This JavaScript code will create the marks shown in the image on this page.

// Create a new line mark.
var mark = new ImageGear.Web.UI.Mark(ImageGear.Web.UI.MarkType.Line);

// Set various properties.
var points = mark.get_points();
points.setPoint(0, new ImageGear.Web.UI.Point(75, 175));
points.setPoint(1, new ImageGear.Web.UI.Point(175, 100));
mark.set_headFillColor('#7070ff');
mark.set_startHeadAngle(45);
mark.set_startHeadLength(10);
mark.set_startHeadType(ImageGear.Web.UI.LineHeadType.Solid);
mark.set_lineWidth(3);

// Add the mark to the page.
// Adding them after setting the properties avoids a lot of needless markChanged events.
$find('PageView1').get_artPage().addMark(mark);

// Create a new line mark.
// Note that if you skip this step, you will overwrite the properties of the original mark and the second call to addMark() will do nothing because the mark is already associated with the ArtPage.
mark = new ImageGear.Web.UI.Mark(ImageGear.Web.UI.MarkType.Line);

// Set various properties.
points = mark.get_points();
points.setPoint(0, new ImageGear.Web.UI.Point(100, 200));
points.setPoint(1, new ImageGear.Web.UI.Point(200, 125));
mark.set_lineColor('#a0a0ff');
mark.set_endHeadAngle(30);
mark.set_endHeadLength(25);
mark.set_endHeadType(ImageGear.Web.UI.LineHeadType.Pointer);
mark.set_startHeadAngle(10);
mark.set_startHeadLength(35);
mark.set_startHeadType(ImageGear.Web.UI.LineHeadType.PointerSolid);

// Add the mark to the page.
// Adding them after setting the properties avoids a lot of needless markChanged events.
$find('PageView1').get_artPage().addMark(mark);

This property specifies the type of shape or arrowhead drawn on the end of a line. A similar property is available for the start of a line: startHeadType. If you change the value of this property, this object will raise its propertyChanged event.

This figure shows two lines; the left one does not have an arrowhead and the right one has an end head type of Pointer.

Mark types: This property is valid for Line and Polyline marks.
Valid values: Some members of the LineHeadType enumeration.
Default value: ImageGear.Web.UI.LineHeadType.None

ImageGear for .NET name: EndHeadType
NotateXpress (version 10) name: EndPointStyle

Reference

Mark class
Mark Members