Giving arguments to styles

Remember that in Figure 5.5, we defined the vertex style in the following way:

\tikzset{vertex/.style = {mytext, shape = circle,
  ball color = blue}}

We can introduce an argument when we intend to have different colors with the same style. One argument is easily supported; we can write the following, similar to arguments in macros:

\tikzset{vertex/.style = {mytext, shape = circle,
  ball color = #1}}

Now, we can change our code for Figure 5.5 to choose colors as arguments:

\node[vertex=blue] (A) {A};
\node[vertex=green, right = 4 cm of A] (B) {B};

So, #1 represents an argument in our style, and with style=value, we set that value for #1. We can specify a value that’s used when no value is given using the so-called .default handler:

\tikzset{vertex/.default=blue}

Now, we can write \node[vertex] for a blue node by default, and \node[vertex=green] for a green node.

We may write style={value} to avoid misunderstandings...