feat(zoom): add zoom api

`config.ui.zoom_width` sets the percentage to zoom

Author: cameronr

lua/opencode/api.lua

@@ -16,6 +16,10 @@ function M.swap_position()
   require('opencode.ui.ui').swap_position()
 end
 
+function M.toggle_zoom()
+  require('opencode.ui.ui').toggle_zoom()
+end
+
 function M.open_input()
   core.open({ new_session = false, focus = 'input', start_insert = true })
 end
@@ -898,6 +902,11 @@ M.commands = {
     fn = M.toggle_pane,
   },
 
+  toggle_zoom = {
+    desc = 'Toggle window zoom',
+    fn = M.toggle_zoom,
+  },
+
   swap = {
     desc = 'Swap pane position left/right',
     fn = M.swap_position,

lua/opencode/config.lua

@@ -23,6 +23,7 @@ M.defaults = {
       ['<leader>oq'] = { 'close', desc = 'Close Opencode window' },
       ['<leader>os'] = { 'select_session', desc = 'Select session' },
       ['<leader>op'] = { 'configure_provider', desc = 'Configure provider' },
+      ['<leader>oz'] = { 'toggle_zoom', desc = 'Toggle zoom' },
       ['<leader>od'] = { 'diff_open', desc = 'Open diff view' },
       ['<leader>o]'] = { 'diff_next', desc = 'Next diff' },
       ['<leader>o['] = { 'diff_prev', desc = 'Previous diff' },
@@ -86,6 +87,7 @@ M.defaults = {
     position = 'right',
     input_position = 'bottom',
     window_width = 0.40,
+    zoom_width = 0.8,
     input_height = 0.15,
     picker_width = 100,
     display_model = true,

lua/opencode/state.lua

@@ -35,6 +35,7 @@
 ---@field opencode_server OpencodeServer|nil
 ---@field api_client OpencodeApiClient
 ---@field event_manager EventManager|nil
+---@field pre_zoom_width integer|nil
 ---@field required_version string
 ---@field opencode_cli_version string|nil
 ---@field append fun( key:string, value:any)
@@ -60,6 +61,7 @@ local _state = {
   display_route = nil,
   current_mode = nil,
   last_output = 0,
+  pre_zoom_width = nil,
   -- context
   last_sent_context = nil,
   current_context_config = {},

lua/opencode/ui/ui.lua

@@ -1,4 +1,3 @@
-local M = {}
 local config = require('opencode.config')
 local state = require('opencode.state')
 local renderer = require('opencode.ui.renderer')
@@ -7,6 +6,8 @@ local input_window = require('opencode.ui.input_window')
 local footer = require('opencode.ui.footer')
 local topbar = require('opencode.ui.topbar')
 
+local M = {}
+
 ---@param windows OpencodeWindowState?
 function M.close_windows(windows)
   if not windows then
@@ -244,4 +245,24 @@ function M.swap_position()
   end)
 end
 
+function M.toggle_zoom()
+  local windows = state.windows
+  if not windows or not state.windows.output_win or not state.windows.input_win then
+    return
+  end
+
+  local width
+
+  if state.pre_zoom_width then
+    width = state.pre_zoom_width
+    state.pre_zoom_width = nil
+  else
+    state.pre_zoom_width = vim.api.nvim_win_get_width(windows.output_win)
+    width = math.floor(config.ui.zoom_width * vim.o.columns)
+  end
+
+  vim.api.nvim_win_set_config(windows.input_win, { width = width })
+  vim.api.nvim_win_set_config(windows.output_win, { width = width })
+end
+
 return M

tests/unit/api_spec.lua

@@ -518,4 +518,29 @@ describe('opencode.api', function()
       state.current_model = original_model
     end)
   end)
+
+  describe('toggle_zoom', function()
+    it('calls ui.toggle_zoom when toggle_zoom is called', function()
+      stub(ui, 'toggle_zoom')
+
+      api.toggle_zoom()
+
+      assert.stub(ui.toggle_zoom).was_called()
+    end)
+
+    it('is available in the commands table', function()
+      local cmd = api.commands['toggle_zoom']
+      assert.truthy(cmd, 'toggle_zoom command should exist')
+      assert.equal('Toggle window zoom', cmd.desc)
+      assert.is_function(cmd.fn)
+    end)
+
+    it('routes through command interface', function()
+      stub(ui, 'toggle_zoom')
+
+      api.commands.toggle_zoom.fn({})
+
+      assert.stub(ui.toggle_zoom).was_called()
+    end)
+  end)
 end)