在ggplot2中将点与背景png对齐

Question

我正在尝试在 384 孔板实验中创建与发光值对应的点网格。我将盘子绘制为 .png 文件并覆盖网格，这样每个点都应该位于盘子的一个孔中。提供示例代码和数据。

是否可以使用 ggplot2 执行此操作？

我正在使用以下代码（提供的示例数据）：

library(ggplot2)
library(png)
library(RCurl)
library(grid)

example.gg <- read.csv("https://docs.google.com/spreadsheets/d/e/2PACX-1vRcX5aMZGCp9Bs3BRZSg8k4o-kbSjOO5z3LsRxgIv4qJHz1fG-Argruje32OuZ2Tt2qPaNGksGr4Jia/pub?output=csv",
            row.names = 1)
example.gg$Row <- factor(example.gg$Row, levels = rev(sort(unique(example.gg$Row))))

png.img <- readPNG(getURLContent("https://i.imgur.com/QeSO7d3.png"))
img.rg <- rasterGrob(png.img, interpolate=TRUE)

gp <- ggplot(example.gg,
             aes(x = Col, y = Row, col = Lum)) +
  annotation_custom(img.rg, xmin=-Inf, xmax=Inf, ymin=-Inf, ymax=Inf) +
  geom_point(shape = 15) + 
  theme_void()
gp

这是制作的图像：

回答

感谢的原始回答。

gp <- ggplot(example.gg,
             aes(x = Col, y = Row, col = Lum)) +
  annotation_custom(img.rg, 
                    xmin = -2,
                    xmax = 27,
                    ymin = -1,
                    ymax = 18) +
  geom_point(shape = 15, size = 2.5) + 
  theme_void()
gp + coord_fixed(clip = "off") +
  theme(plot.margin = unit(c(3, 6, 5, 2), "lines"),
        legend.position = c(1.2, 0.5)) +
  scale_colour_gradientn(colours = pals::ocean.haline(100))

Answer 1

通过xmin/xmax & ymin/ymax手动调整图片位置，固定行列间距coord_fixed(clip = "off) 并在 theme 中扩展 plot.margin 我能够得到一些看起来可行的东西。

library(ggplot2)
library(png)
library(RCurl)
library(grid)

example.gg <- read.csv("https://docs.google.com/spreadsheets/d/e/2PACX-1vRcX5aMZGCp9Bs3BRZSg8k4o-kbSjOO5z3LsRxgIv4qJHz1fG-Argruje32OuZ2Tt2qPaNGksGr4Jia/pub?output=csv",
            row.names = 1)
example.gg$Row <- factor(example.gg$Row, levels = sort(unique(example.gg$Row)))

png.img <- readPNG(getURLContent("https://i.imgur.com/QeSO7d3.png"))
img.rg <- rasterGrob(png.img, interpolate=TRUE)

gp <- ggplot(example.gg,
       aes(x = Col, y = Row, col = Lum)) +
  annotation_custom(
    img.rg,
    xmin = -2,
    xmax = 27,
    ymin = -1,
    ymax = 18
  ) +
  geom_point(shape = 15) +
  coord_fixed(clip = "off") +
  theme_void() +
  theme(plot.margin = unit(c(3, 2, 5, 2), "lines"))
  
gp

^{由 reprex package (v2.0.1)}

于 2022-02-14 创建

Answer 2

我喜欢挑战，所以这是一个单一的 ggplot 调用，不依赖任何 png 文件

ggplot(example.gg, aes(factor(Col, levels = 1:24), Row, fill = Lum)) + 
  geom_tile(size = 6, color = "white") + 
  geom_label(label = "  ", fill = NA, label.padding = unit(0.3, "lines")) +
  annotation_custom(roundrectGrob(gp = gpar(fill = NA)), xmin = -2, 
                    xmax = 26, ymin = -1, ymax = 19) +
  annotation_custom(roundrectGrob(gp = gpar(fill = NA), r = unit(0.01, "npc")), 
                    xmin = 0.5, xmax = 24.5, ymin = 0.5, ymax = 16.5) +
  annotation_custom(polygonGrob(
    x = c(0.05, 0.99, 1, 1, 0.99, 0.05, 0, 0, 0.05), 
    y = c(0, 0, 0.01, 0.99, 1, 1, 0.9, 0.1, 0), gp = gpar(fill = NA)),
    xmin = -1.5, xmax = 25, ymin = 0, ymax = 18) +
  scale_fill_gradientn(colours = pals::ocean.haline(100)) +
  theme_void() + 
  coord_equal(clip = "off") +
  scale_x_discrete(expand = c(0.03, 0)) +
  guides(x = guide_axis(position = "top")) +
  theme(axis.text = element_text(size = 18),
        axis.text.x.top = element_text(size = 12),
        plot.margin = margin(20, 20, 20, 40),
        legend.box.margin =  margin(20, 20, 20, 40))

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