[QUESTION] Providing more horizontal room for the labels in tanglegram

[mooibroekd]

When plotting a tanglegram() to compare two dendrograms my labels are not fully showing. I am aware that I can adjust the font size, but that would make the labels more difficult to read. I would rather have a way to expand the space for the labels. I could not find an option to do so when making the plot.

Is it possible to extend the space used by the labels through an option?

################################################################################
## Dendrogram a
################################################################################
a <- list()  # initialize empty object
# define merging pattern: 
#    negative numbers are leaves, 
#    positive are merged clusters (defined by row number in $merge)
a$merge <- matrix(c(-1, -2,
                    -3, -4,
                    1,  2), nc=2, byrow=TRUE ) 
a$height <- c(1, 1.5, 3)    # define merge heights
a$order <- 1:4              # order of leaves(trivial if hand-entered)
a$labels <- c("AAAAAAA",
              "BBBBBBB",
              "CCCCCCC",
              "DDDDDDD")    # labels of leaves
class(a) <- "hclust"        # make it an hclust object

#convert to a dendrogram object if needed
ad <- as.dendrogram(a) |> 
  dendextend::set("labels_to_char") # make sure the labels are characters

# dendrogam b
bd <- ad
################################################################################
## Combine using match_order_by_labels
################################################################################

# no warning message:
ab <- dendextend::dendlist(ad,
                           bd) |>
  dendextend::tanglegram()

^{Created on 2024-04-20 with reprex v2.1.0}

[mooibroekd]

The tanglegram() function has the parameters left_dendo_mar and right_dendo_mar. These use the defined margins like margin_inner. When this variable is increased from the default parameter, it will show the labels without overlapping. In the reprex below the default value of margin_inner = 3 is replaced by margin_inner = 5 and this shows the labels nicely.

################################################################################
## Dendrogram a
################################################################################
a <- list()  # initialize empty object
# define merging pattern: 
#    negative numbers are leaves, 
#    positive are merged clusters (defined by row number in $merge)
a$merge <- matrix(c(-1, -2,
                    -3, -4,
                    1,  2), nc=2, byrow=TRUE ) 
a$height <- c(1, 1.5, 3)    # define merge heights
a$order <- 1:4              # order of leaves(trivial if hand-entered)
a$labels <- c("AAAAAAA",
              "BBBBBBB",
              "CCCCCCC",
              "DDDDDDD")    # labels of leaves
class(a) <- "hclust"        # make it an hclust object

#convert to a dendrogram object if needed
ad <- as.dendrogram(a) |> 
  dendextend::set("labels_to_char") # make sure the labels are characters

# dendrogam b
bd <- ad
################################################################################
## Combine using match_order_by_labels
################################################################################

# no warning message:
ab <- dendextend::dendlist(ad,
                           bd) |>
  dendextend::tanglegram(margin_inner = 5)

^{Created on 2024-04-26 with reprex v2.1.0}

I do think the documentation might benefit from giving some more information about the use of margins. Additionally, the lab.cex parameter can be used to increase the font size of the labels.

[talgalili]

Just to say thanks for closing this while giving your answer.