Added polygonal regions.

plugin.yml

@@ -178,15 +178,20 @@ commands:
     //count:
         description: Counts the number of a certain type of block
         usage: /<command> <block>
-    /size:
+    /m:
         description: Get information about the selection
         usage: /<command> 
+        aliases: ['//size']
     /shift:
         description: Shift the selection area
         usage: /<command> <amount> [direction]
     /expand:
         description: Expand the selection area
         usage: /<command> <amount> [reverse-amount] <direction>
+    /sel:
+        description: Choose a region selector
+        usage: /<command> [type]
+        aliases: [',']
     /inset:
         description: Inset the selection area
         usage: /<command> [-hv] <amount>
@@ -299,6 +304,10 @@ commands:
     /drain:
         description: Drain a pool
         usage: /<command> <radius>
-    /version:
+    version:
         description: Get WorldEdit version
         usage: /<command> 
+        aliases: ['ver']
+    reload:
+        description: Reload WorldEdit
+        usage: /<command> 

src/com/sk89q/worldedit/LocalSession.java

@@ -28,8 +28,9 @@ import com.sk89q.worldedit.tools.SinglePickaxe;
 import com.sk89q.worldedit.tools.BlockTool;
 import com.sk89q.worldedit.tools.Tool;
 import com.sk89q.worldedit.bags.BlockBag;
+import com.sk89q.worldedit.regions.CuboidRegionSelector;
 import com.sk89q.worldedit.regions.Region;
-import com.sk89q.worldedit.regions.CuboidRegion;
+import com.sk89q.worldedit.regions.RegionSelector;
 
 /**
  * An instance of this represents the WorldEdit session of a user. A session
@@ -51,9 +52,9 @@ public class LocalSession {
     
     private LocalConfiguration config;
     
+    private LocalWorld selectionWorld;
+    private RegionSelector regionSelector = new CuboidRegionSelector();
     private boolean placeAtPos1 = false;
-    private Vector pos1, pos2;
-    private Region region;
     private LinkedList<EditSession> history = new LinkedList<EditSession>();
     private int historyPointer = 0;
     private CuboidClipboard clipboard;
@@ -147,25 +148,41 @@ public class LocalSession {
     }
 
     /**
-     * Checks to make sure that position 1 is defined.
+     * Get the region selector for defining the selection. If the selection
+     * was defined for a different world, the old selection will be discarded.
      * 
-     * @throws IncompleteRegionException
+     * @param world 
+     * @return position
      */
-    private void checkPos1() throws IncompleteRegionException {
-        if (pos1 == null) {
-            throw new IncompleteRegionException();
+    public RegionSelector getRegionSelector(LocalWorld world) {
+        if (selectionWorld == null) {
+            selectionWorld = world;
+        } else if (!selectionWorld.equals(world)) {
+            selectionWorld = world;
+            regionSelector.clear();
         }
+        return regionSelector;
     }
 
     /**
-     * Checks to make sure that position 2 is defined.
-     *
-     * @throws IncompleteRegionException
+     * Get the region selector. This won't check worlds so make sure that
+     * this region selector isn't used blindly.
+     * 
+     * @return position
      */
-    private void checkPos2() throws IncompleteRegionException {
-        if (pos2 == null) {
-            throw new IncompleteRegionException();
-        }
+    public RegionSelector getRegionSelector() {
+        return regionSelector;
+    }
+
+    /**
+     * Set the region selector.
+     * 
+     * @param world
+     * @param selector
+     */
+    public void setRegionSelector(LocalWorld world, RegionSelector selector) {
+        selectionWorld = world;
+        regionSelector = selector;
     }
 
     /**
@@ -173,80 +190,50 @@ public class LocalSession {
      * 
      * @return 
      */
+    @Deprecated
     public boolean isRegionDefined() {
-        return pos1 != null && pos2 != null;
+        return regionSelector.isDefined();
     }
 
     /**
-     * Gets defined position 1.
+     * Returns true if the region is fully defined for the specified world.
      * 
-     * @return position 1
-     * @throws IncompleteRegionException
+     * @param world 
+     * @return 
      */
-    public Vector getPos1() throws IncompleteRegionException {
-        checkPos1();
-        return pos1;
-    }
-
-    /**
-     * Sets position 1.
-     *
-     * @param pt
-     */
-    public void setPos1(Vector pt) {
-        pos1 = pt;
-        if (pos1 != null && pos2 != null) {
-            region = new CuboidRegion(pos1, pos2);
+    public boolean isSelectionDefined(LocalWorld world) {
+        if (selectionWorld == null || !selectionWorld.equals(world)) {
+            return false;
         }
+        return regionSelector.isDefined();
     }
 
     /**
-     * Gets position 2.
-     * 
-     * @return position 2
-     * @throws IncompleteRegionException
-     */
-    public Vector getPos2() throws IncompleteRegionException {
-        checkPos2();
-        return pos2;
-    }
-
-    /**
-     * Sets position 2.
-     *
-     * @param pt
-     */
-    public void setPos2(Vector pt) {
-        pos2 = pt;
-        if (pos1 != null && pos2 != null) {
-            region = new CuboidRegion(pos1, pos2);
-        }
-    }
-
-    /**
-     * Update session position 1/2 based on the currently set region,
-     * provided that the region is of a cuboid.
-     */
-    public void learnRegionChanges() {
-        if (region instanceof CuboidRegion) {
-            CuboidRegion cuboidRegion = (CuboidRegion)region;
-            pos1 = cuboidRegion.getPos1();
-            pos2 = cuboidRegion.getPos2();
-        }
-    }
-
-    /**
-     * Get the region. If you change the region, you should
-     * call learnRegionChanges().
+     * Use <code>getSelection()</code>.
      * 
      * @return region
      * @throws IncompleteRegionException
      */
+    @Deprecated
     public Region getRegion() throws IncompleteRegionException {
-        if (region == null) {
+        return regionSelector.getRegion();
+    }
+
+    /**
+     * Get the selection region. If you change the region, you should
+     * call learnRegionChanges().  If the selection is defined in
+     * a different world, the <code>IncompleteRegionException</code>
+     * exception will be thrown.
+     * 
+     * @param world 
+     * @return region
+     * @throws IncompleteRegionException
+     */
+    public Region getSelection(LocalWorld world) throws IncompleteRegionException {
+        if (selectionWorld == null || !selectionWorld.equals(world)) {
             throw new IncompleteRegionException();
         }
-        return region;
+        return regionSelector.getRegion();
     }
 
     /**
@@ -353,8 +340,7 @@ public class LocalSession {
             return player.getBlockIn();
         }
 
-        checkPos1();
-        return pos1;
+        return regionSelector.getPrimaryPosition();
     }
 
     /**

src/com/sk89q/worldedit/Vector2D.java

@@ -145,6 +145,15 @@ public class Vector2D {
         return new Vector2D(x, z);
     }
 
