* `on.touch_press(x,y, dx,dy, pressure)` -- called when you touch a
  multi-touch screen. Provides in `x` and `y` the point on the screen at which
  the touch occurred.
  (Based on [LÖVE](https://love2d.org/wiki/love.touchpressed).)

* `on.touch_release(x,y, dx,dy, pressure)` -- called when you release a touch.
  Provides the same arguments as `on.touch_press()` above.
  (Based on [LÖVE](https://love2d.org/wiki/love.touchreleased).)
* `on.touch_move(x,y, dx,dy, pressure)` -- called when you move any finger on
  a multi-touch screen. Provides the same arguments as `on.touch_press()`
  above, with `dx` and `dy` containing the amount moved since the previous
  call to `touch_move`.
  (Based on [LÖVE](https://love2d.org/wiki/love.touchmoved).)

end
function App.touchpressed(x,y, dx,dy, pressure)
  if Mode == 'error' then return end
  Cursor_time = 0  -- ensure cursor is visible immediately after it moves
  if on.touch_press then on.touch_press(x,y, dx,dy, pressure) end
end
function App.touchreleased(x,y, dx,dy, pressure)
  if Mode == 'error' then return end
  Cursor_time = 0  -- ensure cursor is visible immediately after it moves
  if on.touch_release then on.touch_release(x,y, dx,dy, pressure) end
end
function App.touchmoved(x,y, dx,dy, pressure)
  if on.touch_move then on.touch_move(x,y, dx,dy, pressure) end

  --   on.touch_press (see love.touchpressed)
  --   on.touch_release (see love.touchreleased)
  --   on.touch_move (see love.touchmoved)