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-moz-context-properties

Non-standard
This feature is non-standard and is not on a standards track. Do not use it on production sites facing the Web: it will not work for every user. There may also be large incompatibilities between implementations and the behavior may change in the future.

Note: This feature is available since Firefox 55, but is only currently supported with SVG images loaded via chrome:// or resource:// URLs. To experiment with the feature in SVG on the Web it is necessary to set the svg.context-properties.content.enabled pref to true.

If you reference an SVG image in a webpage (such as with the <img> element or as a background image), the SVG image can coordinate with the embedding element (its context) to have the image adopt property values set on the embedding element. To do this the embedding element needs to list the properties that are to be made available to the image by listing them as values of the -moz-context-properties property, and the image needs to opt in to using those properties by using values such as the context-fill value.

Syntax

/* Keyword values */
-moz-context-properties: fill;
-moz-context-properties: fill, stroke;

/* Global values */
-moz-context-properties: inherit;
-moz-context-properties: initial; 
-moz-context-properties: unset;

Values

fill
Expose the fill value set on the image to the embedded SVG.
stroke
Expose the stoke value set on the image to the embedded SVG.
fill-opacity
Expose the fill-opacity value set on the image to the embedded SVG.
stroke-opacity
Expose the stoke-opacity value set on the image to the embedded SVG.

Formal syntax

none | [ fill | stroke ]#

Example

In this example we have a simple SVG embedded using an <img> element.

You first need to specify on the embedding element the properties whose values you wish to expose to the embedded SVG, using the -moz-context-properties property. For example:

.img1 {
  width: 100px;
  height: 100px;
  -moz-context-properties: fill, stroke;
  fill: lime;
  stroke: purple;
}

Now you've done this, the SVG image can use the values of the fill and stroke properties, for example:

<img class="img1" src="data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg'>
                       <rect width='100%' height='100%' stroke-width='30px'
                       fill='context-fill red' stroke='context-stroke' fill-opacity='0.5'/></svg>">

Here we've set the image src to a data URI containing a simple SVG image; the <rect> inside has been made to take its fill and stroke values from the fill and stroke set on the <img> element by giving them the context-fill/context-stroke keywords in their values, along with a fallback color for the fill (red) which will be used in the case that the SVG is loaded standalone in a top-level window (where it will have no context element to provide context values). Note that if a color is set directly on the SVG, but then the context color is also specified, the context color overrides the direct color.

Note: You can find a working example on Github.

Initial value none
Applies to replaced elements
Inherited no
Media visual
Computed value as specified
Animation type discrete
Canonical order the unique non-ambiguous order defined by the formal grammar

Specifications

This property it is not defined in any CSS standard.

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support ? 55 (55)[1] No support ? ?
Feature Android Android Webview Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile Chrome for Android
Basic support No support ? 55.0 (55)[1] No support ? ? ?

This feature is available since Firefox 55, but only enabled fully on Nightly; on other versions of Firefox you'll have to set the svg.context-properties.content.enabled pref to true, if the images aren't referenced via a chrome:// or resource:// URL.

© 2005–2017 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/CSS/-moz-context-properties