@@ -198,6 +198,7 @@ importFrom(ggplot2,guides)

 importFrom(ggplot2,labeller)

 importFrom(ggplot2,last_plot)

 importFrom(ggplot2,layer)

+importFrom(ggplot2,layer_scales)

 importFrom(ggplot2,position_nudge)

 importFrom(ggplot2,scale_color_manual)

 importFrom(ggplot2,scale_fill_discrete)

@@ -205,8 +206,10 @@ importFrom(ggplot2,scale_fill_gradient)

 importFrom(ggplot2,scale_fill_manual)

 importFrom(ggplot2,scale_x_continuous)

 importFrom(ggplot2,scale_x_date)

+importFrom(ggplot2,scale_x_discrete)

 importFrom(ggplot2,scale_x_reverse)

 importFrom(ggplot2,scale_y_continuous)

+importFrom(ggplot2,scale_y_discrete)

 importFrom(ggplot2,theme)

 importFrom(ggplot2,theme_bw)

 importFrom(ggplot2,theme_void)

@@ -1,6 +1,7 @@

 # ggtree 2.1.1

 + convert roxygen documents using markdown (2019-11-01, Fri)

++ extend `xlim2` and `ylim2` to support discrete scale.

 + `xlim2` and `ylim2` to uniformize axis limits of ggplot objects (2019-10-31, Thu)

   - <https://yulab-smu.github.io/treedata-book/chapter7.html#composite_plot>

   - <https://yulab-smu.github.io/treedata-book/docs/chapter10.html#axis_align>

@@ -95,14 +95,19 @@ axis_align <- function(gg, limits = NULL, axis) {

 yrange <- function(gg) {

-    ggrange(gg, "y.range")

+    ggrange(gg, "y")

 }

 xrange <- function(gg) {

-    ggrange(gg, "x.range")

+    ggrange(gg, "x")

 }

+##' @importFrom ggplot2 layer_scales

 ggrange <- function(gg, var) {

+    res <- layer_scales(gg)[[var]]$range$range

+    if (is.character(res)) return(res)

+

+    var <- paste0(var, ".range")

     ggplot_build(gg)$layout$panel_params[[1]][[var]]

 }

@@ -22,15 +22,23 @@ ggplot_add.facet_xlim <- function(object, plot, object_name) {

 ##' @method ggplot_add axisAlign

+##' @importFrom ggplot2 scale_x_discrete

+##' @importFrom ggplot2 scale_y_discrete

 ##' @export

 ggplot_add.axisAlign <- function(object, plot, object_name) {

     limits <- object$limits

+

     ## expand_limits <- object$expand_limits

     ## limits[1] <- limits[1] + (limits[1] * expand_limits[1]) - expand_limits[2]

     ## limits[2] <- limits[2] + (limits[2] * expand_limits[3]) + expand_limits[4]

-    lim_x <- scale_x_continuous(limits=limits, expand=c(0,0))

-    lim_y <- scale_y_continuous(limits = limits, expand = c(0, 0))

+    if (is.numeric(limits)) {

+        lim_x <- scale_x_continuous(limits=limits, expand=c(0,0))

+        lim_y <- scale_y_continuous(limits = limits, expand = c(0, 0))

+    } else {

+        lim_x <- scale_x_discrete(limits=limits, expand = c(0, 0.6))

+        lim_y <- scale_y_discrete(limits = limits, expand = c(0, 0.6))

+    }

     if (object$axis == 'x') {

         ## if (object$by == "x") {