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);
  }