position in this direction.

‘round’

The image is repeated as often as will fit within the mask painting area. If it doesn't fit a whole number of times, it is rescaled so that it does. See the formula under ‘mask-size’. If the mask painting area is larger than the mask positioning area, then the pattern repeats to fill the mask painting area.

‘no-repeat’

The image is placed once and not repeated in this direction.

Unless one of the two keywords is ‘no-repeat’, the whole mask painting area will be tiled, i.e., not just one vertical strip and one horizontal strip.

Example(s):

body { mask: url(pendant.png); mask-repeat: repeat-y; mask-position: center; }

Example(s):

body { background-color: blue; mask-image: url(dot-mask.png) luminance; mask-repeat: space; }

The effect of ‘space’: the mask image of a dot is tiled to cover the whole mask painting area and the mask images are equally spaced.

See the section “Layering multiple mask images” for how ‘mask-repeat’ interacts with other comma-separated mask properties to form each mask image layer.

6.3. The ‘mask-position’ property

If mask images have been specified, this property specifies their initial position (after any resizing) within their corresponding mask painting area.

Where

= [ [ left | center | right | top | bottom | | ] | [ left | center | right | | ] [ top | center | bottom | | ] | [ center | [ left | right ] [ | ]? ] && [ center | [ top | bottom ] [ | ]? ] ]

If only one value is specified, the second value is assumed to be ‘center’. If two values are given, a length or percentage as the first value represents the horizontal position (or offset) and a length or percentage as the second value represents the vertical position (or offset). and values here represent an offset of the top left corner of the mask image from the top left corner of the mask painting area.

Note that a pair of keywords can be reordered while a combination of keyword and length or percentage cannot. So ‘center left’ is valid while ‘50% left’ is not.

If three or four values are given, then each or represents an offset and must be preceded by a keyword, which specifies from which edge the offset is given. For example, ‘mask-position: bottom 10px right 20px’ represents a ‘10px’ vertical offset up from the bottom edge and a ‘20px’ horizontal offset leftward from the right edge. If three values are given, the missing offset is assumed to be zero.

Positive values represent an offset inward from the edge of the mask painting area. Negative values represent an offset outward from the edge of the mask painting area.

The following declarations give the stated (horizontal, vertical) offsets from the top left corner:

mask-position: left 10px top 15px; /* 10px, 15px / mask-position: left top ; / 0px, 0px / mask-position: 10px 15px; / 10px, 15px / mask-position: left 15px; / 0px, 15px / mask-position: 10px top ; / 10px, 0px / mask-position: left top 15px; / 0px, 15px / mask-position: left 10px top ; / 10px, 0px */

A percentage for the horizontal offset is relative to (width of mask painting area - width of mask image). A percentage for the vertical offset is relative to (height of mask painting area - height of mask image), where the size of the image is the size given by ‘mask-size’.

For example, with a value pair of ‘0% 0%’, the upper left corner of the image is aligned with the upper left corner of, usually, the box's padding edge. A value pair of ‘100% 100%’ places the lower right corner of the image in the lower right corner of the area. With a value pair of ‘75% 50%’, the point 75% across and 50% down the image is to be placed at the point 75% across and 50% down the area.

Diagram of the meaning of ‘mask-position: 75% 50%’.

A length value gives a fixed length as the offset. For example, with a value pair of ‘2cm 1cm’, the upper left corner of the image is placed 2cm to the right and 1cm below the upper left corner of the mask painting area.

‘top’

Computes to ‘0%’ for the vertical position if one or two values are given, otherwise specifies the top edge as the origin for the next offset.

‘right’

Computes to ‘100%’ for the horizontal position if one or two values are given, otherwise specifies the right edge as the origin for the next offset.

‘bottom’

Computes to ‘100%’ for the vertical position if one or two values are given, otherwise specifies the bottom edge as the origin for the next offset.

‘left’

Computes to ‘0%’ for the horizontal position if one or two values are given, otherwise specifies the left edge as the origin for the next offset.

‘center’

Computes to ‘50%’ (‘left 50%’) for the horizontal position if the horizontal position is not otherwise specified, or ‘50%’ (‘top 50%’) for the vertical position if it is.

The following ‘mask’ shorthand declarations use keywords to set ‘mask-position’ to the stated percentage values.

body { mask: url("banner.jpeg") right top } /* 100% 0% / body { mask: url("banner.jpeg") top center } / 50% 0% / body { mask: url("banner.jpeg") center } / 50% 50% / body { mask: url("banner.jpeg") bottom } / 50% 100% */

In the example below, the (single) image is placed in the lower-right corner of the viewport.

body { mask-image: url("logo.png"); mask-position: 100% 100%; mask-repeat: no-repeat; }

Mask positions can also be relative to other corners than the top left. E.g., the following puts the background image 10px from the bottom and 3em from the right:

mask-position: right 3em bottom 10px

See the section “Layering multiple mask images” for how ‘mask-position’ interacts with other comma-separated mask properties to form each mask image layer.

