Another tile map example. This one scrolls by pixels, not by tiles.
It’s done by using a layer bigger than the screen. It draws one extra tile column and one extra row. Fine scrolling uses the layer offset, but it redraws all tiles when the next row or column appears.
There are other ways to do scrolling: You could do it entirely with the layer offset, without redrawing the tiles, but then the map size is limited by the maximum layer size.
Get LowRes Coder to use this program.