App.screen.init{width=800, height=600}
  check_eq(Text.starty(Editor_state, 1), Editor_state.top+Drawing_padding_top, 'baseline/y')
  check_eq(Editor_state.lines[1].h, 128, 'baseline/y')
  check_eq(#Editor_state.lines[1].shapes, 0, 'baseline/#shapes')
  check_eq(Text.starty(Editor_state, 1), Editor_state.top+Drawing_padding_top, 'baseline/y')
  check_eq(Text.starty(Editor_state, 1), Editor_state.top+Drawing_padding_top, 'baseline/y')
  check_eq(Text.starty(Editor_state, 1), Editor_state.top+Drawing_padding_top, 'baseline/y')
  check_eq(Text.starty(Editor_state, 1), Editor_state.top+Drawing_padding_top, 'baseline/y')
  check_eq(Text.starty(Editor_state, 1), Editor_state.top+Drawing_padding_top, 'baseline/y')
  check_eq(Text.starty(Editor_state, 1), Editor_state.top+Drawing_padding_top, 'baseline/y')
  check_eq(Text.starty(Editor_state, 1), Editor_state.top+Drawing_padding_top, 'baseline/y')
  check_eq(Text.starty(Editor_state, 1), Editor_state.top+Drawing_padding_top, 'baseline/y')
  check_eq(Text.starty(Editor_state, 1), Editor_state.top+Drawing_padding_top, 'baseline/y')
  check_eq(#drawing.shapes, 1, 'baseline/#shapes')
  check_eq(#drawing.points, 2, 'baseline/#points')
  check_eq(drawing.shapes[1].mode, 'line', 'baseline/shape:1')
  check_eq(Editor_state.lines[1].h, 128, 'baseline/y')
  check_eq(#Editor_state.lines[1].shapes, 0, 'baseline/#shapes')
  check_eq(Editor_state.lines[1].h, 128, 'baseline/y')
  check_eq(#Editor_state.lines[1].shapes, 0, 'baseline/#shapes')
  check_eq(Editor_state.lines[1].h, 128, 'baseline/y')
  check_eq(#Editor_state.lines[1].shapes, 0, 'baseline/#shapes')
  check_eq(Editor_state.lines[1].h, 128, 'baseline/y')
  check_eq(#Editor_state.lines[1].shapes, 0, 'baseline/#shapes')
  check_eq(Editor_state.lines[1].h, 128, 'baseline/y')
  check_eq(#Editor_state.lines[1].shapes, 0, 'baseline/#shapes')
  check_eq(Editor_state.lines[1].h, 128, 'baseline/y')
  check_eq(#Editor_state.lines[1].shapes, 0, 'baseline/#shapes')
  check_eq(Editor_state.lines[1].h, 128, 'baseline/y')
  check_eq(#Editor_state.lines[1].shapes, 0, 'baseline/#shapes')
  check_eq(Editor_state.lines[1].h, 128, 'baseline/y')
  check_eq(#Editor_state.lines[1].shapes, 0, 'baseline/#shapes')
  check_eq(Editor_state.lines[1].h, 128, 'baseline/y')
  check_eq(#Editor_state.lines[1].shapes, 0, 'baseline/#shapes')
  check_nil(App.filesystem['foo'], 'early')
  Editor_state = edit.initialize_test_state()
  Editor_state.filename = 'foo'
  Editor_state.lines = load_array{}
  Text.redraw_all(Editor_state)
  edit.draw(Editor_state)
  -- click on button to create drawing
  edit.run_after_mouse_click(Editor_state, 8,Editor_state.top+8, 1)
  -- file not immediately saved
  edit.update(Editor_state, 0.01)

  local starty = Text.starty(State, line_index)
  if pmx < State.right and pmy > starty and pmy < starty+Drawing.pixels(line.h, State.width) then
    love.graphics.rectangle('line', State.left,starty, State.width,Drawing.pixels(line.h, State.width))
      icon[State.current_drawing_mode](State.right-22, starty+4)
      icon[State.previous_drawing_mode](State.right-22, starty+4)
  local my = Drawing.coord(pmy-starty, State.width)
    Drawing.draw_shape(line, shape, starty, State.left,State.right)
  local function py(y) return Drawing.pixels(y, State.width)+starty end
  Drawing.draw_pending_shape(line, starty, State.left,State.right)
function Drawing.in_current_drawing(State, x,y, left,right)
  return Drawing.in_drawing(State, State.lines.current_drawing_index, x,y, left,right)
end
function Drawing.in_drawing(State, line_index, x,y, left,right)
  assert(State.lines[line_index].mode == 'drawing')
  local starty = Text.starty(State, line_index)
  if starty == nil then return false end  -- outside current page
  local drawing = State.lines[line_index]
  local width = right-left
  return y >= starty and y < starty + Drawing.pixels(drawing.h, width) and x >= left and x < right
end
  local starty = Text.starty(State, drawing_index)
  local cy = Drawing.coord(y-starty, State.width)
  local starty = Text.starty(State, State.lines.current_drawing_index)
  if starty == nil then
  local my = Drawing.coord(pmy-starty, State.width)
    if Drawing.in_current_drawing(State, pmx,pmy, State.left,State.right) then
    if Drawing.in_current_drawing(State, pmx, pmy, State.left,State.right) then
    local starty = Text.starty(State, State.lines.current_drawing_index)
        local mx,my = Drawing.coord(x-State.left, State.width), Drawing.coord(y-starty, State.width)
        local mx,my = Drawing.coord(x-State.left, State.width), Drawing.coord(y-starty, State.width)
          App.mouse_move(State.left+Drawing.pixels(p2.x, State.width), starty+Drawing.pixels(p2.y, State.width))
        local mx,my = Drawing.coord(x-State.left, State.width), Drawing.coord(y-starty, State.width)
          local mx,my = Drawing.coord(x-State.left, State.width), Drawing.coord(y-starty, State.width)
          local mx,my = Drawing.coord(x-State.left, State.width), Drawing.coord(y-starty, State.width)
        local mx,my = Drawing.coord(x-State.left, State.width), Drawing.coord(y-starty, State.width)
        local mx,my = Drawing.coord(x-State.left, State.width), Drawing.coord(y-starty, State.width)
