bridge.c

design_patterns code设计模式书中的源码 对学习设计模式的人很有帮助的

/*
*/
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;
}
/*
*/