三均线系统（EMA20/49/89）

#property copyright "XAUOF 指标工坊"
#property version   "1.00"

#property indicator_chart_window
#property indicator_buffers 3
#property indicator_plots   3

// 第一条线 EMA20 - 默认白色实线
#property indicator_type1   DRAW_LINE
#property indicator_color1  clrWhite
#property indicator_width1  2
#property indicator_label1  "EMA20"

// 第二条线 EMA49 - 默认绿色虚线
#property indicator_type2   DRAW_LINE
#property indicator_color2  clrLime
#property indicator_width2  1
#property indicator_style2  STYLE_DOT
#property indicator_label2  "EMA49"

// 第三条线 EMA89 - 默认红色虚线
#property indicator_type3   DRAW_LINE
#property indicator_color3  clrRed
#property indicator_width3  1
#property indicator_style3  STYLE_DOT
#property indicator_label3  "EMA89"

//--- 可调参数
input int Period1 = 20;              // EMA20 周期
input int Period2 = 49;              // EMA49 周期
input int Period3 = 89;              // EMA89 周期
input color Color1 = clrWhite;       // EMA20 颜色
input color Color2 = clrLime;        // EMA49 颜色
input color Color3 = clrRed;         // EMA89 颜色
input int Width1 = 2;                // EMA20 线宽
input int Width2 = 1;                // EMA49 线宽
input int Width3 = 1;                // EMA89 线宽
input ENUM_LINE_STYLE Style1 = STYLE_SOLID;  // EMA20 线型（实线/虚线/点线）
input ENUM_LINE_STYLE Style2 = STYLE_DOT;    // EMA49 线型
input ENUM_LINE_STYLE Style3 = STYLE_DOT;    // EMA89 线型

//--- 指标缓冲区
double Ema20Buffer[];
double Ema49Buffer[];
double Ema89Buffer[];

//--- 指标句柄
int handle20;
int handle49;
int handle89;

//+------------------------------------------------------------------+
//| 初始化函数                                                        |
//+------------------------------------------------------------------+
int OnInit()
{
    // 绑定缓冲区到绘图序号
    SetIndexBuffer(0, Ema20Buffer, INDICATOR_DATA);
    SetIndexBuffer(1, Ema49Buffer, INDICATOR_DATA);
    SetIndexBuffer(2, Ema89Buffer, INDICATOR_DATA);
    
    // 创建 EMA 指标句柄
    handle20 = iMA(_Symbol, PERIOD_CURRENT, Period1, 0, MODE_EMA, PRICE_CLOSE);
    handle49 = iMA(_Symbol, PERIOD_CURRENT, Period2, 0, MODE_EMA, PRICE_CLOSE);
    handle89 = iMA(_Symbol, PERIOD_CURRENT, Period3, 0, MODE_EMA, PRICE_CLOSE);
    
    // 检查句柄是否创建成功
    if(handle20 == INVALID_HANDLE || handle49 == INVALID_HANDLE || handle89 == INVALID_HANDLE)
    {
        Print("均线句柄创建失败");
        return INIT_FAILED;
    }
    
    // 应用用户自定义的颜色、线宽和线型
    PlotIndexSetInteger(0, PLOT_LINE_COLOR, Color1);
    PlotIndexSetInteger(0, PLOT_LINE_WIDTH, Width1);
    PlotIndexSetInteger(0, PLOT_LINE_STYLE, Style1);
    
    PlotIndexSetInteger(1, PLOT_LINE_COLOR, Color2);
    PlotIndexSetInteger(1, PLOT_LINE_WIDTH, Width2);
    PlotIndexSetInteger(1, PLOT_LINE_STYLE, Style2);
    
    PlotIndexSetInteger(2, PLOT_LINE_COLOR, Color3);
    PlotIndexSetInteger(2, PLOT_LINE_WIDTH, Width3);
    PlotIndexSetInteger(2, PLOT_LINE_STYLE, Style3);
    
    // 设置指标短名称（显示在图表左上角）
    IndicatorSetString(INDICATOR_SHORTNAME, StringFormat("三均线 EMA(%d/%d/%d)", Period1, Period2, Period3));
    
    // 设置小数位数跟随品种
    IndicatorSetInteger(INDICATOR_DIGITS, _Digits);
    
    return INIT_SUCCEEDED;
}

//+------------------------------------------------------------------+
//| 计算函数                                                          |
//+------------------------------------------------------------------+
int OnCalculate(const int rates_total,
                const int prev_calculated,
                const datetime &time[],
                const double &open[],
                const double &high[],
                const double &low[],
                const double &close[],
                const long &tick_volume[],
                const long &volume[],
                const int &spread[])
{
    // 检查各个句柄是否已经计算完成
    if(BarsCalculated(handle20) < rates_total) return 0;
    if(BarsCalculated(handle49) < rates_total) return 0;
    if(BarsCalculated(handle89) < rates_total) return 0;
    
    // 从句柄拷贝数据到缓冲区
    if(CopyBuffer(handle20, 0, 0, rates_total, Ema20Buffer) < rates_total) return 0;
    if(CopyBuffer(handle49, 0, 0, rates_total, Ema49Buffer) < rates_total) return 0;
    if(CopyBuffer(handle89, 0, 0, rates_total, Ema89Buffer) < rates_total) return 0;
    
    // 返回本次计算的 K 线数量
    return rates_total;
}

//+------------------------------------------------------------------+
//| 清理函数                                                          |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
{
    // 释放指标句柄
    if(handle20 != INVALID_HANDLE) IndicatorRelease(handle20);
    if(handle49 != INVALID_HANDLE) IndicatorRelease(handle49);
    if(handle89 != INVALID_HANDLE) IndicatorRelease(handle89);
}