--- a/gui.d	Wed May 13 15:42:39 2009 +0930
+++ b/gui.d	Wed May 13 17:50:25 2009 +0930
@@ -10,7 +10,11 @@
 import tk.types;
 import tk.events;
 
+import std.stdio;
+import tk.geometry2;
+
 void main(string[] args) {
+    /*
     Main.init(args);
     auto window = new MainWindow("Title");
     auto event_handler = new ToolStack();
@@ -18,4 +22,16 @@
     window.add(canvas);
     window.showAll();
     Main.run();
+    */
+
+    Point2 p1 = Point2(3.0, 5.0);
+    writefln("%s", p1);
+
+    Point2 p2 = Point2(1.0, 2.0);
+    writefln("%s", p2);
+
+    writefln("%s", p1 - p2);
+
+    Rectangle2 r = Rectangle2(p1, p2);
+    writefln("%s", r);
 }

--- a/tk/geometry2.d	Wed May 13 15:42:39 2009 +0930
+++ b/tk/geometry2.d	Wed May 13 17:50:25 2009 +0930
@@ -1,12 +1,114 @@
 module tk.geometry2;
 
+private import std.stdio;
+private import std.math;
+
 struct Point2 {
-    this(double x, double y) {
+    this(in double x, in double y) {
+        _x = x;
+        _y = y;
+    }
+
+    Point2 opAdd(in Vector2 v) const {
+        return Point2(_x + v._x, _y + v._y);
+    }
+
+    Point2 opSub(in Vector2 v) const {
+        return Point2(_x - v._x, _y - v._y);
+    }
+
+    Vector2 opSub(in Point2 p) const {
+        return Vector2(_x - p._x, _y - p._y);
+    }
+
+    string toString() /* const */ {
+        return std.string.format("(%f, %f)", _x, _y);
+    }
+
+    double x() const { return _x; }
+    double y() const { return _y; }
+
+    private {
+        double _x, _y;
+    }
+}
+
+struct Vector2 {
+    this(in double x, in double y) {
         _x = x;
         _y = y;
     }
 
+    Vector2 opAdd(in Vector2 v) const {
+        return Vector2(_x + v._x, _y + v._y);
+    }
+
+    Vector2 opSub(in Vector2 v) const {
+        return Vector2(_x - v._x, _y - v._y);
+    }
+
+    Vector2 opNeg() const {
+        return Vector2(-_x, -_y);
+    }
+
+    Vector2 opMul_r(double d) const {
+        return Vector2(d * _x, d * _y);
+    }
+
+    Vector2 opDiv(double d) const {
+        return Vector2(_x / d, _y / d);
+    }
+
+    double length() const {
+        return sqrt(_x * _x + _y * _y);
+    }
+
+    string toString() /* const */ {
+        return std.string.format("[%f, %f]", _x, _y);
+    }
+
+    double x() const { return _x; }
+    double y() const { return _y; }
+
     private {
-        immutable double _x, _y;
+        double _x, _y;
     }
 }
+
+struct Rectangle2 {
+    this(in Point2 position, Vector2 size) {
+        this(position.x, position.y, size.x, size.y);
+    }
+
+    this(Point2 corner1, Point2 corner2) {
+        this(corner1.x, corner1.y, corner2.x - corner1.x, corner2.y - corner1.y);
+    }
+
+    // Intersection
+    Rectangle2 opAnd(in Rectangle2 r) const {
+        // FIXME
+        return Rectangle2(3.2, 5.3, 3.2, 2.3);
+    }
+
+    // Union
+    Rectangle2 opOr(in Rectangle2 r) const {
+        // FIXME
+        return Rectangle2(3.2, 5.3, 5.8, 2.1);
+    }
+
+    string toString() {
+        return std.string.format("{%s, %s}", mPosition, mSize);
+    }
+
+    private {
+        this(double x, double y, double w, double h) {
+            if (w < 0.0) { x += w; w = -w; }
+            if (h < 0.0) { y += h; h = -h; }
+            mPosition = Point2(x, y);
+            mSize = Vector2(w, h);
+        }
+
+        Point2 mPosition;
+        Vector2 mSize;
+    }
+}