12 KiB
12 KiB
DRAW_BARS
The DRAW_BARS style draws bars on the values of four indicator buffers, which contain the Open, High, Low and Close prices. It is used for creating custom indicators as bars, including those in a separate subwindow of a chart and on other financial instruments.
The color of bars can be set using the compiler directives or dynamically using the PlotIndexSetInteger() function. Dynamic changes of the plotting properties allows "to enliven" indicators, so that their appearance changes depending on the current situation.
The indicator is drawn only to those bars, for which non-empty values of all four indicator buffers are set. To specify what value should be considered as "empty", set this value in the PLOT_EMPTY_VALUE property:
//--- The 0 (empty) value will mot participate in drawing
PlotIndexSetDouble(index_of_plot_DRAW_BARS,PLOT_EMPTY_VALUE,0);
Always explicitly fill in the values of the indicator buffers, set an empty value in a buffer to skip bars.
The number of required buffers for plotting DRAW_BARS is 4. All buffers for the plotting should go one after the other in the given order: Open, High, Low and Close. None of the buffers can contain only empty values, since in this case nothing is plotted.
An example of the indicator that draws bars on a selected financial instrument in a separate window. The color of bars changes randomly every N ticks. The N parameter is set in external parameters of the indicator for the possibility of manual configuration (the Parameters tab in the indicator's Properties window).
Please note that for plot1 with the DRAW_BARS style, the color is set using the compiler directive #property, and then in the OnCalculate() function the color is set randomly from an earlier prepared list.
//+------------------------------------------------------------------+
//| DRAW_BARS.mq5 |
//| Copyright 2011, MetaQuotes Software Corp. |
//| https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2000-2024, MetaQuotes Ltd."
#property link "https://www.mql5.com"
#property version "1.00"
#property description "An indicator to demonstrate DRAW_BARS"
#property description "It draws bars of a selected symbol in a separate window"
#property description "The color and width of bars, as well as the symbol are changed randomly"
#property description "every N ticks"
#property indicator_separate_window
#property indicator_buffers 4
#property indicator_plots 1
//--- plot Bars
#property indicator_label1 "Bars"
#property indicator_type1 DRAW_BARS
#property indicator_color1 clrGreen
#property indicator_style1 STYLE_SOLID
#property indicator_width1 1
//--- input parameters
input int N=5; // The number of ticks to change the type
input int bars=500; // The number of bars to show
input bool messages=false; // Show messages in the "Expert Advisors" log
//--- Indicator buffers
double BarsBuffer1[];
double BarsBuffer2[];
double BarsBuffer3[];
double BarsBuffer4[];
//--- Symbol name
string symbol;
//--- An array to store colors
color colors[]={clrRed,clrBlue,clrGreen,clrPurple,clrBrown,clrIndianRed};
//+------------------------------------------------------------------+
//| Custom indicator initialization function |
//+------------------------------------------------------------------+
int OnInit()
{
//--- If bars is very small - complete the work ahead of time
if(bars<50)
{
Comment("Please specify a larger number of bars! The operation of the indicator has been terminated");
return(INIT_PARAMETERS_INCORRECT);
}
//--- indicator buffers mapping
SetIndexBuffer(0,BarsBuffer1,INDICATOR_DATA);
SetIndexBuffer(1,BarsBuffer2,INDICATOR_DATA);
SetIndexBuffer(2,BarsBuffer3,INDICATOR_DATA);
SetIndexBuffer(3,BarsBuffer4,INDICATOR_DATA);
//--- The name of the symbol, for which the bars are drawn
symbol=_Symbol;
//--- Set the display of the symbol
PlotIndexSetString(0,PLOT_LABEL,symbol+" Open;"+symbol+" High;"+symbol+" Low;"+symbol+" Close");
IndicatorSetString(INDICATOR_SHORTNAME,"DRAW_BARS("+symbol+")");
//--- An empty value
PlotIndexSetDouble(0,PLOT_EMPTY_VALUE,0.0);
//---
return(INIT_SUCCEEDED);
}
//+------------------------------------------------------------------+
//| Custom indicator iteration function |
//+------------------------------------------------------------------+
