-moz-context-properties

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.

Specifications

This property it is not defined in any CSS standard.

Browser compatibility

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.