diff --git a/scripts/tilemap.lua b/scripts/tilemap.lua
new file mode 100644
index 000000000..0c2c37615
--- /dev/null
+++ b/scripts/tilemap.lua
@@ -0,0 +1,266 @@
+-- Copyright (C) 2019-2020  Igara Studio S.A.
+--
+-- This file is released under the terms of the MIT license.
+-- Read LICENSE.txt for more information.
+
+-- This version of Aseprite doesn't support tilemaps
+if TilesetMode == nil then return end
+
+dofile('./test_utils.lua')
+
+local rgba = app.pixelColor.rgba
+
+-- Check constants
+assert(TilemapMode.PIXELS == 0)
+assert(TilemapMode.TILES == 1)
+assert(TilesetMode.STACK == 2)
+assert(TilesetMode.MANUAL == 0)
+assert(TilesetMode.AUTO == 1)
+assert(TilesetMode.STACK == 2)
+
+----------------------------------------------------------------------
+-- Tests drawing in the tilemap
+----------------------------------------------------------------------
+
+do
+  local spr = Sprite(32, 32)
+  assert(spr.layers[1].isImage)
+  assert(not spr.layers[1].isTilemap)
+
+  ----------------------------------------------------------------------
+  -- Create a tilemap
+  ----------------------------------------------------------------------
+
+  app.command.NewLayer{ tilemap=true }
+  assert(#spr.layers == 2)
+  local tilemapLay = spr.layers[2]
+  assert(tilemapLay.isImage)
+  assert(tilemapLay.isTilemap)
+  assert(#tilemapLay.cels == 0)
+
+  ----------------------------------------------------------------------
+  -- Draw the first pixel on the tilemap so a new tile is created
+  ----------------------------------------------------------------------
+
+  app.useTool{
+    tool='pencil',
+    color=Color{ r=0, g=0, b=0 },
+    layer=tilemapLay,
+    tilesetMode=TilesetMode.STACK,
+    points={ Point(2, 2), Point(3, 2) }}
+  assert(#tilemapLay.cels == 1)
+  assert(tilemapLay:cel(1).image.colorMode == ColorMode.TILEMAP)
+  local tilemapCel = tilemapLay:cel(1)
+  assert(tilemapCel.bounds == Rectangle(0, 0, 16, 16))
+
+  assert(#spr.tilesets == 1) -- one tileset
+  assert(spr.tilesets[1] == tilemapLay.tileset)
+
+  local tileset = tilemapLay.tileset
+  assert(#tileset == 1) -- one tile
+
+  tilemapCel.position = Point(2, 2)
+  assert(tilemapCel.bounds == Rectangle(2, 2, 16, 16))
+  assert(#tileset == 1)
+
+  assert(tilemapCel.image.width == 1)
+  assert(tilemapCel.image.height == 1)
+  assert(tilemapCel.image:getPixel(0, 0) == 0)
+
+  ----------------------------------------------------------------------
+  -- Draw a second pixel with locked mode (new tiles are not generated)
+  ----------------------------------------------------------------------
+
+  app.useTool{
+    tool='pencil',
+    color=Color{ r=0, g=0, b=0 },
+    cel=tilemapCel,
+    tilesetMode=TilesetMode.MANUAL,
+    points={ Point(0, 0) }}
+
+  assert(tilemapCel.bounds == Rectangle(2, 2, 16, 16))
+  assert(#tileset == 1)
+
+  ----------------------------------------------------------------------
+  -- Draw pixels generating new tiles
+  ----------------------------------------------------------------------
+
+  app.useTool{
+    tool='pencil',
+    color=Color{ r=0, g=0, b=0 },
+    cel=tilemapCel,
+    tilesetMode=TilesetMode.STACK,
+    points={ Point(0, 0) }}
+
+  assert(tilemapCel.bounds == Rectangle(-14, -14, 32, 32))
+  assert(#tileset == 3)
+  assert(not tileset:getTile(0):isEmpty())
+  assert(not tileset:getTile(1):isEmpty())
+  assert(tileset:getTile(2):isEmpty())
+  assert(tilemapCel.image.width == 2)
+  assert(tilemapCel.image.height == 2)
+  assert(tilemapCel.image:getPixel(0, 0) == 1)
+  assert(tilemapCel.image:getPixel(1, 0) == 2)
+  assert(tilemapCel.image:getPixel(0, 1) == 2)
+  assert(tilemapCel.image:getPixel(1, 1) == 0)
+
+  app.useTool{
+    tool='pencil',
+    color=Color{ r=0, g=0, b=0 },
+    cel=tilemapCel,
+    tilesetMode=TilesetMode.STACK,
+    points={ Point(19, 19) }}
+
+  assert(tilemapCel.bounds == Rectangle(-14, -14, 48, 48))
+  assert(#tilemapLay.tileset == 4)
+  assert(not tileset:getTile(3):isEmpty())
+  assert(tilemapCel.image.width == 3)
+  assert(tilemapCel.image.height == 3)
+  assert(tilemapCel.image:getPixel(0, 0) == 1)
+  assert(tilemapCel.image:getPixel(1, 0) == 2)
+  assert(tilemapCel.image:getPixel(2, 0) == 2)
+  assert(tilemapCel.image:getPixel(0, 1) == 2)
+  assert(tilemapCel.image:getPixel(1, 1) == 0)