6.4. The ‘mask-clip’ property

Determines the mask painting area, which determines the area that is affected by the mask. The painted content of an element may be resricted to this area. The syntax of the property is given with

= border-box | padding-box | content-box | none

Values have the following meanings:

‘border-box’

The painted content is rectricted to (clipped to) the border box respectively painting box for objects without associated layout box.

‘padding-box’

The painted content is rectricted to (clipped to) the padding box.

‘content-box’

respectively object bounding box [SVG11] for objects without associated layout box.

The painted content is rectricted to (clipped to) the content box.

‘none’

The painted content is not restricted (not clipped). The mask painting area is set to the bounding client rect.

Note that there is no corresponding box for ‘padding-box’ on objects without associated layout box and ‘content-box’ is choosen instead.

See the section “Layering multiple mask images” for how ‘mask-clip’ interacts with other comma-separated mask properties to form each mask image layer.

6.5. The ‘mask-origin’ property

For elements rendered as a single box, specifies the mask positioning area. For elements rendered as multiple boxes (e.g., inline boxes on several lines, boxes on several pages) specifies which boxes ‘box-decoration-break’ operates on to determine the mask positioning area(s).

‘padding-box’

The position is relative to the padding box. (For single boxes ‘0 0’ is the upper left corner of the padding edge, ‘100% 100%’ is the lower right corner.)

‘border-box’

The position is relative to the border box respectively painting box for objects without associated layout box.

‘content-box’

The position is relative to the content box respectively object bounding box [SVG11] for objects without associated layout box.

Note that there is no corresponding box for ‘padding-box’ on objects without associated layout box and ‘content-box’ is choosen instead.

Note that if ‘mask-clip’ is ‘padding-box’, ‘mask-origin’ is ‘border-box’, ‘mask-position’ is ‘top left’ (the initial value), and the element has a non-zero border, then the top and left of the mask image will be clipped.

See the section “Layering multiple mask images” for how ‘mask-origin’ interacts with other comma-separated mask properties to form each mask image layer.

Needs to be resolved where the origin for ‘mask-clip: none’ should be.

6.6. The ‘mask-size’ property

Specifies the size of the mask images. Where

= [ | | auto ]{1,2} | cover | contain

Values have the following meanings:

‘contain’

Scale the image, while preserving its intrinsic aspect ratio (if any), to the largest size such that both its width and its height can fit inside the mask positioning area.

‘cover’

Scale the image, while preserving its intrinsic aspect ratio (if any), to the smallest size such that both its width and its height can completely cover the mask positioning area.

[ | | auto ]{1,2}

The first value gives the width of the corresponding image, the second value its height. If only one value is given the second is assumed to be ‘auto’.

A percentage is relative to the background positioning area.

An ‘auto’ value for one dimension is resolved by using the image's intrinsic ratio and the size of the other dimension, or failing that, using the image's intrinsic size, or failing that, treating it as 100%.

If both values are ‘auto’ then the intrinsic width and/or height of the image should be used, if any, the missing dimension (if any) behaving as ‘auto’ as described above. If the image has neither an intrinsic width nor an intrinsic height, its size is determined as for ‘contain’.

Negative values are not allowed.

Here are some examples. The first example stretches the mask image independently in both dimensions to completely cover the content area:

div { mask-image: url(plasma.png); mask-repeat: no-repeat; mask-size: 100% 100%; mask-origin: content-box }

The second example stretches the image so that exactly two copies fit horizontally. The aspect ratio is preserved:

p { mask-image: url(tubes.png); mask-size: 50% auto; mask-origin: border-box }

This example forces the mask image to be 15 by 15 pixels:

para { mask-size: 15px 15px; mask-image: url(tile.png)}

This example uses the image's intrinsic size. Note that this is the only possible behavior in CSS level 1 and 2.

body { mask-size: auto; /* default */ mask-image: url(flower.png) }

The following example rounds the height of the image to 33.3%, up from the specified value of 30%. At 30%, three images would fit entirely and a fourth only partially. After rounding, three images fit. The width of the image is 20% of the mask area width and is not rounded.

p { mask-image: url(chain.png); mask-repeat: no-repeat round; mask-size: 20% 30% }

If ‘mask-repeat’ is ‘round’ for one (or both) dimensions, there is a second step. The UA must scale the image in that dimension (or both dimensions) so that it fits a whole number of times in the mask positioning area. In the case of the width (height is analogous):

If X ≠ 0 is the width of the image after step one andW is the width of the mask positioning area, then the rounded width X' = W / round(W / X) where round() is a function that returns the nearest natural number (integer greater than zero).

If ‘mask-repeat’ is ‘round’ for one dimension only and if ‘mask-size’ is ‘auto’ for the other dimension, then there is a third step: that other dimension is scaled so that the original aspect ratio is restored.

