Users' Knowledge Base

This function was requested on the main list, and was solved with the help of several expert programmers from the list. Thanks guys!

This function can be copied to an include file that is included in each program from which you might want to synchronize the datetime range for all visible windows. The function places a small [R] button at the right top of your chart. Clicking this button will set the datetime ranges of all windows equal to the one you click the button in. Note that this window has to be active for the button to work, i.e., if the window was not active (selected) it will require two clicks for the button to respond.

function RangeAllWindows()
{
    MX = GetCursorXPosition( 1 );
    MY = GetCursorYPosition( 1 );
    LeftClick = GetCursorMouseButtons() == 9;

    // Place Ranging Button
    ButtonSize=20;
    X2 = Status( "pxchartright" )+1;
    X1 = X2 - ButtonSize;
    Y1 = 0;
    Y2 = Y1 + ButtonSize;
    GfxSelectFont( "Tahoma", ButtonSize / 1.5, 800 );
    GfxSelectPen( colorBlack , 1 );
    GfxSelectSolidBrush( colorYellow );
    GfxRectangle( X1, Y1, X2, Y2 );
    GfxSetTextColor( colorBlack );
    GfxSetBkMode( 1 );
    GfxDrawText( "R", X1, Y1, X2, Y2, 41 );
    OnButton = MX >= X1 AND MY >= Y1 AND MX <= X2 AND MY <= Y2;

    if ( OnButton AND LeftClick )
    {
        DT = DateTime();
        BI = BarIndex();
        FirstBarIndex = Status( "firstvisiblebarindex" );
        LastBarIndex = Status( "lastvisiblebarindex" );
        FirstDateTime = LastValue( ValueWhen( FirstBarIndex == BI, DT ) );
        LastDateTime = LastValue( ValueWhen( LastBarIndex == BI, DT ) );
        FirstDateTimestr = DateTimeToStr( FirstDateTime );
        LastDateTimestr = DateTimeToStr( LastDateTime );
        AB = CreateObject( "Broker.Application" );
        docs = AB.Documents;
        Qty = docs.Count;

        for ( i = 0; i < Qty; i++ ) // Range all windows
        {
            doc = docs.Item( i );
            AW = doc.ActiveWindow;
            AW.Activate();
            AW.ZoomToRange( FirstDateTimestr, LastDateTimestr );
            // correct shift due to blank bars
            WSHShell = CreateObject( "WScript.Shell" );
            WSHShell.AppActivate( "AmiBroker" );
            WSHShell.Sendkeys( "{PGDN}" );
        }
    }
}

//Demo Code
RangeAllWindows();
Plot(C,"",1,128);

Filed by Herman at 7:17 am under AFL - Utilities and Functions
Comments Off on Equalize X-Range for all windows

Code developed and kindly donated by Murthy Suresh.

{
    dd_ = StrToNum( StrRight( aaaammdd, 2 ) );    //printf(WriteVal(dd_) + " "  );
    mm_ = StrToNum( StrMid( aaaammdd, 4, 2 ) );    //printf(WriteVal(mm_) + " "  );
    aa_ = StrToNum( StrLeft( aaaammdd, 4 ) );    //printf(WriteVal(aa_) + " " + "\n" );
    Date_Num = ( 10000 * ( aa_ - 1900 ) ) + ( 100 * mm_ ) + dd_;
    RESULT = Date_Num;
    return RESULT;
}

function Time_To_Num( strTime ) // format for time is hh:mm:ss
{
    /*
    //do something to raise alert  if length does not match
    ????PopupWindow("Current time is: " + Now(),"Alert", 2,
    640*mtRandom(), 480*mtRandom());
    */
    hh_t = StrToNum( StrLeft( strTime, 2 ) );    //printf(WriteVal( hh_t ) + " "  );
    mm_t = StrToNum( StrMid( strTime, 3, 2 ) );    //printf(WriteVal( mm_t ) + " "  );
    ss_t = StrToNum( StrRight( strTime, 2 ) );    //printf(WriteVal( ss_t ) + " "  + "\n"  );
    Time_Num = 10000 * hh_t + 100 * mm_t + ss_t;
    RESULT = Time_Num;
    return RESULT;

Filed by Herman at 11:13 pm under AFL - Utilities and Functions,Uncategorized
Comments Off on Date and Time to Number Conversions

