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Drawing Styles

When creating a custom indicator, you can specify one of 18 types of graphical plotting (as displayed in the main chart window or a chart subwindow), whose values are specified in the ENUM_DRAW_TYPE enumeration.

In one custom indicator, it is permissible to use any indicator building/drawing types. Each construction type requires specification of one to five global arrays for storing data necessary for drawing. These data arrays must be bound with indicator buffers using the SetIndexBuffer() function. The type of data from ENUM_INDEXBUFFER_TYPE should be specified for each buffer.

Depending on the drawing style, you may need one to four value buffers (marked as INDICATOR_DATA). If a style admits dynamic alternation of colors (all styles contain COLOR in their names), then you'll need one more buffer of color (indicated type INDICATOR_COLOR_INDEX). The color buffers are always bound after value buffers corresponding to the style.

ENUM_DRAW_TYPE

ID

Description

Data buffers

Color buffers

DRAW_NONE

Not drawn

1

0

DRAW_LINE

Line

1

0

DRAW_SECTION

Section

1

0

DRAW_HISTOGRAM

Histogram from the zero line

1

0

DRAW_HISTOGRAM2

Histogram of the two indicator buffers

2

0

DRAW_ARROW

Drawing arrows

1

0

DRAW_ZIGZAG

Style Zigzag allows vertical section on the bar

2

0

DRAW_FILLING

Color fill between the two levels

2

0

DRAW_BARS

Display as a sequence of bars

4

0

DRAW_CANDLES

Display as a sequence of candlesticks

4

0

DRAW_COLOR_LINE

Multicolored line

1

1

DRAW_COLOR_SECTION

Multicolored section

1

1

DRAW_COLOR_HISTOGRAM

Multicolored histogram from the zero line

1

1

DRAW_COLOR_HISTOGRAM2

Multicolored histogram of the two indicator buffers

2

1

DRAW_COLOR_ARROW

Drawing multicolored arrows

1

1

DRAW_COLOR_ZIGZAG

Multicolored ZigZag

2

1

DRAW_COLOR_BARS

Multicolored bars

4

1

DRAW_COLOR_CANDLES

Multicolored candlesticks

4

1

 

To refine the display of the selected drawing type identifiers listed in ENUM_PLOT_PROPERTY are used.

For functions PlotIndexSetInteger() and PlotIndexGetInteger()

ENUM_PLOT_PROPERTY_INTEGER

ID

Description

Property type

PLOT_ARROW

Arrow code for style DRAW_ARROW

uchar

PLOT_ARROW_SHIFT

Vertical shift of arrows for style DRAW_ARROW

int

PLOT_DRAW_BEGIN

Number of initial bars without drawing and values in the DataWindow

int

PLOT_DRAW_TYPE

Type of graphical construction

ENUM_DRAW_TYPE

PLOT_SHOW_DATA

Sign of display of construction values in the DataWindow

bool

PLOT_SHIFT

Shift of indicator plotting along the time axis in bars

int

PLOT_LINE_STYLE

Drawing line style

ENUM_LINE_STYLE

PLOT_LINE_WIDTH

The thickness of the drawing line

int

PLOT_COLOR_INDEXES

The number of colors

int

PLOT_LINE_COLOR

The index of a buffer containing the drawing color

color       modifier = index number of colors

 

For the function PlotIndexSetDouble()

ENUM_PLOT_PROPERTY_DOUBLE

ID

Description

Property type

PLOT_EMPTY_VALUE

An empty value for plotting, for which there is no drawing

double

For the function PlotIndexSetString()

ENUM_PLOT_PROPERTY_STRING

ID

Description

Property type

PLOT_LABEL

The name of the indicator graphical series to display in the DataWindow. When working with complex graphical styles requiring several indicator buffers for display, the names for each buffer can be specified using ";" as a separator. Sample code is shown in DRAW_CANDLES

string

5 styles can be used for drawing lines in custom indicators. They are valid only for the line thickness 0 or 1.

ENUM_LINE_STYLE

ID

Description

STYLE_SOLID

Solid line

STYLE_DASH

Broken line

STYLE_DOT

Dotted line

STYLE_DASHDOT

Dash-dot line

STYLE_DASHDOTDOT

Dash - two points

 

To set the line drawing style and the type of drawing, the PlotIndexSetInteger() function is used. For the Fibonacci extensions the thickness and drawing style of levels can be indicated using the ObjectSetInteger() function.

Example:

#property indicator_chart_window
#property indicator_buffers 1
#property indicator_plots   1
//--- indicator buffers
double         MABuffer[];
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
void OnInit()
  {
//--- Bind the Array to the indicator buffer with index 0
   SetIndexBuffer(0,MABuffer,INDICATOR_DATA);
//--- Set the line drawing
   PlotIndexSetInteger(0,PLOT_DRAW_TYPE,DRAW_LINE);
//--- Set the style line
   PlotIndexSetInteger(0,PLOT_LINE_STYLE,STYLE_DOT);
//--- Set line color
   PlotIndexSetInteger(0,PLOT_LINE_COLOR,clrRed);
//--- Set line thickness
   PlotIndexSetInteger(0,PLOT_LINE_WIDTH,1);
//--- Set labels for the line
   PlotIndexSetString(0,PLOT_LABEL,"Moving Average");
//---
  }
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int OnCalculate(const int rates_total,
                 const int prev_calculated,
                 const datetime &time[],
                 const double &open[],
                 const double &high[],
                 const double &low[],
                 const double &close[],
                 const long &tick_volume[],
                 const long &volume[],
                 const int &spread[])
  {
//--- 
   for(int i=prev_calculated;i<rates_total;i++)
     {
      MABuffer[i]=close[i];
     }
//--- return value of prev_calculated for next call
   return(rates_total);
  }

 


Updated: 2015.12.03