In this example the mask image is shown at its intrinsic size:

div { mask-image: url(image1.png); mask-repeat: repeat; /* default / mask-size: auto } / default */

In the following example, the mask is shown with a width of 3em and its height is scaled proportionally to keep the original aspect ratio:

div { mask-image: url(image2.png); mask-repeat: repeat; /* default / mask-size: 3em } / = '3em auto' */

In the following example, the mask is shown with a width of approximately 3em: scaled so that it fits a whole number of times in the width of the mask. The height is scaled proportionally to keep the original aspect ratio:

div { mask-image: url(image3.png); mask-repeat: round repeat; mask-size: 3em auto }

In the following example, the mask image is shown with a width of 3em and a height that is either the height corresponding to that width at the original aspect ratio or slightly less:

div { mask-image: url(image4.png); mask-repeat: repeat round; mask-size: 3em auto }

In the following example, the mask image is shown with a height of approximately 4em: scaled slightly so that it fits a whole number of times in the mask height. The width is the approximately the width that correspond to a 4em height at the original aspect ratio: scaled slightly so that it fits a whole number of times in the mask width.

div { mask-image: url(image5.png); mask-repeat: round; mask-size: auto 4em }

If the mask image's width or height resolves to zero, this causes the image not to be displayed. (The effect is the same as if it had been a transparent image.)

See the section “Layering multiple mask images” for how ‘mask-size’ interacts with other comma-separated mask properties to form each mask image layer.

6.7. The ‘mask’ property

Where

= || [ / ]? || || {1,2}

Currently Mozilla needs to differ between CSS Image and Mask resource right after parsing and before loading the resource. This is not possible with the current ‘mask’ property definition.

= [ | child | ] [ alpha | luminance ] ?

= select(#)

‘<url>’

A URL reference to a ‘mask’ element. For example ‘url(commonmasks.xml#mask)’.

‘child’

A keyword to indicate that the last child ‘mask’ element should be used as the mask source. It is equivalent to ‘select(mask:last-of-type)’.

‘<child-selector>’

A comma-separated list of compound selectors scoped at the element to which the ‘mask’ property is applied. The first matching element in tree order (as defined in [DOM]) as a result of evaluating the list of selectors is taken as the mask source. If there are no matching elements the mask source is invalid.

‘<compound-selector>’

A compound selector as defined in [SELECTORS4].

‘alpha’

A value of ‘alpha’ indicates that the alpha values of the mask content of the referenced mask element should be used as the mask values. See Calculating mask values.

‘luminance’

A value of ‘luminance’ indicates that the luminance values of the mask content of the referenced mask element should be used as the mask values. See Calculating mask values.

The keywords ‘alpha’ or ‘luminance’ may be used together with a reference to a ‘mask’ element. If either keyword is specified the effect is to override the value of the ‘mask-type’ property on the referenced ‘mask’ element.

In the following example, the ‘mask-type’ property sets the mask type value for the ‘mask’ element to ‘alpha’. The ‘mask’ property has a reference to this ‘mask’ element and the keyword ‘luminance’. The ‘mask’ property will override the definition of ‘mask-type’ to ‘luminance’.

An invalid or non-existent mask source is ignored and no masking is applied.

Note that the properties ‘mask-image’, ‘mask-repeat’, ‘mask-position’, ‘mask-clip’, ‘mask-origin’ and ‘mask-size’ have no affect on ‘mask’ elements.

6.8. The ‘mask-type’ property

The ‘mask-type’ property defines whether the content of the ‘mask’ is treated as as luminance mask or alpha mask, as described in Calculating mask values.

Values have the following meanings:

‘luminance’

Indicates that the luminance values of the mask should be used.

‘alpha’

Indicates that the alpha values of the mask should be used.

The ‘mask-type’ property is a presentation attribute for SVG elements.

6.9. The ‘mask’ element

Attribute definitions:

maskUnits = "userSpaceOnUse | objectBoundingBox"

Defines the coordinate system for attributes ‘x’,‘y’, ‘width’ and ‘height’.
If maskUnits="userSpaceOnUse", ‘x’, ‘y’,‘width’ and ‘height’ represent values in the current user coordinate system in place at the time when the ‘mask’ element is referenced (i.e., the user coordinate system for the element referencing the ‘mask’ element via the ‘mask’ property).
If maskUnits="objectBoundingBox", ‘x’, ‘y’,‘width’ and ‘height’ represent fractions or percentages of the bounding box of the element to which the mask is applied. (See object bounding box units.)
If attribute ‘maskUnits’ is not specified, then the effect is as if a value of ‘objectBoundingBox’ were specified.
Animatable: yes.

maskContentUnits = "userSpaceOnUse |objectBoundingBox"

Defines the coordinate system for the contents of the ‘mask’.
If maskContentUnits="userSpaceOnUse", the user coordinate system for the contents of the ‘mask’ element is the current user coordinate system in place at the time when the ‘mask’ element is referenced (i.e., the user coordinate system for the element referencing the ‘mask’ element via the ‘mask’ property).
If maskContentUnits="objectBoundingBox", the user coordinate system for the contents of the ‘mask’ is established using the bounding box of the element to which the mask is applied. (See object bounding box units.)
If attribute ‘maskContentUnits’ is not specified, then the effect is as if a value of ‘userSpaceOnUse’ were specified.
Animatable: yes.

x = " | "

