function Text.draw(line, line_index, cursor_line, cursor_pos)

function Text.compute_fragments(line, line_width)
  line.fragments = {}
  local x = 25
  -- try to wrap at word boundaries
  for frag in line.data:gmatch('%S*%s*') do
    local frag_text = love.graphics.newText(love.graphics.getFont(), frag)
    local frag_width = math.floor(frag_text:getWidth()*Zoom)
--?     print('x: '..tostring(x)..'; '..tostring(line_width-x)..'px to go')
--?     print('frag: ^'..frag..'$ is '..tostring(frag_width)..'px wide')
    if x + frag_width > line_width then
      while x + frag_width > line_width do
        if x < 0.8*line_width then
          -- long word; chop it at some letter
          -- We're not going to reimplement TeX here.
          local b = Text.nearest_cursor_pos(frag, line_width - x)
--?           print('space for '..tostring(b)..' graphemes')
          local frag1 = string.sub(frag, 1, b)
          local frag1_text = love.graphics.newText(love.graphics.getFont(), frag1)
          local frag1_width = math.floor(frag1_text:getWidth()*Zoom)
--?           print('inserting '..frag1..' of width '..tostring(frag1_width)..'px')
          table.insert(line.fragments, {data=frag1, text=frag1_text})
          frag = string.sub(frag, b+1)
          frag_text = love.graphics.newText(love.graphics.getFont(), frag)
          frag_width = math.floor(frag_text:getWidth()*Zoom)
        end
        x = 25  -- new line
      end
    end
    if #frag > 0 then
--?       print('inserting '..frag..' of width '..tostring(frag_width)..'px')
      table.insert(line.fragments, {data=frag, text=frag_text})
    end
  end
end
function Text.draw(line, line_width, line_index, cursor_line, cursor_pos)
  love.graphics.setColor(0.75,0.75,0.75)
  love.graphics.line(line_width, 0, line_width, Screen_height)

  local love_text = love.graphics.newText(love.graphics.getFont(), line.data)
  love.graphics.draw(love_text, 25,line.y, 0, Zoom)
  if line_index == cursor_line then
    -- cursor
    love.graphics.print('_', Text.cursor_x(line.data, cursor_pos), line.y+6)  -- drop the cursor down a bit to account for the increased font size

  -- wrap long lines
  local x = 25
  local y = line.y
  local pos = 1
  if line.fragments == nil then
    Text.compute_fragments(line, line_width)
  end
  for _, f in ipairs(line.fragments) do
    local frag, frag_text = f.data, f.text
    -- render fragment
    local frag_width = math.floor(frag_text:getWidth()*Zoom)
    if x + frag_width > line_width then
      assert(x > 25)  -- no overfull lines
      y = y + math.floor(15*Zoom)
      x = 25
    end
    love.graphics.draw(frag_text, x,y, 0, Zoom)
    -- render cursor if necessary
    local frag_len = utf8.len(frag)
    if line_index == cursor_line then
      if pos <= cursor_pos and pos + frag_len > cursor_pos then
        -- cursor
        love.graphics.print('_', x+Text.cursor_x2(frag, cursor_pos-pos+1), y+6)  -- drop the cursor down a bit to account for the increased font size
      end
    end
    x = x + frag_width
    pos = pos + frag_len

  return y

-- manual tests:
--  draw with small line_width of 100
--  short words break on spaces
--  long words break when they must

  Lines[Cursor_line].fragments = nil

    Lines[Cursor_line].fragments = nil

        Lines[Cursor_line].fragments = nil

        Lines[Cursor_line-1].fragments = nil

        Lines[Cursor_line].fragments = nil

        Lines[Cursor_line].fragments = nil

function Text.cursor_x2(s, cursor_pos)
  local s_before_cursor = s:sub(1, cursor_pos-1)
  local text_before_cursor = love.graphics.newText(love.graphics.getFont(), s_before_cursor)
  return math.floor(text_before_cursor:getWidth()*Zoom)
end

        Text.draw(line, line_index, Cursor_line, Cursor_pos)

        y = Text.draw(line, 100, line_index, Cursor_line, Cursor_pos)
--?         y = Text.draw(line, Drawing_width, line_index, Cursor_line, Cursor_pos)

--?   os.exit(1)