How to get price at trend line already drawn as price moves?

[Kaone01]

Hi Everyone,

I have a trendline that is already drawn moving upward on chart. I need to get the price value for this trendline for the current candle time as candles get formed going forward.

How can I programmatically get the value on the trend line for my current candle time?

ObjectGetValueByShift didn't work as it gave the same result as below:

The mq4 code below seems to only give me price for when the trendline was created, but it keeps on giving me the same value on every candle going forward.  I expect the value to increase because my trendline is upward, I need just the value price on that trendline for the latest candle time as price moves.

double dTrendlinePrice = ObjectGetValueByShift("TrendlineName", 0);

Thanks in advance 

[Stanislav Korotky]

A slightly MT4-ish code is as follows (it's taken from my article which is not yet translated into English):

double getCurrentPrice(const string name)
{
  int type = (int)ObjectGetInteger(0, name, OBJPROP_TYPE);
  if(type == OBJ_TREND)
  {
    datetime dt1 = (datetime)ObjectGetInteger(0, name, OBJPROP_TIME, 0);
    datetime dt2 = (datetime)ObjectGetInteger(0, name, OBJPROP_TIME, 1);
    int i1 = iBarShift(NULL, 0, dt1, true);
    int i2 = iBarShift(NULL, 0, dt2, true);
    if(i1 <= i2 || i1 == -1 || i2 == -1)
    {
      Print("Incorrect line: ", name);
      return 0;
    }
    double p1 = ObjectGetDouble(0, name, OBJPROP_PRICE, 0);
    double p2 = ObjectGetDouble(0, name, OBJPROP_PRICE, 1);
        
    double k = -(p1 - p2)/(i2 - i1);
    double b = -(i1 * p2 - i2 * p1)/(i2 - i1);
        
    return b;
  }
  //...
}

The line should have direction (ray) into the future.

[Kaone01]

Stanislav Korotky:

A slightly MT4-ish code is as follows (it's taken from my article which is not yet translated into English):

The line should have direction (ray) into the future.

Thanks Stanislav, the line does have Ray checked into the future, but the function getCurrentPrice(...) returns 0 and the error seems to be "Incorrect line: "

I tried to print more before that condition and below are the values for i1 and i2:

getCurrentPrice i1[-1] i2[0]

Any idea why I get that?

[Kaone01]

Thanks a lot Stanislav, 

I have changed the exact to give the nearest value if the bar is invalid, thus set parameters as follows iBarShift(NULL, 0, dt1, false)and that worked perfect.

[Stanislav Korotky]

Kaone01:

Thanks Stanislav, the line does have Ray checked into the future, but the function getCurrentPrice(...) returns 0 and the error seems to be "Incorrect line: "

I tried to print more before that condition and below are the values for i1 and i2:

getCurrentPrice i1[-1] i2[0]

Any idea why I get that?

A line can be treated as incorrect only in 2 cases:

- if it's drawn in wrong direction from future to past (from the right to the left), whereas it should go from the left to the right;

- the end point of the line is in future (non existing yet bar);