The x-axis coordinate of one corner of the rectangle for the largest possible offscreen buffer. Note that the clipping path used to render any graphics within the mask will consist of the intersection of the current clipping path associated with the given object and the rectangle defined by ‘x’, ‘y’,‘width’ and ‘height’.
If the attribute is not specified, the effect is as if a value of ‘-10%’ were specified.
Animatable: yes.

y = " | "

The y-axis coordinate of one corner of the rectangle for the largest possible offscreen buffer.
If the attribute is not specified, the effect is as if a value of ‘-10%’ were specified.
Animatable: yes.

width = " | "

The width of the largest possible offscreen buffer. Note that the clipping path used to render any graphics within the mask will consist of the intersection of the current clipping path associated with the given object and the rectangle defined by ‘x’,‘y’, ‘width’ and ‘height’.
A negative value or a value of zero disables rendering of the element.
If the attribute is not specified, the effect is as if a value of ‘120%’ were specified.
Animatable: yes.

height = " | "

The height of the largest possible offscreen buffer.
A negative value or a value of zero disables rendering of the element.
If the attribute is not specified, the effect is as if a value of ‘120%’ were specified.
Animatable: yes.

CSS properties inherit into the ‘mask’ element from its ancestors; properties do not inherit from the element referencing the ‘mask’ element.

‘mask’ elements are never rendered directly; their only usage is as something that can be referenced using the ‘mask’ property. The ‘opacity’, ‘filter’ and ‘display’ properties do not apply to the ‘mask’ element; thus, ‘mask’ elements are not directly rendered even if the ‘display’ property is set to a value other than ‘none’, and ‘mask’ elements are available for referencing even when the ‘display’ property on the ‘mask’ element or any of its ancestors is set to none.

7. Mask Box Image

With ‘mask-box-image’ a mask can be split into nine pieces: four corners, four edges and the middle piece as demonstrated in the figure below.

Pieces of a mask box image.

These pieces may be sliced, scaled and stretched in various ways to fit the size of the mask image area.

The mask image in the following example is split into four corners with dimensions of 75 pixels, four edges and the middle piece that is stretched and scaled.

Example for ‘mask-box-image’. The object on the left is the object to mask. The second image is the alpha mask and the last image the masked object.

div { background: linear-gradient(bottom, #F27BAA 0%, #FCC8AD 100%); mask-box-image-slice: 25 fill; mask-box-image-repeat: stretch; mask-box-image-source: url(mask.png); }

7.1. The ‘mask-box-image-source’ property

Specifies an image to be used as mask. If the value is ‘none’ or if the image cannot be displayed (or the property doesn't apply), the content won't get masked.

7.2. The ‘mask-box-image-slice’ property

This property specifies inward offsets from the top, right, bottom, and left edges of the mask image, dividing it into nine regions: four corners, four edges and a middle. The middle image part is discarded (treated as fully transparent black) unless the ‘fill’ keyword is present.

When four values are specified, they set the offsets on the top, right, bottom and left sides in that order. If the left is missing, it is the same as the right; if the bottom is missing, it is the same as the top; if the right is missing, it is the same as the top.

Percentages are relative to the size of the mask image: the width of the image for the horizontal offsets, the height for vertical offsets.

Numbers represent pixels in the mask image (if the image is a raster image) or vector coordinates (if the image is a vector image).

‘fill’

The ‘fill’ keyword, if present, causes the middle part of the mask image to be preserved. (By default it is discarded, i.e., treated as transparent black.)

Negative values are not allowed and values bigger than the size of the image are interpreted as ‘100%’.

The regions given by the ‘mask-box-image-slice’ values may overlap. However if the sum of the right and left widths is equal to or greater than the width of the image, the images for the top and bottom edge and the middle part are empty, which has the same effect as if a nonempty transparent image had been specified for those parts. Analogously for the top and bottom values.

If the image must be sized to determine the slices (for example, for SVG images with no intrinsic size), then it is sized as for an auto-sized background, using the mask box image area as the default object size in place of the mask positioning area.

Diagram illustrating the cuts corresponding to the value ‘25% 30% 12% 20%’

7.3. The ‘mask-box-image-width’ property

The mask image is drawn inside an area called the mask box image area. This is an area whose boundaries by default correspond to the mask box, see ‘mask-box-image-outset’.

The four values of ‘mask-box-image-width’ specify offsets that are used to divide the mask box image area into nine parts. They represent inward distances from the the top, right, bottom, and left sides of the area, respectively. If the left width is missing, it is the same as the right; if the bottom is missing, it is the same as the top; if the right is missing, it is the same as the top. Values have the following meanings:

Percentages refer to the size of the mask box image area: the width of the area for horizontal offsets, the height for vertical offsets.

Numbers represent multiples of the corresponding computed ‘border-width’.

‘auto’

If ‘auto’ is specified then the mask box image width is the intrinsic width or height (whichever is applicable) of the corresponding image slice (see ‘mask-box-image-slice’). If the image does not have the required intrinsic dimension then the corresponding ‘border-width’ is used instead.

Note that for SVG elements without an associated layout box the ‘border-width’ is considered to be ‘0’.

Negative values are not allowed for any ‘mask-box-image-width’ values.