+    /**
+     * Gets a BlockVector version.
+     * 
+     * @return BlockVector
+     */
+    public BlockVector2D toBlockVector2D() {
+        return new BlockVector2D(this);
+    }
+
     /**
      * Checks if another object is equivalent.
      *

src/com/sk89q/worldedit/WorldEdit.java

@@ -35,6 +35,7 @@ import com.sk89q.worldedit.LocalSession.CompassMode;
 import com.sk89q.worldedit.bags.BlockBag;
 import com.sk89q.worldedit.blocks.*;
 import com.sk89q.worldedit.commands.*;
+import com.sk89q.worldedit.regions.RegionSelector;
 import com.sk89q.worldedit.scripting.*;
 import com.sk89q.worldedit.tools.BlockTool;
 import com.sk89q.worldedit.tools.Tool;
@@ -782,13 +783,9 @@ public class WorldEdit {
 
         if (itemInHand == config.wandItem && session.isToolControlEnabled()
                 && player.hasPermission("worldedit.selection.pos")) {
-            session.setPos2(clicked);
-            
-            try {
-                player.print("Second position set to " + clicked
-                        + " (" + session.getRegion().getSize() + ").");
-            } catch (IncompleteRegionException e) {
-                player.print("Second position set to " + clicked + ".");
+            RegionSelector selector = session.getRegionSelector(player.getWorld());
+            if (selector.selectSecondary(clicked)) {
+                selector.explainSecondarySelection(player, clicked);
             }
 
             return true;
@@ -823,19 +820,9 @@ public class WorldEdit {
                     return false;
                 }
 
-                try {
-                    if (session.getPos1().equals(clicked)) {
-                        return false;
-                    }
-                } catch (IncompleteRegionException e) {
-                }
-
-                session.setPos1(clicked);
-                try {
-                    player.print("First position set to " + clicked
-                            + " (" + session.getRegion().getSize() + ").");
-                } catch (IncompleteRegionException e) {
-                    player.print("First position set to " + clicked + ".");
+                RegionSelector selector = session.getRegionSelector(player.getWorld());
+                if (selector.selectPrimary(clicked)) {
+                    selector.explainPrimarySelection(player, clicked);
                 }
 
                 return true;

src/com/sk89q/worldedit/bukkit/WorldEditPlugin.java

@@ -208,7 +208,8 @@ public class WorldEditPlugin extends JavaPlugin {
      */
     public Region getPlayerSelection(Player player)
             throws IncompleteRegionException {
-        return controller.getSession(wrapPlayer(player)).getRegion();
+        return controller.getSession(wrapPlayer(player))
+                .getSelection(new BukkitWorld(player.getWorld()));
     }
     
     /**

src/com/sk89q/worldedit/commands/ChunkCommands.java

@@ -70,7 +70,7 @@ public class ChunkCommands {
             LocalSession session, LocalPlayer player, EditSession editSession)
             throws WorldEditException {
 
-        Set<Vector2D> chunks = session.getRegion().getChunks();
+        Set<Vector2D> chunks = session.getSelection(player.getWorld()).getChunks();
 
         for (Vector2D chunk : chunks) {
             player.print(NestedFileChunkStore.getFilename(chunk));
@@ -91,7 +91,7 @@ public class ChunkCommands {
 
         LocalConfiguration config = we.getConfiguration();
         
-        Set<Vector2D> chunks = session.getRegion().getChunks();
+        Set<Vector2D> chunks = session.getSelection(player.getWorld()).getChunks();
         FileOutputStream out = null;
 
         if (config.shellSaveType == null) {

src/com/sk89q/worldedit/commands/ClipboardCommands.java

@@ -47,7 +47,7 @@ public class ClipboardCommands {
             LocalSession session, LocalPlayer player, EditSession editSession)
             throws WorldEditException {
             
-        Region region = session.getRegion();
+        Region region = session.getSelection(player.getWorld());
         Vector min = region.getMinimumPoint();
         Vector max = region.getMaximumPoint();
         Vector pos = player.getBlockIn();
@@ -79,7 +79,7 @@ public class ClipboardCommands {
             block = we.getBlock(player, args.getString(0));
         }
             
-        Region region = session.getRegion();
+        Region region = session.getSelection(player.getWorld());
         Vector min = region.getMinimumPoint();
         Vector max = region.getMaximumPoint();
         Vector pos = player.getBlockIn();
@@ -90,7 +90,7 @@ public class ClipboardCommands {
         clipboard.copy(editSession);
         session.setClipboard(clipboard);
 
-        editSession.setBlocks(session.getRegion(), block);
+        editSession.setBlocks(session.getSelection(player.getWorld()), block);
         player.print("Block(s) cut.");
     }
     

src/com/sk89q/worldedit/commands/RegionCommands.java

@@ -53,10 +53,10 @@ public class RegionCommands {
         int affected;
         
         if (pattern instanceof SingleBlockPattern) {
-            affected = editSession.setBlocks(session.getRegion(),
+            affected = editSession.setBlocks(session.getSelection(player.getWorld()),
                     ((SingleBlockPattern)pattern).getBlock());
         } else {
-            affected = editSession.setBlocks(session.getRegion(), pattern);
+            affected = editSession.setBlocks(session.getSelection(player.getWorld()), pattern);
         }
         
         player.print(affected + " block(s) have been changed.");
@@ -86,10 +86,10 @@ public class RegionCommands {
 
         int affected = 0;
         if (to instanceof SingleBlockPattern) {
-            affected = editSession.replaceBlocks(session.getRegion(), from,
+            affected = editSession.replaceBlocks(session.getSelection(player.getWorld()), from,
                     ((SingleBlockPattern)to).getBlock());
         } else {
-            affected = editSession.replaceBlocks(session.getRegion(), from, to);
+            affected = editSession.replaceBlocks(session.getSelection(player.getWorld()), from, to);
         }
         
         player.print(affected + " block(s) have been replaced.");
@@ -109,7 +109,7 @@ public class RegionCommands {
 
         Pattern pat = we.getBlockPattern(player, args.getString(0));
 
-        Region region = session.getRegion();
+        Region region = session.getSelection(player.getWorld());
         int affected = 0;
         if (pat instanceof SingleBlockPattern) {
             affected = editSession.overlayCuboidBlocks(region,
@@ -133,7 +133,7 @@ public class RegionCommands {
             throws WorldEditException {
 
         BaseBlock block = we.getBlock(player, args.getString(0));
-        int affected = editSession.makeCuboidWalls(session.getRegion(), block);
+        int affected = editSession.makeCuboidWalls(session.getSelection(player.getWorld()), block);
         
         player.print(affected + " block(s) have been changed.");
     }
@@ -151,7 +151,7 @@ public class RegionCommands {
             throws WorldEditException {
 
