Size of candles (text) - indicator for MetaTrader 5

About synchronization of bars and graphical objects.

Graphical objects accounting

The names of objects are stored in the m_arr_names[] array, its size is equal to the InpNumberOfBars input. Why do we use an array instead of a simple string variable? This is a kind of reserve for the future.

Forming an object name

The name of the object corresponding to the 'index' bar is formed by the following formula:

name[index] = m_prefix + ("high_" or "low_") + TimeToString(time[index])

When you need to delete all objects

Indicators are unloaded in the following cases:

• removing the indicator form the chart;
• closing the terminal (if the indicator was running on the chart);
• loading a template, if the indicator is running on this chart;
• closing the chart on which the indicator was running;
• changing the profile, if the indicator is running on one of the charts of the previous profile;
• changing the symbol and/or timeframe of the chart, on which the indicator is running;
• changing the indicator inputs.

Therefore, we completely delete created graphical objects:

• in OnDeinit()
• in OnInit() (this is just in case, if there are undeleted orphan objects)
• in OnCalculate(), when prev_calculated==0.

Maintaining a constant number of graphical objects:

when a new bar (bars) appears, the prev_calculated!=rates_total condition triggers. In this case, all objects are deleted, and the m_arr_names[] array is cleared.