Added an extending cuboid selector.

It can be used with //sel extend.
Also made //sel carry over some information about the selection into the new selection mode.
Also cleaned up the source of the RegionSelectors and the //sel command a bit.

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

@@ -28,9 +28,11 @@ 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.ExtendingCuboidRegionSelector;
 import com.sk89q.worldedit.regions.Polygonal2DRegionSelector;
 import com.sk89q.worldedit.regions.Region;
 import com.sk89q.worldedit.regions.RegionOperationException;
+import com.sk89q.worldedit.regions.RegionSelector;
 import com.sk89q.worldedit.blocks.*;
 
 /**
@@ -597,7 +599,7 @@ public class SelectionCommands {
 
     @Command(
         aliases = { "/sel", ";" },
-        usage = "[cuboid|poly]",
+        usage = "[cuboid|extend|poly]",
         desc = "Choose a region selector",
         min = 0,
         max = 1
@@ -606,21 +608,30 @@ public class SelectionCommands {
             LocalSession session, LocalPlayer player, EditSession editSession)
             throws WorldEditException {
 
+        final LocalWorld world = player.getWorld();
         if (args.argsLength() == 0) {
-            session.getRegionSelector(player.getWorld()).clear();
+            session.getRegionSelector(world).clear();
             return;
         }
-        String typeName = args.getString(0);
+
+        final String typeName = args.getString(0);
+        final RegionSelector oldSelector = session.getRegionSelector(world);
+
+        final RegionSelector selector;
         if (typeName.equalsIgnoreCase("cuboid")) {
-            session.setRegionSelector(player.getWorld(), new CuboidRegionSelector());
-            session.dispatchCUISelection(player);
+            selector = new CuboidRegionSelector(oldSelector);
             player.print("Cuboid: left click for point 1, right click for point 2");
+        } else if (typeName.equalsIgnoreCase("extend")) {
+            selector = new ExtendingCuboidRegionSelector(oldSelector);
+            player.print("Cuboid: left click for a starting point, right click to extend");
         } else if (typeName.equalsIgnoreCase("poly")) {
-            session.setRegionSelector(player.getWorld(), new Polygonal2DRegionSelector());
-            session.dispatchCUISelection(player);
+            selector = new Polygonal2DRegionSelector();
             player.print("2D polygon selector: Left/right click to add a point.");
         } else {
-            player.printError("Only 'cuboid' and 'poly' are accepted.");
+            player.printError("Only 'cuboid', 'extend' and 'poly' are accepted.");
+            return;
         }
+        session.setRegionSelector(world, selector);
+        session.dispatchCUISelection(player);
     }
 }

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

@@ -39,29 +39,54 @@ public class CuboidRegionSelector implements RegionSelector, CUIPointBasedRegion
     protected BlockVector pos2;
     protected CuboidRegion region = new CuboidRegion(new Vector(), new Vector());
 
+    public CuboidRegionSelector() {
+    }
+
+    public CuboidRegionSelector(RegionSelector oldSelector) {
+        if (oldSelector instanceof CuboidRegionSelector) {
+            final CuboidRegionSelector cuboidRegionSelector = (CuboidRegionSelector) oldSelector;
+
+            pos1 = cuboidRegionSelector.pos1;
+            pos2 = cuboidRegionSelector.pos2;
+        } else {
+            final Region oldRegion;
+            try {
+                oldRegion = oldSelector.getRegion();
+            } catch (IncompleteRegionException e) {
+                return;
+            }
+
+            pos1 = oldRegion.getMinimumPoint().toBlockVector();
+            pos2 = oldRegion.getMaximumPoint().toBlockVector();
+        }
+
+        region.setPos1(pos1);
+        region.setPos2(pos2);
+    }
+
     public boolean selectPrimary(Vector pos) {
-        if (pos1 != null && pos1.equals(pos)) {
+        if (pos.equals(pos1)) {
             return false;
         }
+
         pos1 = pos.toBlockVector();
         region.setPos1(pos1);
         return true;
     }
 
     public boolean selectSecondary(Vector pos) {
-        if (pos2 != null && pos2.equals(pos)) {
+        if (pos.equals(pos2)) {
             return false;
         }
+
         pos2 = pos.toBlockVector();
         region.setPos2(pos2);
         return true;
     }
 