If two opposite ‘mask-box-image-width’ offsets are large enough that they overlap, then the used values of all ‘mask-box-image-width’ offsets are proportionally reduced until they no longer overlap. In mathematical notation: Given Lwidth as the width of the mask box image area, Lheight as its height, andWside as the mask image width offset for the side side, let f = min(Lwidth/(Wleft+Wright),Lheight/(Wtop+Wbottom)). If f < 1, then all W are reduced by multiplying them by f.

7.4. The ‘mask-box-image-outset’ property

The values specify the amount by which the mask box image area extends beyond the border box. If it has four values, they set the outsets on the top, right, bottom and left sides in that order. If the left is missing, it is the same as the right; if the bottom is missing, it is the same as the top; if the right is missing, it is the same as the top.

As with ‘mask-box-image-width’, a represents a multiple of the corresponding ‘border-width’. Negative values are not allowed for any of the ‘mask-box-image-outset’ values.

Note that for SVG elements without associated layout box the ‘border-width’ is considered to be ‘0’.

7.5. The ‘mask-box-image-repeat’ property

This property specifies how the images for the sides and the middle part of the mask image are scaled and tiled. The first keyword applies to the horizontal sides, the second to the vertical ones. If the second keyword is absent, it is assumed to be the same as the first. Values have the following meanings:

‘stretch’

The image is stretched to fill the area.

‘repeat’

The image is tiled (repeated) to fill the area.

‘round’

The image is tiled (repeated) to fill the area. If it does not fill the area with a whole number of tiles, the image is rescaled so that it does.

‘space’

The image is tiled (repeated) to fill the area. If it does not fill the area with a whole number of tiles, the extra space is distributed around the tiles.

7.6. The ‘mask-box-image’ property

This is a shorthand property for setting ‘mask-box-image-source’, ‘mask-box-image-slice’, ‘mask-box-image-width’, ‘mask-box-image-outset’ and ‘mask-box-image-repeat’. Omitted values are set to their initial values.

7.7.Masking with the mask-box-image

After the mask-box-image given by ‘mask-box-image-source’ is sliced by the ‘mask-box-image-slice’ values, the resulting nine images are scaled, positioned, and tiled into their corresponding mask image regions in four steps:

1. Scale to ‘mask-box-image-width’.
   • The two images for the top and bottom edges are made as tall as the top and bottom mask image area parts, respectively, and their width is scaled proportionally.
   • The images for the left and right edge are made as wide as the left and right mask image area parts, respectively, and their height is scaled proportionally.
   • The corner images are scaled to be as wide and as tall as the two mask-box-image edges they are part of.
   • The middle image's width is scaled by the same factor as the top image unless that factor is zero or infinity, in which case the scaling factor of the bottom is substituted, and failing that, the width is not scaled. The height of the middle image is scaled by the same factor as the left image unless that factor is zero or infinity, in which case the scaling factor of the right image is substituted, and failing that, the height is not scaled.
2. Scale to ‘mask-box-image-repeat’.
   • If the first keyword is ‘stretch’, the top, middle and bottom images are further scaled to be as wide as the middle part of the mask image area. The height is not changed any further.
   • If the first keyword is ‘round’, the top, middle and bottom images are resized in width, so that exactly a whole number of them fit in the middle part of the mask-box-image area, exactly as for ‘round’ in the ‘mask-image-repeat’ property.
   • If the first keyword is ‘repeat’ or ‘space’, the top, middle, and bottom images are not changed any further.
   • The effects of ‘stretch’, ‘round’, ‘repeat’, and ‘space’ for the second keyword are analogous, acting on the height of the left, middle and right images.
3. Position the first tile.
   • If the first keyword is ‘repeat’, the top, middle, and bottom images are centered horizontally in their respective areas. Otherwise the images are placed at the left edge of their respective parts of the mask-box-image area.
   • If the second keyword is ‘repeat’, the left, middle, and right images are centered vertically in their respective areas. Otherwise the images are placed at the top edge of their respective parts of the mask-box-image area.
4. Tile and mask.
   • The images are then tiled to fill their respective areas. All tiles are used together to mask the element and its descendants after drawing all stacking levels.
   • In the case of ‘space’, any partial tiles are discarded and the extra space distributed before, after, and between the tiles. (I.e. the gap before the first tile, the gap after the last tile, and the gaps between tiles are equalized.) Note that this can result in empty mask-box-image side areas.

8. Clipping paths

The clipping path restricts the region to which paint can be applied, the so-called clipping region. Conceptually, any parts of the drawing that lie outside of this region are not drawn. This includes any content, background, borders, text decoration, outline and visible scrolling mechanism of the element to which the clipping path is applied, and those of its descendants.

An element's ancestors may also clip portions of their content (e.g., via their own ‘clip’ or ‘clip-path’ properties and/or if their ‘overflow’ property is not ‘visible’). What is rendered is the cumulative intersection.

If the clipping region exceeds the bounds of the UA's document window, content may be clipped to that window by the native operating environment.

8.1. The ‘clip-path’ property

= | child |

‘<shape>’

A basic shape function as defined in CSS3 Exclusions. Percentage values are resolved against the bounding client rect. (See [CSS3-EXCLUSIONS].)

