-- create a drawing with a line
  App.screen.init{width=Test_margin_left+256, height=300}  -- drawing coordinates 1:1 with pixels
  Editor_state = edit.initialize_test_state()
  Editor_state.filename = 'foo'
  Editor_state.lines = load_array{'```lines', '```', ''}
  Text.redraw_all(Editor_state)
  edit.check_locs(Editor_state)
  Editor_state.current_drawing_mode = 'line'
  edit.draw(Editor_state)
  -- draw a line
  edit.run_after_mouse_press(Editor_state, Editor_state.left+5, Editor_state.top+Drawing_padding_top+6, 1)
  edit.run_after_mouse_release(Editor_state, Editor_state.left+35, Editor_state.top+Drawing_padding_top+36, 1)
  local drawing = Editor_state.lines[1]
  check_eq(#drawing.shapes, 1, 'baseline/#shapes')
  check_eq(#drawing.points, 2, 'baseline/#points')
  check_eq(drawing.shapes[1].mode, 'line', 'baseline/shape:1')
  local p1 = drawing.points[drawing.shapes[1].p1]
  local p2 = drawing.points[drawing.shapes[1].p2]
  check_eq(p1.x, 5, 'baseline/p1:x')
  check_eq(p1.y, 6, 'baseline/p1:y')
  check_eq(p2.x, 35, 'baseline/p2:x')
  check_eq(p2.y, 36, 'baseline/p2:y')
  check_nil(p2.name, 'baseline/p2:name')
  -- enter 'name' mode without moving the mouse
  edit.run_after_keychord(Editor_state, 'C-n')
  check_eq(Editor_state.current_drawing_mode, 'name', 'mode:1')
end
function test_move_point()
  -- create a drawing with a line
  App.screen.init{width=Test_margin_left+256, height=300}  -- drawing coordinates 1:1 with pixels
  Editor_state = edit.initialize_test_state()
  Editor_state.filename = 'foo'
  Editor_state.lines = load_array{'```lines', '```', ''}
  Text.redraw_all(Editor_state)
  Editor_state.current_drawing_mode = 'line'
  edit.draw(Editor_state)
  edit.run_after_mouse_press(Editor_state, Editor_state.left+5, Editor_state.top+Drawing_padding_top+6, 1)
  edit.run_after_mouse_release(Editor_state, Editor_state.left+35, Editor_state.top+Drawing_padding_top+36, 1)
  local drawing = Editor_state.lines[1]
  check_eq(#drawing.shapes, 1, 'baseline/#shapes')
  check_eq(#drawing.points, 2, 'baseline/#points')
  check_eq(drawing.shapes[1].mode, 'line', 'baseline/shape:1')
function test_move_point()
  -- click outside the drawing
  edit.run_after_mouse_click(Editor_state, App.screen.width-5, App.screen.height-5, 1)
  -- press a key
  edit.run_after_text_input(Editor_state, 'a')
  -- key goes to text
  check_eq(Editor_state.lines[2].data, 'a')
  check_eq(#drawing.shapes, 1, 'baseline/#shapes')
  check_eq(#drawing.points, 2, 'baseline/#points')
  check_eq(drawing.shapes[1].mode, 'line', 'baseline/shape:1')
  local p1 = drawing.points[drawing.shapes[1].p1]
  local p2 = drawing.points[drawing.shapes[1].p2]
  check_eq(p1.x, 5, 'baseline/p1:x')
  check_eq(p1.y, 6, 'baseline/p1:y')
  check_eq(p2.x, 35, 'baseline/p2:x')
  check_eq(p2.y, 36, 'baseline/p2:y')
  check_nil(p2.name, 'baseline/p2:name')
  -- enter 'name' mode without moving the mouse
  edit.run_after_keychord(Editor_state, 'C-n')
  check_eq(Editor_state.current_drawing_mode, 'name', 'mode:1')
  -- hit backspace
  edit.run_after_keychord(Editor_state, 'backspace')
  -- no crash
end
function test_name_point_then_exit_drawing()
  -- draw a line
  edit.run_after_mouse_press(Editor_state, Editor_state.left+5, Editor_state.top+Drawing_padding_top+6, 1)
  edit.run_after_mouse_release(Editor_state, Editor_state.left+35, Editor_state.top+Drawing_padding_top+36, 1)
  local drawing = Editor_state.lines[1]
function test_name_point_then_hit_backspace()
  -- create a drawing with a line
  App.screen.init{width=Test_margin_left+256, height=300}  -- drawing coordinates 1:1 with pixels
  Editor_state = edit.initialize_test_state()
  Editor_state.filename = 'foo'
  Editor_state.lines = load_array{'```lines', '```', ''}
  Text.redraw_all(Editor_state)
  Editor_state.current_drawing_mode = 'line'
  edit.draw(Editor_state)

