New theme() parameters allow to set the style for horizontal and vertical facet labels separately:

stripBackgroundX and stripBackgroundY parameters set the background of horizontal and vertical facet labels respectively, specified with elementRect();
stripTextX and stripTextY - horizontal and vertical facet labels, specified with elementText().

In [1]:

%useLatestDescriptors
%use lets-plot

%use dataframe

In [2]:

LetsPlot.getInfo()

Out[2]:

Lets-Plot Kotlin API v.4.9.0. Frontend: Notebook with dynamically loaded JS. Lets-Plot JS v.4.5.1.

In [3]:

val df = dataFrameOf("animal_type", "animal", "weight", "diet")(
    "pet", "cat", 5, "carnivore",
    "pet", "dog", 10, "carnivore",
    "pet", "rabbit", 2, "herbivore",
    "pet", "hamster", 1, "herbivore",

    "farm", "cow", 500, "herbivore",
    "farm", "pig", 100, "carnivore",
    "farm", "horse", 700, "herbivore",
)

In [4]:

val p = letsPlot(df.toMap()) { x = "animal"; y = "weight" } +
    geomBar(stat = Stat.identity) +
    facetGrid(x = "animal_type", y = "diet", scales = "free") +
    themeBW()

p

Out[4]:

Change the style for facet labels:

In [5]:

p + theme(stripTextX = elementText(face = "bold"),
          stripBackgroundX = elementRect(fill = "pink"),
          stripTextY = elementText(face = "italic"),
          stripBackgroundY = elementRect(fill = "light_blue"))

Out[5]:

Hide horizontal facet labels:

In [6]:

p + theme(stripTextX = elementBlank())

Out[6]:

Horizontal and Vertical Facet Labels¶