For SVG percentage values might be resolved according to the painted bounding box and not bounding client rect (alias object bounding box).

8.2. The ‘clip-rule’ property

‘nonzero’

See description of ‘fill-rule’ property [SVG11].

‘evenodd’

See description of ‘fill-rule’ property [SVG11].

The ‘clip-rule’ property only applies to graphics elements that are contained within a ‘clipPath’ element.

The following fragment of code will cause an evenodd clipping rule to be applied to the clipping path because ‘clip-rule’ is specified on the ‘path’ element that defines the clipping shape:

whereas the following fragment of code will not cause an evenodd clipping rule to be applied because the ‘clip-rule’ is specified on the referencing element, not on the object defining the clipping shape:

8.3. The ‘clip’ property

With this specification the ‘clip’ property is deprecated. Authors are encouraged to use the ‘clip-path’ property instead. UAs must support the ‘clip’ property.

The ‘clip’ property applies only to absolutely positioned elements. In SVG, it applies to elements which establish a new viewport, ‘pattern’ elements and ‘marker’ elements. Values have the following meanings:

‘auto’

The element does not clip.

In CSS 2.1, the only valid value is: rect(, , , ) where and specify offsets from the top border edge of the box, and , and specify offsets from the left border edge of the box. Authors should separate offset values with commas. User agents must support separation with commas, but may also support separation without commas (but not a combination), because a previous revision of this specification was ambiguous in this respect.

, , , and may either have a value or ‘auto’. Negative lengths are permitted. The value ‘auto’ means that a given edge of the clipping region will be the same as the edge of the element's generated border box (i.e., ‘auto’ means the same as ‘0’ for and , the same as the used value of the height plus the sum of vertical padding and border widths for , and the same as the used value of the width plus the sum of the horizontal padding and border widths for , such that four ‘auto’ values result in the clipping region being the same as the element's border box).

When coordinates are rounded to pixel coordinates, care should be taken that no pixels remain visible when and have the same value (or and have the same value), and conversely that no pixels within the element's border box remain hidden when these values are ‘auto’.

Example: The following two rules:

p#one { clip: rect(5px, 40px, 45px, 5px); }
p#two { clip: rect(5px, 55px, 45px, 5px); }

and assuming both Ps are 50 by 55 pixel, will create, respectively, the rectangular clipping regions delimited by the dashed lines in the following illustrations:

This diagram illustrates two block boxes, one above the other, with rectangular clipping regions of different dimensions. (Seelong description.)

8.4. The ‘clipPath’ element

Attribute definitions:

clipPathUnits = "userSpaceOnUse |objectBoundingBox"

Defines the coordinate system for the contents of the ‘clipPath’.
If clipPathUnits="userSpaceOnUse", the contents of the ‘clipPath’ represent values in the current user coordinate system in place at the time when the ‘clipPath’ element is referenced (i.e., the user coordinate system for the element referencing the ‘clipPath’ element via the ‘clip-path’ property).
If clipPathUnits="objectBoundingBox", then the user coordinate system for the contents of the ‘clipPath’ element is established using the bounding box of the element to which the clipping path is applied (see object bounding box units).
If attribute ‘clipPathUnits’ is not specified, then the effect is as if a value of ‘userSpaceOnUse’ were specified.
Animatable: yes.

CSS properties inherit into the ‘clipPath’ element from its ancestors; properties do not inherit from the element referencing the ‘clipPath’ element.

‘clipPath’ elements are never rendered directly; their only usage is as something that can be referenced using the ‘clip-path’ property. The ‘display’ property does not apply to the ‘clipPath’ element; thus, ‘clipPath’ elements are not directly rendered even if the ‘display’ property is set to a value other than none, and ‘clipPath’ elements are available for referencing even when the ‘display’ property on the ‘clipPath’ element or any of its ancestors is set to none.

A ‘clipPath’ element can contain ‘path’ elements, ‘text’ elements, basic shapes (such as ‘circle’) or a ‘use’ element. If a ‘use’ element is a child of a ‘clipPath’ element, it must directly reference‘path’, ‘text’ or basic shapes elements. Indirect references are an error and the ‘clipPath’ element must be ignored.

The raw geometry of each child element exclusive of rendering properties such as ‘fill’, ‘stroke’, ‘stroke-width’ within a ‘clipPath’ conceptually defines a 1-bit mask (with the possible exception of anti-aliasing along the edge of the geometry) which represents the silhouette of the graphics associated with that element. Anything outside the outline of the object is masked out. If a child element is made invisible by ‘display’ or ‘visibility’ it does not contribute to the clipping path. When the ‘clipPath’ element contains multiple child elements, the silhouettes of the child elements are logically OR'd together to create a single silhouette which is then used to restrict the region onto which paint can be applied. Thus, a point is inside the clipping path if it is inside any of the children of the ‘clipPath’.