  assert(State.lines[State.cursor1.line].mode == 'text')
  local byte_offset = Text.offset(State.lines[State.cursor1.line].data, State.cursor1.pos)
  State.lines[State.cursor1.line].data = string.sub(State.lines[State.cursor1.line].data, 1, byte_offset-1)..t..string.sub(State.lines[State.cursor1.line].data, byte_offset)
  Text.clear_screen_line_cache(State, State.cursor1.line)
  State.cursor1.pos = State.cursor1.pos+1

        if len > 0 then
          local byte_offset = Text.offset(p.name, len-1)
          if len == 1 then byte_offset = 0 end
          p.name = string.sub(p.name, 1, byte_offset)
          record_undo_event(State, {before=before, after=snapshot(State, State.lines.current_drawing_index)})
        end
      end
    end
    schedule_save(State)
  elseif State.lines.current_drawing and State.current_drawing_mode == 'name' then
    if chord == 'return' then
      State.current_drawing_mode = State.previous_drawing_mode
      State.previous_drawing_mode = nil
    else
      local before = snapshot(State, State.lines.current_drawing_index)
      local drawing = State.lines.current_drawing
      local p = drawing.points[drawing.pending.target_point]
      if chord == 'escape' then
        p.name = nil
        record_undo_event(State, {before=before, after=snapshot(State, State.lines.current_drawing_index)})
      elseif chord == 'backspace' then
        local len = utf8.len(p.name)
  elseif State.lines.current_drawing and State.current_drawing_mode == 'name' then
    local before = snapshot(State, State.lines.current_drawing_index)
    local drawing = State.lines.current_drawing
    local p = drawing.points[drawing.pending.target_point]
    p.name = p.name..t
    record_undo_event(State, {before=before, after=snapshot(State, State.lines.current_drawing_index)})
--?   print('text input', t)
  if State.search_term then
    State.search_term = State.search_term..t
    State.search_text = nil
    Text.search_next(State)
--?   print('release', State.cursor1.line)
  if State.lines.current_drawing then
--?   print('press', State.cursor1.line)
  if mouse_press_consumed_by_any_button_handler(State, x,y, mouse_button) then
    -- press on a button and it returned 'true' to short-circuit
    return
  end
  for line_index,line in ipairs(State.lines) do
        button(State, 'draw', {x=State.left-Margin_left+4, y=y+4, w=12,h=12, color={1,1,0},
          icon = icon.insert_drawing,
          onpress1 = function()
                       Drawing.before = snapshot(State, line_index-1, line_index)
                       table.insert(State.lines, line_index, {mode='drawing', y=y, h=256/2, points={}, shapes={}, pending={}})
                       table.insert(State.line_cache, line_index, {})
                       if State.cursor1.line >= line_index then
                         State.cursor1.line = State.cursor1.line+1
                       end
                       schedule_save(State)
                       record_undo_event(State, {before=Drawing.before, after=snapshot(State, line_index-1, line_index+1)})
                     end,
        })
  if loc1.line > #State.lines then return true end
  local l = State.lines[loc1.line]
  if l.mode ~= 'text' then return false end  -- pos is irrelevant to validity for a drawing line
  return loc1.pos > #State.lines[loc1.line].data
end
function edit.cursor_on_text(State)
  return State.cursor1.line <= #State.lines
      and State.lines[State.cursor1.line].mode == 'text'
end
function edit.put_cursor_on_first_text_line(State)

  return loc1.line > #State.lines
      or loc1.pos > #State.lines[loc1.line].data