-    public void explainPrimarySelection(LocalPlayer player,
-            LocalSession session, Vector pos) {
+    public void explainPrimarySelection(LocalPlayer player, LocalSession session, Vector pos) {
         if (pos1 != null && pos2 != null) {
-            player.print("First position set to " + pos1
-                    + " (" + region.getArea() + ").");
+            player.print("First position set to " + pos1 + " (" + region.getArea() + ").");
         } else {
             player.print("First position set to " + pos1 + ".");
         }
@@ -69,11 +94,9 @@ public class CuboidRegionSelector implements RegionSelector, CUIPointBasedRegion
         session.dispatchCUIEvent(player, new SelectionPointEvent(0, pos, getArea()));
     }
 
-    public void explainSecondarySelection(LocalPlayer player,
-            LocalSession session, Vector pos) {
+    public void explainSecondarySelection(LocalPlayer player, LocalSession session, Vector pos) {
         if (pos1 != null && pos2 != null) {
-            player.print("Second position set to " + pos2
-                    + " (" + region.getArea() + ").");
+            player.print("Second position set to " + pos2 + " (" + region.getArea() + ").");
         } else {
             player.print("Second position set to " + pos2 + ".");
         }
@@ -85,6 +108,7 @@ public class CuboidRegionSelector implements RegionSelector, CUIPointBasedRegion
         if (pos1 != null) {
             session.dispatchCUIEvent(player, new SelectionPointEvent(0, pos1, getArea()));
         }
+
         if (pos2 != null) {
             session.dispatchCUIEvent(player, new SelectionPointEvent(1, pos2, getArea()));
         }
@@ -129,7 +153,7 @@ public class CuboidRegionSelector implements RegionSelector, CUIPointBasedRegion
     }
 
     public List<String> getInformationLines() {
-        List<String> lines = new ArrayList<String>();
+        final List<String> lines = new ArrayList<String>();
 
         if (pos1 != null) {
             lines.add("Position 1: " + pos1);
@@ -150,16 +174,21 @@ public class CuboidRegionSelector implements RegionSelector, CUIPointBasedRegion
         if (pos1 != null) {
             player.dispatchCUIEvent(new SelectionPointEvent(0, pos1, getArea()));
         }
+
         if (pos2 != null) {
             player.dispatchCUIEvent(new SelectionPointEvent(1, pos2, getArea()));
         }
     }
 
     public int getArea() {
-        if (pos1 != null && pos2 != null) {
-            return region.getArea();
+        if (pos1 == null) {
+            return -1;
         }
 
-        return -1;
+        if (pos2 == null) {
+            return -1;
+        }
+
+        return region.getArea();
     }
 }

src/main/java/com/sk89q/worldedit/regions/ExtendingCuboidRegionSelector.java

@@ -0,0 +1,106 @@
+// $Id$
+/*
+ * 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.BlockVector;
+import com.sk89q.worldedit.LocalPlayer;
+import com.sk89q.worldedit.LocalSession;
+import com.sk89q.worldedit.Vector;
+
+/**
+ * Alternative selector for cuboids.
+ *
+ * @author sk89q
+ */
+public class ExtendingCuboidRegionSelector extends CuboidRegionSelector {
+    public ExtendingCuboidRegionSelector() {
+    }
+
+    public ExtendingCuboidRegionSelector(RegionSelector oldSelector) {
+        super(oldSelector);
+
+        if (pos1 == null || pos2 == null) {
+            return;
+        }
+
+        pos1 = region.getMinimumPoint().toBlockVector();
+        pos2 = region.getMaximumPoint().toBlockVector();
+        region.setPos1(pos1);
+        region.setPos2(pos2);
+    }
+
+    @Override
+    public boolean selectPrimary(Vector pos) {
+        if (pos.equals(pos1) && pos.equals(pos2)) {
+            return false;
+        }
+
+        pos1 = pos2 = pos.toBlockVector();
+        region.setPos1(pos1);
+        region.setPos2(pos2);
+        return true;
+    }
+
+    @Override
+    public boolean selectSecondary(Vector pos) {
+        if (pos1 == null || pos2 == null) {
+            return selectPrimary(pos);
+        }
+
+        if (region.contains(pos)) {
+            return false;
+        }
+
+        double x1 = Math.min(pos.getX(), pos1.getX());
+        double y1 = Math.min(pos.getY(), pos1.getY());
+        double z1 = Math.min(pos.getZ(), pos1.getZ());
+
+        double x2 = Math.max(pos.getX(), pos2.getX());
+        double y2 = Math.max(pos.getY(), pos2.getY());
+        double z2 = Math.max(pos.getZ(), pos2.getZ());
+
+        final BlockVector o1 = pos1;
+        final BlockVector o2 = pos2;
+        pos1 = new BlockVector(x1, y1, z1);
+        pos2 = new BlockVector(x2, y2, z2);
+        region.setPos1(pos1);
+        region.setPos2(pos2);
+
+        assert(region.contains(o1));
+        assert(region.contains(o2));
+        assert(region.contains(pos));
+
+        return true;
+    }
+
+    @Override
+    public void explainPrimarySelection(LocalPlayer player, LocalSession session, Vector pos) {
+        player.print("Started selection at " + pos + " (" + region.getArea() + ").");
+
+        explainRegionAdjust(player, session);
+    }
+
+    @Override
+    public void explainSecondarySelection(LocalPlayer player, LocalSession session, Vector pos) {
+        player.print("Extended selection to encompass " + pos + " (" + region.getArea() + ").");
+
+        explainRegionAdjust(player, session);
+    }
+}

