Start for drag placement.

Assets/Scripts/MapEditor/DragPlacement.cs

+using System.Collections;
+using System.Collections.Generic;
+using UnityEngine;
+
+
+// This script should be attached the the prefab of the left side cap.
+// Set mid to the prefab that should be placed between the caps.
+// The right cap will be the flipped version of the left cap.
+public class DragPlacement : MonoBehaviour
+{
+	public GameObject cap;
+	public GameObject mid;
+
+	public static GameObject instance;	// Current instance of this script
+
+	public void endDrag(Vector3 pos)
+	{
+		Vector2 dir = pos - transform.position;
+
+		// Moved further left/right
+		if(Mathf.Abs(dir.x) > Mathf.Abs(dir.y))
+		{
+			placeX((int)pos.x);
+		}
+		// Moved further up/down
+		else
+		{
+			placeY((int)pos.y);
+		}
+	}
+
+	private void placeX(int x)
+	{
+		// Placeing left
+		if(x < transform.position.x)
+		{
+			// Place start cap and flip
+			GameObject go = World.set(transform.position, cap);
+			go.transform.localScale = new Vector3(go.transform.localScale.x * -1,
+													go.transform.localScale.y,
+													go.transform.localScale.z);
+
+			// Place mid
+			for(int i = (int)transform.position.x; i > x; i--)
+			{
+				World.set(i, transform.position.y, transform.position.z, mid);
+			}
+			// Place cap
+			World.set(x, transform.position.y, transform.position.z, cap);
+		}
+
+		// Placing right
+		else
+		{
+			// Place start cap
+			World.set(transform.position, cap);
+
+			// Place mid
+			for(int i = (int)transform.position.x; i < x; i++)
+			{
+				World.set(i, transform.position.y, transform.position.z, mid);
+			}
+			// Place cap
+			GameObject go = World.set(x, transform.position.y, transform.position.z, cap);
+			go.transform.localScale = new Vector3(go.transform.localScale.x * -1,
+													go.transform.localScale.y,
+													go.transform.localScale.z);
+		}
+	}
+
+	private void placeY(int y)
+	{
+		// Placeing down
+		if(y < transform.position.y)
+		{
+			// Place start cap and flip
+			GameObject go = World.set(transform.position, cap);
+			go.transform.localScale = new Vector3(go.transform.localScale.x,
+													go.transform.localScale.y * -1,
+													go.transform.localScale.z);
+			go.transform.Rotate(new Vector3(0, 0, -90));
+
+
+			// Place mid
+			for(int i = (int)transform.position.y; i > y; i--)
+			{
+				go = World.set(transform.position.x, i, transform.position.z, mid);
+				go.transform.Rotate(new Vector3(0, 0, -90));
+			}
+			// Place cap
+			go = World.set(y, transform.position.y, transform.position.z, cap);
+			go.transform.Rotate(new Vector3(0, 0, -90));	
+		}
+
+		// Placing up
+		else
+		{
+			// Place start cap and flip
+			GameObject go = World.set(transform.position, cap);
+			go.transform.Rotate(new Vector3(0, 0, 90));
+
+
+			// Place mid
+			for(int i = (int)transform.position.y; i < y; i++)
+			{
+				go = World.set(transform.position.x, i, transform.position.z, mid);
+				go.transform.Rotate(new Vector3(0, 0, 90));
+			}
+			// Place cap
+			go = World.set(y, transform.position.y, transform.position.z, cap);
+			go.transform.localScale = new Vector3(go.transform.localScale.x,
+													go.transform.localScale.y * -1,
+													go.transform.localScale.z);
+			go.transform.Rotate(new Vector3(0, 0, 90));	
+		}
+	}
+}