    local drawing_index,drawing = Drawing.current_drawing(State)
    local starty = Text.starty(State, drawing_index)
    local mx,my = Drawing.coord(App.mouse_x()-State.left, State.width), Drawing.coord(App.mouse_y()-starty, State.width)
    local drawing_index,drawing = Drawing.current_drawing(State)
    local starty = Text.starty(State, drawing_index)
    local mx,my = Drawing.coord(App.mouse_x()-State.left, State.width), Drawing.coord(App.mouse_y()-starty, State.width)
    local drawing_index,drawing = Drawing.current_drawing(State)
    local starty = Text.starty(State, drawing_index)
    local mx,my = Drawing.coord(App.mouse_x()-State.left, State.width), Drawing.coord(App.mouse_y()-starty, State.width)
    local drawing_index,drawing,_,i,p = Drawing.select_point_at_mouse(State)
    local drawing_index,drawing,_,point_index,p = Drawing.select_point_at_mouse(State)
      if Drawing.in_drawing(State, drawing_index, x,y, State.left,State.right) then
        return drawing_index,drawing
      local starty = Text.starty(State, drawing_index)
      if Drawing.in_drawing(State, drawing_index, x,y, State.left,State.right) then
        local mx,my = Drawing.coord(x-State.left, State.width), Drawing.coord(y-starty, State.width)
            return drawing,starty,i,shape
      local starty = Text.starty(State, drawing_index)
      if Drawing.in_drawing(State, drawing_index, x,y, State.left,State.right) then
        local mx,my = Drawing.coord(x-State.left, State.width), Drawing.coord(y-starty, State.width)
            return drawing_index,drawing,starty,i,point
      if Drawing.in_drawing(State, drawing_index, x,y, State.left,State.right) then
        return drawing
      end
    end
  end
end
function Drawing.contains_point(shape, p)
  if shape.mode == 'freehand' then
    -- not supported
  elseif shape.mode == 'line' or shape.mode == 'manhattan' then
    return shape.p1 == p or shape.p2 == p
  elseif shape.mode == 'polygon' or shape.mode == 'rectangle' or shape.mode == 'square' then
    return table.find(shape.vertices, p)
  elseif shape.mode == 'circle' then
    return shape.center == p
  elseif shape.mode == 'arc' then
    return shape.center == p
    -- ugh, how to support angles
  elseif shape.mode == 'deleted' then
    -- already done
  else
          end
        end
      end
    end
  end
end
function Drawing.select_drawing_at_mouse(State)
  for drawing_index,drawing in ipairs(State.lines) do
    if drawing.mode == 'drawing' then
      local x, y = App.mouse_x(), App.mouse_y()
        for i,point in ipairs(drawing.points) do
          end
        end
      end
    end
  end
end
function Drawing.select_point_at_mouse(State)
  for drawing_index,drawing in ipairs(State.lines) do
    if drawing.mode == 'drawing' then
      local x, y = App.mouse_x(), App.mouse_y()
        for i,shape in ipairs(drawing.shapes) do
      end
    end
  end
  return nil
end
function Drawing.select_shape_at_mouse(State)
  for drawing_index,drawing in ipairs(State.lines) do
    if drawing.mode == 'drawing' then
      local x, y = App.mouse_x(), App.mouse_y()
    if drawing then
      if State.previous_drawing_mode == nil then
        -- don't clobber
        State.previous_drawing_mode = State.current_drawing_mode
      end
      State.current_drawing_mode = 'name'
      p.name = ''
      drawing.pending = {mode=State.current_drawing_mode, target_point=point_index}
      State.lines.current_drawing_index = drawing_index
      State.lines.current_drawing = drawing
    end
  elseif chord == 'C-d' and not App.mouse_down(1) then
    local _,drawing,_,i,p = Drawing.select_point_at_mouse(State)
    if drawing then
      for _,shape in ipairs(drawing.shapes) do
        if Drawing.contains_point(shape, i) then
          if shape.mode == 'polygon' then
            local idx = table.find(shape.vertices, i)
    if drawing then
      if State.previous_drawing_mode == nil then
        State.previous_drawing_mode = State.current_drawing_mode
      end
      State.current_drawing_mode = 'move'
      drawing.pending = {mode=State.current_drawing_mode, target_point=p, target_point_index=i}
      State.lines.current_drawing_index = drawing_index
      State.lines.current_drawing = drawing
    end
  elseif chord == 'C-n' and not App.mouse_down(1) then
    local center = drawing.points[drawing.pending.center]
    drawing.pending.radius = round(geom.dist(center.x,center.y, mx,my))
    drawing.pending.start_angle = geom.angle(center.x,center.y, mx,my)
  elseif App.mouse_down(1) and chord == 'o' then
    State.current_drawing_mode = 'circle'
    local _,drawing = Drawing.current_drawing(State)
    if drawing.pending.mode == 'freehand' then
      drawing.pending.center = Drawing.find_or_insert_point(drawing.points, drawing.pending.points[1].x, drawing.pending.points[1].y, State.width)
    elseif drawing.pending.mode == 'line' or drawing.pending.mode == 'manhattan' then
      drawing.pending.center = drawing.pending.p1
    elseif drawing.pending.mode == 'polygon' or drawing.pending.mode == 'rectangle' or drawing.pending.mode == 'square' then
      drawing.pending.center = drawing.pending.vertices[1]
    end
