Example of how to use CiCustom

After some in depth debugging, I realized I've been using CiCustom wrong. The documentation is unclear but by implementation it is now apparent that CiCustom was intended to derive subclasses. Making custom indicator classes is very easy of you use the following pattern. 

1. Inherit CiCustom
2. Make a custom Create method that's applicable to the indicator setup. 
3. Override the Initialize method. 

#include <indicators/custom.mqh>
#include <mqlparams.mqh>

#define INDICATOR_NAME "alexstal_zigzagprof"
#define INITIAL_BUFFER_SIZE 2048

class CiZigZagProf : public CiCustom {
protected:
   virtual bool      Initialize(const string symbol, 
                                const ENUM_TIMEFRAMES period, 
                                const int num_params, 
                                const MqlParam &params[]
                     ) override;  
public:
   virtual bool      Create(string symbol, 
                            ENUM_TIMEFRAMES period, 
                            int zigzag_period, 
                            int min_amplitude = 10, 
                            int min_motion = 0,
                            bool use_smaller_tf = true
                     );                         
   virtual double    upBuffer(int index) { return this.GetData(0, index); }
   virtual double    dnBuffer(int index) { return this.GetData(1, index); }
};
//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
bool CiZigZagProf::Create(  string symbol, 
                            ENUM_TIMEFRAMES tf, 
                            int zigzag_period, 
                            int min_amplitude = 10, 
                            int min_motion = 0,
                            bool use_smaller_tf = true
) {
   // #1 Setup the MQL params array for the custom indicator.
   CMqlParams params;
   params.Set(INDICATOR_NAME, TYPE_STRING)
         .Set(zigzag_period, TYPE_UCHAR)
         .Set(min_amplitude, TYPE_UCHAR)
         .Set(min_motion, TYPE_UCHAR)
         .Set(use_smaller_tf, TYPE_BOOL);
   // #2 Call the parent Create method with the params
   if (!CiCustom::Create(symbol, tf, IND_CUSTOM, params.Total(), params.params))
      return false;
   // #3 Resize the buffer to the desired initial size
   if (!this.BufferResize(INITIAL_BUFFER_SIZE))
      return false;
   return true;
}
//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
bool CiZigZagProf::Initialize(const string symbol, 
                              const ENUM_TIMEFRAMES period, 
                              const int num_params, 
                              const MqlParam &params[]
) {
   // #1 Specify if this indicator redraws
   this.Redrawer(true);
   // #2 Specify the number of indicator buffers to be used. 
   if (!this.NumBuffers(2))
      return false; 
   // #3 Call super.Initialize 
   if (!CiCustom::Initialize(symbol, period, num_params, params))
      return false;
   return true;
}