Author: Guangchuang Yu School of Basic Medical Sciences, Southern Medical University
Date: 2025-08-24

# Shadow Text Grob and Layer

#### Guangchuang Yu
School of Basic Medical Sciences, Southern Medical University

#### 2025-08-24

## shadow text grob: `shadowtextGrob()` and `grid.shadowtext()`

    library(shadowtext)
    grid.shadowtext("grid is awesome", gp=gpar(cex=3, col="white"), rot=45)
    grid.shadowtext("hello world", y=0.85, gp=gpar(cex=5, col="steelblue"), bg.colour="firebrick")
    grid.shadowtext("R you ready!!!", y=.1, gp=gpar(cex=4, col="firebrick"))

## ggplot2 layer: `geom_shadowtext()`

    library(ggplot2)

    random_text <- function(n=1, length=10) {
        d <- data.frame(n=1:n, length=length)
        sapply(1:nrow(d), function(i) {
            paste(sample(c(0:9, letters, LETTERS),
                         d$length[i], replace=TRUE),
                  collapse="")
        })
    }

    n <- 10
    set.seed(2017-10-27)
    d <- data.frame(x = rnorm(n), y=rnorm(n),
                    label = random_text(n),
                    angle = sample(0:360, 10))
    p <- ggplot(d, aes(x, y)) + xlim(-2, 2.2) + ylim(-2, 2.4)

    p + geom_shadowtext(aes(label=label, angle=angle), size=5)

    p + geom_shadowtext(aes(label=label, angle=angle, color=label),
                        bg.colour='firebrick', size=5) +
        theme(legend.position="none")

axis text is also supported:

    x <- c("a","b","c","d","e","f")
    y <- c("10", "9","-10","11","-3","-15")
    data <- data.frame(x, y)
    data$y <- as.numeric(as.character(data$y))

    data$category <- ifelse(as.numeric(data$y)<0, 0, 1)
    data$category <- as.factor(data$category)

    g <- ggplot(data, aes(x = x, y = y)) +
        geom_bar(stat = "identity", aes(fill = category))

    g + theme(axis.text.x = element_shadowtext(
                                    colour = "white",
                                      size = 12,face = "bold"))