function source.initialize_window_geometry()
  -- Initialize window width/height and make window resizable.
  --
  -- I get tempted to have opinions about window dimensions here, but they're
  -- non-portable:
  --  - maximizing doesn't work on mobile and messes things up
  --  - maximizing keeps the title bar on screen in Linux, but off screen on
  --    Windows. And there's no way to get the height of the title bar.
  -- It seems more robust to just follow LÖVE's default window size until
  -- someone overrides it.
  App.screen.width, App.screen.height, App.screen.flags = App.screen.size()
  source.initialize_window_geometry()
  Editor_state = edit.initialize_state(Margin_top, Margin_left, App.screen.width-Margin_right)

function run.initialize_window_geometry()
  -- Initialize window width/height and make window resizable.
  --
  -- I get tempted to have opinions about window dimensions here, but they're
  -- non-portable:
  --  - maximizing doesn't work on mobile and messes things up
  --  - maximizing keeps the title bar on screen in Linux, but off screen on
  --    Windows. And there's no way to get the height of the title bar.
  -- It seems more robust to just follow LÖVE's default window size until
  -- someone overrides it.
  run.initialize_window_geometry()
  Editor_state = edit.initialize_state(Margin_top, Margin_left, App.screen.width-Margin_right)
  Editor_state.font_height = font_height
  Editor_state.line_height = math.floor(font_height*1.3)

  initialize_window_geometry(App.width('m'))

  initialize_window_geometry()

function initialize_window_geometry(em_width)

function initialize_window_geometry()