Can expand and reduce canvass with lctrl and lshift. (Bug: all tiles get erased :c)

data/scripts/level.lua

@@ -19,6 +19,86 @@ function LevelLoadTiles()
 	TileCreateObjects()
 end
 
+
+function LevelExpandCanvas(horizontal,vertical)
+	local h = LevelGetTileWidth()
+	local v = LevelGetTileHeight()
+
+	-- get new canvas size
+	local newCanvasH = h + math.abs(horizontal)
+	local newCanvasV = v + math.abs(vertical)
+
+	-- lets make a new temporal canvas
+	local ExpandedLevel = {}
+	for i = 1, newCanvasV do
+		ExpandedLevel[i] = {}
+		for j = 1, newCanvasH do
+			ExpandedLevel[i][j] = InstanceTile(0)
+		end
+	end
+
+	-- lets guess how the new canvas and positions are offset
+	local expand_h = 0
+	if horizontal < 0 then
+		expand_h = -horizontal
+	end
+
+	local expand_v = 0
+	if vertical < 0 then
+		expand_v = -vertical
+	end
+
+	-- get data from old canvas to new canvas
+	for i = 1, #LevelTiles do
+		for j = 1, #LevelTiles[i] do
+			ExpandedLevel[i+expand_v][j+expand_h] = InstanceTile(LevelTiles[i][j])
+		end
+	end
+
+	-- use new canvas
+	LevelTiles = ExpandedLevel
+end
+
+
+function LevelReduceCanvas(horizontal,vertical)
+	local h = LevelGetTileWidth()
+	local v = LevelGetTileHeight()
+
+	-- get new canvas size
+	local newCanvasH = h - math.abs(horizontal)
+	local newCanvasV = v - math.abs(vertical)
+
+	-- lets make a new temporal canvas
+	local ExpandedLevel = {}
+	for i = 1, newCanvasV do
+		ExpandedLevel[i] = {}
+		for j = 1, newCanvasH do
+			ExpandedLevel[i][j] = InstanceTile(0)
+		end
+	end
+
+	-- lets guess how the new canvas and positions are offset
+	local expand_h = 0
+	if horizontal < 0 then
+		expand_h = -horizontal
+	end
+
+	local expand_v = 0
+	if vertical < 0 then
+		expand_v = -vertical
+	end
+
+	-- get data from old canvas to new canvas
+	for i = 1, #ExpandedLevel do
+		for j = 1, #ExpandedLevel[i] do
+			ExpandedLevel[i][j] = InstanceTile(LevelTiles[i+expand_v][j+expand_h])
+		end
+	end
+
+	-- use new canvas
+	LevelTiles = ExpandedLevel
+end
+
 function LevelGetTileData()
 	for k, v in pairs(tileset) do
 		if v == LevelData.tileset then
@@ -79,7 +159,7 @@ function LevelIndexTiles()
 -- instance level tiles according to the Properties
 	for i = 1, #LevelTiles do
 		for j = 1, #LevelTiles[i] do
-			InstanceTile(i,j,LevelTiles[i][j])
+			SetTile(i,j,LevelTiles[i][j])
 		end
 	end
 end
@@ -117,9 +197,8 @@ function TileDataInitialize()
 	end
 end
 
-function InstanceTile(i,j,id)
-	LevelTiles[i][j] = {}
-	local tile = LevelTiles[i][j]
+function InstanceTile(id)
+	local tile = {}
 
 	tile.id = id
 	local Properties = TileData[tile.id]
@@ -137,6 +216,12 @@ function InstanceTile(i,j,id)
 			tile.display = Properties.force
 		end
 	end
+
+	return tile
+end
+
+function SetTile(i,j,id)
+	LevelTiles[i][j] = InstanceTile(id)
 end
 
 function TileGetType(tile)