The color of the filled part of this layer. This color can be specified as rgba with an alpha component and the color's opacity will not affect the opacity of the 1px stroke, if it is used.
The opacity of the entire fill layer. In contrast to the fill-color, this value will also affect the 1px stroke around the fill, if the stroke is used.
Name of image in sprite to use for drawing image fills. For seamless patterns, image width and height must be a factor of two (2, 4, 8, ..., 512). Note that zoom-dependent expressions will be evaluated only at integer zoom levels.