feat: add responsive capabilities for horizontal direction (#618)

* add responsiveness options

* update readme

* fix code style

* address PR comments

* address PR comments

README.md

@@ -221,6 +221,12 @@ require("toggleterm").setup{
       return term.name
     end
   },
+  responsiveness = {
+    -- breakpoint in terms of `vim.o.columns` at which terminals will start to stack on top of each other
+    -- instead of next to each other
+    -- default = 0 which means the feature is turned off
+    horizontal_breakpoint = 135,
+  }
 }
 ```
 

lua/toggleterm/config.lua

@@ -14,6 +14,9 @@ local function shade(color, factor) return colors.shade_color(color, factor) end
 ---@field name_formatter fun(term: Terminal):string
 ---@field enabled boolean
 
+--- @class Responsiveness
+--- @field horizontal_breakpoint number
+
 --- @class ToggleTermConfig
 --- @field size number
 --- @field shade_filetypes string[]
@@ -37,6 +40,7 @@ local function shade(color, factor) return colors.shade_color(color, factor) end
 --- @field winbar WinbarOpts
 --- @field autochdir boolean
 --- @field title_pos '"left"' | '"center"' | '"right"'
+--- @field responsiveness Responsiveness
 
 ---@type ToggleTermConfig
 local config = {
@@ -65,6 +69,9 @@ local config = {
     winblend = 0,
     title_pos = "left",
   },
+  responsiveness = {
+    horizontal_breakpoint = 0,
+  },
 }
 
 ---Derive the highlights for a toggleterm and merge these with the user's preferences

lua/toggleterm/ui.lua

@@ -224,6 +224,7 @@ end
 local split_commands = {
   horizontal = {
     existing = "rightbelow vsplit",
+    existing_stacked = "rightbelow split",
     new = "botright split",
     resize = "resize",
   },
@@ -316,7 +317,13 @@ function M.open_split(size, term)
     local split_win = windows[#windows]
     if config.persist_size then M.save_window_size(term.direction, split_win.window) end
     api.nvim_set_current_win(split_win.window)
-    vim.cmd(commands.existing)
+    local window_width = vim.o.columns
+    local horizontal_breakpoint = config.responsiveness.horizontal_breakpoint
+    if term.direction == "horizontal" and window_width < horizontal_breakpoint then
+      vim.cmd(commands.existing_stacked)
+    else
+      vim.cmd(commands.existing)
+    end
   else
     vim.cmd(commands.new)
   end

stylua.toml

@@ -2,4 +2,4 @@ column_width = 100
 indent_type = "Spaces"
 quote_style = "AutoPreferDouble"
 indent_width = 2
-collapse_simple_statement = 'Always'
+collapse_simple_statement = "Always"