Assets/Scripts/MapEditor/MapEditor.cs

@@ -81,7 +81,8 @@ public class MapEditor : MonoBehaviour
     {
         if(!World.Ready())
         {
-            Debug.LogError("World not initialized! Please set a width, height, and depth in the inspector and click \"Set\".");
+            Debug.LogError("World not initialized!\n"
+                            +"Please set a width, height, and depth in the inspector and click \"Set\".");
             return;
         }
 
@@ -90,27 +91,40 @@ public class MapEditor : MonoBehaviour
             if(Tiles == null)
                 GameObject.FindObjectOfType<MapEditor>().setupTilesParent();
 
+            // Placing non-empty tile
             if(Tile != null)
             {
-                if(!World.posIsThis(pos, Tile))
+                // Not a drag place tile
+                if(Tile.GetComponent<DragPlacement>() == null)
                 {
-                    Debug.Log("new");
-                    GameObject go = (GameObject)GameObject.Instantiate(Tile, new Vector3(pos.x, pos.y, Layer), Quaternion.identity);
-                    go = PrefabUtility.ConnectGameObjectToPrefab(go, Tile);
-
-                    go.transform.position = new Vector3(pos.x, pos.y, Layer);
-
-                    SpriteRenderer sr = go.GetComponent<SpriteRenderer>();
-                    if(sr != null)
+                    if(!World.posIsThis(pos, Tile))
                     {
-                        sr.sortingOrder = layer * -World.SORTING_ORDER_MULT;
+                        Debug.Log("new");
+                        GameObject go = (GameObject)GameObject.Instantiate(Tile, new Vector3(pos.x, pos.y, Layer), Quaternion.identity);
+                        go = PrefabUtility.ConnectGameObjectToPrefab(go, Tile);
+
+                        go.transform.position = new Vector3(pos.x, pos.y, Layer);
+
+                        SpriteRenderer sr = go.GetComponent<SpriteRenderer>();
+                        if(sr != null)
+                        {
+                            sr.sortingOrder = layer * -World.SORTING_ORDER_MULT;
+                        }
+                        go.transform.parent = Tiles;
+                        World.set(pos, layer, go);
                     }
-                    go.transform.parent = Tiles;
-                    World.set(pos, layer, go);
                 }
+
+                // Is a drag place tile
                 else
-                    Debug.Log("new");
+                {
+                    if(DragPlacement.instance == null)
+                    {   // Start new drag placement
+                                            // Need to detect when not holding mouse to end drag placement
+                    }
+                }
             }
+            // Placing empty tile (delete)
             else
             {
                 World.set(pos, layer, null);

Assets/Scripts/MapEditor/World.cs

@@ -58,19 +58,19 @@ public static class World
     public static void giveMap(GameObject[][][] newMap) { map = newMap; }
 
 
-    public static bool set(Vector3 pos, GameObject go) { return set(pos.x, pos.y, pos.z, go); }
-    public static bool set(Vector2 pos, float z, GameObject go) { return set(pos.x, pos.y, z, go); }
-    public static bool set(Vector2 pos, int z, GameObject go) { return set((int)pos.x, (int)pos.y, z, go); }
-    public static bool set(float x, float y, float z, GameObject go) { return set((int)x, (int)y, (int)z, go); }
-    public static bool set(int x, int y, int z, GameObject go)
+    public static GameObject set(Vector3 pos, GameObject go) { return set(pos.x, pos.y, pos.z, go); }
+    public static GameObject set(Vector2 pos, float z, GameObject go) { return set(pos.x, pos.y, z, go); }
+    public static GameObject set(Vector2 pos, int z, GameObject go) { return set((int)pos.x, (int)pos.y, z, go); }
+    public static GameObject set(float x, float y, float z, GameObject go) { return set((int)x, (int)y, (int)z, go); }
+    public static GameObject set(int x, int y, int z, GameObject go)
     {
         if(!posInBounds(x, y, z))
-            return false;
+            return null;
         
         destroyPos(x, y, z);
 
         map[x][y][z] = go;
-        return true;
+        return go;
     }