         BaseBlock block = we.getBlock(player, args.getString(0));
-        int affected = editSession.makeCuboidFaces(session.getRegion(), block);
+        int affected = editSession.makeCuboidFaces(session.getSelection(player.getWorld()), block);
         player.print(affected + " block(s) have been changed.");
     }
 
@@ -172,7 +172,7 @@ public class RegionCommands {
             iterations = args.getInteger(0);
         }
 
-        HeightMap heightMap = new HeightMap(editSession, session.getRegion());
+        HeightMap heightMap = new HeightMap(editSession, session.getSelection(player.getWorld()));
         HeightMapFilter filter = new HeightMapFilter(new GaussianKernel(5, 1.0));
         int affected = heightMap.applyFilter(filter, iterations);
         player.print("Terrain's height map smoothed. " + affected + " block(s) changed.");
@@ -203,7 +203,7 @@ public class RegionCommands {
             replace = new BaseBlock(0);
         }
 
-        int affected = editSession.moveCuboidRegion(session.getRegion(),
+        int affected = editSession.moveCuboidRegion(session.getSelection(player.getWorld()),
                 dir, count, true, replace);
         player.print(affected + " blocks moved.");
     }
@@ -226,7 +226,7 @@ public class RegionCommands {
         Vector dir = we.getDirection(player,
                 args.argsLength() > 1 ? args.getString(1).toLowerCase() : "me");
 
-        int affected = editSession.stackCuboidRegion(session.getRegion(),
+        int affected = editSession.stackCuboidRegion(session.getSelection(player.getWorld()),
                 dir, count, !args.hasFlag('a'));
         player.print(affected + " blocks changed. Undo with //undo");
     }

src/com/sk89q/worldedit/commands/SelectionCommands.java

@@ -27,7 +27,10 @@ import com.sk89q.minecraft.util.commands.CommandContext;
 import com.sk89q.minecraft.util.commands.CommandPermissions;
 import com.sk89q.worldedit.*;
 import com.sk89q.worldedit.data.ChunkStore;
+import com.sk89q.worldedit.regions.CuboidRegionSelector;
+import com.sk89q.worldedit.regions.Polygonal2DRegionSelector;
 import com.sk89q.worldedit.regions.Region;
+import com.sk89q.worldedit.regions.RegionOperationException;
 import com.sk89q.worldedit.blocks.*;
 
 /**
@@ -48,14 +51,14 @@ public class SelectionCommands {
             LocalSession session, LocalPlayer player, EditSession editSession)
             throws WorldEditException {
         
-        session.setPos1(player.getBlockIn());
-        
-        if (session.isRegionDefined()) {
-            player.print("First position set to " + player.getBlockIn()
-                    + " (" + session.getRegion().getSize() + ").");
-        } else {
-            player.print("First position set to " + player.getBlockIn() + ".");
+        if (!session.getRegionSelector(player.getWorld())
+                .selectPrimary(player.getBlockIn())) {
+            player.printError("Position already set.");
+            return;
         }
+
+        session.getRegionSelector(player.getWorld())
+                .explainPrimarySelection(player, player.getBlockIn());
     }
 
     @Command(
@@ -69,15 +72,16 @@ public class SelectionCommands {
     public static void pos2(CommandContext args, WorldEdit we,
             LocalSession session, LocalPlayer player, EditSession editSession)
             throws WorldEditException {
-        
-        session.setPos2(player.getBlockIn());
-        
-        if (session.isRegionDefined()) {
-            player.print("Second position set to " + player.getBlockIn()
-                    + " (" + session.getRegion().getSize() + ").");
-        } else {
-            player.print("Second position set to " + player.getBlockIn() + ".");
+
+        if (!session.getRegionSelector(player.getWorld())
+                .selectSecondary(player.getBlockIn())) {
+            player.printError("Position already set.");
+            return;
         }
+
+
+        session.getRegionSelector(player.getWorld())
+                .explainSecondarySelection(player, player.getBlockIn());
     }
 
     @Command(
@@ -95,13 +99,14 @@ public class SelectionCommands {
         Vector pos = player.getBlockTrace(300);
         
         if (pos != null) {
-            session.setPos1(pos);
-            if (session.isRegionDefined()) {
-                player.print("First position set to " + pos
-                        + " (" + session.getRegion().getSize() + ").");
-            } else {
-                player.print("First position set to " + pos.toString() + " .");
+            if (!session.getRegionSelector(player.getWorld())
+                    .selectPrimary(pos)) {
+                player.printError("Position already set.");
+                return;
             }
+
+            session.getRegionSelector(player.getWorld())
+                    .explainPrimarySelection(player, pos);
         } else {
             player.printError("No block in sight!");
         }
@@ -122,14 +127,14 @@ public class SelectionCommands {
         Vector pos = player.getBlockTrace(300);
         
         if (pos != null) {
-            session.setPos2(pos);
-            
-            if (session.isRegionDefined()) {
-                player.print("Second position set to " + pos
-                        + " (" + session.getRegion().getSize() + ").");
-            } else {
-                player.print("Second position set to " + pos.toString() + " .");
+            if (!session.getRegionSelector(player.getWorld())
+                    .selectSecondary(pos)) {
+                player.printError("Position already set.");
+                return;
             }
+
+            session.getRegionSelector(player.getWorld())
+                    .explainSecondarySelection(player, pos);
         } else {
             player.printError("No block in sight!");
         }
@@ -151,8 +156,10 @@ public class SelectionCommands {
         Vector min = new Vector(min2D.getBlockX() * 16, 0, min2D.getBlockZ() * 16);
         Vector max = min.add(15, 127, 15);
 
-        session.setPos1(min);
-        session.setPos2(max);
+        CuboidRegionSelector selector = new CuboidRegionSelector();
+        selector.selectPrimary(min);
+        selector.selectSecondary(max);
+        session.setRegionSelector(player.getWorld(), selector);
 
         player.print("Chunk selected: "
                 + min2D.getBlockX() + ", " + min2D.getBlockZ());
@@ -213,14 +220,18 @@ public class SelectionCommands {
         // sky and bedrock.
         if (args.getString(0).equalsIgnoreCase("vert")
                 || args.getString(0).equalsIgnoreCase("vertical")) {
-            Region region = session.getRegion();
-            int oldSize = region.getSize();
-            region.expand(new Vector(0, 128, 0));
-            region.expand(new Vector(0, -128, 0));
-            session.learnRegionChanges();
-            int newSize = region.getSize();
-            player.print("Region expanded " + (newSize - oldSize)
-                    + " blocks [top-to-bottom].");
+            Region region = session.getSelection(player.getWorld());
+            try {
+                int oldSize = region.getArea();
+                region.expand(new Vector(0, 128, 0));
+                region.expand(new Vector(0, -128, 0));
+                session.getRegionSelector().learnChanges();
+                int newSize = region.getArea();
+                player.print("Region expanded " + (newSize - oldSize)
+                        + " blocks [top-to-bottom].");
+            } catch (RegionOperationException e) {
+                player.printError(e.getMessage());
+            }
             
             return;
         }
@@ -246,16 +257,16 @@ public class SelectionCommands {
             dir = we.getDirection(player, "me");
         }
 
