图形的基本对称

1.关于任意平行于x轴直线图像的对称

2.关于任意平行于y轴直线图像的对称

3.关于任意点的对称

4.关于直线y=x对称

5.关于直线y=-x对称

编译器：vs2013

// x对称.cpp : 定义控制台应用程序的入口点。
//

#include "stdafx.h"
#include<stdio.h>
#include"graphics.h"
#include<stdlib.h>

//函数声明
void SymmetricalY(int a[], int y);//关于x的直线对称
void SymmetricalX(int a[], int x);//关于y的直线对称
void Symmetricalxy(int a[], int x, int y);//关于随机点对称
void Symmetricaly_x(int a[]);//关于y=x对称
void Symmetricaly__x(int a[]);    //关于y=-x对称

int main()
{
    int gdriver = DETECT, gmove;
    int a[28] = { 100, 100, 150, 150, 250, 150, 250, 0, 350, 150, 450, 150, 500, 200, 450, 250, 350, 250, 250, 400, 250, 250, 150, 250, 100, 300, 100, 100 };

    //关于x的直线对称
    /*int x;
    
    printf("please input the line x= ");
    scanf_s("%d", &x);

    initgraph(&gdriver, &gmove, "");

    drawpoly(14, a);

    SymmetricalX(a, x);*/

    //关于y的直线对称
    /*int y;

    printf("please input the line y= ");
    scanf_s("%d", &y);

    initgraph(&gdriver, &gmove, "");

    drawpoly(14, a);

    SymmetricalY(a, y);*/

    //关于随机点对称
    /*int x, y;

    printf("please inout the point:
");
    scanf_s("%d%d", &x, &y);

    initgraph(&gdriver, &gmove, "");

    drawpoly(14, a);
    Symmetricalxy(a,  x,  y);*/

    //关于y=x对称
    /*initgraph(&gdriver, &gmove, "");
    drawpoly(14, a);
    Symmetricaly_x(a);*/

    //关于y=-x对称
    initgraph(&gdriver, &gmove, "");
    drawpoly(14, a);
    Symmetricaly__x(a);

    system("pause");

    closegraph();

    return 0;
}

//绕任意x直线对称
void SymmetricalX(int a[], int x)
{
    int i,b[28];

    for (i = 0; i < 28; i = i + 2)
    {
        b[i] = 2 * x - a[i];
        b[i + 1] = a[i + 1];
    }

    drawpoly(14,b);
}

//绕任意y直线对称
void SymmetricalY(int a[], int y)
{
    int i, b[28];

    for (i = 0; i < 28; i = i + 2)
    {
        b[i+1] = 2 * y - a[i+1];
        b[i] = a[i];
    }

    drawpoly(14, b);
}

//关于某一点对称
void Symmetricalxy(int a[], int x, int y)
{
    int i, b[28];

    for (i = 0; i < 28; i = i + 2)
    {
        //平移至原点
        b[i] = a[i] - x;
        b[i + 1] = a[i + 1] - y;
        //原点的对称变换
        b[i] = -b[i];
        b[i + 1] = -b[i+1];
        //平移回去
        b[i] = b[i] + x;
        b[i + 1] = b[i + 1] + y;
    }

    drawpoly(14, b);
}

//关于y=x对称
void Symmetricaly_x(int a[])
{
    int i, b[28];

    for (i = 0; i < 28; i = i + 2)
    {
        //交换xy的坐标值
        b[i + 1] = a[i];
        b[i] = a[i + 1];
    }

    drawpoly(14, b);
}

//关于y=-x对称
void Symmetricaly__x(int a[])
{
    int i, b[28];

    for (i = 0; i < 28; i = i + 2)
    {
        //交换负xy的坐标值
        b[i + 1] = -a[i];
        b[i] = -a[i + 1];
    }

    drawpoly(14, b);
}