chord diagram

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library(circlize)
library(dplyr)

## 
## Attaching package: 'dplyr'

## The following objects are masked from 'package:stats':
## 
##     filter, lag

## The following objects are masked from 'package:base':
## 
##     intersect, setdiff, setequal, union

library(RColorBrewer)

df = data.frame(from = c("B", "C", "D", "A", "B"), to = c("A", "B", "C", "B", "D"), value = c(2, 5, 6, 4, 1))
lab <- data.frame(factor = c("A", "B", "C", "D"), label = c("JPMM Home", "Andrew Carroll Gray", "jimbogray", "DSG"))

grid.cols <- brewer.pal(4, "Set1")
names(grid.cols) <- c("A", "B", "C", "D")


circos.clear()

circos.par(start.degree = 90, gap.degree = 3, track.margin = c(-0.1, 0.1),
           cell.padding = c(0,0),
           points.overflow.warning = FALSE)

par(mar = rep(0, 4), bg = "lightgrey")

chordDiagram(df, directional = 1, link.arr.type = "big.arrow", 
             transparency = 0.1, link.sort = TRUE, annotationTrack = "grid",
             direction.type = c("arrows", "diffHeight"), diffHeight  = -0.04,
             annotationTrackHeight = c(0.01, 0.01), col = grid.cols[df$from], grid.col = grid.cols,
             link.largest.ontop = TRUE,
             order = c("A", "B", "C", "D"))

circos.trackPlotRegion(
  bg.border = NA,
  track.index=1,
  panel.fun = function (x,y) {
  xlim = get.cell.meta.data("xlim")
  sector.index = get.cell.meta.data("sector.index")
  theta = mean(get.cell.meta.data("xplot")) %% 360
  if(theta < 90 || theta > 270) {
    text.facing = "clockwise"
    text.adj = c(0, 0.5)
    pos = 4
  } else {
    text.facing = "reverse.clockwise"
    text.adj = c(1, 0.5)
    pos = 2
  }
  
  circos.text(x = mean(xlim), y = 1, labels = lab$label[lab$factor == sector.index], 
              facing = text.facing, pos = pos, col = "white")
})