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[])
{
static int ticks=0;
//--- Calculate ticks to change the style, color and width of the line
ticks++;
//--- If a sufficient number of ticks has been accumulated
if(ticks>=N)
{
//--- Select a new symbol from the Market watch window
symbol=GetRandomSymbolName();
//--- Change the line properties
ChangeLineAppearance();
int tries=0;
//--- Make 5 attempts to fill in the buffers with the prices from symbol
while(!CopyFromSymbolToBuffers(symbol,rates_total) && tries<5)
{
//--- A counter of calls of the CopyFromSymbolToBuffers() function
tries++;
}
//--- Reset the counter of ticks to zero
ticks=0;
}
//--- return value of prev_calculated for next call
return(rates_total);
}
//+------------------------------------------------------------------+
//| Fill in the indicator buffers with prices |
//+------------------------------------------------------------------+
bool CopyFromSymbolToBuffers(string name,int total)
{
//--- In the rates[] array, we will copy Open, High, Low and Close
MqlRates rates[];
//--- The counter of attempts
int attempts=0;
//--- How much has been copied
int copied=0;
//--- Make 25 attempts to get a timeseries on the desired symbol
while(attempts<25 && (copied=CopyRates(name,_Period,0,bars,rates))<0)
{
Sleep(100);
attempts++;
if(messages) PrintFormat("%s CopyRates(%s) attempts=%d",__FUNCTION__,name,attempts);
}
//--- If failed to copy a sufficient number of bars
if(copied!=bars)
{
//--- Form a message string
string comm=StringFormat("For the symbol %s, managed to receive only %d bars of %d requested ones",
name,
copied,
bars
);
//--- Show a message in a comment in the main chart window
Comment(comm);
//--- Show the message
if(messages) Print(comm);
return(false);
}
else
{
//--- Set the display of the symbol
PlotIndexSetString(0,PLOT_LABEL,name+" Open;"+name+" High;"+name+" Low;"+name+" Close");
IndicatorSetString(INDICATOR_SHORTNAME,"DRAW_BARS("+name+")");
}
//--- Initialize buffers with empty values
ArrayInitialize(BarsBuffer1,0.0);
ArrayInitialize(BarsBuffer2,0.0);
ArrayInitialize(BarsBuffer3,0.0);
ArrayInitialize(BarsBuffer4,0.0);
//--- Copy prices to the buffers
for(int i=0;i<copied;i++)
{
//--- Calculate the appropriate index for the buffers
int buffer_index=total-copied+i;
//--- Write the prices to the buffers
BarsBuffer1[buffer_index]=rates[i].open;
BarsBuffer2[buffer_index]=rates[i].high;
BarsBuffer3[buffer_index]=rates[i].low;
BarsBuffer4[buffer_index]=rates[i].close;
}
return(true);
}
//+------------------------------------------------------------------+
//| Randomly returns a symbol from the Market Watch |
//+------------------------------------------------------------------+
string GetRandomSymbolName()
{
//--- The number of symbols shown in the Market watch window
int symbols=SymbolsTotal(true);
//--- The position of a symbol in the list - a random number from 0 to symbols
int number=MathRand()%symbols;
//--- Return the name of a symbol at the specified position
return SymbolName(number,true);
}
//+------------------------------------------------------------------+
//| Changes the appearance of bars |
//+------------------------------------------------------------------+
void ChangeLineAppearance()
{
//--- A string for the formation of information about the bar properties
string comm="";
//--- A block for changing the color of bars
int number=MathRand(); // Get a random number
//--- The divisor is equal to the size of the colors[] array
int size=ArraySize(colors);
//--- Get the index to select a new color as the remainder of integer division
int color_index=number%size;
//--- Set the color as the PLOT_LINE_COLOR property
PlotIndexSetInteger(0,PLOT_LINE_COLOR,colors[color_index]);
//--- Write the line color
comm=comm+"\r\n"+(string)colors[color_index];
//--- A block for changing the width of bars
number=MathRand();
//--- Get the width of the remainder of integer division
int width=number%5; // The width is set from 0 to 4
//--- Set the color as the PLOT_LINE_WIDTH property
PlotIndexSetInteger(0,PLOT_LINE_WIDTH,width);
//--- Write the line width
comm=comm+"\r\nWidth="+IntegerToString(width);
//--- Write the symbol name
comm="\r\n"+symbol+comm;
//--- Show the information on the chart using a comment
Comment(comm);
}