    drawing.pending.mode = 'circle'
  elseif chord == 'C-u' and not App.mouse_down(1) then
    drawing.pending.mode = 'arc'
    local j = Drawing.find_or_insert_point(drawing.points, mx,my, State.width)
    while #drawing.pending.vertices >= 2 do
      table.remove(drawing.pending.vertices)
    end
    table.insert(drawing.pending.vertices, j)
  elseif chord == 'C-o' and not App.mouse_down(1) then
    State.current_drawing_mode = 'circle'
  elseif App.mouse_down(1) and chord == 'a' and State.current_drawing_mode == 'circle' then
    local j = Drawing.find_or_insert_point(drawing.points, mx,my, State.width)
    table.insert(drawing.pending.vertices, j)
  elseif App.mouse_down(1) and chord == 'p' and (State.current_drawing_mode == 'rectangle' or State.current_drawing_mode == 'square') then
function Drawing.keychord_press(State, chord)
        if mx >= 0 and mx < 256 and my >= 0 and my < drawing.h then
          local center = drawing.points[drawing.pending.center]
          drawing.pending.end_angle = geom.angle_with_hint(center.x,center.y, mx,my, drawing.pending.end_angle)
          table.insert(drawing.shapes, drawing.pending)
        end
      elseif drawing.pending.mode == 'name' then
        -- drop it
      else
        if mx >= 0 and mx < 256 and my >= 0 and my < drawing.h then
          local center = drawing.points[drawing.pending.center]
          drawing.pending.radius = round(geom.dist(center.x,center.y, mx,my))
          table.insert(drawing.shapes, drawing.pending)
        end
      elseif drawing.pending.mode == 'arc' then
          if mx >= 0 and mx < 256 and my >= 0 and my < drawing.h then
            local first = drawing.points[drawing.pending.vertices[1]]
            local second = drawing.points[drawing.pending.vertices[2]]
            local thirdx,thirdy, fourthx,fourthy = Drawing.complete_square(first.x,first.y, second.x,second.y, mx,my)
            table.insert(drawing.pending.vertices, Drawing.find_or_insert_point(drawing.points, thirdx,thirdy, State.width))
            table.insert(drawing.pending.vertices, Drawing.find_or_insert_point(drawing.points, fourthx,fourthy, State.width))
            table.insert(drawing.shapes, drawing.pending)
          end
        end
      elseif drawing.pending.mode == 'circle' then
          if mx >= 0 and mx < 256 and my >= 0 and my < drawing.h then
            local first = drawing.points[drawing.pending.vertices[1]]
            local second = drawing.points[drawing.pending.vertices[2]]
            local thirdx,thirdy, fourthx,fourthy = Drawing.complete_rectangle(first.x,first.y, second.x,second.y, mx,my)
            table.insert(drawing.pending.vertices, Drawing.find_or_insert_point(drawing.points, thirdx,thirdy, State.width))
            table.insert(drawing.pending.vertices, Drawing.find_or_insert_point(drawing.points, fourthx,fourthy, State.width))
            table.insert(drawing.shapes, drawing.pending)
          end
        else
          -- too few points; draw nothing
        end
      elseif drawing.pending.mode == 'square' then
        if mx >= 0 and mx < 256 and my >= 0 and my < drawing.h then
          table.insert(drawing.pending.vertices, Drawing.find_or_insert_point(drawing.points, mx,my, State.width))
          table.insert(drawing.shapes, drawing.pending)
        end
      elseif drawing.pending.mode == 'rectangle' then
          table.insert(drawing.shapes, drawing.pending)
        end
      elseif drawing.pending.mode == 'polygon' then
        if mx >= 0 and mx < 256 and my >= 0 and my < drawing.h then
          if math.abs(mx-p1.x) > math.abs(my-p1.y) then
            drawing.pending.p2 = Drawing.find_or_insert_point(drawing.points, mx, p1.y, State.width)
          else
            drawing.pending.p2 = Drawing.find_or_insert_point(drawing.points, p1.x, my, State.width)
          end
          local p2 = drawing.points[drawing.pending.p2]
        if mx >= 0 and mx < 256 and my >= 0 and my < drawing.h then
          drawing.pending.p2 = Drawing.find_or_insert_point(drawing.points, mx,my, State.width)
          table.insert(drawing.shapes, drawing.pending)
        end
      elseif drawing.pending.mode == 'manhattan' then
        local p1 = drawing.points[drawing.pending.p1]
    if drawing.pending then
      if drawing.pending.mode == nil then
        -- nothing pending
      elseif drawing.pending.mode == 'freehand' then
        -- the last point added during update is good enough
        Drawing.smoothen(drawing.pending)
        table.insert(drawing.shapes, drawing.pending)
      elseif drawing.pending.mode == 'line' then
function Drawing.mouse_release(State, x,y, mouse_button)
      drawing.pending.target_point.x = mx
      drawing.pending.target_point.y = my
      Drawing.relax_constraints(drawing, drawing.pending.target_point_index)
    end
  else
    -- do nothing
  end
end
function Drawing.relax_constraints(drawing, p)
  for _,shape in ipairs(drawing.shapes) do
    if shape.mode == 'manhattan' then
      if shape.p1 == p then
        shape.mode = 'line'
      elseif shape.p2 == p then
        shape.mode = 'line'
      end
    elseif shape.mode == 'rectangle' or shape.mode == 'square' then
      for _,v in ipairs(shape.vertices) do
