修改万花筒模拟程序，增加在窗口的中线上对称绘制四个小矩形的功能。同时让程序每次随机选择将四个小矩形画在窗口的对角线上还是画在中线上
#include<iostream>
#include "rect.h"     //ezWinLibrary的头文件
#include "uniform.h"  //ezWinLibrary的头文件
using namespace std;

const float WIN_SIZE = 12.0;
const int   MAX_SIZE = 3;

SimpleWindow W("KaleidoWindow", WIN_SIZE, WIN_SIZE);  //创建一个窗口

//产生随机的颜色。color是ezWin图形库中定义的表示颜色的枚举类型
color RandomColor()
{
    return (color) Uniform(0, MaxColors - 1);
}

//随机产生正方形与中心的距离
float RandomOffSet(int Range, float TrinketSize)  
{
    float OffSet = Uniform(0,Range * 10) / 10.0f;

    //正方形与中心的距离必须大于其边长的一半
    if (OffSet < TrinketSize / 2.0f)              
    {
       OffSet = TrinketSize / 2.0f;
    }
    return OffSet;
}

//随机设置正方形的边长
float RandomTrinketetSize( int MaxSize )           
{
    return Uniform(10, MaxSize * 10)/10.0f;
}
int Kaleidoscope()
{
    const float Center = WIN_SIZE / 2;                   //窗口中心
    const float Size   = RandomTrinketetSize(MAX_SIZE);  //设置正方形边长
    const color Color1 = RandomColor();                     //产生随机颜色
    const color Color2 = RandomColor();                     
    float OffSet = RandomOffSet(MAX_SIZE, Size);         //设置正方形与中心的距离

    //创建四个矩形
    RectangleShape Trinket1(W, Center + OffSet, Center + OffSet, Color1, Size, Size);
    RectangleShape Trinket2(W, Center - OffSet, Center + OffSet, Color2, Size, Size);
    RectangleShape Trinket3(W, Center - OffSet, Center - OffSet, Color1, Size, Size);
    RectangleShape Trinket4(W, Center + OffSet, Center - OffSet, Color2, Size, Size);
    //绘制四个矩形
    Trinket1.Draw();
    Trinket2.Draw();
    Trinket3.Draw();
    Trinket4.Draw();

    return 0;
}

int ApiMain()
{   
    W.Open();
    W.SetTimerCallback(Kaleidoscope);
    W.StartTimer(500);
    return 0;
}