end
function test_up_arrow_scrolls_up_by_one_line_skipping_drawing()
  -- display lines 3/4/5 with a drawing just off screen at line 2
  App.screen.init{width=120, height=60}
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{'abc', '```lines', '```', 'def', 'ghi', 'jkl'}
  Text.redraw_all(Editor_state)
  Editor_state.cursor1 = {line=3, pos=1}
  Editor_state.screen_top1 = {line=3, pos=1}
  Editor_state.screen_bottom1 = {}
  edit.draw(Editor_state)
  local y = Editor_state.top
  App.screen.check(y, 'def', 'baseline/screen:1')
  y = y + Editor_state.line_height
  App.screen.check(y, 'ghi', 'baseline/screen:2')
  y = y + Editor_state.line_height
  App.screen.check(y, 'jkl', 'baseline/screen:3')
  -- after hitting the up arrow the screen scrolls up to previous text line
  edit.run_after_keychord(Editor_state, 'up')
  check_eq(Editor_state.screen_top1.line, 1, 'screen_top')
  check_eq(Editor_state.cursor1.line, 1, 'cursor')
end
function test_up_arrow_scrolls_up_by_one_screen_line()

-- return the final y, and position of start of final screen line drawn
function Text.draw(State, line_index, y, startpos, hide_cursor)
  -- wrap long lines
  local x = State.left
  local pos = 1
          return y, screen_line_starting_pos
      if line_index == State.cursor1.line then
  if Focus == 'edit' and not hide_cursor and State.search_term == nil then
    if line_index == State.cursor1.line and State.cursor1.pos == pos then
      Text.draw_cursor(State, x, y)
    if State.cursor1.pos <= utf8.len(State.lines[State.cursor1.line].data) then
    if State.cursor1.pos <= utf8.len(State.lines[State.cursor1.line].data) then
  local byte_offset = Text.offset(State.lines[State.cursor1.line].data, State.cursor1.pos)
  table.insert(State.lines, State.cursor1.line+1, {mode='text', data=string.sub(State.lines[State.cursor1.line].data, byte_offset)})
  table.insert(State.line_cache, State.cursor1.line+1, {})
  State.lines[State.cursor1.line].data = string.sub(State.lines[State.cursor1.line].data, 1, byte_offset-1)
  Text.clear_screen_line_cache(State, State.cursor1.line)
  State.cursor1 = {line=State.cursor1.line+1, pos=1}
    if State.screen_top1.line == 1 and State.screen_top1.pos == 1 then break end
  State.cursor1 = {line=State.screen_top1.line, pos=State.screen_top1.pos}
  -- If a line/paragraph gets to a page boundary, I often want to scroll
  -- before I get to the bottom.
  -- However, only do this if it makes forward progress.
  if bot2.screen_line > 1 then
    bot2.screen_line = math.max(bot2.screen_line-10, 1)
  end
    State.screen_top1 = {line=State.screen_bottom1.line, pos=State.screen_bottom1.pos}
  State.cursor1 = {line=State.screen_top1.line, pos=State.screen_top1.pos}
  State.cursor1.pos = 1
    State.screen_top1 = {line=State.cursor1.line, pos=State.cursor1.pos}  -- copy
  State.cursor1.pos = utf8.len(State.lines[State.cursor1.line].data) + 1
  -- skip some whitespace
  -- skip some non-whitespace
  if Text.cursor_out_of_screen(State) then
    Text.snap_cursor_to_bottom_of_screen(State)
  assert(State.lines[State.cursor1.line].mode == 'text')
--?   print('to2:', State.cursor1.line, State.cursor1.pos)
--?   print('to2: =>', top2.line, top2.screen_line, top2.screen_pos)
  top2.screen_pos = 1  -- start of screen line
--?   print('snap', State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos, State.screen_bottom1.line, State.screen_bottom1.pos)
--?     print(y, 'top2:', top2.line, top2.screen_line, top2.screen_pos)
  local start_screen_line_index = Text.screen_line_index(line_cache.screen_line_starting_pos, line_cache.startpos)
  for screen_line_index = start_screen_line_index,#line_cache.screen_line_starting_pos do