        if v == p then
          shape.mode = 'polygon'
        end
      end
    end
  end
end
      if drawing.pending.mode == 'freehand' then
        table.insert(drawing.pending.points, {x=mx, y=my})
      elseif drawing.pending.mode == 'move' then
        drawing.pending.target_point.x = mx
        drawing.pending.target_point.y = my
        Drawing.relax_constraints(drawing, drawing.pending.target_point_index)
      end
    end
  elseif State.current_drawing_mode == 'move' then
  if App.mouse_down(1) then
    -- some event cleared starty just this frame
    -- draw in this frame will soon set starty
    -- just skip this frame
    return
  end
    -- all the action is in mouse_release
  if State.current_drawing_mode == 'freehand' then
    drawing.pending = {mode=State.current_drawing_mode, points={{x=cx, y=cy}}}
  elseif State.current_drawing_mode == 'line' or State.current_drawing_mode == 'manhattan' then
    local j = Drawing.find_or_insert_point(drawing.points, cx, cy, State.width)
    drawing.pending = {mode=State.current_drawing_mode, p1=j}
  elseif State.current_drawing_mode == 'polygon' or State.current_drawing_mode == 'rectangle' or State.current_drawing_mode == 'square' then
    local j = Drawing.find_or_insert_point(drawing.points, cx, cy, State.width)
    drawing.pending = {mode=State.current_drawing_mode, vertices={j}}
  elseif State.current_drawing_mode == 'circle' then
    local j = Drawing.find_or_insert_point(drawing.points, cx, cy, State.width)
    drawing.pending = {mode=State.current_drawing_mode, center=j}
  elseif State.current_drawing_mode == 'move' then
  local cx = Drawing.coord(x-State.left, State.width)
function Drawing.mouse_press(State, drawing_index, x,y, mouse_button)
end
  local width = right-left
  -- after mouse_release
end
function Drawing.draw_shape(drawing, shape, top, left,right)
  local width = right-left
  local function px(x) return Drawing.pixels(x, width)+left end
  local function py(y) return Drawing.pixels(y, width)+top end
  if shape.mode == 'freehand' then
    local prev = nil
    for _,point in ipairs(shape.points) do
      if prev then
        love.graphics.line(px(prev.x),py(prev.y), px(point.x),py(point.y))
      end
      prev = point
    end
  elseif shape.mode == 'line' or shape.mode == 'manhattan' then
    local p1 = drawing.points[shape.p1]
    local p2 = drawing.points[shape.p2]
    love.graphics.line(px(p1.x),py(p1.y), px(p2.x),py(p2.y))
  elseif shape.mode == 'polygon' or shape.mode == 'rectangle' or shape.mode == 'square' then
    local prev = nil
    for _,point in ipairs(shape.vertices) do
      local curr = drawing.points[point]
      if prev then
        love.graphics.line(px(prev.x),py(prev.y), px(curr.x),py(curr.y))
      end
      prev = curr
    end
    -- close the loop
    local curr = drawing.points[shape.vertices[1]]
    love.graphics.line(px(prev.x),py(prev.y), px(curr.x),py(curr.y))
  elseif shape.mode == 'circle' then
    -- TODO: clip
    local center = drawing.points[shape.center]
    love.graphics.circle('line', px(center.x),py(center.y), Drawing.pixels(shape.radius, width))
  elseif shape.mode == 'arc' then
    local center = drawing.points[shape.center]
    love.graphics.arc('line', 'open', px(center.x),py(center.y), Drawing.pixels(shape.radius, width), shape.start_angle, shape.end_angle, 360)
  elseif shape.mode == 'deleted' then
    -- ignore
  else
  for i,p in ipairs(line.points) do
    if p.deleted == nil then
      if Drawing.near(p, mx,my, State.width) then
        App.color(Focus_stroke_color)
        love.graphics.circle('line', px(p.x),py(p.y), Same_point_distance)
      else
        App.color(Stroke_color)
        love.graphics.circle('fill', px(p.x),py(p.y), 2)
      end
      if p.name then
        -- TODO: clip
        local x,y = px(p.x)+5, py(p.y)+5
        love.graphics.print(p.name, x,y)
        if State.current_drawing_mode == 'name' and i == line.pending.target_point then
          -- create a faint red box for the name
          App.color(Current_name_background_color)
  end
  local function px(x) return Drawing.pixels(x, State.width)+State.left end
  for _,shape in ipairs(line.shapes) do
    end
    if App.mouse_down(1) and love.keyboard.isDown('h') then
      draw_help_with_mouse_pressed(State, line_index)
      return
    end
  end
  if line.show_help then
    draw_help_without_mouse_pressed(State, line_index)
    return
  end
  local mx = Drawing.coord(pmx-State.left, State.width)
    else
    if icon[State.current_drawing_mode] then
    App.color(Icon_color)

  local starty = Text.starty(State, drawing_index)
  local y = starty+10
  love.graphics.rectangle('fill', State.left,starty, State.width, math.max(Drawing.pixels(drawing.h, State.width),y-starty))
  local starty = Text.starty(State, drawing_index)
  local y = starty+10
  love.graphics.rectangle('fill', State.left,starty, State.width, math.max(Drawing.pixels(drawing.h, State.width),y-starty))
end
end
function current_shape(State, shape)
  if State.current_drawing_mode == 'freehand' then
    return 'freehand stroke'
  elseif State.current_drawing_mode == 'line' then
    return 'straight line'
