How to interpret API documentation function parameters?

Question

Is there a standard to interpret the syntax of function interfaces in API documentations and if yes, how is it defined?

Here is an example on how to change the color

Answer 1

The brackets mean that the property is optional. Be aware though that if you want to set some property at the nTh rank, you have to either declare properties for the leading one or declare them as undefined :

fillPath() //good
fillPath ( someFillColor ) //good
fillPath ( someFillColor, mode ) //good
fillPath ( undefined, mode ) //good
fillPath ( mode ) //bad
fillPath ( undefined ) //really bad