For a given graphics element, the actual clipping path used will be the intersection of the clipping path specified by its ‘clip-path’ property (if any) with any clipping paths on its ancestors, as specified by the ‘clip-path’ property on the elements which establish a new viewport. (See [SVG11])

A couple of notes:

• The ‘clipPath’ element itself and its child elements do not inherit clipping paths from the ancestors of the‘clipPath’ element.
• The ‘clipPath’ element or any of its children can specify property ‘clip-path’.
  If a valid ‘clip-path’ reference is placed on a ‘clipPath’ element, the resulting clipping path is the intersection of the contents of the ‘clipPath’ element with the referenced clipping path.
  If a valid ‘clip-path’ reference is placed on one of the children of a ‘clipPath’ element, then the given child element is clipped by the referenced clipping path before OR'ing the silhouette of the child element with the silhouettes of the other child elements.
• An empty clipping path will completely clip away the element that had the ‘clip-path’ property applied.

8.5. Clipping paths, geometry, and pointer events

A clipping path is conceptually equivalent to a custom viewport for the referencing element. Thus, it affects the rendering of an element, but not the element's inherent geometry. The bounding client rect of a clipped element (that is, an element which references a ‘clipPath’ element via a ‘clip-path’ property, or a child of the referencing element) must remain the same as if it were not clipped.

By default, pointer events must not be dispatched on the clipped (non-visible) regions of a shape. For example, a circle with a radius of 10 which is clipped to a circle with a radius of 5 will not receive ‘click’ events outside the smaller radius. Later versions of this specification may define new properties to enable fine-grained control over the interactions between hit testing and clipping.

9. Security

9.1. Origin Restrictions

External references to resources like ‘mask’ or ‘clipPath’ must not violate the same origin restrictions [CORS].

This restriction includes:

• Any images, either as content or via styling, that are not exposed with CORS
• Any tainted canvas
• Any cross-origin content referenced by ‘xlink:href’ or

If content falls under this restriction, the resource must be rejected. The element is drawn as if the resource was not specified (i.e. the ‘clip-path’ or ‘mask’ property were set to ‘none’).

10. DOM interfaces

10.1. Interface SVGClipPathElement

The SVGClipPathElement interface corresponds to the ‘clipPath’ element.

interface SVGClipPathElement : SVGDefinitionElement { readonly attribute SVGAnimatedEnumeration clipPathUnits; };

SVGClipPathElement implements SVGUnitTypes;

clipPathUnits (readonly SVGAnimatedEnumeration)

Corresponds to attribute ‘clipPathUnits’ on the given ‘clipPath’ element. Takes one of the constants defined in SVGUnitTypes.

10.2. Interface SVGMaskElement

The SVGMaskElement interface corresponds to the ‘mask’ element.

interface SVGMaskElement : SVGDefinitionElement {

// Mask Types const unsigned short SVG_MASKTYPE_LUMINANCE = 0; const unsigned short SVG_MASKTYPE_ALPHA = 1;

readonly attribute SVGAnimatedEnumeration maskUnits; readonly attribute SVGAnimatedEnumeration maskContentUnits; readonly attribute SVGAnimatedLength x; readonly attribute SVGAnimatedLength y; readonly attribute SVGAnimatedLength width; readonly attribute SVGAnimatedLength height; };

SVGMaskElement implements SVGUnitTypes;

SVG_MASKTYPE_LUMINANCE (unsigned short)

Corresponds to value ‘luminance’.

SVG_MASKTYPE_ALPHA (unsigned short)

Corresponds to value ‘alpha’.

maskUnits (readonly SVGAnimatedEnumeration)

Corresponds to attribute ‘maskUnits’ on the given ‘mask’ element. Takes one of the constants defined in SVGUnitTypes.

maskContentUnits (readonly SVGAnimatedEnumeration)

Corresponds to attribute ‘maskContentUnits’ on the given ‘mask’ element. Takes one of the constants defined in SVGUnitTypes.

x (readonly SVGAnimatedLength)

Corresponds to attribute ‘x’ on the given ‘mask’ element.

y (readonly SVGAnimatedLength)

Corresponds to attribute ‘y’ on the given ‘mask’ element.

width (readonly SVGAnimatedLength)

Corresponds to attribute ‘width’ on the given ‘mask’ element.

height (readonly SVGAnimatedLength)

Corresponds to attribute ‘height’ on the given ‘mask’ element.

References

Normative references

[CORS]

Anne van Kesteren. Cross-Origin Resource Sharing. 3 April 2012. W3C Working Draft. (Work in progress.) URL: http://www.w3.org/TR/2012/WD-cors-20120403/

[CSS21]

Bert Bos; et al. Cascading Style Sheets Level 2 Revision 1 (CSS 2.1) Specification. 7 June 2011. W3C Recommendation. URL: http://www.w3.org/TR/2011/REC-CSS2-20110607

[CSS3-EXCLUSIONS]

Vincent Hardy; Rossen Atanassov; Alan Stearns. CSS Exclusions and Shapes Module Level 3. 3 May 2012. W3C Working Draft. (Work in progress.) URL: http://www.w3.org/TR/2012/WD-css3-exclusions-20120503/

[CSS3-IMAGES]

