组合多个stat_function行和原始数据点的图例

Question

我有以下代码：

library("ggplot2")

data <- data.frame(c(0,1,2,3,4,5), c(-0.2, 0.6, 2.1, 3.8, 6.05, 7.6))
colnames(data) <- c("X", "Y")

f1 <- function(x)
{
    x - 0.2
}

f2 <- function(x)
{
    ifelse(x>=1.9,-2+x+0.1,0)
}

m <- function(x)
{
    f1(x) + f2(x)
}

graph <- ggplot(data, aes(X,Y, colour="Data")) + geom_point(stat = "identity") + xlim(c(0,5))
graph <- graph + scale_shape_discrete(name = "Data")

g1 <- stat_function(fun=f1, linetype="dashed", aes(colour="Function A"))
g2 <- stat_function(fun=f2, linetype="dashed", aes(colour="Function B"))
gm <- stat_function(fun=m,  aes(colour="Model"))

graph <- graph + g1 + g2 + gm
graph <- graph + scale_colour_manual(values = c("black", "red", "red", "red"))
print(graph)

产生以下图表：

图例中并不能真正区分各种功能。我宁愿期待像这样的传奇：

是否有可能生产类似的东西？

Answer 1

这是一种（稍微丑陋）的可能性：

ggplot(data, aes(x = X, y = Y, colour = "Data")) +
  geom_point() +
  geom_line(aes(linetype = "Data"), alpha = 0) +
  stat_function(fun = f1, aes(colour = "Function A", linetype = "Function A")) +
  stat_function(fun = f2, aes(colour = "Function B", linetype = "Function B")) +
  stat_function(fun = m, aes(colour = "Model", linetype = "model")) +
  scale_linetype_manual(values = c("blank", "dashed", "dashed", "solid"),
                        guide = FALSE) +
  scale_colour_manual(values = c("black", "red", "red", "red"),
                      guide = guide_legend(override.aes = list(
                        linetype = c("blank", "dashed", "dashed", "solid"),
                        size = c(2, 0, 0, 0)),
                        title = NULL))

我为＆＃34; Data＆＃34;创建了一个空白虚拟线。积分（geom_line [...] alpha = 0）;将linetype移至aes内，移除linetype传奇（scale_linetype_manual [...] guide = FALSE）;使用linetype更改了size并在图例中指向guide_legend(override.aes。