how to create script to draw a trend line

William Roeder 2011.06.18 12:22 #1

void TLine( string name, datetime T0, double P0, datetime T1, double P1
          , color clr, bool ray=false ){                #define WINDOW_MAIN 0
    if (!Show.Objects)  return;
    /**/ if(ObjectMove( name, 0, T0, P0 ))      ObjectMove(name, 1, T1, P1);
    else if(!ObjectCreate( name, OBJ_TREND, WINDOW_MAIN, T0, P0, T1, P1 ))
        Alert("ObjectCreate(",name,",TREND) failed: ", GetLastError() );
    else if (!ObjectSet( name, OBJPROP_RAY, ray ))
        Alert("ObjectSet(", name, ",Ray) failed: ", GetLastError());
    if (!ObjectSet(name, OBJPROP_COLOR, clr )) // Allow color change
        Alert("ObjectSet(", name, ",Color) [2] failed: ", GetLastError());
    string  P0t = PriceToStr(P0);           if (MathAbs(P0 - P1) >= Point)
            P0t = StringConcatenate(P0t, " to ", PriceToStr(P1));
    if (!ObjectSetText(name, P0t, 10))
        Alert("ObjectSetText(",name,") [2] failed: ", GetLastError());
}
void HLine(string name, double P0, color clr){  //      #define WINDOW_MAIN 0
    if (!Show.Objects)  return;
    /**/ if (ObjectMove( name, 0, Time[0], P0 )){}
    else if(!ObjectCreate( name, OBJ_HLINE, WINDOW_MAIN, Time[0], P0 ))
        Alert("ObjectCreate(",name,",HLINE) failed: ", GetLastError() );
    if (!ObjectSet(name, OBJPROP_COLOR, clr )) // Allow color change
        Alert("ObjectSet(", name, ",Color) [1] failed: ", GetLastError() );
    if (!ObjectSetText(name, PriceToStr(P0), 10))
        Alert("ObjectSetText(",name,") [1] failed: ", GetLastError());
}
string  PriceToStr(double p){
    string pFrc = DoubleToStr(p, Digits);       if(Digits.pips==0) return(pFrc);
    string pPip = DoubleToStr(p, Digits-1);
    if (pPip+"0" == pFrc)       return(pPip);           return(pFrc);          }
//++++ These are adjusted for 5 digit brokers.
int     pips2points;    // slippage  3 pips    3=points    30=points
double  pips2dbl;       // Stoploss 15 pips    0.0015      0.00150
int     Digits.pips;    // DoubleToStr(dbl/pips2dbl, Digits.pips)
int     init(){
    if (Digits == 5 || Digits == 3){    // Adjust for five (5) digit brokers.
                pips2dbl    = Point*10; pips2points = 10;   Digits.pips = 1;
    } else {    pips2dbl    = Point;    pips2points =  1;   Digits.pips = 0; }
    // OrderSend(... Slippage.Pips * pips2points, Bid - StopLossPips * pips2dbl

[Deleted] 2011.06.19 11:26 #2

Thanks WHRoeder much, but when compile, I got the error "Show.Objects" and "Digits.pips" not defined. Is it a seperate library or in another code file

William Roeder 2011.06.19 14:11 #3

tuanha:
Thanks WHRoeder much, but when compile, I got the error "Show.Objects" and "Digits.pips" not defined. Is it a seperate library or in another code file

When in doubt, THINK

Digits.pips was defined just above the init()

The show.objects was an external and init() also contained

    if (IsTesting() && !IsVisualMode()){    Show.Comments   = false;
                                            Show.Objects    = false;    }

[Deleted] 2011.06.20 11:05 #4

WHRoeder:
When in doubt, THINK

Digits.pips was defined just above the init()
The show.objects was an external and init() also contained

This is entire my code, I still not know why it not display the price. Please correct if I wrong.

"

//+------------------------------------------------------------------+
//| Price display.mq4 |
//| Copyright © 2009, MetaQuotes Software Corp. |
//| http://www.metaquotes.net |
//+------------------------------------------------------------------+
#property copyright "Copyright © 2009, MetaQuotes Software Corp."
#property link "http://www.metaquotes.net"
double HiPrice, LoPrice, Range;
datetime StartTime;
string Trendline;
int pips2points; // slippage 3 pips 3=points 30=points
double pips2dbl; // Stoploss 15 pips 0.0015 0.00150
int Digits.pips; // DoubleToStr(dbl/pips2dbl, Digits.pips)
extern bool Show.Objects = true;
extern bool Show.Comments = true ;

