The protractor annotation object consists of two rulers joined at a point to create an angle. The center point is the CenterPoint. The first line ends at the FirstPoint and the second point ends at the SecondPoint.
The AnnProtractorObject class derives from the AnnPolyRulerObject class and adds the following attributes:
For more information on the characteristics of the rulers themselves, refer to Using Rulers in Annotation Objects. The AngularUnit property indicates which unit of measure is being used for the angle between the two rulers. For each possible value of the AngularUnit property there is a corresponding abbreviation for the unit of measure. This abbreviation is given in the AngularUnitsAbbreviation property. The Acute property indicates whether to draw the inside (acute) angle or the outside angle of the protractor. The ArcRadius property contains the arc radius of the protractor. To display the angle of the protractor, set the AnnObject.Labels["angletext"].isvisible property to true. The precision of the value displayed for the angle of the ruler can be set using the AnglePrecision property. This property indicates how many digits to display to the right of the decimal point in the angle.
Direct Show .NET | C API | Filters
Media Foundation .NET | C API | Transforms