  elseif State.current_drawing_mode == 'manhattan' then
    return 'horizontal/vertical line'
  elseif State.current_drawing_mode == 'circle' and shape and shape.start_angle then
    return 'arc'
  else
    return State.current_drawing_mode
  end
  love.graphics.print("You're currently drawing a "..current_shape(State, drawing.pending), State.left+30,y)
  y = y + State.line_height
  love.graphics.print('Things you can do now:', State.left+30,y)
  y = y + State.line_height
  if State.current_drawing_mode == 'freehand' then
    love.graphics.print('* Release the mouse button to finish drawing the stroke', State.left+30,y)
    y = y + State.line_height
  elseif State.current_drawing_mode == 'line' or State.current_drawing_mode == 'manhattan' then
    love.graphics.print('* Release the mouse button to finish drawing the line', State.left+30,y)
    y = y + State.line_height
  elseif State.current_drawing_mode == 'circle' then
    if drawing.pending.mode == 'circle' then
      love.graphics.print('* Release the mouse button to finish drawing the circle', State.left+30,y)
      y = y + State.line_height
      love.graphics.print("* Press 'a' to draw just an arc of a circle", State.left+30,y)
    else
      love.graphics.print('* Release the mouse button to finish drawing the arc', State.left+30,y)
    end
    y = y + State.line_height
  elseif State.current_drawing_mode == 'polygon' then
    love.graphics.print('* Release the mouse button to finish drawing the polygon', State.left+30,y)
    y = y + State.line_height
    love.graphics.print("* Press 'p' to add a vertex to the polygon", State.left+30,y)
    y = y + State.line_height
  elseif State.current_drawing_mode == 'rectangle' then
    if #drawing.pending.vertices < 2 then
      love.graphics.print("* Press 'p' to add a vertex to the rectangle", State.left+30,y)
      y = y + State.line_height
    else
      love.graphics.print('* Release the mouse button to finish drawing the rectangle', State.left+30,y)
      y = y + State.line_height
      love.graphics.print("* Press 'p' to replace the second vertex of the rectangle", State.left+30,y)
      y = y + State.line_height
    end
  elseif State.current_drawing_mode == 'square' then
    if #drawing.pending.vertices < 2 then
      love.graphics.print("* Press 'p' to add a vertex to the square", State.left+30,y)
      y = y + State.line_height
    else
      love.graphics.print('* Release the mouse button to finish drawing the square', State.left+30,y)
      y = y + State.line_height
      love.graphics.print("* Press 'p' to replace the second vertex of the square", State.left+30,y)
      y = y + State.line_height
    end
  end
  love.graphics.print("* Press 'esc' then release the mouse button to cancel the current shape", State.left+30,y)
  y = y + State.line_height
  y = y + State.line_height
  if State.current_drawing_mode ~= 'line' then
    love.graphics.print("* Press 'l' to switch to drawing lines", State.left+30,y)
    y = y + State.line_height
  end
  if State.current_drawing_mode ~= 'manhattan' then
    love.graphics.print("* Press 'm' to switch to drawing horizontal/vertical lines", State.left+30,y)
    y = y + State.line_height
  end
  if State.current_drawing_mode ~= 'circle' then
    love.graphics.print("* Press 'o' to switch to drawing circles/arcs", State.left+30,y)
    y = y + State.line_height
  end
  if State.current_drawing_mode ~= 'polygon' then
    love.graphics.print("* Press 'g' to switch to drawing polygons", State.left+30,y)
    y = y + State.line_height
  end
  if State.current_drawing_mode ~= 'rectangle' then
    love.graphics.print("* Press 'r' to switch to drawing rectangles", State.left+30,y)
    y = y + State.line_height
  end
  if State.current_drawing_mode ~= 'square' then
    love.graphics.print("* Press 's' to switch to drawing squares", State.left+30,y)
    y = y + State.line_height
  end
  App.color(Help_background_color)
  App.color(Help_color)
end
function draw_help_with_mouse_pressed(State, drawing_index)
  local drawing = State.lines[drawing_index]
  love.graphics.print("Things you can do:", State.left+30,y)
  y = y + State.line_height
  love.graphics.print("* Press the mouse button to start drawing a "..current_shape(State), State.left+30,y)
  y = y + State.line_height
  love.graphics.print("* Hover on a point and press 'ctrl+u' to pick it up and start moving it,", State.left+30,y)
  y = y + State.line_height
  App.color(Help_color)

  if y < State.top then
  local screen_bottom1 = Text.screen_bottom1(State)
  return screen_bottom1.line, Text.pos_at_end_of_screen_line(State, screen_bottom1)
end
function Text.cut_selection(State)
  if State.selection1.line == nil then return end
  local result = Text.selection(State)
  Text.delete_selection(State)
  return result
end
function Text.delete_selection(State)
  if State.selection1.line == nil then return end
  local minl,maxl = minmax(State.selection1.line, State.cursor1.line)
  local before = snapshot(State, minl, maxl)
  Text.delete_selection_without_undo(State)
  record_undo_event(State, {before=before, after=snapshot(State, State.cursor1.line)})
end
function Text.delete_selection_without_undo(State)
  if State.selection1.line == nil then return end