By Dennis Brown

The popup window is a great tool in debugging and can help you to keep track of what your code is doing or it can be used to alert you to special situations in your normally running formula. A common problem is that if you call PopupWindow() from a loop or if one gets generated on every AFL pass, you can get hundreds or even thousands of pop-ups piling up on your screen. Tomasz posted a simple work-around on the AmiBroker Feedback Center that took care of the problem in some cases (Suggestion 1528):

The following is a more complete version of this solution that adds a popupID to keep track of each individual popup window and re-enable the popup after its specified timeout period, or if any of the displayed text changes:

function GetSecondNum()
{
    Time = Now( 4 );
    Seconds = int( Time % 100 );
    Minutes = int( Time / 100 % 100 );
    Hours = int( Time / 10000 % 100 );
    SecondNum = int( Hours * 60 * 60 + Minutes * 60 + Seconds );
    return SecondNum;
}

function PopupWindowEx( popupID, bodytext, captiontext, timeout, left, top )
{
    displayText = bodytext + captiontext;
    if ( ( StaticVarGetText( "prevPopup" + popupID ) != displayText) OR ( StaticVarGet( "prevPopupTime" + popupID ) < GetSecondNum() ) )
    {
        StaticVarSetText( "prevPopup" + popupID, displayText);
        StaticVarSet( "prevPopupTime" + popupID, GetSecondNum() + timeout );
        PopupWindow( bodytext, Captiontext + popupID, timeout, Left, top );
    }
}

PopupWindowEx( "ID:1", "testing", "test alert ", 5, -1, -1 );
PopupWindowEx( "ID:2", "testing", "test alert ", 5, 0, 0 );

Filed by Herman at 1:03 pm under AFL - Utilities and Functions,Uncategorized
Comments Off on Popup Window: Preventing pile-ups

When starting up AmiBroker the chart range defaults to the last number of bars set in Preferences. This means that in virtually all cases you have to manually zoom and restore the chart range you were previously working with. This post presents a function that will restore the last used range before you shut down AmiBroker. If you like to use this function routinely, you can copy the functions below to your default #Include file and place this call at the top of your code:

<p>RestoreLastUsedRange();</p>

This function checks the contents of a static variable named “StartUp”+ChartIDStr. This static variable will return a NULL the first time it is called. When this happens, the ZoomToIndex() is called. This function retrieves the last used range for the current chartID from your hard disk and zooms to this range. The Plot() and Title statements are added to help you verify proper operation. You can also uncomment the two _TRACE() commands and start up DebugView for further diagnostic purposes.

If you do not have it yet, be sure to create a folder for the PersistentVariables, as shown at the top of the code. This is where the First and Last Indexes, which point to the start and end of the range being restored, are saved in a small file. You can open these with Notepad to help debugging operations.

//Pay attention to the double slashes in the path line. They need to be there.

// This creates the folder for PersistentPath variables if it doesn't exist
PersistentPath = StaticVarGetText( "~PersistentPath" );

if ( PersistentPath == "" ) // Ensures this folder exists
{
    PersistentPath = "PersistentVariables\\";
    fmkdir( PersistentPath );
    StaticVarSetText( "~PersistentPath", PersistentPath );
}

function PersistentVarGet( VarName )

{
    global PersistentPath;
    fh = fopen( PersistentPath + VarName + ".pva", "r" );

    if ( fh )
    {
        String = fgets( fh );
        fclose( fh );
    }
    else
        string = "";

    Number = StrToNum( String );

    return Number;
}

function PersistentVarSet( VarName, Number )
{
    global PersistentPath;
    String = NumToStr( Number, 1.3, False );
    fh = fopen( PersistentPath + VarName + ".pva", "w" );

    if ( fh )
    {
        fputs( String, fh );
        fclose( fh );
    }

    return fh;
}

procedure ZoomToIndex( FirstBarIndex, LastBarIndex )
{
    DT = DateTime();
    BI = BarIndex();
    FirstDateTime = LastValue( ValueWhen( FirstBarIndex == BI, DT ) );
    LastDateTime = LastValue( ValueWhen( LastBarIndex == BI, DT ) );

    FirstDateTimestr = DateTimeToStr( FirstDateTime );
    LastDateTimestr = DateTimeToStr( LastDateTime );