#define WINDOW_MAIN 0

void TLine( string name, datetime T0, double P0, datetime T1, double P1, color clr, bool ray=false )
{

if (!Show.Objects) return;
/**/ if(ObjectMove( name, 0, T0, P0 )) ObjectMove(name, 1, T1, P1);
else if(!ObjectCreate( name, OBJ_TREND, WINDOW_MAIN, T0, P0, T1, P1 ))
Alert("ObjectCreate(",name,",TREND) failed: ", GetLastError() );
else if (!ObjectSet( name, OBJPROP_RAY, ray ))
Alert("ObjectSet(", name, ",Ray) failed: ", GetLastError());
if (!ObjectSet(name, OBJPROP_COLOR, clr )) // Allow color change
Alert("ObjectSet(", name, ",Color) [2] failed: ", GetLastError());
string P0t = PriceToStr(P0); if (MathAbs(P0 - P1) >= Point)
P0t = StringConcatenate(P0t, " to ", PriceToStr(P1));
if (!ObjectSetText(name, P0t, 10))
Alert("ObjectSetText(",name,") [2] failed: ", GetLastError());
}

void HLine(string name, double P0, color clr)
{
if (!Show.Objects) return;
/**/ if (ObjectMove( name, 0, Time[0], P0 )){}
else if(!ObjectCreate( name, OBJ_HLINE, WINDOW_MAIN, Time[0], P0 ))
Alert("ObjectCreate(",name,",HLINE) failed: ", GetLastError() );
if (!ObjectSet(name, OBJPROP_COLOR, clr )) // Allow color change
Alert("ObjectSet(", name, ",Color) [1] failed: ", GetLastError() );
if (!ObjectSetText(name, PriceToStr(P0), 10))
Alert("ObjectSetText(",name,") [1] failed: ", GetLastError());
}

string PriceToStr(double p)
{
string pFrc = DoubleToStr(p, Digits);
if(Digits.pips==0) return(pFrc);
string pPip = DoubleToStr(p, Digits-1);
if (pPip+"0" == pFrc) return(pPip);
return(pFrc);
}
//++++ These are adjusted for 5 digit brokers.

int init()
{
if (Digits == 5 || Digits == 3)
{
// Adjust for five (5) digit brokers.
pips2dbl = Point*10;
pips2points = 10;
Digits.pips = 1;
}
else
{
pips2dbl = Point;
pips2points = 1;
Digits.pips = 0;
}

int shift = iBarShift(NULL, 0,Time[0])+1;
HiPrice = iHigh(NULL, 0,shift);
LoPrice = iLow(NULL, 0,shift);
StartTime = iTime(NULL, 0,shift);

TLine("name 123", StartTime, HiPrice, StartTime, LoPrice, MediumSlateBlue, false );
}
//+------------------------------------------------------------------+

"

Many thanks WHRoeder.This is my first script, why not use "ShowObjects" and "ShowComments" instead of "Show.Objects" ? Is there any profits from there ?

Posting code snippets in Arrows and Alert not MA EA - problems

William Roeder 2011.06.20 12:55 #5

int shift = iBarShift(NULL, 0,Time[0])+1;  // Equivalent to shift    =1
HiPrice = iHigh(NULL, 0,shift);            // Equivalent to HiPrice  =High[1]
LoPrice = iLow(NULL, 0,shift);             // Equivalent to LoPrice  = Low[1]
StartTime = iTime(NULL, 0,shift);          // Equivalent to StartTime=Time[1]
TLine("name 123", StartTime, HiPrice, StartTime, LoPrice, MediumSlateBlue, false );

I don't know why you're using those calls instead of the simpler equivalent code. Same startTime would be a vertical line and MT doesn't show it. Start time/end time must be different. Try just

TLine("name", Time[1], High[1], Time[0], Low[1], MediumSlateBlue);

why not use "ShowObjects" and "ShowComments" instead of "Show.Objects" ? Is there any profits from there ?
Show.Objects, Show_Objects, and ShowObjects are just variable names, programmer's choice. My pattern:
Capitalized.Capitalized
Externals (Read Only)

lowerCase.lowerCase
Global variables (shared among several functions)

lowerCaseNoDots
Function variables

ALL_CAPITALS #define's

and I group related items by the first part of the name, e.g. color Color.SL, Color.TP, Color.Open

Capitalized.Capitalized	Externals (Read Only)
lowerCase.lowerCase	Global variables (shared among several functions)
lowerCaseNoDots	Function variables
ALL_CAPITALS	#define's

Question about partially close open order at new [Archive!] Any rookie question,

[Deleted] 2011.06.23 06:33 #6

I already modified as your instruction, it displayed the trendline on screen but still not displayed the text near top and bottom of trendline. And when I move the trendline, it still not update/display the value at both end of trend line.

Is it possible to program the trendline like this ?

This is the same Indicators with alerts/signal Trendline tool, bug or