/**/class Body {  public:   void Ref();   void Unref();   int RefCount(); private:};class Handle {  public:    Handle& operator=(const Handle& other);  private:    Body* _body;};/**/Handle& Handle::operator= (const Handle& other)  {    other._body->Ref();    _body->Unref();    if (_body->RefCount() == 0) {        delete _body;    }    _body = other._body;    return *this;}/**/#include "Geom.H"#include "math.h"class Window;class View {  public:    DrawOn(Window*);};class WindowImp;struct Display;typedef unsigned int Drawable;typedef struct XXX { int y; }  *GC;extern XDrawRectangle(    Display*,    Drawable,    GC,    int,    int,    unsigned int,    unsigned int);struct PPOINTL {    Coord x;    Coord y;};const int GPI_ERROR = 1;typedef int HPS;int GpiBeginPath(HPS, unsigned long);int GpiSetCurrentPosition(HPS, PPOINTL*);int GpiPolyLine(HPS, unsigned long, PPOINTL*);int GpiEndPath(HPS);void  ReportError();void GpiStrokePath(HPS, unsigned long, unsigned long);class WindowSystemFactory {  public:    static WindowSystemFactory* Instance();    WindowImp* MakeWindowImp();};/**/class Window {public:    Window(View* contents);    // requests handled by window    virtual void DrawContents();/**/    virtual void Open();    virtual void Close();    virtual void Iconify();    virtual void Deiconify();/**/    // requests forwarded to implementation    virtual void SetOrigin(const Point& at);    virtual void SetExtent(const Point& extent);    virtual void Raise();    virtual void Lower();/**/    virtual void DrawLine(const Point&, const Point&);    virtual void DrawRect(const Point&, const Point&);    virtual void DrawPolygon(const Point[], int n);    virtual void DrawText(const char*, const Point&);/**/protected:    WindowImp* GetWindowImp();    View* GetView();/**/private:    WindowImp* _imp;    View* _contents; // the window's contents};/**/class WindowImp {public:    virtual void ImpTop() = 0;    virtual void ImpBottom() = 0;    virtual void ImpSetExtent(const Point&) = 0;    virtual void ImpSetOrigin(const Point&) = 0;/**/    virtual void DeviceRect(Coord, Coord, Coord, Coord) = 0;    virtual void DeviceText(const char*, Coord, Coord) = 0;    virtual void DeviceBitmap(const char*, Coord, Coord) = 0;    // lots more functions for drawing on windows...protected:    WindowImp();};/**/class ApplicationWindow : public Window {public:    // ...    virtual void DrawContents();};void ApplicationWindow::DrawContents () {    GetView()->DrawOn(this);}/**/class IconWindow : public Window {public:    // ...    virtual void DrawContents();private:    const char* _bitmapName;};/**/void IconWindow::DrawContents() {    WindowImp* imp = GetWindowImp();    if (imp != 0) {        imp->DeviceBitmap(_bitmapName, 0.0, 0.0);    }}/**/void Window::DrawRect (const Point& p1, const Point& p2) {    WindowImp* imp = GetWindowImp();    imp->DeviceRect(p1.X(), p1.Y(), p2.X(), p2.Y());}/**/class XWindowImp : public WindowImp {public:    XWindowImp();    virtual void DeviceRect(Coord, Coord, Coord, Coord);    // remainder of public interface...private:    // lots of X window system-specific state, including:    Display* _dpy;    Drawable _winid;  // window id    GC _gc;           // window graphic context};/**/class PMWindowImp : public WindowImp {public:    PMWindowImp();    virtual void DeviceRect(Coord, Coord, Coord, Coord);    // remainder of public interface...private:    // lots of PM window system-specific state, including:    HPS _hps;};/**/void XWindowImp::DeviceRect (    Coord x0, Coord y0, Coord x1, Coord y1) {    int x = round(min(x0, x1));    int y = round(min(y0, y1));    int w = round(abs(x0 - x1));    int h = round(abs(y0 - y1));    XDrawRectangle(_dpy, _winid, _gc, x, y, w, h);}/**/void PMWindowImp::DeviceRect (    Coord x0, Coord y0, Coord x1, Coord y1) {    Coord left = min(x0, x1);    Coord right = max(x0, x1);    Coord bottom = min(y0, y1);    Coord top = max(y0, y1);/**/    PPOINTL point[4];/**/    point[0].x = left;    point[0].y = top;    point[1].x = right;   point[1].y = top;    point[2].x = right;   point[2].y = bottom;    point[3].x = left;    point[3].y = bottom;/**/    if (        (GpiBeginPath(_hps, 1L) == false) ||        (GpiSetCurrentPosition(_hps, &point[3]) == false) ||        (GpiPolyLine(_hps, 4L, point) == GPI_ERROR)  ||        (GpiEndPath(_hps) == false)    ) {        // report error/**/    } else {        GpiStrokePath(_hps, 1L, 0L);    }}/**/WindowImp* Window::GetWindowImp () {    if (_imp == 0) {        _imp = WindowSystemFactory::Instance()->MakeWindowImp();    }    return _imp;}/**/