Elika J. Etemad; Tab Atkins Jr. CSS Image Values and Replaced Content Module Level 3. 17 April 2012. W3C Candidate Recommendation. (Work in progress.) URL: http://www.w3.org/TR/2012/CR-css3-images-20120417/

[DOM]

Anne van Kesteren; Aryeh Gregor; Ms2ger. DOM4. 5 April 2012. W3C Working Draft. (Work in progress.) URL: http://www.w3.org/TR/2012/WD-dom-20120405/

[SELECTORS4]

Elika J. Etemad. Selectors Level 4. 23 August 2012. W3C Working Draft. (Work in progress.) URL: http://www.w3.org/TR/2012/WD-selectors4-20120823/

[SVG11]

Erik Dahlström; et al. Scalable Vector Graphics (SVG) 1.1 (Second Edition). 16 August 2011. W3C Recommendation. URL: http://www.w3.org/TR/2011/REC-SVG11-20110816/

[SVG2]

Cameron McCormack; Scalable Vector Graphics (SVG) 2. 28 August 2012. W3C Working Draft. (Work in progress.) URL: http://www.w3.org/TR/2012/WD-SVG2-20120828/

Other references

[CSS3-TRANSFORMS]

Simon Fraser; et al. CSS Transforms. 11 September 2012. W3C Working Draft. (Work in progress.) URL: http://www.w3.org/TR/2012/WD-css3-transforms-20120911/

[CSS3BG]

Bert Bos; Elika J. Etemad; Brad Kemper. CSS Backgrounds and Borders Module Level 3. 24 July 2012. W3C Candidate Recommendation. (Work in progress.) URL: http://www.w3.org/TR/2012/CR-css3-background-20120724/

[CSSOM-VIEW]

Anne van Kesteren. CSSOM View Module. 4 August 2011. W3C Working Draft. (Work in progress.) URL: http://www.w3.org/TR/2011/WD-cssom-view-20110804/

Index

• ‘alpha’, 6.1.
• ‘auto’
  • ‘mask-box-image-width’ value, 7.3.
  • ‘mask-size’ value, 6.6.
• ‘border-box’
  • ‘mask-clip’ value, 6.4.
  • ‘mask-origin’ value, 6.5.
• , 8.3.
• ‘bottom’
  • ‘mask-position’ value, 6.3.
• bounding client rect, 4., 8.1., 8.5.
• , 6.4.
• ‘center’
  • ‘mask-position’ value, 6.3.
• ‘child’, 6.7.
• , 6.7.
• ‘’, 6.7.
• clip, 8.3.
• clipPath, 8.4.
• clip-path, 8.1.
• clip-rule, 8.2.
• , 8.1.
• ‘’, 6.7.
• ‘contain’, 6.6.
• ‘content-box’,6.5.
  • ‘mask-clip’ value, 6.4.
• ‘cover’, 6.6.
• ‘evenodd’, 8.2.
• ‘fill’, 7.2.
• , 6.1.
• layers, 5.1.
• , 8.3.
• ‘left’
  • ‘mask-position’ value, 6.3.
• local coordinate system, 4.
• ‘luminance’, 6.1.
• mask, 6.7., 6.9., 4.
• mask-box-image, 7.6.
• mask box image area, 7.4.
• mask-box-image-outset, 7.4.
• mask-box-image-repeat, 7.5.
• mask-box-image-slice, 7.2.
• mask-box-image-source, 7.1.
• mask-box-image-width, 7.3.
• mask-clip, 6.4.
• , 6.1.
• mask-image, 6.1.
• mask image area, 7.
• , 6.7.
• mask-origin, 6.5.
• mask painting area, 6.4., 6.2., 6.2., 6.2., 6.2., 6.2., 6.2., 6.3., 6.3., 6.3.
• mask-position, 6.3.
• mask positioning area, 6.5., 6.6.
• mask-repeat, 6.2.
• , 6.6.
• mask-size, 6.6.
• , 6.7.
• mask source, 4.
• mask-type, 6.8.
• ‘none’, 6.1.
  • ‘mask-clip’ value, 6.4.
• ‘nonzero’, 8.2.
• ‘no-repeat’
  • ‘mask-repeat’ value, 6.2.
• object bounding box units, 4., 8.4.
• ‘padding-box’
  • ‘mask-clip’ value, 6.4.
  • ‘mask-origin’ value, 6.5.
• , 6.3.
• ‘repeat’
  • ‘mask-box-image-repeat’ value, 7.5.
  • ‘mask-repeat’ value, 6.2.
• , 6.2.
• ‘repeat-x’, 6.2.
• ‘repeat-y’, 6.2.
• , 8.3.
• ‘right’
  • ‘mask-position’ value, 6.3.
• ‘round’
  • ‘mask-box-image-repeat’ value, 7.5.
  • ‘mask-repeat’ value, 6.2.
• ‘’,8.1.
• ‘space’
  • ‘mask-box-image-repeat’ value, 7.5.
  • ‘mask-repeat’ value, 6.2.
• ‘stretch’, 7.5.
• , 8.3.
• ‘top’
  • ‘mask-position’ value, 6.3.
• ‘’, 6.7.
• user coordinate system, 4.

Property index