mql4如何自定义画图

mql4里很多自定义指标，将自定义指标拖入途中就能看到曲线图，俗话说，有图有真像，图是如何画的呢？我一直比较好奇，比如iMACD技术参数的图如下：

 

这个图是如何画的呢？

问题1，银色的线垂直的线如何画，红色的曲线如何画

问题2， 两条线的数据是如何获取的 ？

带着这2个问题，我们看下这个源码

还好Mql开放了这个源代码，我们可以研究下， 源码如下

//+------------------------------------------------------------------+
//|                                                  Custom MACD.mq4 |
//|                      Copyright ?2004, MetaQuotes Software Corp. |
//|                                       http://www.metaquotes.net/ |
//+------------------------------------------------------------------+
#property  copyright "Copyright ?2004, MetaQuotes Software Corp."
#property  link      "http://www.metaquotes.net/"
//---- indicator settings
#property  indicator_separate_window
#property  indicator_buffers 2
#property  indicator_color1  Silver
#property  indicator_color2  Red
#property  indicator_width1  2
//---- indicator parameters
extern int FastEMA=12;
extern int SlowEMA=26;
extern int SignalSMA=9;
//---- indicator buffers
double     MacdBuffer[];
double     SignalBuffer[];

//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int init()
  {
//---- drawing settings
   SetIndexStyle(0,DRAW_HISTOGRAM);
   SetIndexStyle(1,DRAW_LINE);
   SetIndexDrawBegin(1,SignalSMA);
   IndicatorDigits(Digits+1);
//---- indicator buffers mapping
   SetIndexBuffer(0,MacdBuffer);
   SetIndexBuffer(1,SignalBuffer);
//---- name for DataWindow and indicator subwindow label
   IndicatorShortName("MACD("+FastEMA+","+SlowEMA+","+SignalSMA+")");
   SetIndexLabel(0,"MACD");
   SetIndexLabel(1,"Signal");
//---- initialization done
   return(0);
  }
//+------------------------------------------------------------------+
//| Moving Averages Convergence/Divergence                           |
//+------------------------------------------------------------------+
int start()
  {
   int limit;
   int counted_bars=IndicatorCounted();
//---- last counted bar will be recounted
   if(counted_bars>0) counted_bars--;
   limit=Bars-counted_bars;
//---- macd counted in the 1-st buffer
   for(int i=0; i<limit; i++)
      MacdBuffer[i]=iMA(NULL,0,FastEMA,0,MODE_EMA,PRICE_CLOSE,i)-iMA(NULL,0,SlowEMA,0,MODE_EMA,PRICE_CLOSE,i);
//---- signal line counted in the 2-nd buffer
   for(i=0; i<limit; i++)
      SignalBuffer[i]=iMAOnArray(MacdBuffer,Bars,SignalSMA,0,MODE_SMA,i);
//---- done
   return(0);
  }
//+------------------------------------------------------------------+

 

#property  indicator_buffers 2

定义了有2条线

#property  indicator_color1  Silver

#property  indicator_color2  Red

定义颜色 ，银色和红色

#property  indicator_width1  2

定义线的宽度。

extern int FastEMA=12;
extern int SlowEMA=26;
extern int SignalSMA=9;

iMACD的参数，我也不太明白，但是这对理解图的画法不影响，先不去管它。

//---- indicator buffers
double     MacdBuffer[];
double     SignalBuffer[];

这里是重点，存放数据的数组。

int init()
  {
   //---- drawing settings

   SetIndexStyle(0,DRAW_HISTOGRAM);//设置第一条线的显示方式，这里就是垂直
   SetIndexStyle(1,DRAW_LINE);//水平线显示
   SetIndexDrawBegin(1,SignalSMA); //设置开始画的位置

   IndicatorDigits(Digits+1);
//---- indicator buffers mapping
   SetIndexBuffer(0,MacdBuffer);
   SetIndexBuffer(1,SignalBuffer);
//---- name for DataWindow and indicator subwindow label
   IndicatorShortName("MACD("+FastEMA+","+SlowEMA+","+SignalSMA+")");
   SetIndexLabel(0,"MACD");
   SetIndexLabel(1,"Signal");
//---- initialization done
   return(0);
  }

 具体我就不一一解释了，后面有英文的注释，应该比较容易明白 ，因为系统没有ima的指标图，通过修改这个代码，我们可以画出iMA的指标图

//+------------------------------------------------------------------+
//|                                                  Custom MACD.mq4 |
//|                      Copyright ?2004, MetaQuotes Software Corp. |
//|                                       http://www.metaquotes.net/ |
//+------------------------------------------------------------------+
#property  copyright "Copyright ?2004, MetaQuotes Software Corp."
#property  link      "http://www.metaquotes.net/"
//---- indicator settings
#property  indicator_separate_window

#property  indicator_color1  Red

#property  indicator_width1  2

extern int SlowEMA=26;
extern int ma_shift=0;

double     MacdBuffer[];
double     SignalBuffer[];

//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int init()
  {

   SetIndexStyle(0,DRAW_HISTOGRAM);

   IndicatorDigits(Digits+1);

   SetIndexBuffer(0,MacdBuffer);

   SetIndexLabel(0,"iMA");

   return(0);
  }
//+------------------------------------------------------------------+
//| Moving Averages Convergence/Divergence                           |
//+------------------------------------------------------------------+
int start()
  {
   int limit;
   int counted_bars=IndicatorCounted();
//---- last counted bar will be recounted
   if(counted_bars>0) counted_bars--;
   limit=Bars-counted_bars;
//---- macd counted in the 1-st buffer
   for(int i=0; i<limit; i++)
      MacdBuffer[i]=iMA(NULL,0,SlowEMA,ma_shift,MODE_EMA,PRICE_CLOSE,i);
//---- done
   return(0);
  }
//+------------------------------------------------------------------+

创建这个脚本的时候请选择Custom indicator 模板来创建，编译后，就可以运行这个脚本了。

希望这篇文章能够对学习mql的朋友有所帮助.

MQL 虽然语法不难，但是那些技术指标好是难懂，希望有兴趣的朋友能够一起学习，探讨，共同进步！