+  assert(tilemapCel.image:getPixel(2, 1) == 2)
+  assert(tilemapCel.image:getPixel(0, 2) == 2)
+  assert(tilemapCel.image:getPixel(1, 2) == 2)
+  assert(tilemapCel.image:getPixel(2, 2) == 3)
+end
+
+----------------------------------------------------------------------
+-- Tests drawing when the grid origin is in a negative position
+----------------------------------------------------------------------
+
+do
+  local spr = Sprite(32, 32)
+  app.command.NewLayer{ tilemap=true }
+  local tilemapLay = spr.layers[2]
+
+  app.useTool{
+    tool='pencil',
+    color=Color{ r=0, g=255, b=0 },
+    layer=tilemapLay,
+    tilesetMode=TilesetMode.STACK,
+    points={ Point(0, 0) }}
+  local tilemapCel = tilemapLay:cel(1)
+  assert(tilemapCel.bounds == Rectangle(0, 0, 16, 16))
+
+  local tileset = tilemapLay.tileset
+  assert(#tileset == 1) -- one tile
+
+  tilemapCel.position = Point(-1, -1)
+  assert(tilemapCel.bounds == Rectangle(-1, -1, 16, 16))
+
+  app.useTool{
+    tool='pencil',
+    color=Color{ r=255, g=0, b=0 },
+    cel=tilemapCel,
+    tilesetMode=TilesetMode.STACK,
+    points={ Point(0, 0) }}
+
+  assert(tilemapCel.bounds == Rectangle(-1, -1, 16, 16))
+  assert(#tileset == 2)
+
+  local img = tileset:getTile(1)
+
+  assert(img:getPixel(0, 0) == rgba(0, 255, 0, 255))
+  assert(img:getPixel(1, 0) == rgba(0, 0, 0, 0))
+  assert(img:getPixel(2, 0) == rgba(0, 0, 0, 0))
+
+  assert(img:getPixel(0, 1) == rgba(0, 0, 0, 0))
+  assert(img:getPixel(1, 1) == rgba(255, 0, 0, 255))
+  assert(img:getPixel(2, 1) == rgba(0, 0, 0, 0))
+
+  assert(img:getPixel(0, 2) == rgba(0, 0, 0, 0))
+  assert(img:getPixel(1, 2) == rgba(0, 0, 0, 0))
+  assert(img:getPixel(2, 2) == rgba(0, 0, 0, 0))
+end
+
+----------------------------------------------------------------------
+-- Tests that extra tiles are not created
+----------------------------------------------------------------------
+
+do
+  local spr = Sprite(32, 32)
+  app.command.NewLayer{ tilemap=true }
+  local tilemapLay = spr.layers[2]
+
+  app.useTool{
+    tool='pencil',
+    color=Color{ r=0, g=255, b=0 },
+    layer=tilemapLay,
+    tilesetMode=TilesetMode.STACK,
+    points={ Point(0, 0) }}
+  local tilemapCel = tilemapLay:cel(1)
+  tilemapCel.position = Point(-1, -1)
+
+  app.useTool{
+    tool='pencil',
+    color=Color{ r=255, g=0, b=0 },
+    cel=tilemapCel,
+    tilesetMode=TilesetMode.STACK,
+    points={ Point(30, 30) }}
+
+  assert(tilemapCel.bounds == Rectangle(-1, -1, 32, 32))
+end
+
+----------------------------------------------------------------------
+-- Tests moving tiles
+----------------------------------------------------------------------
+
+do
+  local spr = Sprite(32, 32)
+  app.command.NewLayer{ tilemap=true }
+  local tilemapLay = spr.layers[2]
+
+  app.useTool{
+    tool='ellipse',
+    color=Color{ r=0, g=0, b=0 },
+    layer=tilemapLay,
+    tilesetMode=TilesetMode.STACK,
+    points={ Point(0, 0), Point(31, 31) }}
+
+  local ts = tilemapLay.tileset
+  assert(#ts == 4)
+
+  local imgs = { ts:getTile(0),
+                 ts:getTile(1),
+                 ts:getTile(2),
+                 ts:getTile(3) }
+
+  -- No op = move tile 0 before the tile 0, result=0,1,2,3
+  app.range.tiles = { 0 }
+  app.command.MoveTiles{ before=0 }
+  expect_eq(imgs[0+1], ts:getTile(0))
+  expect_eq(imgs[1+1], ts:getTile(1))
+  expect_eq(imgs[2+1], ts:getTile(2))
+  expect_eq(imgs[3+1], ts:getTile(3))
+
+  -- Move tile 1 before tile 0, result=1,0,2,3
+  app.range.tiles = { 1 }
+  app.command.MoveTiles{ before=0 }
+  expect_eq(imgs[1+1], ts:getTile(0))
+  expect_eq(imgs[0+1], ts:getTile(1))
+  expect_eq(imgs[2+1], ts:getTile(2))
+  expect_eq(imgs[3+1], ts:getTile(3))
+  app.undo()
+
+  -- Move tiles 0 and 1 before 3, result=2,0,1,3
+  app.range.tiles = { 0, 1 }
+  app.command.MoveTiles({ before=3 })
+  expect_eq(imgs[2+1], ts:getTile(0))
+  expect_eq(imgs[0+1], ts:getTile(1))
+  expect_eq(imgs[1+1], ts:getTile(2))
+  expect_eq(imgs[3+1], ts:getTile(3))
+  app.undo()
+
+  -- Move tiles 0 and 2 before 2, result=1,0,2,3
+  app.range.tiles = { 0, 2 }
+  app.command.MoveTiles({ before=2 })
+  expect_eq(imgs[1+1], ts:getTile(0))
+  expect_eq(imgs[0+1], ts:getTile(1))
+  expect_eq(imgs[2+1], ts:getTile(2))
+  expect_eq(imgs[3+1], ts:getTile(3))
+  app.undo()
+
+end