Could there be a function that plots a PNG grid that you can click with locator() (see my blog about locator or my {plunderplot} package); the returned point is evaluated; and the PNG is updated so the clicked zone is now black. Then you can click another square, or the same one to return its colour to white.
Could there be a function that plots a PNG grid that you can click with
locator()(see my blog about locator or my {plunderplot} package); the returned point is evaluated; and the PNG is updated so the clicked zone is now black. Then you can click another square, or the same one to return its colour to white.