Bridge模式 - 《Design patterns Explained》心得

最常用的模式之一。

GOF：將抽象部分與它的實現部分分離，使它們都可以獨立地變化。

#include "createElement.h"

extern"C" DLLEXPORT int MdlMain
(
int     argc,
char**  argv
)
{
    DPoint3d pts[] = {
        {0,0,0},
        {10000,0,0},
        {10000,10000,0},
        {0,10000,0}
    };
    Transform tr;
    DPoint3d translate = {15000,0,0};
    mdlTMatrix_getIdentity (&tr);
    mdlTMatrix_setTranslation (&tr, &translate);

    Drawing* draw1 = new v1Drawing;
    Drawing* draw2 = new v2Drawing;

    shape* r1 = new Rectangle (draw1, pts[0], pts[1], pts[2], pts[3]);

    mdlTMatrix_transformPointArray (pts, &tr, 4);
    shape* r2 = new Rectangle (draw2, pts[0], pts[1], pts[2], pts[3]);

    r1->draw ( );
    r2->draw ( );

    delete r1;
    delete r2;

    shape* c1 = new Circle (draw1, pts[0], 5000);
    shape* c2 = new Circle (draw2, pts[1], 5000);

    c1->draw ( );
    c2->draw ( );
    
    delete c1;
    delete c2;
    delete draw1;
    delete draw2;

    return EXIT_SUCCESS;
}

H文件

#ifndef CREATEELEMENT_H
#define CREATEELEMENT_H

#include <MicroStationAPI.h>

class ElementDraw1
{
public:
    static void drawline    (const DPoint3d orig, const DPoint3d& end);
    static void drawCircle (const DPoint3d& center, double radius);
};

class ElementDraw2
{
public:
    static void draw_a_line     (const DPoint3d orig, const DPoint3d& end);
    static void draw_a_Circle   (const DPoint3d& center, double radius);
};

//
class Drawing
{
public:
    virtual void drawLine   (const DPoint3d& orig, const DPoint3d& end) = 0;
    virtual void drawCircle (const DPoint3d& center, double radius) = 0;
};

class v1Drawing : public Drawing
{
public:
    virtual void drawLine (const DPoint3d& orig, const DPoint3d& end);
    virtual void drawCircle (const DPoint3d& center, double radius);

};

class v2Drawing : public Drawing
{
public:
    virtual void drawLine (const DPoint3d& orig, const DPoint3d& end);
    virtual void drawCircle (const DPoint3d& center, double radius);

};

//
class shape
{
    Drawing* _draw;
public:
    virtual void drawLine(const DPoint3d& orig,const DPoint3d& end )
    {
        _draw->drawLine (orig, end);
    }

    virtual void drawCircle(const DPoint3d& center,double radius)
    {
        _draw->drawCircle (center, radius);
    }

    virtual void draw ( ) = 0;

protected:
    shape (Drawing* drawp) :_draw (drawp) {};
};

class Rectangle : public shape
{
    DPoint3d pt [4];
public:
    Rectangle (Drawing* d,
        const DPoint3d& pt0,
        const DPoint3d& pt1,
        const DPoint3d& pt2,
        const DPoint3d& pt3) : shape (d) 
    {
        pt[0] = pt0;
        pt[1] = pt1;
        pt[2] = pt2;
        pt[3] = pt3;
    };
    virtual void draw ( );
};

class Circle : public shape
{
    DPoint3d m_orig;
    double m_radius;
public:
    Circle (Drawing* d,const DPoint3d orig,double radius) : 
        shape (d),
        m_orig(orig),
        m_radius(radius) {};

    virtual void draw ( );
};

#endif // CREATEELEMENT_H

cpp

#include "createElement.h"

inline void _drawLine (const DPoint3d& orig, const DPoint3d& end, UInt32* color, Int32* sty)
{
    MSElement li;
    DPoint3d pts [] = { orig, end };
    mdlLine_create (&li, NULL, pts);
    mdlElement_setSymbology (&li, color, 0, sty);
    mdlElement_add (&li);
}

inline void _drawCircle(const DPoint3d& center,double radius,UInt32* color,Int32* sty)
{
    MSElement arc;
    mdlArc_create (&arc, NULL, (DPoint3d*) ¢er, radius, radius, NULL, 0, fc_2pi);
    mdlElement_setSymbology (&arc, color, 0, sty);
    mdlElement_add (&arc);
}

void ElementDraw1::drawline (const DPoint3d orig, const DPoint3d& end)
{
    UInt32 color = 2;
    Int32 sty = 1;
    _drawLine (orig, end,&color,&sty);
}

void ElementDraw1::drawCircle (const DPoint3d& center, double radius)
{
    UInt32 color = 2;
    Int32 sty = 1;
    _drawCircle (center, radius, &color, &sty);
}

void ElementDraw2::draw_a_line (const DPoint3d orig, const DPoint3d& end)
{
    UInt32 color = 1;
    Int32 sty = 2;
    _drawLine (orig, end, &color, &sty);
}

void ElementDraw2::draw_a_Circle (const DPoint3d& center, double radius)
{
    UInt32 color = 1;
    Int32 sty = 2;
    _drawCircle(center,radius,&color,&sty);
}

void v1Drawing::drawLine (const DPoint3d& orig, const DPoint3d& end)
{
    ElementDraw1::drawline (orig, end);
}

void v1Drawing::drawCircle (const DPoint3d& center, double radius)
{
    ElementDraw1::drawCircle (center, radius);
}

void v2Drawing::drawLine (const DPoint3d& orig, const DPoint3d& end)
{
    ElementDraw2::draw_a_line (orig, end);
}

void v2Drawing::drawCircle (const DPoint3d& center, double radius)
{
    ElementDraw2::draw_a_Circle (center, radius);
}

void Rectangle::draw ( )
{
    drawLine (pt[0], pt[1]);
    drawLine (pt[1], pt[2]);
    drawLine (pt[2], pt[3]);
    drawLine (pt[3], pt[0]);
}

void Circle::draw ( )
{
    drawCircle (m_orig, m_radius);
}