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)

  source.initialize_window_geometry(App.width('m'))

  source.initialize_window_geometry()

function source.initialize_window_geometry(em_width)

function source.initialize_window_geometry()

run = {}
Editor_state = {}
-- called both in tests and real run
function run.initialize_globals()
  -- tests currently mostly clear their own state
  -- blinking cursor
  Cursor_time = 0
end
-- called only for real run
function run.initialize(arg)
  log_new('run')
  if Settings then
    run.load_settings()
  else
    run.initialize_default_settings()
  end

    Editor_state.filename = arg[1]
    load_from_disk(Editor_state)
    Text.redraw_all(Editor_state)
    Editor_state.screen_top1 = {line=1, pos=1}
    Editor_state.cursor1 = {line=1, pos=1}
  else
    load_from_disk(Editor_state)
    Text.redraw_all(Editor_state)
  end
  edit.check_locs(Editor_state)
  -- keep a few blank lines around: https://merveilles.town/@akkartik/110084833821965708
  love.window.setTitle('text.love - '..Editor_state.filename)
  if #arg > 1 then
    print('ignoring commandline args after '..arg[1])
  end
  if rawget(_G, 'jit') then
    jit.off()
    jit.flush()
  end

end
function run.load_settings()
  love.graphics.setFont(love.graphics.newFont(Settings.font_height))

  App.screen.flags.resizable = true
  App.screen.width, App.screen.height = Settings.width, Settings.height
  App.screen.resize(App.screen.width, App.screen.height, App.screen.flags)

  Editor_state = edit.initialize_state(Margin_top, Margin_left, App.screen.width-Margin_right, Settings.font_height, math.floor(Settings.font_height*1.3))
  Editor_state.filename = Settings.filename
  Editor_state.screen_top1 = Settings.screen_top
  Editor_state.cursor1 = Settings.cursor
end

function run.initialize_default_settings()
  local font_height = 20
  love.graphics.setFont(love.graphics.newFont(font_height))
  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)
  Settings = run.settings()
end

  run.initialize_window_geometry(App.width('m'))

  run.initialize_window_geometry()

function run.initialize_window_geometry(em_width)

function run.initialize_window_geometry()

  App.screen.width, App.screen.height, App.screen.flags = App.screen.size()
  App.screen.flags.resizable = true
  App.screen.resize(App.screen.width, App.screen.height, App.screen.flags)
end
function run.resize(w, h)
--?   print(("Window resized to width: %d and height: %d."):format(w, h))
  App.screen.width, App.screen.height = w, h
  Text.redraw_all(Editor_state)
  Editor_state.selection1 = {}  -- no support for shift drag while we're resizing
  Editor_state.right = App.screen.width-Margin_right
  Editor_state.width = Editor_state.right-Editor_state.left
  Text.tweak_screen_top_and_cursor(Editor_state, Editor_state.left, Editor_state.right)
end
function run.file_drop(file)
  -- first make sure to save edits on any existing file
  if Editor_state.next_save then
    save_to_disk(Editor_state)
  end
  -- clear the slate for the new file
  App.initialize_globals()
  Editor_state.filename = file:getFilename()
  file:open('r')
  Editor_state.lines = load_from_file(file)
  file:close()
  Text.redraw_all(Editor_state)
  Editor_state.screen_top1 = {line=1, pos=1}
  Editor_state.cursor1 = {line=1, pos=1}
  -- keep a few blank lines around: https://merveilles.town/@akkartik/110084833821965708
  love.window.setTitle('text.love - '..Editor_state.filename)
end
function run.draw()
  edit.draw(Editor_state)
end
function run.update(dt)
  Cursor_time = Cursor_time + dt
  edit.update(Editor_state, dt)
end
function run.quit()
  edit.quit(Editor_state)
end
function run.settings()

  return {
    x=Settings.x, y=Settings.y, displayindex=Settings.displayindex,
    width=App.screen.width, height=App.screen.height,
    font_height=Editor_state.font_height,

    screen_top=Editor_state.screen_top1, cursor=Editor_state.cursor1
  }

end
function run.mouse_press(x,y, mouse_button)
  Cursor_time = 0  -- ensure cursor is visible immediately after it moves
  return edit.mouse_press(Editor_state, x,y, mouse_button)
end
function run.mouse_release(x,y, mouse_button)
  Cursor_time = 0  -- ensure cursor is visible immediately after it moves
  return edit.mouse_release(Editor_state, x,y, mouse_button)
end
function run.mouse_wheel_move(dx,dy)
  Cursor_time = 0  -- ensure cursor is visible immediately after it moves
  return edit.mouse_wheel_move(Editor_state, dx,dy)
end
function run.text_input(t)
  Cursor_time = 0  -- ensure cursor is visible immediately after it moves
  return edit.text_input(Editor_state, t)
end
function run.keychord_press(chord, key)
  Cursor_time = 0  -- ensure cursor is visible immediately after it moves
  return edit.keychord_press(Editor_state, chord, key)
end
function run.key_release(key, scancode)
  Cursor_time = 0  -- ensure cursor is visible immediately after it moves
  return edit.key_release(Editor_state, key, scancode)
end

  run.initialize_window_geometry()
function run.initialize_window_geometry()