DiagrammeR流程图垂直节点对齐与箭头优化技术咨询

Got it, let's tackle those flowchart problems one by one. I've revised your code to address all the layout alignment, straight arrow, and optional polyline arrow requests:

library(DiagrammeR)
grViz("digraph flowchart {
  # Set global node defaults to avoid repetition
  node [fontname = Helvetica]
  
  # node type 1: starting and ending node
  node [shape = oval]
  start [label = '@@1']
  pro2 [label = '@@6']

  # node type 2: decision
  node [shape = diamond]
  dec1 [label = '@@2']
  dec2 [label = '@@3']
  dec3 [label = '@@4']

  # node type 3: process node
  node [shape = rectangle]
  pro1 [label = '@@5']
  pro3 [label = '@@7']

  # Rank adjustments for vertical alignment
  {rank = same; start dec1 dec2 pro1}  # Align START, decision1, decision2, process1 vertically
  {rank = same; pro3 dec3 pro2}        # Align process3, decision3, END vertically

  # Edge definitions with fixes
  edge[tailclip = true, headclip = true];
  
  # Basic flow
  start -> dec1 [dir=forward]
  dec1 -> dec2 [label = '', headport = 'n', tailport = 's']  # Straight vertical arrow
  dec1 -> pro3 [label = '', headport = 'n', tailport = 'e']
  
  # Fix decision2 to process1: straight vertical arrow
  dec2 -> pro1 [label = '', tailport = 's', headport = 'n']
  
  dec2 -> pro3 [label = '']
  
  # Fix process3 to decision3: straight vertical arrow
  pro3 -> dec3 [label = '', tailport = 's', headport = 'n']
  
  dec3 -> pro2 [label = '', tailport = 's', headport = 'n']  # Straight vertical arrow
  dec3 -> pro3 [label = '', headport = 'e', tailport = 'e']
  
  # Optional: Polyline arrow from process1 to decision1 (horizontal then vertical then horizontal)
  # Add a hidden dummy node to create the polyline path
  node [shape=point, style=invisible]
  dummy1 [pos=""]
  {rank = same; pro1 dummy1}  # Align dummy node with process1 horizontally
  pro1 -> dummy1 [dir=none]
  dummy1 -> dec1 [headport='w']
}
[1]: 'START'
[2]: 'decision 1'
[3]: 'decision 2'
[4]: 'decision 3'
[5]: 'process 1'
[6]: 'END'
[7]: 'process 3'
")

Key Changes Explained: #

1. Vertical Alignment & Straight Arrow for Process 1

   • Added {rank = same; start dec1 dec2 pro1} to ensure all these nodes sit on the same horizontal level, fixing the left offset of process1.
   • Updated the dec2 -> pro1 edge to use tailport = 's' and headport = 'n', forcing a straight vertical line instead of a curved one.

2. Vertical Alignment & Straight Arrow for Decision 3 & END

   • Added {rank = same; pro3 dec3 pro2} to align process3, decision3, and END vertically.
   • Changed pro3 -> dec3 to use tailport = 's' and headport = 'n' for a straight vertical arrow.

3. Polyline Arrow (Optional)

   • Added an invisible dummy node (dummy1) aligned horizontally with process1.
   • Split the pro1 -> dec1 arrow into two segments: first a horizontal line to the dummy node, then a vertical/horizontal line to dec1's west port, creating the desired polyline path.

This should give you a clean, aligned flowchart with all the requested arrow behaviors!

内容的提问来源于stack exchange，提问作者alittleboy