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

@@ -19,7 +19,7 @@
 
 package com.sk89q.worldedit.regions;
 
-import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 import com.sk89q.worldedit.BlockVector;
 import com.sk89q.worldedit.BlockVector2D;
@@ -42,22 +42,24 @@ public class Polygonal2DRegionSelector implements RegionSelector, CUIPointBasedR
     protected Polygonal2DRegion region = new Polygonal2DRegion();
 
     public boolean selectPrimary(Vector pos) {
-        if (pos1 != null && pos1.equals(pos)) {
+        if (pos.equals(pos1)) {
             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()) {
+            final List<BlockVector2D> points = region.getPoints();
+
+            final BlockVector2D lastPoint = points.get(region.size() - 1);
+            if (lastPoint.getBlockX() == pos.getBlockX() && lastPoint.getBlockZ() == pos.getBlockZ()) {
                 return false;
             }
 
@@ -68,20 +70,21 @@ public class Polygonal2DRegionSelector implements RegionSelector, CUIPointBasedR
 
         region.addPoint(pos);
         region.expandY(pos.getBlockY());
+
         return true;
     }
 
-    public void explainPrimarySelection(LocalPlayer player,
-            LocalSession session, Vector pos) {
+    public void explainPrimarySelection(LocalPlayer player, LocalSession session, Vector pos) {
         player.print("Starting a new polygon at " + pos + ".");
+
         session.dispatchCUIEvent(player, new SelectionShapeEvent(getTypeId()));
         session.dispatchCUIEvent(player, new SelectionPoint2DEvent(0, pos, getArea()));
         session.dispatchCUIEvent(player, new SelectionMinMaxEvent(region.minY, region.maxY));
     }
 
-    public void explainSecondarySelection(LocalPlayer player,
-            LocalSession session, Vector pos) {
+    public void explainSecondarySelection(LocalPlayer player, LocalSession session, Vector pos) {
         player.print("Added point #" + region.size() + " at " + pos + ".");
+
         session.dispatchCUIEvent(player, new SelectionPoint2DEvent(region.size() - 1, pos, getArea()));
         session.dispatchCUIEvent(player, new SelectionMinMaxEvent(region.minY, region.maxY));
     }
@@ -94,6 +97,7 @@ public class Polygonal2DRegionSelector implements RegionSelector, CUIPointBasedR
         if (pos1 == null) {
             throw new IncompleteRegionException();
         }
+
         return pos1;
     }
 
@@ -115,8 +119,7 @@ public class Polygonal2DRegionSelector implements RegionSelector, CUIPointBasedR
 
     public void learnChanges() {
         BlockVector2D pt = region.getPoints().get(0);
-        pos1 = new BlockVector(pt.getBlockX(),
-                region.getMinimumPoint().getBlockY(), pt.getBlockZ());
+        pos1 = new BlockVector(pt.getBlockX(), region.getMinimumPoint().getBlockY(), pt.getBlockZ());
     }
 
     public void clear() {
@@ -129,9 +132,7 @@ public class Polygonal2DRegionSelector implements RegionSelector, CUIPointBasedR
     }
 
     public List<String> getInformationLines() {
-        List<String> lines = new ArrayList<String>();
-        lines.add("# points: " + region.size());
-        return lines;
+        return Collections.singletonList("# points: " + region.size());
     }
 
     public String getTypeId() {
@@ -147,11 +148,11 @@ public class Polygonal2DRegionSelector implements RegionSelector, CUIPointBasedR
     }
 
     public void describeCUI(LocalPlayer player) {
-        List<BlockVector2D> points = region.getPoints();
+        final List<BlockVector2D> points = region.getPoints();
         for (int id = 0; id < points.size(); id++) {
             player.dispatchCUIEvent(new SelectionPoint2DEvent(id, points.get(id), getArea()));
         }
+
         player.dispatchCUIEvent(new SelectionMinMaxEvent(region.minY, region.maxY));
     }
-
 }