    local screen_line_starting_pos = line_cache.screen_line_starting_pos[screen_line_index]
    local screen_line_starting_byte_offset = Text.offset(line.data, screen_line_starting_pos)
--?     print('iter', y, screen_line_index, screen_line_starting_pos, string.sub(line.data, screen_line_starting_byte_offset))
      if screen_line_index < #line_cache.screen_line_starting_pos and mx > State.left + Text.screen_line_width(State, line_index, screen_line_index) then
        return line_cache.screen_line_starting_pos[screen_line_index+1]-1
      local s = string.sub(line.data, screen_line_starting_byte_offset)
--?       print('return', mx, Text.nearest_cursor_pos(s, mx, State.left), '=>', screen_line_starting_pos + Text.nearest_cursor_pos(s, mx, State.left) - 1)
      return screen_line_starting_pos + Text.nearest_cursor_pos(s, mx, State.left) - 1
function Text.eq1(a, b)
  return a.line == b.line and a.pos == b.pos
  return a.pos < b.pos
end
function Text.le1(a, b)
  if a.line < b.line then
  if a.line > b.line then
  return a.pos <= b.pos
  elseif State.lines[loc2.line-1].mode == 'drawing' then
    return {line=loc2.line-1, screen_line=1, screen_pos=1}
    local l = State.lines[loc2.line-1]
    return {line=loc2.line-1, screen_line=#State.line_cache[loc2.line-1].screen_line_starting_pos, screen_pos=1}
function starts_with(s, prefix)
  if #s < #prefix then
    return false
  end
  for i=1,#prefix do
    if s:sub(i,i) ~= prefix:sub(i,i) then
      return false
    end
  end
  return true
function ends_with(s, suffix)
  if #s < #suffix then
    return false
  end
  for i=0,#suffix-1 do
    if s:sub(#s-i,#s-i) ~= suffix:sub(#suffix-i,#suffix-i) then
      return false
    end
  end
  return true
end
end
      State.cursor1 = {
          line=State.screen_bottom1.line,
          pos=Text.to_pos_on_line(State, State.screen_bottom1.line, State.right-5, App.screen.height-5),
      }
    end
  end
end
-- slightly expensive since it redraws the screen
function Text.cursor_out_of_screen(State)
  App.draw()
  return State.cursor_y == nil
  -- this approach is cheaper and almost works, except on the final screen
  -- where file ends above bottom of screen
--?   local botpos = Text.pos_at_start_of_screen_line(State, State.cursor1)
--?   local botline1 = {line=State.cursor1.line, pos=botpos}
--?   return Text.lt1(State.screen_bottom1, botline1)
end
  end
end
    Text.populate_screen_line_starting_pos(State, loc2.line-1)
  else
end
    return false
  end
    return true
  end
end
function Text.lt1(a, b)
  if a.line < b.line then
    return true
  end
  if a.line > b.line then
    return false
  end
    end
    y = nexty
  end
  assert(false)
end
function Text.screen_line_width(State, line_index, i)
  local line = State.lines[line_index]
  local line_cache = State.line_cache[line_index]
  local start_pos = line_cache.screen_line_starting_pos[i]
  local start_offset = Text.offset(line.data, start_pos)
  local screen_line
  if i < #line_cache.screen_line_starting_pos then
    local past_end_pos = line_cache.screen_line_starting_pos[i+1]
    local past_end_offset = Text.offset(line.data, past_end_pos)
    screen_line = string.sub(line.data, start_offset, past_end_offset-1)
  else
    screen_line = string.sub(line.data, start_pos)
  end
  local screen_line_text = App.newText(love.graphics.getFont(), screen_line)
  return App.width(screen_line_text)
end
      end
--?         print('past end of non-final line; return')
    local nexty = y + State.line_height
    if my < nexty then
      -- On all wrapped screen lines but the final one, clicks past end of
      -- line position cursor on final character of screen line.
      -- (The final screen line positions past end of screen line as always.)