-        Region region = session.getRegion();
-        int oldSize = region.getSize();
+        Region region = session.getSelection(player.getWorld());
+        int oldSize = region.getArea();
         region.expand(dir.multiply(change));
         
         if (reverseChange != 0) {
             region.expand(dir.multiply(reverseChange));
         }
-        
-        session.learnRegionChanges();
-        int newSize = region.getSize();
+
+        session.getRegionSelector().learnChanges();
+        int newSize = region.getArea();
         
         player.print("Region expanded " + (newSize - oldSize) + " blocks.");
     }
@@ -294,16 +305,20 @@ public class SelectionCommands {
             dir = we.getDirection(player, "me");
         }
 
-        Region region = session.getRegion();
-        int oldSize = region.getSize();
-        region.contract(dir.multiply(change));
-        if (reverseChange != 0) {
-            region.contract(dir.multiply(reverseChange));
+        try {
+            Region region = session.getSelection(player.getWorld());
+            int oldSize = region.getArea();
+            region.contract(dir.multiply(change));
+            if (reverseChange != 0) {
+                region.contract(dir.multiply(reverseChange));
+            }
+            session.getRegionSelector().learnChanges();
+            int newSize = region.getArea();
+            
+            player.print("Region contracted " + (oldSize - newSize) + " blocks.");
+        } catch (RegionOperationException e) {
+            player.printError(e.getMessage());
         }
-        session.learnRegionChanges();
-        int newSize = region.getSize();
-        
-        player.print("Region contracted " + (oldSize - newSize) + " blocks.");
     }
 
     @Command(
@@ -327,12 +342,16 @@ public class SelectionCommands {
             dir = we.getDirection(player, "me");
         }
 
-        Region region = session.getRegion();
-        region.expand(dir.multiply(change));
-        region.contract(dir.multiply(change));
-        session.learnRegionChanges();
-        
-        player.print("Region shifted.");
+        try {
+            Region region = session.getSelection(player.getWorld());
+            region.expand(dir.multiply(change));
+            region.contract(dir.multiply(change));
+            session.getRegionSelector().learnChanges();
+            
+            player.print("Region shifted.");
+        } catch (RegionOperationException e) {
+            player.printError(e.getMessage());
+        }
     }
 
     @Command(
@@ -349,23 +368,27 @@ public class SelectionCommands {
             throws WorldEditException {
         int change = args.getInteger(0);
 
-        Region region = session.getRegion();
+        Region region = session.getSelection(player.getWorld());
         
-        if (!args.hasFlag('h')) {
-            region.expand((new Vector(0, 1, 0)).multiply(change));
-            region.expand((new Vector(0, -1, 0)).multiply(change));
+        try {
+            if (!args.hasFlag('h')) {
+                region.expand((new Vector(0, 1, 0)).multiply(change));
+                region.expand((new Vector(0, -1, 0)).multiply(change));
+            }
+            
+            if (!args.hasFlag('v')) {
+                region.expand((new Vector(1, 0, 0)).multiply(change));
+                region.expand((new Vector(-1, 0, 0)).multiply(change));
+                region.expand((new Vector(0, 0, 1)).multiply(change));
+                region.expand((new Vector(0, 0, -1)).multiply(change));
+            }
+
+            session.getRegionSelector().learnChanges();
+            
+            player.print("Region outset.");
+        } catch (RegionOperationException e) {
+            player.printError(e.getMessage());
         }
-        
-        if (!args.hasFlag('v')) {
-            region.expand((new Vector(1, 0, 0)).multiply(change));
-            region.expand((new Vector(-1, 0, 0)).multiply(change));
-            region.expand((new Vector(0, 0, 1)).multiply(change));
-            region.expand((new Vector(0, 0, -1)).multiply(change));
-        }
-        
-        session.learnRegionChanges();
-        
-        player.print("Region outset.");
     }
 
     @Command(
@@ -382,7 +405,7 @@ public class SelectionCommands {
             throws WorldEditException {
         int change = args.getInteger(0);
 
-        Region region = session.getRegion();
+        Region region = session.getSelection(player.getWorld());
         
         if (!args.hasFlag('h')) {
             region.contract((new Vector(0, 1, 0)).multiply(change));
@@ -395,14 +418,14 @@ public class SelectionCommands {
             region.contract((new Vector(0, 0, 1)).multiply(change));
             region.contract((new Vector(0, 0, -1)).multiply(change));
         }
-        
-        session.learnRegionChanges();
+
+        session.getRegionSelector().learnChanges();
         
         player.print("Region inset.");
     }
 
     @Command(
-        aliases = {"/size"},
+        aliases = {"/m", "//size"},
         usage = "",
         desc = "Get information about the selection",
         min = 0,
@@ -412,17 +435,21 @@ public class SelectionCommands {
     public static void size(CommandContext args, WorldEdit we,
             LocalSession session, LocalPlayer player, EditSession editSession)
             throws WorldEditException {
-        
-        Region region = session.getRegion();
+
+        Region region = session.getSelection(player.getWorld());
         Vector size = region.getMaximumPoint()
                 .subtract(region.getMinimumPoint())
                 .add(1, 1, 1);
+
+        player.print("Type: " + session.getRegionSelector().getTypeName());
+        
+        for (String line : session.getRegionSelector().getInformationLines()) {
+            player.print(line);
+        }
         
-        player.print("First position: " + session.getPos1());
-        player.print("Second position: " + session.getPos2());
         player.print("Size: " + size);
-        player.print("Distance: " + region.getMaximumPoint().distance(region.getMinimumPoint()));
-        player.print("# of blocks: " + region.getSize());
+        player.print("Cuboid distance: " + region.getMaximumPoint().distance(region.getMinimumPoint()));
+        player.print("# of blocks: " + region.getArea());
     }
 
     @Command(
@@ -440,7 +467,7 @@ public class SelectionCommands {
         Set<Integer> searchIDs = we.getBlockIDs(player,
                 args.getString(0), true);
         player.print("Counted: " +
-                editSession.countBlocks(session.getRegion(), searchIDs));
+                editSession.countBlocks(session.getSelection(player.getWorld()), searchIDs));
     }
 
     @Command(
@@ -457,12 +484,12 @@ public class SelectionCommands {
             throws WorldEditException {
         
         List<Countable<Integer>> distribution =
-            editSession.getBlockDistribution(session.getRegion());
+            editSession.getBlockDistribution(session.getSelection(player.getWorld()));
         
         Logger logger = Logger.getLogger("Minecraft.WorldEdit");
         
         if (distribution.size() > 0) { // *Should* always be true
-            int size = session.getRegion().getSize();
+            int size = session.getSelection(player.getWorld()).getArea();
     
             player.print("# total blocks: " + size);
             
