Extending trandlines to right or left

Yes, it's possible. Pay attention to object property OBJPROP_RAY for OBJ_TREND.

Thanks Roger. I tried that and it worked for extending the line to the right but NOT to the left.
Thanks for your reply.

ForexWatchman

Hi, ForexWatchman,

this shouldn't be too hard. I actually wrote down this idea, assuming that value and time 1 are on the left and value and time 2 are the right coordinates of the trendline...

extern int ExtensionLeft;
extern int ExtensionRight;

int TrendlineModify(string Name)
   {
   int      BarPeriod=Period
   double   Value1=ObjectGet(Name, OBJPROP_PRICE1);
   double   Value2=ObjectGet(Name, OBJPROP_PRICE2);
   datetime Time1=ObjectGet(Name, OBJPROP_TIME1);
   datetime Time2=ObjectGet(Name, OBJPROP_TIME2);
   
   double Delta=(Value2-Value1)/(((Time2-Time1)/60)/Barperiod);
   
   double   NewValue1=Value1-Delta*ExtensionLeft;
   double   NewValue2=Value2+Delta*ExtensionRight;
   
   datetime TimeNew1=Time1-(BarPeriod*60)*ExtensionLeft;
   datetime TimeNew2=Time2+(BarPeriod*60)*ExtensionRight;
   
   ObjectDelete(Name);
   ObjectCreate(Name,OBJ_TREND,0,TimeNew1,NewValue1,TimeNew2,NewValue2);
   }

I do not guarantee that this works, but this might be an idea to build further ones on. Anyway I am not shure if the datetime values are really expressed in seconds from 1970...which in case I am wrong make calculations more complex...