基于R语言Gmisc包绘制研究患者入组流程图的技术求助

我帮你梳理下代码里的核心问题，一步步调整后就能得到符合需求的患者纳入流程图啦～

首先你遇到的Error in coords(vert$grp_a/b) : Must inherit from class 'box', but has class 'NULL'，是因为spreadVertical(org_cohort = org_cohort, included = included, grps = grp_a)这行用法不对——spreadVertical不需要grps这种命名参数，直接传递要垂直排列的box就行，所以原来的vert对象里根本没有grp_a元素，自然会报NULL错误。

下面是修正后的完整代码，同时解决了布局混乱、框体截断的问题：

# 安装并加载所需包（如果未安装）
if (!require("Gmisc")) install.packages("Gmisc")
library(Gmisc, quietly = TRUE)
library(glue)
library(htmlTable)
library(grid)
library(magrittr)

# 创建所有流程图框，设置宽度避免文本截断
org_cohort <- boxGrob(
  glue("Patients with pancreatic cancer admitted to the University Clinic of Essen",
       "from 01/2002 to 08/2020",
       "n = {pop}", pop = txtInt(909), .sep = "\n"),
  width = 0.4
)

included <- boxGrob(
  glue("Patients with genetic sequencing and survival data",
       "n = {incl}", incl = txtInt(412), .sep = "\n"),
  width = 0.4
)

grp_a <- boxGrob(
  glue("Patients treated with FOLFIRINOX or Gemcitabine / nab-Paclitaxel",
       "n = {recr}", recr = txtInt(179), .sep = "\n"),
  width = 0.4
)

grp_b <- boxGrob(
  glue("Patients with genetic sequencing data via MAPK-TRON panel",
       "n = {recr}", recr = txtInt(185), .sep = "\n"),
  width = 0.4
)

excluded_1 <- boxGrob(
  glue("Excluded (n = {tot}):",
       " - No survival data: {NoSurv}",
       " - No MAPK-Tron panel and early available abdominal CT-scan: {NoMAPKCT}",
       tot = txtInt(506), NoSurv = txtInt(300), NoMAPKCT = txtInt(206), .sep = "\n"),
  just = "left",
  width = 0.4
)

excluded_2 <- boxGrob(
  glue("Excluded (n = {NoFGP}):",
       " - No FOLFIRINOX or Gemcitabine / nab-Paclitaxel as 1st line: {NoFGP}",
       NoFGP = txtInt(233), .sep = "\n"),
  just = "left",
  width = 0.4
)

excluded_3 <- boxGrob(
  glue("Excluded (n = {NoMAPK}):",
       " - No sequencing data available: {NoMAPK}",
       NoMAPK = txtInt(227), .sep = "\n"),
  just = "left",
  width = 0.4
)

# 初始化绘图页面
grid.newpage()

# 1. 垂直排列顶层两个框：原始队列 -> 纳入队列
vert_top <- spreadVertical(org_cohort, included)

# 2. 水平排列两个子组，对齐到纳入队列的下方
grps <- spreadHorizontal(grp_a, grp_b)
# 将子组移动到纳入队列的正下方，保持合适垂直间距
grps <- moveBox(grps, y = coords(vert_top$included)$bottom - 0.1)

# 3. 放置排除框到对应主框的右侧，对齐中间位置
excluded_1 <- moveBox(excluded_1, 
                      x = coords(vert_top$included)$right + 0.1,
                      y = coords(vert_top$included)$center_y)
excluded_2 <- moveBox(excluded_2,
                      x = coords(grps$grp_a)$right + 0.1,
                      y = coords(grps$grp_a)$center_y)
excluded_3 <- moveBox(excluded_3,
                      x = coords(grps$grp_b)$right + 0.1,
                      y = coords(grps$grp_b)$center_y)

# 绘制箭头连接
connectGrob(vert_top$org_cohort, vert_top$included, type = "vert") %>% grid.draw()
connectGrob(vert_top$included, grps$grp_a, type = "N") %>% grid.draw()
connectGrob(vert_top$included, grps$grp_b, type = "N") %>% grid.draw()
connectGrob(vert_top$included, excluded_1, type = "L") %>% grid.draw()
connectGrob(grps$grp_a, excluded_2, type = "L") %>% grid.draw()
connectGrob(grps$grp_b, excluded_3, type = "L") %>% grid.draw()

# 绘制所有框体
vert_top %>% grid.draw()
grps %>% grid.draw()
excluded_1 %>% grid.draw()
excluded_2 %>% grid.draw()
excluded_3 %>% grid.draw()

关键修改点说明： #

1. 解决NULL错误：删除了错误的grps = grp_a参数，改用spreadVertical直接传递要排列的box，再单独处理两个子组的水平布局，确保每个box都能被正确索引。
2. 避免框体截断：给每个boxGrob设置了width = 0.4，你可以根据文本长度调整这个值（比如0.35或0.45），确保所有内容都能完整显示。
3. 清晰的布局逻辑：把布局分成顶层垂直排列、子组水平排列、排除框定位三个独立步骤，更容易理解和微调位置。
4. 正确的箭头渲染：用grid.draw()替代print，确保箭头能在grid绘图环境中正确显示。

内容的提问来源于stack exchange，提问作者Pharmacos