    AB = CreateObject( "Broker.Application" );
    AW = AB.ActiveWindow;
    AW.ZoomToRange( FirstDateTimestr, LastDateTimestr );
    //_TRACE( FirstDateTimestr +", "+LastDateTimestr );
}

function RestoreLastUsedRange()
{
    if ( Status( "Action" ) == 1 ) // Only perform ranging in an indicator
    {
        // is this a "start-up execution?
        ChartIDStr = NumToStr( GetChartID(), 1.0, False );
        PrevFirstBarIndex = PersistentVarGet( "FirstBarIndex" + ChartIDStr ); // Recall last positions
        PrevLastBarIndex = PersistentVarGet( "LastBarIndex" + ChartIDStr );

        if ( IsNull( StaticVarGet( "StartUp" + ChartIDStr ) ) )
        {
            ZoomToIndex( PrevFirstBarIndex, PrevLastBarIndex );
            StaticVarSet( "StartUp" + ChartIDStr, True );
            //_TRACE( "# StartUp Zoom: CHARTID: " + ChartIDStr + ", PrevFirstBI: " + PrevFirstBarIndex + ", PrevLastBI: " + PrevLastBarIndex );
        }

        // Update zoom range on disk
        FirstBarIndex = Status( "firstvisiblebarindex" );

        LastBarIndex = Status( "lastvisiblebarindex" );

        if ( PrevFirstBarIndex != FirstBarIndex OR PrevLastBarIndex != LastBarIndex )
        {
            PersistentVarSet( "FirstBarIndex" + ChartIDStr, FirstBarIndex );
            PersistentVarSet( "LastBarIndex" + ChartIDStr, LastBarIndex );
            //_TRACE( "# Update Zoom Range: CHARTID: " + ChartIDStr + ", FirstBI: " + FirstBarIndex + ", LastBI: " + LastBarIndex );
        }
    }
}

_SECTION_BEGIN( "RESTORE RANGE" );

if ( ParamTrigger( "Clear all Static Variables", "CLEAR" ) )
    StaticVarRemove( "*" );

Plot( C, "", 1, 128 );

SetBarsRequired( sbrAll, sbrAll );

RestoreLastUsedRange();

Title = "\n" +
        " ChartIDStr: " + NumToStr( GetChartID(), 1.0, False ) + "\n" +
        " FirstIndex: " + Status( "firstvisiblebarindex" ) + "\n" +
        "  LastIndex: " + Status( "Lastvisiblebarindex" ) + "\n" +
        "Selected BI: " + BarIndex();
_SECTION_END();

Edited by Al Venosa.

Filed by Herman at 1:54 pm under AFL - Utilities and Functions
Comments Off on Restore Last Used Range v2

Creating composites is a lot of fun and can provide useful information about market and sector movements. However, when creating many composites, you will sooner or later find that your database is bloated with obsolete composites. The first requirement is to create a function to delete composites. Dingo kindly provided the following example code, which will be used to provide a variety of other useful functions. Note that the functions below can be used to delete both tickers and composites; the procedure is the same. The formula is designed to be run as an indicator but can be adapted to run in a scan, etc.

Filed by Herman at 8:08 pm under Using the AddToComposite()
Comments Off on Deleting Tickers and Composites

The AddToComposite() (ATC) is an extremely powerful function. Topics in this category will not repeat ATC topics covered elsewhere, so be sure to follow the following links for more information and applications:

The AmiBroker AFL Reference: ADDTOCOMPOSITE
Calculating multiple-security statistics with AddToComposite function
Introduction to AddToComposite
Multiple time-frame indicators
Search this users’ Knowledge Base for applications

Also be sure to browse the applications listed at the bottom of the AFL Reference for the ATC.

Filed by Herman at 9:51 pm under Using the AddToComposite()
Comments Off on Introduction to the ATC

This post offers a variety of zoom functions to help you analyze charts better. For example, you can zoom in on the cursor-selected bar, or you can step forward and backward from signal to signal or over custom price conditions. These functions are made possible by the ZoomToRange OLE function, which lets you zoom in on a specific date range.