  Text.populate_screen_line_starting_pos(State, line_index)
  return y < line_cache.starty + State.line_height*(#line_cache.screen_line_starting_pos - Text.screen_line_index(line_cache.screen_line_starting_pos, line_cache.startpos) + 1)
end
-- convert mx,my in pixels to schema-1 coordinates
--?   print('snap =>', State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos, State.screen_bottom1.line, State.screen_bottom1.pos)
  Text.redraw_all(State)  -- if we're scrolling, reclaim all fragments to avoid memory leaks
    if top2.line == 1 and top2.screen_line == 1 then break end
--?   print('cursor pos '..tostring(State.cursor1.pos)..' is on the #'..tostring(top2.screen_line)..' screen line down')
  local y = App.screen.height - State.line_height
  -- duplicate some logic from love.draw
  while true do
  -- slide to start of screen line
  local top2 = Text.to2(State, State.cursor1)
  return screen_lines[#screen_lines] <= State.cursor1.pos
end
function Text.move_cursor_down_to_next_text_line_while_scrolling_again_if_necessary(State)
    State.screen_top1 = {
      line=State.cursor1.line,
      pos=Text.pos_at_start_of_screen_line(State, State.cursor1),
    }
    Text.redraw_all(State)  -- if we're scrolling, reclaim all fragments to avoid memory leaks
  end
end
  if State.cursor1.pos > 1 then
    State.cursor1.pos = State.cursor1.pos-1
  end
end
function Text.match(s, pos, pat)
  local start_offset = Text.offset(s, pos)
  assert(start_offset)
  local end_offset = Text.offset(s, pos+1)
  assert(end_offset > start_offset)
  local curr = s:sub(start_offset, end_offset-1)
  return curr:match(pat)
end
function Text.left(State)
function Text.word_right(State)
  -- skip some whitespace
  while true do
    if State.cursor1.pos > utf8.len(State.lines[State.cursor1.line].data) then
      break
    end
    if Text.match(State.lines[State.cursor1.line].data, State.cursor1.pos, '%S') then
      break
    end
    Text.right_without_scroll(State)
  end
  while true do
  while true do
    if State.cursor1.pos == 1 then
      break
    end
    if Text.match(State.lines[State.cursor1.line].data, State.cursor1.pos-1, '%S') then
      break
    end
    Text.left(State)
  end
  if Text.cursor_out_of_screen(State) then
    Text.snap_cursor_to_bottom_of_screen(State)
  end
end
function Text.word_left(State)
  end
end
function Text.end_of_line(State)
  if Text.lt1(State.cursor1, State.screen_top1) then
  else
    -- move down one screen line in current line
    local scroll_down = Text.le1(State.screen_bottom1, State.cursor1)
--?     print('cursor is NOT at final screen line of its line')
    local screen_line_starting_pos, screen_line_index = Text.pos_at_start_of_screen_line(State, State.cursor1)
    Text.populate_screen_line_starting_pos(State, State.cursor1.line)
    local new_screen_line_starting_pos = State.line_cache[State.cursor1.line].screen_line_starting_pos[screen_line_index+1]
--?     print('switching pos of screen line at cursor from '..tostring(screen_line_starting_pos)..' to '..tostring(new_screen_line_starting_pos))
    local new_screen_line_starting_byte_offset = Text.offset(State.lines[State.cursor1.line].data, new_screen_line_starting_pos)
    local s = string.sub(State.lines[State.cursor1.line].data, new_screen_line_starting_byte_offset)
    State.cursor1.pos = new_screen_line_starting_pos + Text.nearest_cursor_pos(s, State.cursor_x, State.left) - 1
--?     print('cursor pos is now', State.cursor1.line, State.cursor1.pos)
    if scroll_down then
--?       print('scroll up preserving cursor')
      Text.snap_cursor_to_bottom_of_screen(State)
--?       print('screen top after:', State.screen_top1.line, State.screen_top1.pos)
    end
    State.screen_top1 = {
      line=State.cursor1.line,
      pos=Text.pos_at_start_of_screen_line(State, State.cursor1),
    }
    Text.redraw_all(State)  -- if we're scrolling, reclaim all fragments to avoid memory leaks
  end
end
  Text.move_cursor_down_to_next_text_line_while_scrolling_again_if_necessary(State)
--?   print('top now', State.screen_top1.line)
  Text.redraw_all(State)  -- if we're scrolling, reclaim all fragments to avoid memory leaks
--?   print('pagedown end')
end
function Text.up(State)
  end
--?   print('setting top to', State.screen_top1.line, State.screen_top1.pos)
  local new_top1 = Text.to1(State, bot2)
  if Text.lt1(State.screen_top1, new_top1) then
    State.screen_top1 = new_top1
  else
  local bot2 = Text.to2(State, State.screen_bottom1)
  Text.move_cursor_down_to_next_text_line_while_scrolling_again_if_necessary(State)
