Indicator code correction

A thousand apologies if this has been dealth with elsewhere. I want to plot a version of MACD on price chart. I tried making a new indicator for this. The outcome is not showing although it is listed among the indicators on the chart. I recogn some amendment will fix it. Please help to amend it if you can.
Here is the code:
//+------------------------------------------------------------------+
//| MACDChart.mq4 |
//| Copyright 2014, MetaQuotes Software Corp. |
//| http://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2014, MetaQuotes Software Corp."
#property link "http://www.mql5.com"
#property version "1.00"
#property strict
#property indicator_chart_window
//+------------------------------------------------------------------+
#property indicator_buffers 3
#property indicator_color1 Blue
#property indicator_color2 Red
#property indicator_color3 Green
//---- input parameters
extern int FastMAPeriod=12;
extern int SlowMAPeriod=26;
extern int SignalMAPeriod=9;
//---- buffers
double MACDLineBuffer[];
double SignalLineBuffer[];
double HistogramBuffer[];
//---- variables
double alpha = 0;
double alpha_1 = 0;
//+------------------------------------------------------------------+
//| Custom indicator initialization function |
//+------------------------------------------------------------------+
int init()
{
IndicatorDigits(MarketInfo(Symbol(),MODE_DIGITS)+1);
//---- indicators
SetIndexStyle(0,DRAW_LINE);
SetIndexBuffer(0,MACDLineBuffer);
SetIndexDrawBegin(0,SlowMAPeriod);
SetIndexStyle(1,DRAW_LINE,STYLE_DOT);
SetIndexBuffer(1,SignalLineBuffer);
SetIndexDrawBegin(1,SlowMAPeriod+SignalMAPeriod);
SetIndexStyle(2,DRAW_HISTOGRAM);
SetIndexBuffer(2,HistogramBuffer);
SetIndexDrawBegin(2,SlowMAPeriod+SignalMAPeriod);
//---- name for DataWindow and indicator subwindow label
IndicatorShortName("MACD("+FastMAPeriod+","+SlowMAPeriod+","+SignalMAPeriod+")");
SetIndexLabel(0,"MACD");
SetIndexLabel(1,"Signal");
//----
alpha = 2.0 / (SignalMAPeriod + 1.0);
alpha_1 = 1.0 - alpha;
//----
return(0);
}
//+------------------------------------------------------------------+
//| Custom indicator deinitialization function |
//+------------------------------------------------------------------+
int deinit()
{
//----

//----
return(0);
}
//+------------------------------------------------------------------+
//| Custom indicator iteration function |
//+------------------------------------------------------------------+
int start()
{
int limit;
int counted_bars = IndicatorCounted();
//---- check for possible errors
if (counted_bars<0) return(-1);
//---- last counted bar will be recounted
if (counted_bars>0) counted_bars--;
limit = Bars - counted_bars;
for(int i=limit; i>=0; i--)
{
MACDLineBuffer[i] = iMA(NULL,0,FastMAPeriod,0,MODE_EMA,PRICE_CLOSE,i) - iMA(NULL,0,SlowMAPeriod,0,MODE_EMA,PRICE_CLOSE,i);
SignalLineBuffer[i] = alpha*MACDLineBuffer[i] + alpha_1*SignalLineBuffer[i+1];
HistogramBuffer[i] = MACDLineBuffer[i] - SignalLineBuffer[i];
}

//----
return(0);
}
//+------------------------------------------------------------------+

The result of your calculation is out of the price chart range ...

Thanks FerruFx for commenting. Can you be kind enough to suggest what I should delete, add or amend?
Much appreciated.
bobomini

That's the formula which has to be modified.

BTW, if you plot the 2 EMAs (fast and slow) on the chart, you have the histogram 0 line cross.

Hi bobomini,

I'm looking at some other macd code, but by adding "+ Bid" to this line:


some information is off-set from the very bottom of the chart towards the price line.


The size value of the histo bars is at price scale; in pips.

It might be easier to find a custom macd that draws trend lines in the indicator window.
Bring those values at corresponding price points into the chart to draw a copy there.
Has likely been done, because your idea is good ...

Btw, the macd values can be seen in Data Window, no matter what.

apipshort