To exercise and test the functions below, copy and Insert the code to an Indicator pane, open the Param window, and click on various options to see how the functions work. For demo purposes, three zoom events are provided: Buy, Sell, and Mondays. In your own application, you would assign other conditions to the event variable, such as, for example, gaps, price patterns, etc. Stepping from Event to Event would allow you to visually analyze the chart surrounding events. The Param window looks like this:

Zoom Increment is the number of bars added to the display with each zoom in/out action. WindowWidth is the number of bars displayed when jumping from event to event.
The program uses a FocusBar to which zoom dimensions are referenced. Yellow text is attached to the FocusBar on the chart to identify it. You can add other information to this PlotText(). For example, if you were analyzing buy, sell, short, and cover signals, you could add trade prices and indicator values, if you so desired. The Green histogram at the bottom of the chart indicates where the selected events occur. See an example chart below showing buy signals. The green histogram bar occurs just before the green buy arrow on the chart.

Descriptions for the function below are presented ahead of the functions themselves so that you can copy all the code in one step.

ZoomToIndex( FirstBarIndex, LastBarIndex)
Calling the ZoomToIndex() will zoom your chart to display a window ranging from the first argument (FirstBarIndex) to the second argument (LastBarIndex). While you cannot zoom in closer than ten bars using the Zoom In/Out buttons on your AB Toolbar, this function lets you zoom all the way down to a two-bar window. Since most Indicators use periods expressed in bars and not in dates, the function uses the BarIndex to set the window width.

ZoomToCursor( ZoomWidth )
This function lets you zoom in to the cursor position and display the number of bars assigned to ZoomWidth. The values of important variables are displayed in the chart Title for educational purposes.

ZoomOut( ZoomWidth )
This function zooms out by increasing the number of bars displayed by ZoomWidth bars.

ZoomIn( ZoomWidth )
This function zooms in by reducing the number of bars displayed by ZoomWidth bars.

ZoomToNext( Event, ZoomWidth )
This function lets you jump to the next occurrence of a TRUE value in the Event Array. It also focuses on the event with a window of ZoomWidth bars. The most important application for this function would probably be to analyze trades by stepping from signal to signal and to visually inspect custom events or price patterns.

ZoomToPrev( Event, ZoomWidth )
This function is similar to the one above, but it jumps (retreats) to the previous event.

MarkFocus()
This function places the Yellow text at the FocusBar. You may want to customize the text displayed.

ZoomAllOut()
This function zooms out to display all bars in the database.

RightJustifyChart
When trading Real-Time, your signals are generated by prices from the Last Bar whether this bar is visible or not. If, during intense trading, you miss the fact that your Chart is not fully right justified, you may see and hear orders going out while no actions show on your Chart. While such confusion usually doesn’t last long, it could delay discretionary trades and even trick you into thinking there may be a coding problem, causing you to initiate debugging code. This function right-justifies your chart, and if it is triggered at the start of your session, it will prevent you from working with a shifted chart.

procedure ZoomToIndex( FirstBarIndex, LastBarIndex)
{
StaticVarSet("FirstBarIndex",FirstBarIndex);
StaticVarSet("LastBarIndex",LastBarIndex);
DT = DateTime();
BI = BarIndex();
LastDateTime = LastValue(ValueWhen( LastBarIndex == BI, DT ));
FirstDateTime = LastValue(ValueWhen( FirstBarIndex == BI, DT ));
LastDateTimestr = DateTimeToStr( LastDateTime );
FirstDateTimestr = DateTimeToStr( FirstDateTime );
AB = CreateObject("Broker.Application");
AW = AB.ActiveWindow;
AW.ZoomToRange( FirstDateTimestr, LastDateTimestr );
} 

procedure ZoomToCursor( ZoomWidth )
{
local ZoomWidth;
BI = BarIndex();
SBI = SelectedValue(BI);
LBI = LastValue(BI);
CursorIndex= Nz(StaticVarGet("CursorIndex"));
FirstBarIndex = Max(0,SBI - ZoomWidth);
LastBarIndex = Min( LBI, SBI + ZoomWidth );
ZoomToIndex( FirstBarIndex, LastBarIndex);
} 

procedure ZoomOut( ZoomWidth )
{
local ZoomWidth;
BI = BarIndex();
LBI = LastValue(BI);
LastVisiblebar = Status("LastVisibleBar");
FirstVisibleBar= Status("FirstVisibleBar");
FirstBarIndex = Max( 0, FirstVisibleBar - ZoomWidth);
LastBarIndex = Min( LBI, LastVisibleBar + ZoomWidth );
ZoomToIndex( FirstBarIndex, LastBarIndex);
} 

