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Chart Price Max/Min

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Does anyone know how mt4 calculates CHART_PRICE_MAX and CHART_PRICE_MIN ?
Pre-build 600

WindowPriceMax

Returns the maximal value of the vertical scale of the specified subwindow of the current chart

Chart Operations

WindowPriceMin

Returns the minimal value of the vertical scale of the specified subwindow of the current chart

Chart Operations

List of MQL4 Functions - MQL4 Reference

Post-build 600

CHART_PRICE_MAX

Chart maximum

ChartSetDouble, ChartGetDouble

CHART_PRICE_MIN

Chart minimum

ChartSetDouble, ChartGetDouble

List of MQL4 Constants - MQL4 Reference

                                                         #define WINDOW_MAIN 0
void     GetChartLimits(int&iLeft, int&iRight, double&top, double&bot,int iW=0){
      /* MT4 build 445: In the tester (visual mode,) on the first tick, these
       * routines return left=100, right=37 (depends on default bar scaling.)
       * This is what the chart looks like when you maximize it while it is
       * generating the FXT file. On ticks after that, it appears like the
       * left/right are correct but the hi/lo are one tick behind the displayed
       * chart. On the start of a new bar, the hi/lo can be off when a recent
       * extreme drops off but the scale hasn't resized. I tried calling
       * WindowRedraw() first but that did not change results. I don't know
       * about live charts.                                                   */
   top      = WindowPriceMax(iW);   iLeft    = WindowFirstVisibleBar();
   bot      = WindowPriceMin(iW);   iRight   = iLeft-WindowBarsPerChart();
   if(top-bot < pips2dbl)  top    = bot+pips2dbl;     // Avoid scroll bug / div0
   if(iRight < 0)          iRight = 0;                // Chart is shifted.
}  // GetChartLimits
////////////////////////////////////////////////////////////////////////////////
int iLeft,iRight; double top,bot;   GetChartLimits(iLeft, iRight, top, bot);
whroeder1:
Pre-build 600 Post-build 600
Thank you for the reply. It's easier to get the data from the tester than what I had intended to do.

Hi, thanks for the previous answer. How do we get the maximum and minimum prices of a second chart, not the chart on which the EA is run? E.g.:

   long first_chart  = ChartID();
   long second_chart = ChartOpen("EURUSD", PERIOD_H1);
   
   // 1st style of function call for ChartGetDouble()
   Print(ChartGetDouble(first_chart, CHART_PRICE_MIN), " ", ChartGetDouble(first_chart, CHART_PRICE_MAX)); // prints correct values
   ChartSetInteger(second_chart,CHART_BRING_TO_TOP,0,true); // doesn't make a difference
   Print(ChartGetDouble(second_chart, CHART_PRICE_MIN), " ", ChartGetDouble(second_chart, CHART_PRICE_MAX)); // prints 0 0 

   // 2nd style of function call for ChartGetDouble()
   double p; Print(ChartGetDouble(second_chart, CHART_PRICE_MAX, 0, p)); Print(p); // prints 1 (successful data retrieval) then 0
   
   // Checking chart IDs
   Print(first_chart, " ", second_chart);
   Print(ChartID()); // despite bringing 2nd chart to the top, the 1st chart is still selected

I try to open a second chart and print its maximum and minimum prices but see 0s. I also try the second style of function call but still see a 0. Maybe my call syntax is incorrect?

It feels like the second chart isn't somehow selected, hence my attempt to bring it to the top, but ChartID() remains attached to the first chart.

Navvy1846 #: Maybe my call syntax is incorrect?

No. The compiler already told you that when it succeeded.

It takes time to open a chart. You are not waiting for the chart to open.

Fantastic, thanks! I added a Sleep(0.1*1000); statement and it works now.
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