Align multiple heatmaps generated by ComplexHeatmap using pushViewport()

multiple_ComplexHeatmap.R

library(ComplexHeatmap)

# test data
list_ht <- list()

for(i in 1:8){

  mat1 = matrix(rnorm(80, 2), 8, 10)
  mat1 = rbind(mat1, matrix(rnorm(40, -2), 4, 10))
  rownames(mat1) = paste0("R", 1:12)
  colnames(mat1) = paste0("C", 1:10)


  ht = Heatmap(mat1, name = "rnorm",
    column_title = i)
    list_ht <- append(list_ht, list(ht)) 

}

# Determine the numbers of rows and columns
n_plot <- length(list_ht)
n_row <- ceiling(sqrt(n_plot))
n_col <- ceiling(n_plot/n_row)

# Generate n_row x n_col plot subspace
grid.newpage()
pushViewport(viewport(layout = grid.layout(nr = n_row, nc = n_col)))

for(i in 1:n_plot){
  # Determine the plot subspace
  current_row <- ceiling(i / n_col)
  current_col <- i - (current_row-1) * n_col

  # Plot heatmap in the subspace
  pushViewport(viewport(layout.pos.row = current_row, layout.pos.col = current_col))
  draw(list_ht[[i]], newpage = FALSE)
  upViewport()

}

upViewport()