r - geom_bar 的渐变填充相对于每个条进行缩放并且未映射到变量

Question

我的目标是重现这个图，我的问题是重现每个条中的渐变填充。

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@PavoDive 的好评将我们引导至 a question这基本上是说“你不能用 ggplot2 做到这一点，而且即使你能做到，这也是一个坏主意。”同意这是一个糟糕的图形选择，但出于教学目的，我想重新创建原始版本，然后显示改进。那么，是否有编程解决方案？



使用 ggplot 后面的数据代码我已经接近了，除了每个条形(和微小的刻度线)都相同的一致渐变着色。但是我的努力导致填充的条形与 y 值匹配，而在原始图中，每个条形都填充了相同的模式。我如何达到这种效果？

ggplot(df, aes(x = x, y = y, fill = y)) +
  geom_hline(yintercept = seq(0, .35, .05), color = "grey30", size = 0.5, linetype = "solid") +
  geom_bar(stat = "identity", width = 0.4) +
  scale_fill_gradient(low='green4', high='green1', guide = FALSE) +
  theme(legend.position = "none") +
  theme_minimal() +
  geom_text(data = df, aes(label = scales::percent(y), vjust = -.5)) +
  theme(axis.text.y = element_blank()) +
  theme(axis.ticks = element_blank()) +
  labs(y = "", x = "") +
  ggtitle("Question 15: Do you feel prepared to comply with the upcoming December
          2015 updated requirements of the FRCP that relate to ediscovery") +
  theme(plot.title = element_text(face = "bold", size = 18)) +
  theme(panel.border = element_blank())

数据

df <- data.frame(x = c("Prepared", "Somewhat\nprepared", "Not prepared", "Very prepared"),
                 y = c(.32, .31, .20, .17))
df$x <- factor(df$x, levels = c("Prepared", "Somewhat\nPrepared", "Not Prepared", "Very Prepared"))

Answer 1

这是一个选项，使用 geom_path用缩放 y 来着色而不是条形。这会创建一些新数据( dat )，从 0 到每个 df$y 的序列值(此处为长度 100，在 dat$y 列中)。然后，创建每个序列的缩放版本(从 0 到 1)，用作颜色渐变(称为 dat$scaled )。缩放是通过简单地将每个序列除以其最大值来完成的。

## Make the data for geom_path
mat <- mapply(seq, 0, df$y, MoreArgs = list(length=100))                         # make sequences 0 to each df$y
dat <- stack(data.frame(lapply(split(mat, col(mat)), function(x) x/tail(x,1))))  # scale each, and reshape
dat$x <- rep(df$x, each=100)                                                     # add the x-factors
dat$y <- stack(as.data.frame(mat))[,1]                                           # add the unscaled column
names(dat)[1] <- "scaled"                                                        # rename

## Make the plot
ggplot(dat, aes(x, y, color=scaled)) +                                           # use different data
  ## *** removed some code here ***
  geom_hline(yintercept = seq(0, .35, .05), color = "grey30", size = 0.5, linetype = "solid") +
  theme(legend.position = "none") +
  theme_minimal() +
  geom_text(data = df, aes(label = scales::percent(y), vjust = -.5), color="black") +
  theme(axis.text.y = element_blank()) +
  theme(axis.ticks = element_blank()) +
  labs(y = "", x = "") +
  ggtitle("Question 15: Do you feel prepared to comply with the upcoming December
          2015 updated requirements of the FRCP that relate to ediscovery") +
            theme(plot.title = element_text(face = "bold", size = 18)) +
            theme(panel.border = element_blank()) +
  ## *** Added this code ***            
  geom_path(lwd=20) +
  scale_color_continuous(low='green4', high='green1', guide=F)