--?   print(State.cursor1.line, State.cursor1.pos, State.screen_top1.line, State.screen_top1.pos)
--?   print('pageup end')
end
function Text.pagedown(State)
--?   print('pagedown')
    if State.lines[State.screen_top1.line].mode == 'text' then
      y = y - State.line_height
    elseif State.lines[State.screen_top1.line].mode == 'drawing' then
      y = y - Drawing_padding_height - Drawing.pixels(State.lines[State.screen_top1.line].h, State.width)
    end
end
function Text.pageup(State)
--?   print('pageup')
  -- duplicate some logic from love.draw
  local top2 = Text.to2(State, State.screen_top1)
--?   print(App.screen.height)
  local y = App.screen.height - State.line_height
  while y >= State.top do
--?     print(y, top2.line, top2.screen_line, top2.screen_pos)
      State.selection1 = {line=State.cursor1.line, pos=State.cursor1.pos}
    end
      State.selection1 = {line=State.cursor1.line, pos=State.cursor1.pos}
    end
      State.selection1 = {line=State.cursor1.line, pos=State.cursor1.pos}
    end
      State.selection1 = {line=State.cursor1.line, pos=State.cursor1.pos}
    end
      State.selection1 = {line=State.cursor1.line, pos=State.cursor1.pos}
    end
      State.selection1 = {line=State.cursor1.line, pos=State.cursor1.pos}
    end
      State.selection1 = {line=State.cursor1.line, pos=State.cursor1.pos}
    end
      State.selection1 = {line=State.cursor1.line, pos=State.cursor1.pos}
    end
      State.selection1 = {line=State.cursor1.line, pos=State.cursor1.pos}
    end
      State.selection1 = {line=State.cursor1.line, pos=State.cursor1.pos}
    end
      local byte_start = utf8.offset(State.lines[State.cursor1.line].data, State.cursor1.pos)
      local byte_end = utf8.offset(State.lines[State.cursor1.line].data, State.cursor1.pos+1)
      if byte_start then
        if byte_end then
          State.lines[State.cursor1.line].data = string.sub(State.lines[State.cursor1.line].data, 1, byte_start-1)..string.sub(State.lines[State.cursor1.line].data, byte_end)
        else
          State.lines[State.cursor1.line].data = string.sub(State.lines[State.cursor1.line].data, 1, byte_start-1)
        end
        -- no change to State.cursor1.pos
      before = snapshot(State, State.cursor1.line)
    else
      before = snapshot(State, State.cursor1.line, State.cursor1.line+1)
    end
      State.screen_top1 = {
        line=State.cursor1.line,
        pos=Text.pos_at_start_of_screen_line(State, State.cursor1),
      }
      Text.redraw_all(State)  -- if we're scrolling, reclaim all fragments to avoid memory leaks
    end
    Text.clear_screen_line_cache(State, State.cursor1.line)
    assert(Text.le1(State.screen_top1, State.cursor1))
    schedule_save(State)
    record_undo_event(State, {before=before, after=snapshot(State, State.cursor1.line)})
  elseif chord == 'delete' then
    if State.cursor1.pos > 1 then
      before = snapshot(State, State.cursor1.line)
      local byte_start = utf8.offset(State.lines[State.cursor1.line].data, State.cursor1.pos-1)
      local byte_end = utf8.offset(State.lines[State.cursor1.line].data, State.cursor1.pos)
      if byte_start then
        if byte_end then
          State.lines[State.cursor1.line].data = string.sub(State.lines[State.cursor1.line].data, 1, byte_start-1)..string.sub(State.lines[State.cursor1.line].data, byte_end)
        else
          State.lines[State.cursor1.line].data = string.sub(State.lines[State.cursor1.line].data, 1, byte_start-1)
        end
        State.cursor1.pos = State.cursor1.pos-1
  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
end
  return y, screen_line_starting_pos
end
function Text.draw_cursor(State, x, y)
  -- blink every 0.5s
  if math.floor(Cursor_time*2)%2 == 0 then
    App.color(Cursor_color)
    love.graphics.rectangle('fill', x,y, 3,State.line_height)
  end
  State.cursor_x = x
  State.cursor_y = y+State.line_height
end
function Text.populate_screen_line_starting_pos(State, line_index)
  local line = State.lines[line_index]
    end
        if pos <= State.cursor1.pos and pos + frag_len > State.cursor1.pos then
          if State.search_term then
            if State.lines[State.cursor1.line].data:sub(State.cursor1.pos, State.cursor1.pos+utf8.len(State.search_term)-1) == State.search_term then
              local lo_px = Text.draw_highlight(State, line, x,y, pos, State.cursor1.pos, State.cursor1.pos+utf8.len(State.search_term))
              App.color(Text_color)
              love.graphics.print(State.search_term, x+lo_px,y)