  -- min,max = sorted(State.selection1,State.cursor1)
  local minl,minp = State.selection1.line,State.selection1.pos
  local maxl,maxp = State.cursor1.line,State.cursor1.pos
  if minl > maxl then
    minl,maxl = maxl,minl
    minp,maxp = maxp,minp
  elseif minl == maxl then
    if minp > maxp then
      minp,maxp = maxp,minp
    end
  end
  -- update State.cursor1 and State.selection1
  State.cursor1.line = minl
  State.cursor1.pos = minp
  if Text.lt1(State.cursor1, State.screen_top1) then
    State.screen_top1.line = State.cursor1.line
    State.screen_top1.pos = Text.pos_at_start_of_screen_line(State, State.cursor1)
  end
  State.selection1 = {}
  -- delete everything between min (inclusive) and max (exclusive)
  Text.clear_screen_line_cache(State, minl)
  local min_offset = Text.offset(State.lines[minl].data, minp)
  local max_offset = Text.offset(State.lines[maxl].data, maxp)
  if minl == maxl then
--?     print('minl == maxl')
    State.lines[minl].data = State.lines[minl].data:sub(1, min_offset-1)..State.lines[minl].data:sub(max_offset)
    return
  end
    return State.screen_top1.line, State.screen_top1.pos

  App.screen.init{width=800, height=600}
  edit.run_after_keychord(Editor_state, 'M-right', 'right')
  edit.run_after_keychord(Editor_state, 'M-right', 'right')
  edit.draw(Editor_state)  -- populate line_cache.startpos for each line
  edit.run_after_keychord(Editor_state, 'S-right', 'right')
  edit.run_after_keychord(Editor_state, 'right', 'right')
  edit.draw(Editor_state)  -- populate line_cache.startpos for each line
  edit.draw(Editor_state)  -- populate line_cache.startpos for each line
  edit.draw(Editor_state)  -- populate line_cache.startpos for each line
  edit.draw(Editor_state)  -- populate line_cache.startpos for each line
  edit.run_after_keychord(Editor_state, 'right', 'right')
  check_eq(Editor_state.screen_top1.line, 2, 'screen_top')
  check_eq(Editor_state.cursor1.line, 3, 'cursor:line')
  check_eq(Editor_state.cursor1.pos, 6, 'cursor:pos')
  -- click on first location
  edit.run_after_mouse_press(Editor_state, Editor_state.left+8,Editor_state.top+5, 1)
  edit.run_after_mouse_release(Editor_state, Editor_state.left+8,Editor_state.top+5, 1)
  -- hold down shift and click on a second location
  App.fake_key_press('lshift')
  edit.run_after_mouse_press(Editor_state, Editor_state.left+20,Editor_state.top+5, 1)
  edit.run_after_mouse_release(Editor_state, Editor_state.left+20,Editor_state.top+Editor_state.line_height+5, 1)
  -- hold down shift and click at a third location
  App.fake_key_press('lshift')
  edit.run_after_mouse_press(Editor_state, Editor_state.left+20,Editor_state.top+5, 1)
  edit.run_after_mouse_release(Editor_state, Editor_state.left+8,Editor_state.top+Editor_state.line_height+5, 1)
  App.fake_key_release('lshift')
  -- selection is between first and third location. forget the second location, not the first.
  -- click on first location
  edit.run_after_mouse_press(Editor_state, Editor_state.left+8,Editor_state.top+5, 1)
  edit.run_after_mouse_release(Editor_state, Editor_state.left+8,Editor_state.top+5, 1)
  -- hold down shift and click somewhere else
  App.fake_key_press('lshift')
  edit.run_after_mouse_press(Editor_state, Editor_state.left+20,Editor_state.top+5, 1)
  edit.run_after_mouse_release(Editor_state, Editor_state.left+20,Editor_state.top+Editor_state.line_height+5, 1)
  App.fake_key_release('lshift')
  -- press mouse above first line of text
  edit.run_after_mouse_press(Editor_state, Editor_state.left+8,5, 1)
  check(Editor_state.selection1.line ~= nil, 'selection:line-not-nil')
  check_eq(Editor_state.selection1.line, 1, 'selection:line')
  check_eq(Editor_state.selection1.pos, 1, 'selection:pos')
  -- press and hold on first location
  edit.run_after_mouse_press(Editor_state, Editor_state.left+8,Editor_state.top+5, 1)
  -- drag and release somewhere else
  edit.run_after_mouse_release(Editor_state, Editor_state.left+20,Editor_state.top+Editor_state.line_height+5, 1)
  -- no change to data, selection is reset
  App.fake_key_release('lshift')
  edit.run_after_mouse_release(Editor_state, Editor_state.left+8,Editor_state.top+5, 1)
  check_eq(Editor_state.cursor1.line, 2, 'line')
  check_eq(Editor_state.cursor1.pos, 4, 'pos')
  check_eq(Editor_state.cursor1.pos, 9, 'check')
  Editor_state = edit.initialize_test_state()
  Editor_state.lines = load_array{}
  Text.redraw_all(Editor_state)
  edit.draw(Editor_state)
  edit.run_after_mouse_click(Editor_state, 8,Editor_state.top+8, 1)
  -- cursor skips drawing to always remain on text

-- return y for the next line
  return y
--?   print(State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos)
--?     print(State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos)
--?       print('=>', State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos)
  State.screen_top1 = Text.previous_screen_top1(State)
  State.cursor1 = {line=State.screen_top1.line, pos=State.screen_top1.pos}
  Text.move_cursor_down_to_next_text_line_while_scrolling_again_if_necessary(State)
  Text.redraw_all(State)  -- if we're scrolling, reclaim all fragments to avoid memory leaks
end