@@ -486,4 +513,27 @@ public class SelectionCommands {
             player.printError("No blocks counted.");
         }
     }
+
+    @Command(
+        aliases = {"/sel", ","},
+        usage = "[type]",
+        desc = "Choose a region selector",
+        min = 1,
+        max = 1
+    )
+    public static void select(CommandContext args, WorldEdit we,
+            LocalSession session, LocalPlayer player, EditSession editSession)
+            throws WorldEditException {
+
+        String typeName = args.getString(0);
+        if (typeName.equalsIgnoreCase("cuboid")) {
+            session.setRegionSelector(player.getWorld(), new CuboidRegionSelector());
+            player.print("Cuboid: left click for point 1, right click for point 2");
+        } else if (typeName.equalsIgnoreCase("poly")) {
+            session.setRegionSelector(player.getWorld(), new Polygonal2DRegionSelector());
+            player.print("2D polygon selector: Left/right click to add a point.");
+        } else {
+            player.printError("Only 'cuboid' and 'poly' are accepted.");
+        }
+    }
 }

src/com/sk89q/worldedit/commands/SnapshotUtilCommands.java

@@ -71,7 +71,7 @@ public class SnapshotUtilCommands {
             return;
         }
 
-        Region region = session.getRegion();
+        Region region = session.getSelection(player.getWorld());
         Snapshot snapshot;
 
         if (args.argsLength() > 0) {

src/com/sk89q/worldedit/regions/CuboidRegion.java

@@ -19,6 +19,7 @@
 
 package com.sk89q.worldedit.regions;
 
+import com.sk89q.worldedit.BlockVector;
 import com.sk89q.worldedit.Vector;
 import com.sk89q.worldedit.Vector2D;
 import com.sk89q.worldedit.data.ChunkStore;
@@ -28,7 +29,7 @@ import java.util.HashSet;
 
 /**
  *
- * @author Albert
+ * @author sk89q
  */
 public class CuboidRegion implements Region {
     /**
@@ -80,7 +81,7 @@ public class CuboidRegion implements Region {
      * 
      * @return number of blocks
      */
-    public int getSize() {
+    public int getArea() {
         Vector min = getMinimumPoint();
         Vector max = getMaximumPoint();
 
@@ -288,12 +289,30 @@ public class CuboidRegion implements Region {
         return chunks;
     }
 
+    /**
+     * Returns true based on whether the region contains the point,
+     *
+     * @param pt
+     */
+    public boolean contains(Vector pt) {
+        double x = pt.getX();
+        double y = pt.getY();
+        double z = pt.getZ();
+
+        Vector min = getMinimumPoint();
+        Vector max = getMaximumPoint();
+        
+        return x >= min.getBlockX() && x <= max.getBlockX()
+                && y >= min.getBlockY() && y <= max.getBlockY()
+                && z >= min.getBlockZ() && z <= max.getBlockZ();
+    }
+
     /**
      * Get the iterator.
      * 
-     * @return iterator of Points
+     * @return iterator of points inside the region
      */
-    public Iterator<Vector> iterator() {
+    public Iterator<BlockVector> iterator() {
         throw new UnsupportedOperationException("Not implemented");
     }
 }

src/com/sk89q/worldedit/regions/CuboidRegionSelector.java

@@ -0,0 +1,122 @@
+// $Id$
+/*
+ * WorldEdit
+ * Copyright (C) 2010, 2011 sk89q <http://www.sk89q.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package com.sk89q.worldedit.regions;
+
+import java.util.ArrayList;
+import java.util.List;
+import com.sk89q.worldedit.BlockVector;
+import com.sk89q.worldedit.IncompleteRegionException;
+import com.sk89q.worldedit.LocalPlayer;
+import com.sk89q.worldedit.Vector;
+
+/**
+ * Selector for cuboids.
+ *
+ * @author sk89q
+ */
+public class CuboidRegionSelector implements RegionSelector {
+    protected BlockVector pos1;
+    protected BlockVector pos2;
+    protected CuboidRegion region = new CuboidRegion(new Vector(), new Vector());
+
+    public boolean selectPrimary(Vector pos) {
+        if (pos1 != null && pos1.equals(pos)) {
+            return false;
+        }
+        pos1 = pos.toBlockVector();
+        region.setPos1(pos1);   
+        return true;
+    }
+
+    public boolean selectSecondary(Vector pos) {
+        if (pos2 != null && pos2.equals(pos)) {
+            return false;
+        }
+        pos2 = pos.toBlockVector();
+        region.setPos2(pos2);
+        return true;
+    }
+
+    public void explainPrimarySelection(LocalPlayer player, Vector pos) {
+        if (pos1 != null && pos2 != null) {
+            player.print("First position set to " + pos1
+                    + " (" + region.getArea() + ").");
+        } else {
+            player.print("First position set to " + pos1 + ".");
+        }
+    }
+
+    public void explainSecondarySelection(LocalPlayer player, Vector pos) {
+        if (pos1 != null && pos2 != null) {
+            player.print("Second position set to " + pos1
+                    + " (" + region.getArea() + ").");
+        } else {
+            player.print("Second position set to " + pos1 + ".");
+        }
+    }
+    
+    public BlockVector getPrimaryPosition() throws IncompleteRegionException {
+        if (pos1 == null) {
+            throw new IncompleteRegionException();
+        }
+        
+        return pos1;
+    }
+    
+    public boolean isDefined() {
+        return pos1 != null && pos2 != null;
+    }
+
+    public Region getRegion() throws IncompleteRegionException {
+        if (pos1 == null || pos2 == null) {
+            throw new IncompleteRegionException();
+        }
+        
+        return region;
+    }
+
+    public void learnChanges() {
+        pos1 = region.getPos1().toBlockVector();
+        pos2 = region.getPos2().toBlockVector();
+    }
+    
+    public void clear() {
+        pos1 = null;
+        pos2 = null;
+    }
+
+    public String getTypeName() {
+        return "cuboid";
+    }
+
+    public List<String> getInformationLines() {
+        List<String> lines = new ArrayList<String>();
+        
+        if (pos1 != null) {
+            lines.add("Position 1: " + pos1);
+        }
+        
+        if (pos2 != null) {
+            lines.add("Position 2: " + pos2);
+        }
+        
+        return lines;
+    }
+}