            end
          elseif Focus == 'edit' then
            Text.draw_cursor(State, x+Text.x(frag, State.cursor1.pos-pos+1), y)
            App.color(Text_color)
          end
        end
      end
      x = x + frag_width
    end
    pos = pos + frag_len
  end
        end
        screen_line_starting_pos = pos
        x = State.left
  local screen_line_starting_pos = startpos
  Text.compute_fragments(State, line_index)
  local pos = 1
  initialize_color()
  for _, f in ipairs(line_cache.fragments) do
    App.color(Text_color)
    local frag, frag_text = f.data, f.text
    select_color(frag)
    local frag_len = utf8.len(frag)
--?     print('text.draw:', frag, 'at', line_index,pos, 'after', x,y)
    if pos < startpos then
      -- render nothing
--?       print('skipping', frag)
    else
      -- render fragment
      local frag_width = App.width(frag_text)
      if x + frag_width > State.right then
        assert(x > State.left)  -- no overfull lines
        y = y + State.line_height
        if y + State.line_height > App.screen.height then
  local line = State.lines[line_index]
  local line_cache = State.line_cache[line_index]
  line_cache.starty = y
  line_cache.startpos = startpos

    print(State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos)
--?     print('draw:', y, line_index, line)
    State.screen_bottom1 = {line=line_index, pos=nil}
--?       print('text.draw', y, line_index)
      local startpos = 1
        startpos = State.screen_top1.pos
      State.cursor1.pos = State.cursor1.pos+1
      cursor={line=State.cursor1.line, pos=State.cursor1.pos},
      screen_top={line=State.screen_top1.line, pos=State.screen_top1.pos},
    State.cursor1 = {line=#State.lines, pos=utf8.len(State.lines[#State.lines].data)+1}
  elseif chord == 'C-c' then
    local s = Text.selection(State)
    if s then
      App.setClipboardText(s)
    end
  elseif chord == 'C-x' then
    for _,line_cache in ipairs(State.line_cache) do line_cache.starty = nil end  -- just in case we scroll
    local s = Text.cut_selection(State, State.left, State.right)
    if s then
      App.setClipboardText(s)
    end
    schedule_save(State)
  elseif chord == 'C-v' then
    for _,line_cache in ipairs(State.line_cache) do line_cache.starty = nil end  -- just in case we scroll
    -- We don't have a good sense of when to scroll, so we'll be conservative
    -- and sometimes scroll when we didn't quite need to.
    local before_line = State.cursor1.line
    local before = snapshot(State, before_line)
    local clipboard_data = App.getClipboardText()
    for _,code in utf8.codes(clipboard_data) do
      local c = utf8.char(code)
      if c == '\n' then
        Text.insert_return(State)
      else
        Text.insert_at_cursor(State, c)
      end
    end
    if Text.cursor_out_of_screen(State) then
      Text.snap_cursor_to_bottom_of_screen(State, State.left, State.right)
    end
    schedule_save(State)
    record_undo_event(State, {before=before, after=snapshot(State, before_line, State.cursor1.line)})
    if State.font_height > 2 then
      edit.update_font_settings(State, State.font_height-2)
      Text.redraw_all(State)
    end
  elseif chord == 'C-0' then
    edit.update_font_settings(State, 20)
    Text.redraw_all(State)
  -- undo
  elseif chord == 'C-z' then
    for _,line_cache in ipairs(State.line_cache) do line_cache.starty = nil end  -- just in case we scroll
    local event = undo_event(State)
    if event then
      local src = event.before
      State.screen_top1 = deepcopy(src.screen_top)
      State.cursor1 = deepcopy(src.cursor)
    }
    assert(State.search_text == nil)
      Text.search_next(State)
    elseif chord == 'up' then
      Text.search_previous(State)
    end
    return
  elseif chord == 'C-f' then
    State.search_term = ''
    State.search_backup = {
          State.cursor1 = {
              line=line_index,
              pos=Text.to_pos_on_line(State, line_index, x, y),
          }
--?           print('cursor', State.cursor1.line, State.cursor1.pos)
          if State.mousepress_shift then
            if State.old_selection1.line == nil then
              State.selection1 = State.old_cursor1
            else
              State.selection1 = State.old_selection1
            end
          end
          State.old_cursor1, State.old_selection1, State.mousepress_shift = nil
          if eq(State.cursor1, State.selection1) then
            State.selection1 = {}
          end
          break
        end
      end
    end