-- return the top y coordinate of a given line_index,
-- or nil if no part of it is on screen
function Text.starty(State, line_index)
  -- does not modify State (except to populate line_cache)
  if line_index < State.screen_top1.line then return end
  local loc2 = Text.to2(State, State.screen_top1)
  local y = State.top
  while true do
    if State.lines[loc2.line].mode == 'drawing' then
      y = y + Drawing_padding_top
    end
    if loc2.line == line_index then return y end
    if State.lines[loc2.line].mode == 'text' then
      y = y + State.line_height
    elseif State.lines[loc2.line].mode == 'drawing' then
      y = y + Drawing.pixels(State.lines[loc2.line].h, State.width) + Drawing_padding_bottom
    end
    if y + State.line_height > App.screen.height then break end
    local next_loc2 = Text.next_screen_line(State, loc2)
    if Text.eq2(next_loc2, loc2) then break end  -- end of file
    loc2 = next_loc2
  end
end
function Text.previous_screen_top1(State)
  -- duplicate some logic from love.draw
  -- does not modify State (except to populate line_cache)
  local loc2 = Text.to2(State, State.screen_top1)
    if loc2.line == 1 and loc2.screen_line == 1 and loc2.screen_pos == 1 then break end
    if State.lines[loc2.line].mode == 'text' then
    elseif State.lines[loc2.line].mode == 'drawing' then
      y = y - Drawing_padding_height - Drawing.pixels(State.lines[loc2.line].h, State.width)
    loc2 = Text.previous_screen_line(State, loc2)
  return Text.to1(State, loc2)
  State.screen_top1 = Text.screen_bottom1(State)
end
-- return the location of the start of the bottom-most line on screen
function Text.screen_bottom1(State)
  -- duplicate some logic from love.draw
  -- does not modify State (except to populate line_cache)
  local loc2 = Text.to2(State, State.screen_top1)
  local y = State.top
  while true do
    if State.lines[loc2.line].mode == 'text' then
      y = y + State.line_height
    elseif State.lines[loc2.line].mode == 'drawing' then
      y = y + Drawing_padding_height + Drawing.pixels(State.lines[loc2.line].h, State.width)
    end
    if y + State.line_height > App.screen.height then break end
    local next_loc2 = Text.next_screen_line(State, loc2)
    if Text.eq2(next_loc2, loc2) then break end
    loc2 = next_loc2
  end
  return Text.to1(State, loc2)
--?   print('down', State.cursor1.line, State.cursor1.pos, State.screen_top1.line, State.screen_top1.pos)
    local screen_bottom1 = Text.screen_bottom1(State)
--?   print('down 2', State.cursor1.line, State.cursor1.pos, State.screen_top1.line, State.screen_top1.pos, screen_bottom1.line, screen_bottom1.pos)
    if State.cursor1.line > screen_bottom1.line then
    local screen_bottom1 = Text.screen_bottom1(State)
    local scroll_down = Text.le1(screen_bottom1, State.cursor1)
--?   print('=>', State.cursor1.line, State.cursor1.pos, State.screen_top1.line, State.screen_top1.pos)
  assert(State.lines[loc1.line].mode == 'text')
end
function Text.final_text_loc_on_screen(State)
  local screen_bottom1 = Text.screen_bottom1(State)
  if State.lines[screen_bottom1.line].mode == 'text' then
    return {
      line=screen_bottom1.line,
      pos=Text.pos_at_end_of_screen_line(State, screen_bottom1),
    }
  end
  local loc2 = Text.to2(State, screen_bottom1)
  while true do
    if State.lines[loc2.line].mode == 'text' then break end
    assert(loc2.line > 1 or loc2.screen_line > 1 and loc2.screen_pos > 1)  -- elsewhere we're making sure there's always at least one text line on screen
    loc2 = Text.previous_screen_line(State, loc2)
  end
  local result = Text.to1(State, loc2)
  result.pos = Text.pos_at_end_of_screen_line(State, result)
  return result
--?   print('snap', State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos)
--?   print('snap =>', State.screen_top1.line, State.screen_top1.pos, State.cursor1.line, State.cursor1.pos)
  local starty = Text.starty(State, line_index)
  if starty == nil then return false end  -- outside current page
  if y < starty then return false end
  return y < starty + State.line_height*(#line_cache.screen_line_starting_pos - Text.screen_line_index(line_cache.screen_line_starting_pos, line_cache.startpos) + 1)
  local starty = Text.starty(State, line_index)
  assert(my >= starty, 'failed to map y pixel to line')
  local y = starty
end
function Text.eq2(a, b)
  return a.line == b.line and a.screen_line == b.screen_line and a.screen_pos == b.screen_pos
function Text.next_screen_line(State, loc2)
  if State.lines[loc2.line].mode == 'drawing' then
    return {line=loc2.line+1, screen_line=1, screen_pos=1}
  end
  Text.populate_screen_line_starting_pos(State, loc2.line)
  if loc2.screen_line >= #State.line_cache[loc2.line].screen_line_starting_pos then
    if loc2.line < #State.lines then
      return {line=loc2.line+1, screen_line=1, screen_pos=1}
    else
      return loc2
    end
  else
    return {line=loc2.line, screen_line=loc2.screen_line+1, screen_pos=1}
  end
end
  local screen_bottom1 = Text.screen_bottom1(State)
  elseif State.cursor1.line >= screen_bottom1.line then
      State.cursor1 = Text.final_text_loc_on_screen(State)
    end
  end
end
-- slightly expensive since it redraws the screen