src/com/sk89q/worldedit/regions/Polygonal2DRegion.java

@@ -0,0 +1,527 @@
+// $Id$
+/*
+ * WorldEdit
+ * Copyright (C) 2010, 2011 sk89q <http://www.sk89q.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package com.sk89q.worldedit.regions;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Set;
+import com.sk89q.worldedit.BlockVector;
+import com.sk89q.worldedit.BlockVector2D;
+import com.sk89q.worldedit.Vector;
+import com.sk89q.worldedit.Vector2D;
+import com.sk89q.worldedit.data.ChunkStore;
+
+/**
+ * Represents a 2D polygonal region.
+ *
+ * @author sk89q
+ */
+public class Polygonal2DRegion implements Region {
+    protected List<BlockVector2D> points;
+    protected BlockVector min;
+    protected BlockVector max;
+    protected int minY;
+    protected int maxY;
+    protected boolean hasY = false;
+    
+    /**
+     * Construct the region.
+     */
+    public Polygonal2DRegion() {
+        points = new ArrayList<BlockVector2D>();
+        minY = 0;
+        maxY = 0;
+        hasY = false;
+        recalculate();
+    }
+    
+    /**
+     * Construct the region.
+     * 
+     * @param points
+     * @param minY
+     * @param maxY
+     */
+    public Polygonal2DRegion(List<BlockVector2D> points, int minY, int maxY) {
+        this.points = points;
+        this.minY = minY;
+        this.maxY = maxY;
+        hasY = true;
+        recalculate();
+    }
+    
+    /**
+     * Get the list of points.
+     * 
+     * @return
+     */
+    public List<BlockVector2D> getPoints() {
+        return Collections.unmodifiableList(points);
+    }
+    
+    /**
+     * Recalculate the bounding box of this polygonal region. This should be
+     * called after points have been changed.
+     */
+    protected void recalculate() {
+        if (points.size() == 0) {
+            min = new BlockVector(0, 0, 0);
+            max = new BlockVector(0, 0, 0);
+            return;
+        }
+        
+        int minX = points.get(0).getBlockX();
+        int minZ = points.get(0).getBlockZ();
+        int maxX = points.get(0).getBlockX();
+        int maxZ = points.get(0).getBlockZ();
+        
+        for (BlockVector2D v : points) {
+            int x = v.getBlockX();
+            int z = v.getBlockZ();
+            if (x < minX) minX = x;
+            if (z < minZ) minZ = z;
+            if (x > maxX) maxX = x;
+            if (z > maxZ) maxZ = z;
+        }
+
+        int oldMinY = minY;
+        int oldMaxY = maxY;
+        minY = Math.min(oldMinY, oldMaxY);
+        maxY = Math.max(oldMinY, oldMaxY);
+
+        min = new BlockVector(minX, minY, minZ);
+        max = new BlockVector(maxX, maxY, maxZ);
+    }
+    
+    /**
+     * Add a point to the list.
+     * 
+     * @param pt
+     */
+    public void addPoint(Vector2D pt) {
+        points.add(pt.toBlockVector2D());
+        recalculate();
+    }
+    
+    /**
+     * Add a point to the list.
+     * 
+     * @param pt
+     */
+    public void addPoint(BlockVector2D pt) {
+        points.add(pt);
+        recalculate();
+    }
+    
+    /**
+     * Add a point to the list.
+     * 
+     * @param pt
+     */
+    public void addPoint(Vector pt) {
+        points.add(new BlockVector2D(pt.getBlockX(), pt.getBlockZ()));
+        recalculate();
+    }
+
+    /**
+     * Get the lower point of a region.
+     * 
+     * @return min. point
+     */
+    public Vector getMinimumPoint() {
+        return min;
+    }
+
+    /**
+     * Get the upper point of a region.
+     * 
+     * @return max. point
+     */
+    public Vector getMaximumPoint() {
+        return max;
+    }
+
+    /**
+     * Get the number of blocks in the region.
+     * 
+     * @return number of blocks
+     */
+    public int getArea() {
+        double area = 0;
+        int i, j = points.size() - 1;
+
+        for (i = 0; i < points.size(); i++) {
+            area += (points.get(j).getBlockX() + points.get(i).getBlockX())
+                    * (points.get(j).getBlockZ() - points.get(i).getBlockZ());
+            j = i;
+        }
+
+        return (int)Math.floor(Math.abs(area * 0.5) 
+                * (maxY - minY + 1));
+    }
+
+    /**
+     * Get X-size.
+     *
+     * @return width
+     */
+    public int getWidth() {
+        return max.getBlockX() - min.getBlockX();
+    }
+
+    /**
+     * Get Y-size.
+     *
+     * @return height
+     */
+    public int getHeight() {
+        return max.getBlockY() - min.getBlockY();
+    }
+
+    /**
+     * Get Z-size.
+     *
+     * @return length
+     */
+    public int getLength() {
+        return max.getBlockZ() - min.getBlockZ();
+    }
+
+    /**
+     * Expand the region.
+     *
+     * @param change
+     */
+    public void expand(Vector change) throws RegionOperationException {
+        if (change.getBlockX() != 0 || change.getBlockZ() != 0) {
+            throw new RegionOperationException("Polygons can only be expanded vertically.");
+        }
+        
+        int changeY = change.getBlockY();
+        if (changeY > 0) {
+            maxY += changeY;
+        } else {
+            minY += changeY;
+        }
+        recalculate();
+    }
+
+    /**
+     * Contract the region.
+     *
+     * @param change
+     */
+    public void contract(Vector change) throws RegionOperationException {
+        if (change.getBlockX() != 0 || change.getBlockZ() != 0) {
+            throw new RegionOperationException("Polygons can only be contracted vertically.");
+        }
+        
+        int changeY = change.getBlockY();
+        if (changeY > 0) {
+            minY += changeY;
+        } else {
+            maxY += changeY;
+        }
+        recalculate();
+    }
+
+    /**
+     * Checks to see if a point is inside this region.
+     */
+    @Override
+    public boolean contains(Vector pt) {
+        return contains(points, minY, maxY, pt);
+    }
+
+    /**
+     * Checks to see if a point is inside a region.
+     * 
+     * @param points 
+     * @param minY 
+     * @param maxY 
+     * @param pt 
+     * @return 
+     */
+    public static boolean contains(List<BlockVector2D> points, int minY,
+            int maxY, Vector pt) {
+        if (points.size() < 3) {
+            return false;
+        }
+        
+        int targetX = pt.getBlockX();
+        int targetY = pt.getBlockY();
+        int targetZ = pt.getBlockZ();
+        
+        if (targetY < minY || targetY > maxY) {
+            return false;
+        }
+        
+        boolean inside = false;
+        int npoints = points.size();
+        int xNew, zNew;
+        int xOld, zOld;
+        int x1, z1;
+        int x2, z2;
+        int i;
+
+        xOld = points.get(npoints - 1).getBlockX();
+        zOld = points.get(npoints - 1).getBlockZ();
+        
+        for (i = 0; i < npoints; i++) {
+            xNew = points.get(i).getBlockX();
+            zNew = points.get(i).getBlockZ();
+            
+            if (xNew > xOld) {
+                x1 = xOld - 1;
+                x2 = xNew;