--?     print('selection:', State.selection1.line, State.selection1.pos)
        State.selection1 = {
            line=line_index,
            pos=Text.to_pos_on_line(State, line_index, x, y),
        }
--?         print('selection', State.selection1.line, State.selection1.pos)
        break
      end
    elseif line.mode == 'drawing' then
      local line_cache = State.line_cache[line_index]
      if Drawing.in_drawing(line, line_cache, x, y, State.left,State.right) then
        State.lines.current_drawing_index = line_index
        State.lines.current_drawing = line
        Drawing.before = snapshot(State, line_index)
--?   print('press', State.selection1.line, State.selection1.pos)
  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
    -- give some time for the OS to flush everything to disk
    love.timer.sleep(0.1)
  end
end
      y, State.screen_bottom1.pos = Text.draw(State, line_index, y, startpos, hide_cursor)
      y = y + State.line_height
--?       print('=> y', y)
    elseif line.mode == 'drawing' then
      y = y+Drawing_padding_top
      Drawing.draw(State, line_index, y)
      y = y + Drawing.pixels(line.h, State.width) + Drawing_padding_bottom
    else
      print(line.mode)
      assert(false)
      end
      if line.data == '' then
        -- button to insert new drawing
        button(State, 'draw', {x=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 line_index == State.screen_top1.line then
    if line.mode == 'text' then
    if y + State.line_height > App.screen.height then break end
    assert(false)
  end
  State.cursor_x = nil
  State.cursor_y = nil
  local y = State.top
--?   print('== draw')
  for line_index = State.screen_top1.line,#State.lines do
    local line = State.lines[line_index]
    left = math.floor(left),
    right = math.floor(right),
    width = right-left,
    screen_top1 = {line=1, pos=1},  -- position of start of screen line at top of screen
    cursor1 = {line=1, pos=1},  -- position of cursor
    screen_bottom1 = {line=1, pos=1},  -- position of start of screen line at bottom of screen
    selection1 = {},
    -- some extra state to compute selection between mouse press and release
    old_cursor1 = nil,
    old_selection1 = nil,
    mousepress_shift = nil,
    -- when selecting text, avoid recomputing some state on every single frame
    recent_mouse = {},
    lines = {{mode='text', data=''}},  -- array of lines
    -- Lines can be too long to fit on screen, in which case they _wrap_ into
    -- multiple _screen lines_.
    -- rendering wrapped text lines needs some additional short-lived data per line:
    --   startpos, the index of data the line starts rendering from, can only be >1 for topmost line on screen
    --   starty, the y coord in pixels the line starts rendering from
    --   fragments: snippets of rendered love.graphics.Text, guaranteed to not straddle screen lines
    --   screen_line_starting_pos: optional array of grapheme indices if it wraps over more than one screen line
    line_cache = {},
    -- Given wrapping, any potential location for the text cursor can be described in two ways:
    -- * schema 1: As a combination of line index and position within a line (in utf8 codepoint units)
    -- * schema 2: As a combination of line index, screen line index within the line, and a position within the screen line.
    -- a line is either text or a drawing
    -- a text is a table with:
    --    mode = 'text',
    --    string data,

-- environment for a mutable file
-- TODO: some initialization is also happening in load_settings/initialize_default_settings. Clean that up.

  Editor_state.cursor1 = {line=line.line_number, pos=1}
  -- make sure it's visible
  -- TODO: handle extremely long lines
  Editor_state.screen_top1.line = math.max(0, Editor_state.cursor1.line-5)
  -- show cursor
  Focus = 'edit'
  Log_browser_state.cursor1 = {line=1, pos=1}
end
Section_stack = {}
Section_border_color = {r=0.7, g=0.7, b=0.7}
Cursor_line_background_color = {r=0.7, g=0.7, b=0, a=0.1}
Section_border_padding_horizontal = 30  -- TODO: adjust this based on font height (because we draw text vertically along the borders
Section_border_padding_vertical = 15  -- TODO: adjust this based on font height
log_browser = {}
function log_browser.parse(State)
  for _,line in ipairs(State.lines) do
    if line.data ~= '' then

--?   print('snap', State.screen_top1.line, State.screen_top1.pos, State.screen_top1.posB, State.cursor1.line, State.cursor1.pos, State.screen_bottom1.line, State.screen_bottom1.pos)