function Text.cursor_out_of_screen(State)
    if Text.cursor_out_of_screen(State) then
  if Text.lt1(State.cursor1, State.screen_top1) then
    State.cursor1 = {line=State.screen_top1.line, pos=State.screen_top1.pos}
-- resize helper
function Text.tweak_screen_top_and_cursor(State)
  if State.screen_top1.pos == 1 then return end
  Text.populate_screen_line_starting_pos(State, State.screen_top1.line)
  local line = State.lines[State.screen_top1.line]
  local line_cache = State.line_cache[State.screen_top1.line]
  for i=2,#line_cache.screen_line_starting_pos do
    local pos = line_cache.screen_line_starting_pos[i]
    if pos == State.screen_top1.pos then
      break
    end
    if pos > State.screen_top1.pos then
      -- make sure screen top is at start of a screen line
      local prev = line_cache.screen_line_starting_pos[i-1]
      if State.screen_top1.pos - prev < pos - State.screen_top1.pos then
        State.screen_top1.pos = prev
      else
        State.screen_top1.pos = pos
      end
      break
    end
  end
  -- make sure cursor is on screen
end
  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))
  -- duplicate some logic from Text.draw
end
-- convert mx,my in pixels to schema-1 coordinates
  Text.populate_screen_line_starting_pos(State, line_index)
  Text.redraw_all(State)  -- if we're scrolling, reclaim all fragments to avoid memory leaks
--?   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
end
  Text.populate_screen_line_starting_pos(State, loc1.line)
  local line_cache = State.line_cache[loc1.line]
  local most_recent_final_pos = utf8.len(State.lines[loc1.line].data)+1
  for i=#line_cache.screen_line_starting_pos,1,-1 do
    local spos = line_cache.screen_line_starting_pos[i]
    if spos <= loc1.pos then
      return most_recent_final_pos
    end
    most_recent_final_pos = spos-1
  end
end
function Text.start_of_line(State)
--?     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)
--?       print('screen top before:', State.screen_top1.line, State.screen_top1.pos)
--?       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
  assert(State.cursor1.pos, 'cursor has no pos')
end
function Text.up(State)
  State.cursor1 = {line=State.screen_top1.line, pos=State.screen_top1.pos}
end
function Text.pagedown(State)
  end
    end
      y = y - State.line_height
  local y = App.screen.height - State.line_height
  while y >= State.top do
  -- duplicate some logic from love.draw
    end
    schedule_save(State)
    record_undo_event(State, {before=before, after=snapshot(State, State.cursor1.line)})
  elseif chord == 'backspace' then
    Text.insert_at_cursor(State, '\t')
    if State.cursor_y > App.screen.height - State.line_height then
      Text.populate_screen_line_starting_pos(State, State.cursor1.line)
      Text.snap_cursor_to_bottom_of_screen(State, State.left, State.right)
  Text.insert_at_cursor(State, t)
  if State.cursor_y > App.screen.height - State.line_height then
    Text.populate_screen_line_starting_pos(State, State.cursor1.line)
    Text.snap_cursor_to_bottom_of_screen(State, State.left, State.right)
  end
  record_undo_event(State, {before=before, after=snapshot(State, State.cursor1.line)})
end
function Text.insert_at_cursor(State, t)
end
function Text.screen_line(line, line_cache, i)
  local pos = line_cache.screen_line_starting_pos[i]
  local offset = Text.offset(line.data, pos)
  if i >= #line_cache.screen_line_starting_pos then
    return line.data:sub(offset)
function Text.draw(State, line_index, y, startpos, hide_cursor, show_line_numbers)

    --
    -- On lines that are drawings, pos will be nil.
    cursor1 = {line=1, pos=1},  -- position of cursor; must be on a text line
      y = Text.draw(State, line_index, y, startpos, hide_cursor, show_line_numbers)
      if Drawing.in_drawing(State, line_index, x, y, State.left,State.right) then
  State.selection1 = Text.final_text_loc_on_screen(State)
    State.cursor1 = Text.final_text_loc_on_screen(State)
    State.cursor1 = Text.screen_bottom1(State)
      chord ~= 'C-a' and chord ~= 'C-c' and chord ~= 'C-x' and chord ~= 'backspace' and chord ~= 'delete' and chord ~= 'C-z' and chord ~= 'C-y' and not App.is_cursor_movement(key) then
  edit.draw(State)
  App.fake_mouse_release(x,y, mouse_button)
    Text.delete_selection(State, State.left, State.right)
  end
    edit.put_cursor_on_next_text_line(State)
    edit.clean_up_mouse_press(State)
end
        State.lines.current_drawing_index = line_index
        State.lines.current_drawing = line
        Drawing.before = snapshot(State, line_index)
--?       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
    selection1 = {},
    -- some extra state to compute selection between mouse press and release
    old_cursor1 = nil,
    old_selection1 = nil,
    mousepress_shift = nil,
    screen_top1 = {line=1, pos=1},  -- position of start of screen line at top of screen

  State.cursor1 = {line=State.screen_top1.line, pos=State.screen_top1.pos}

    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.screen_top1 = Text.screen_bottom1(State)

  State.cursor1 = {line=State.screen_top1.line, pos=State.screen_top1.pos}

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