procedure ZoomIn( ZoomWidth )
{
local ZoomWidth;
_TRACE("##");
BI = BarIndex();
LBI = LastValue(BI);
LastVisiblebar = Status("LastVisibleBar");
FirstVisibleBar= Status("FirstVisibleBar");
FirstBarIndex = Max( 0, FirstVisibleBar + ZoomWidth);
LastBarIndex = Min( LBI, LastVisibleBar - ZoomWidth );
ZoomToIndex( FirstBarIndex, LastBarIndex);
} 

procedure ZoomToNext( Event, ZoomWidth )
{
local Event, Zoomwidth;
EventNum = Cum(Event);
BI = BarIndex();
LBI = LastValue(BI);
DT=DateTime();
NextEventNum = Min(Nz(StaticVarGet("EventNumber"))+1, LastValue(EventNum));
NextEventIndex = LastValue(ValueWhen(EventNum == NextEventNum, BI));
StaticVarSet("EventNumber",Max(1, NextEventNum));
FirstBarIndex = Max( 0, NextEventIndex - ZoomWidth );
LastBarIndex = Min( BarCount-1, NextEventIndex + ZoomWidth);
ZoomToIndex( FirstBarIndex, LastBarIndex);
StaticVarSet("FocusIndex",NextEventIndex);
} 

procedure ZoomToPrev(  Event, ZoomWidth )
{
local Event, Zoomwidth;
EventNum = Cum(Event);
BI = BarIndex();
LBI = LastValue(BI);
LastEventNum = LastValue(EventNum);
NextEventNum = Max(1,Nz(StaticVarGet("EventNumber"))-1);
NextEventIndex = LastValue(ValueWhen(EventNum == NextEventNum, BI,1));
StaticVarSet("EventNumber",NextEventNum);
FirstBarIndex = Max( 0, NextEventIndex - ZoomWidth );
LastBarIndex = Min( BarCount-1, NextEventIndex + ZoomWidth);
ZoomToIndex( FirstBarIndex, LastBarIndex);
StaticVarSet("FocusIndex",NextEventIndex);
} 

procedure MarkFocus()
{
global EventNum;
DT=DateTime();
BI = BarIndex();
LBI = LastValue(BI);
FirstBarIndex = Nz(StaticVarGet("FirstBarIndex"));
FocusIndex = Min(LBI,Nz(StaticVarGet("FocusIndex"))+1);
FocusDateStr = NumToStr(DT[FocusIndex],formatDateTime);
ENStr = NumToStr(EventNum[FocusIndex],1.0,False);
PlotText("\n\nFocus\n"+FocusDateStr+"\n"+ENStr,FocusIndex,C[FocusIndex],colorYellow);
} 

procedure ZoomAllOut()
{
BI = BarIndex();
LBI = LastValue(BI);
FirstBarIndex = 0;
LastBarIndex = LBI;
ZoomToIndex( FirstBarIndex, LastBarIndex);
} 

procedure RightJustifyChart( ChartWidth )
{
DT = DateTime();
BI = BarIndex();
FirstDateTime = LastValue( Nz(Ref( DT,-Max(2, ChartWidth) ) ) );
FirstDateTimestr = DateTimeToStr( FirstDateTime );
LastDateTimestr = DateTimeToStr( LastValue(DT) );
AB = CreateObject("Broker.Application");
AW = AB.ActiveWindow;
AW.ZoomToRange( FirstDateTimestr, LastDateTimestr );
} 

SetBarsRequired(1000000,1000000);
GraphXSpace = 20;
_SECTION_BEGIN("ZOOM");
FocusTrigger= ParamTrigger("Focus on Cursor","FOCUS");// zoom out by ZoomIncrement
ZoomInTrigger= ParamTrigger("Zoom in","IN");// zoom in by ZoomIncrement
ZoomOutTrigger= ParamTrigger("Zoom out","OUT");// zoom in by ZoomIncrement
ZoomAllTrigger = ParamTrigger("Zoom max. out","ALL");// zoom out to all bars
ZoomPrevTrigger= ParamTrigger("Go to Next Event","NEXT");// Jump to next event
ZoomNextTrigger= ParamTrigger("Go to Previous Event","PREVIOUS");// Jump to previous event
RJTrigger= ParamTrigger("Right Justify Chart","JUSTIFY");
ZoomIncrement= Param("Zoom Increment",10,1,1000,2);
ZoomWidth= Param("Window Width",20,2,1000,1);
_SECTION_END();
_SECTION_BEGIN("TEST SIGNALS");
ZoomEvent= ParamList("Zoom Event","MONDAY|RSI-BUY|RSI-SELL|TARGET",1);// Test events
ProfitTarget= Param("Profit Target",0.1,0,2,0.01);// Profit target
_SECTION_END(); 

