The color property can be set to a HEX string or to a color object, that is the same as the one used in particles.color options.
This color is set to canvas style background-color property, if this property is not set the background will be transparent.
The image property sets the canvas style background-image property.
This property doesn't have a default value, anyway if you need a background image you need to specify the same CSS syntax with the url() function.
The opacity property sets the color property opacity, so you can set a semi-transparent background.
This value is by default to 1 and it accepts any value between 0 and 1 included.
The position property sets the canvas style background-position property.
This link can be useful to set the right value to this property.
The repeat property sets the canvas style background-repeat property.
This link can be useful to set the right value to this property.
The size property sets the canvas style background-size property.
This link can be useful to set the right value to this property.
The background options used by the canvas element, it's not drawn, it's applied in the style [[include:Options/Background.md]]