### 4.2.2 Properties found in interfaces

Suppose now that we wish to print the lyrics in italics. What form of `\override` command do we need to do this? We first look in the IR page listing ‘All layout objects’, as before, and look for an object that might control lyrics. We find `LyricText`, which looks right. Clicking on this shows the settable properties for lyric text. These include the `font-series` and `font-size`, but nothing that might give an italic shape. This is because the shape property is one that is common to all font objects, so, rather than including it in every layout object, it is grouped together with other similar common properties and placed in an Interface, the `font-interface`.

So now we need to learn how to find the properties of interfaces, and to discover what objects use these interface properties.

Look again at the IR page which describes LyricText. At the bottom of the page is a list of clickable interfaces which LyricText supports. The list has several items, including `font-interface`. Clicking on this brings up the properties associated with this interface, which are also properties of all the objects which support it, including LyricText.

Now we see all the user-settable properties which control fonts, including `font-shape(symbol)`, where `symbol` can be set to `upright`, `italics` or `caps`.

You will notice that `font-series` and `font-size` are also listed there. This immediately raises the question: Why are the common font properties `font-series` and `font-size` listed under `LyricText` as well as under the interface `font-interface` but `font-shape` is not? The answer is that `font-series` and `font-size` are changed from their global default values when a `LyricText` object is created, but `font-shape` is not. The entries in `LyricText` then tell you the values for those two properties which apply to `LyricText`. Other objects which support `font-interface` will set these properties differently when they are created.

Let’s see if we can now construct the `\override` command to change the lyrics to italics. The object is `LyricText`, the property is `font-shape` and the value is `italic`. As before, we’ll omit the context.

As an aside, although it is an important one, note that some properties take values that are symbols, like `italic`, and must be preceded by an apostrophe, `'`. Symbols are then read internally by LilyPond. Note the distinction from arbitrary text strings, which would appear as `"a text string"`; for more details about symbols and strings, see Scheme tutorial.

So we see that the `\override` command needed to print the lyrics in italics is:

>     \override LyricText.font-shape = #'italic

This should be placed just in front of the lyrics we wish to affect, like so:

>     {
>       \key es \major
>       \time 6/8
>       {
>         r4 bes8 bes[( g]) g |
>         g8[( es]) es d[( f]) as |
>         as8 g
>       }
>       \addlyrics {
>         \override LyricText.font-shape = #'italic
>         The man who | feels love's sweet e -- | mo -- tion
>       }
>     }

and the lyrics are all printed in italics.

Note: In lyrics always leave whitespace between the final syllable and the terminating brace.

#### See also

Extending: Scheme tutorial.

其他语言：česky, deutsch, español, français, italiano, 日本語, nederlands。
About automatic language selection.

#### LilyPond — Learning Manual v2.18.2 (稳定分支).