PrevZoomWidth= Nz(StaticVarGet("ZoomWidth"));
ZoomChange= PrevZoomWidth != ZoomWidth; 
StaticVarSet("ZoomWidth",ZoomWidth); 

ZoomAction = FocusTrigger OR ZoomOutTrigger OR ZoomAllTrigger OR ZoomNextTrigger OR ZoomPrevTrigger OR ZoomChange OR ZoomInTrigger OR RJTrigger; 

if( ZoomEvent == "MONDAY" ) Event = DayOfWeek() == 1;
else if( ZoomEvent == "RSI-BUY" ) 
{ 
Event = Cross(30,RSI());// Buy rule to investigate
PlotShapes(IIf(Event,shapeSmallUpTriangle, shapeNone),5,0,C,0);
Sell = 0; 
}
else if( ZoomEvent == "RSI-SELL" ) 
{ 
Event = Cross(RSI(),70);// sell rule to investigate 
PlotShapes(IIf(Event,shapeHollowDownTriangle, shapeNone),4,0,C,0);
Buy = 0; 
}
else if( Zoomevent == "TARGET" ) 
{
Target = Ref(C,1) - C;// Profit target to analyze
Event = Target > ProfitTarget;
PlotShapes(IIf(Event,shapeSmallUpTriangle, shapeNone),5,0,C,0);
}
else Event = 0; 

Plot(C,"",1,128);
EventNum = Cum(Event);
FVBI = Status("FirstVisibleBarIndex");
LVBI = Status("LastVisibleBarIndex");
BI = BarIndex();
SBI = SelectedValue(BI);
LBI = LastValue(BI); 

FirstVisibleBar = Status( "FirstVisibleBar" );
Lastvisiblebar = Status("LastVisibleBar");
for( b = Firstvisiblebar; b < Lastvisiblebar AND b < BarCount; b++)
{
if( Event[b] ) PlotText("\n\n\n\nEvent\n"+NumToStr(EventNum[b],1.0,False),b,L[b],1);
} 

if( GetCursorMouseButtons() == 1 ) 
{
StaticVarSet("CursorIndex",SBI);
EventNum = Cum(Event);
StaticVarSet("EventNumber",SelectedValue(EventNum));
StaticVarSet("FocusIndex",SBI-1);
}
CursorIndex= Nz(StaticVarGet("CursorIndex")); 

if( ZoomAction )
{
CurrentRange= LastVisiblebar-FirstVisibleBar;
VisibleCenter= int((LastVisibleBar + FirstVisibleBar)/2);
PrevEventIndex = LastValue(ValueWhen(Event,BI,1));
NextEventIndex = LastValue(ValueWhen(Event,BI,-1));
FirstBarIndex = Nz(StaticVarGet("FirstBarIndex"));
LastBarIndex = Nz(StaticVarGet("LastBarIndex")); 

if( FocusTrigger) ZoomToCursor( ZoomWidth );
else if( ZoomInTrigger ) ZoomIn( ZoomWidth );
else if( ZoomOutTrigger ) ZoomOut( ZoomWidth );
else if( ZoomNextTrigger ) ZoomToPrev( Event, ZoomWidth );
else if( ZoomPrevTrigger ) ZoomToNext( Event, ZoomWidth );
else if( ZoomAllTrigger ) ZoomAllOut();
else if( RJTrigger ) RightJustifyChart( ZoomWidth );
} 

MArkFocus(); 

Plot(Event,"",5,styleArea|styleOwnScale|styleNoLabel,0,10);
CursorIndex = StaticVarGet("CursorIndex");
EventNumber= StaticVarGet("EventNumber");
Title = "\n"+
"Cursor Index: "+NumToStr(CursorIndex,1.0,False)+"\n"+
"EventNumber: "+NumToStr(EventNumber,1.0,False)+"\n";

Edited by Al Venosa

Filed by Herman at 10:07 pm under AFL - Utilities and Functions
Comments Off on Zoom-to-Range Applications

A useful application is to plot straight lines between entry- and exit-signals, giving you the ability to view at a glance the location and magnitude of profits and losses of your trading system. The LineArray() function enables you to draw straight lines from one event or condition to another. In the chart below, which shows a reversal trading system, note how the lines begin and end at the exact trade prices, green being long and red being short. This gives you a quick impression of the profitability and location of individual trades:

Other applications would be plotting of custom ZigZag lines, price channels, trendlines, breakouts, etc.