+                z1 = zOld;
+                z2 = zNew + 1;
+            } else {
+                x1 = xNew - 1;
+                x2 = xOld;
+                z1 = zNew;
+                z2 = zOld + 1;
+            }
+            
+            if (xNew < targetX == targetX <= xOld) {
+                long v1 = ((long) targetZ - (long) z1) * (long) (x2 - x1);
+                long v2 = ((long) z2 - (long) z1) * (long) (targetX - x1);
+                
+                if (v1 < v2) {
+                    inside = !inside;
+                }
+            }
+            
+            xOld = xNew;
+            zOld = zNew;
+        }
+        
+        return inside;
+    }
+    
+    /**
+     * Get a list of chunks.
+     * 
+     * @return
+     */
+    public Set<Vector2D> getChunks() {
+        Set<Vector2D> chunks = new HashSet<Vector2D>();
+
+        Vector min = getMinimumPoint();
+        Vector max = getMaximumPoint();
+
+        for (int x = min.getBlockX(); x <= max.getBlockX(); x++) {
+            for (int y = min.getBlockY(); y <= max.getBlockY(); y++) {
+                for (int z = min.getBlockZ(); z <= max.getBlockZ(); z++) {
+                    Vector pt = new Vector(x, y, z);
+                    if (contains(pt)) { // Not the best
+                        chunks.add(ChunkStore.toChunk(pt));
+                    }
+                }
+            }
+        }
+
+        return chunks;
+    }
+    
+    /**
+     * Return the number of points.
+     * 
+     * @return
+     */
+    public int size() {
+        return points.size();
+    }
+    
+    /**
+     * Expand the height of the polygon to fit the specified Y.
+     * 
+     * @param y 
+     * @return true if the area was expanded
+     */
+    public boolean expandY(int y) {
+        if (!hasY) {
+            minY = y;
+            maxY = y;
+            hasY = true;
+            return true;
+        } else if (y < minY) {
+            minY = y;
+            return true;
+        } else if (y > maxY) {
+            maxY = y;
+            return true;
+        }
+        
+        return false;
+    }
+
+    /**
+     * Get the iterator.
+     * 
+     * @return iterator of points inside the region
+     */
+    public Iterator<BlockVector> iterator() {
+        return new Polygonal2DRegionIterator(this);
+        
+        /*
+        Incomplete iterator. Where's my yield?!
+        
+        ArrayList<BlockVector> items = new ArrayList<BlockVector>();
+        
+        int nodes, pixelZ, i, j, swap;
+        int n = points.size();
+        int[] nodeX = new int[n];
+
+        int minZ = getMinimumPoint().getBlockZ();
+        int maxZ = getMaximumPoint().getBlockZ();
+        
+        for (pixelZ = minZ; pixelZ < maxZ; pixelZ++) {
+            // Build a list of nodes
+            nodes = 0;
+            j = n - 1;
+            for (i = 0; i < n; i++) {
+                if (points.get(i).getBlockZ() < (double) pixelZ
+                        && points.get(j).getBlockZ() >= (double) pixelZ
+                        || points.get(j).getBlockZ() < (double) pixelZ
+                        && points.get(i).getBlockZ() >= (double) pixelZ) {
+                    nodeX[nodes++] = (int) (points.get(i).getBlockX()
+                            + (pixelZ - points.get(i).getBlockZ())
+                            / (points.get(j).getBlockZ() - points.get(i)
+                                    .getBlockZ())
+                            * (points.get(j).getBlockX() - points.get(i)
+                                    .getBlockX()));
+                }
+                j = i;
+            }
+
+            // Sort the nodes, via a simple bubble sort
+            i = 0;
+            while (i < nodes - 1) {
+                if (nodeX[i] > nodeX[i + 1]) {
+                    swap = nodeX[i];
+                    nodeX[i] = nodeX[i + 1];
+                    nodeX[i + 1] = swap;
+                    if (i > 0)
+                        i--;
+                } else {
+                    i++;
+                }
+            }
+
+            // Fill the pixels between node pairs
+            for (i = 0; i < nodes; i += 2) {
+                for (j = nodeX[i]; j < nodeX[i + 1]; j++) {
+                    for (int y = minY; y >= maxY; y++) {
+                        items.add(new BlockVector(j, y, pixelZ));
+                    }
+                }
+            }
+        }
+        
+        return items.iterator();*/
+    }
+    
+    /**
+     * A terrible polygonal region iterator.
+     */
+    public class Polygonal2DRegionIterator implements Iterator<BlockVector> {
+        protected List<BlockVector2D> points = new ArrayList<BlockVector2D>();
+        protected int minX;
+        protected int minY;
+        protected int minZ;
+        protected int maxX;
+        protected int maxY;
+        protected int maxZ;
+        protected int n;
+        protected int i;
+        protected int curX;
+        protected int curZ;
+        protected int curY;
+        protected BlockVector next;
+        
+        public Polygonal2DRegionIterator(Polygonal2DRegion region) {
+            points = new ArrayList<BlockVector2D>(region.points);
+            Vector min = region.getMinimumPoint();
+            Vector max = region.getMaximumPoint();
+            minX = min.getBlockX();
+            minY = min.getBlockY();
+            minZ = min.getBlockZ();
+            maxX = max.getBlockX();
+            maxY = max.getBlockY();
+            maxZ = max.getBlockZ();
+            n = (maxX - minX + 1) * (maxZ - minZ + 1);
+            i = 0;
+            curX = 0;
+            curZ = 0;
+            curY = minY;
+            next = null;
+            findNext();
+        }
+        
+        private void findNext() {
+            if (i >= n) {
+                next = null;
+                return;
+            }
+            
+            if (next != null && curY <= maxY) {
+                curY++;
+                next = new BlockVector(curX, curY, curZ);
+                if (curY > maxY) {
+                    i++;
+                    curY = minY;
+                } else {
+                    return;
+                }
+            } 
+            
+            while (i < n) {
+                curZ = i / (maxX - minX + 1) + minZ;
+                curX = (i % (maxX - minX + 1)) + minX;
+                BlockVector pt = new BlockVector(curX, minY, curZ);
+                if (contains(points, minY, maxY, pt)) {
+                    next = pt;
+                    return;
+                }
+                i++;
+            }
+            
+            next = null;
+        }
+
+        public boolean hasNext() {
+            return next != null;
+        }
+
+        public BlockVector next() {
+            BlockVector next = this.next;
+            findNext();
+            return next;
+        }
+
+        public void remove() {
+            throw new UnsupportedOperationException("Not supported");
+        }
+    }
+}