There are two afl versions listed below, since I believe many of us use the first method, I decided to show them both for educational purposes.

The first one shows how you should NOT plot LineArrays. This method calls Plot() repeatedly and plots each LineArray segment as it is calculated. This is very resource consuming (executes slow) and may trigger a Warning 502 when you display a lot of data. Do not use this version.

The second version shows how Tomasz (Thanks TJ!) combined the individual LineArray segments inside the loop and then plots them with a single Plot() statement outside the loop. This code executes much faster and will never trigger Warning 502. The technique is simple but shows a clever way to combine array segments. Study it :-) it will come in handy one day!

// This version is only listed to show you how it should NOT be programmed
// Dummy system to generate some signals
Buy = Cross( MACD(), Signal() );
BuyPrice = Open;     // Substitute your own prices
Sell = Cross( Signal(), MACD() );
SellPrice = Close;     // Substitute your own prices
PlotShapes( IIf( Buy, shapeSmallUpTriangle, shapeNone ), colorBrightGreen, 0, BuyPrice, 0 );
PlotShapes( IIf( Sell, shapeSmallDownTriangle, shapeNone ), colorRed, 0, SellPrice, 0 );
Plot( C, "", 1, 128 );
// Plot the Trade Lines
Sig = Buy OR Sell;
y0 = 0;
y1 = C[0];
TPrice = C;
FirstVisibleBar = Status( "FirstVisibleBar" );
Lastvisiblebar = Status( "LastVisibleBar" );

for ( b = Firstvisiblebar; b <= Lastvisiblebar AND b < BarCount; b++ )
{
    if ( Buy[b] )
    {
        Co = colorRed;
        TPrice[b] = BuyPrice[b];
    }

    if ( Sell[b] )
    {
        Co = colorBrightGreen;
        TPrice[b] = SellPrice[b];
    }

    if ( Sig[b] )
    {
        x0 = y0;
        x1 = y1;
        y0 = b;
        y1 = TPrice[b];
        Plot( LineArray( x0, x1, y0, y1 ), "", Co, 1 );
    }
}

// Improved version
// Dummy system to generate some signals
Buy = Cross( MACD(), Signal() );
BuyPrice = O; // Substitute your own prices
Sell = Cross( Signal(), MACD() );
SellPrice = C; // Substitute your own prices
PlotShapes( IIf( Buy, shapeUpTriangle, shapeNone ), colorBrightGreen, 0, BuyPrice, 0 );
PlotShapes( IIf( Sell, shapeDownTriangle, shapeNone ), colorRed, 0, SellPrice, 0 );
Plot( C, "", 1, 128 );

// Plot the Trade Lines
Sig = Buy OR Sell;
y0 = 0;
y1 = C[0];
FirstVisibleBar = Status( "FirstVisibleBar" );
Lastvisiblebar = Status( "LastVisibleBar" );
CombinedColor = colorWhite;
CombinedLine = Null;

for ( b = Firstvisiblebar; b <= Lastvisiblebar AND b < BarCount; b++ )
{

    if ( Buy[b] )
    {
        Co = colorRed;
        TPrice[b] = BuyPrice[b];
    }
    else if ( Sell[b] )
    {
        Co = colorBrightGreen;
        TPrice[b] = SellPrice[b];
    }

    if ( Sig[b] )

    {

        x0 = y0;

        x1 = y1;

        y0 = b;

        y1 = TPrice[b];

        La = LineArray( x0, x1, y0, y1 );

        CombinedLine = IIf( IsNull( la ), CombinedLine, la );
        CombinedColor = IIf( IsNull( La ), CombinedColor, Co );
    }
}

Plot( CombinedLine, "", CombinedColor );

Edited by Al Venosa

Filed by Herman at 9:27 pm under AFL - Utilities and Functions
Comments Off on Plotting Trade-Lines