src/com/sk89q/worldedit/regions/Polygonal2DRegionSelector.java

@@ -0,0 +1,114 @@
+// $Id$
+/*
+ * WorldEdit
+ * Copyright (C) 2010, 2011 sk89q <http://www.sk89q.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package com.sk89q.worldedit.regions;
+
+import java.util.ArrayList;
+import java.util.List;
+import com.sk89q.worldedit.BlockVector;
+import com.sk89q.worldedit.BlockVector2D;
+import com.sk89q.worldedit.IncompleteRegionException;
+import com.sk89q.worldedit.LocalPlayer;
+import com.sk89q.worldedit.Vector;
+
+/**
+ * Selector for polygonal regions.
+ *
+ * @author sk89q
+ */
+public class Polygonal2DRegionSelector implements RegionSelector {
+    protected BlockVector pos1;
+    protected Polygonal2DRegion region = new Polygonal2DRegion();
+    
+    public boolean selectPrimary(Vector pos) {
+        if (pos1 != null && pos1.equals(pos)) {
+            return false;
+        }
+        pos1 = pos.toBlockVector();
+        region = new Polygonal2DRegion();
+        region.addPoint(pos);
+        region.expandY(pos.getBlockY());
+        return true;
+    }
+    
+    public boolean selectSecondary(Vector pos) {
+        if (region.size() > 0) {
+            List<BlockVector2D> points = region.getPoints();
+            BlockVector2D lastPoint = points.get(region.size() - 1);
+            if (lastPoint.getBlockX() == pos.getBlockX()
+                    && lastPoint.getBlockZ() == pos.getBlockZ()) {
+                return false;
+            }
+            
+            if (points.size() >= 20) {
+                return false;
+            }
+        }
+        
+        region.addPoint(pos);
+        region.expandY(pos.getBlockY());
+        return true;
+    }
+
+    public void explainPrimarySelection(LocalPlayer player, Vector pos) {
+        player.print("Starting a new polygon at " + pos + ".");
+    }
+
+    public void explainSecondarySelection(LocalPlayer player, Vector pos) {
+        player.print("Added point #" + region.size() + " at " + pos + ".");
+    }
+
+    public BlockVector getPrimaryPosition() throws IncompleteRegionException {
+        if (pos1 == null) {
+            throw new IncompleteRegionException();
+        }
+        return pos1;
+    }
+
+    public Region getRegion() throws IncompleteRegionException {
+        if (!isDefined()) {
+            throw new IncompleteRegionException();
+        }
+        
+        return region;
+    }
+
+    public boolean isDefined() {
+        return region.size() > 2;
+    }
+
+    public void learnChanges() {
+    }
+
+    public void clear() {
+        pos1 = null;
+        region = new Polygonal2DRegion();
+    }
+
+    public String getTypeName() {
+        return "2Dx1D polygon";
+    }
+
+    public List<String> getInformationLines() {
+        List<String> lines = new ArrayList<String>();
+        lines.add("# points: " + region.size());
+        return lines;
+    }
+
+}

src/com/sk89q/worldedit/regions/Region.java

@@ -19,15 +19,16 @@
 
 package com.sk89q.worldedit.regions;
 
+import com.sk89q.worldedit.BlockVector;
 import com.sk89q.worldedit.Vector;
 import com.sk89q.worldedit.Vector2D;
 import java.util.Set;
 
 /**
  *
- * @author Albert
+ * @author sk89q
  */
-public interface Region extends Iterable<Vector> {
+public interface Region extends Iterable<BlockVector> {
     /**
      * Get the lower point of a region.
      * 
@@ -45,7 +46,7 @@ public interface Region extends Iterable<Vector> {
      * 
      * @return number of blocks
      */
-    public int getSize();
+    public int getArea();
     /**
      * Get X-size.
      *
@@ -68,14 +69,23 @@ public interface Region extends Iterable<Vector> {
      * Expand the region.
      *
      * @param change
+     * @throws RegionOperationException 
      */
-    public void expand(Vector change);
+    public void expand(Vector change) throws RegionOperationException;
     /**
      * Contract the region.
      *
      * @param change
+     * @throws RegionOperationException 
      */
-    public void contract(Vector change);
+    public void contract(Vector change) throws RegionOperationException;
+    /**
+     * Returns true based on whether the region contains the point,
+     *
+     * @param pt
+     * @return 
+     */
+    public boolean contains(Vector pt);
     /**
      * Get a list of chunks.
      * 

src/com/sk89q/worldedit/regions/RegionOperationException.java

@@ -0,0 +1,30 @@
+// $Id$
+/*
+ * WorldEdit
+ * Copyright (C) 2010, 2011 sk89q <http://www.sk89q.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package com.sk89q.worldedit.regions;
+
+import com.sk89q.worldedit.WorldEditException;
+
+public class RegionOperationException extends WorldEditException {
+    private static final long serialVersionUID = -6180325009115242142L;
+    
+    public RegionOperationException(String msg) {
+        super(msg);
+    }
+}

src/com/sk89q/worldedit/regions/RegionSelector.java

@@ -0,0 +1,112 @@
+// $Id$
+/*
+ * WorldEdit
+ * Copyright (C) 2010, 2011 sk89q <http://www.sk89q.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package com.sk89q.worldedit.regions;
+
+import java.util.List;
+import com.sk89q.worldedit.BlockVector;
+import com.sk89q.worldedit.IncompleteRegionException;
+import com.sk89q.worldedit.LocalPlayer;
+import com.sk89q.worldedit.Vector;
+
+/**
+ * Region selection factory.
+ *
+ * @author sk89q
+ */
+public interface RegionSelector {
+    /**
+     * Called when the first point is selected.
+     * 
+     * @param pos
+     * @return true if something changed
+     */
+    public boolean selectPrimary(Vector pos);
+    
+    /**
+     * Called when the second point is selected.
+     * 
+     * @param pos
+     * @return true if something changed
+     */
+    public boolean selectSecondary(Vector pos);
+
+    /**
+     * Tell the player information about his/her primary selection.
+     * 
+     * @param player
+     * @param pos 
+     */
+    public void explainPrimarySelection(LocalPlayer player, Vector pos);
+
+    /**
+     * Tell the player information about his/her secondary selection.
+     * 
+     * @param player
+     * @param pos 
+     */
+    public void explainSecondarySelection(LocalPlayer player, Vector pos);
+    
+    /**
+     * Get the primary position.
+     * 
+     * @return
+     * @throws IncompleteRegionException 
+     */
+    public BlockVector getPrimaryPosition() throws IncompleteRegionException;
+    
+    /**
+     * Get the selection.
+     * 
+     * @return
+     * @throws IncompleteRegionException 
+     */
+    public Region getRegion() throws IncompleteRegionException;
+    
+    /**
+     * Returns whether the region has been fully defined.
+     * 
+     * @return
+     */
+    public boolean isDefined();
+    
+    /**
+     * Update the selector with changes to the region.
+     */
+    public void learnChanges();
+    
+    /**
+     * Clear the selection.
+     */
+    public void clear();
+    
+    /**
+     * Get a lowercase name of this region selector type.
+     * 
+     * @return
+     */
+    public String getTypeName();
+    
+    /**
+     * Get lines of information about the selection.
+     * 
+     * @return
+     */
+    public List<String> getInformationLines();
+}