Annotations

Annotation objects include: Text box, Point, Polyline, Spline, Circle, and Ellipse. Graphical objects can be filled or not filled. Annotations can be grouped into layers.

ImageGear Medical component uses ART marks to represent DICOM annotation objects. When a Presentation State DataSet is applied to an image, ImageGear creates ART marks for each of the annotation objects. These marks can then be edited with the ART API methods.

DICOM Graphic Annotation objects are grouped into Layers. All objects on the same layer have the same color (recommended grayscale value). ImageGear uses ART mark groups to represent layers.

When extracting presentation state from an IGPage that has ART marks attached to it, ART marks are converted to DICOM Graphic Annotation objects or Text Annotation objects. The table below lists ART marks that can be converted, corresponding DICOM Graphic Annotation objects, and properties that Graphic Annotation objects support. Marks that are not listed in this table are ignored.

ART Mark Type	DICOM Graphic Annotation Object	Supported Properties
POINT	POINT	Point coordinates
POLYLINE	POLYLINE	Node coordinates, "Filled" property
FILLED_POLYGON	POLYLINE	Node coordinates, "Filled" property
SPLINE	INTERPOLATED	Node coordinates, "Filled" property
FILLED_ELLIPSE	ELLIPSE	Bounds coordinates, "Filled" property
HOLLOW_ELLIPSE	ELLIPSE	Bounds coordinates, "Filled" property

The following ART marks are saved as DICOM Text Annotation objects:

ImGearARTMarkType	Supported Properties
TYPED_TEXT	Text, bounds coordinates
CALLOUT	Text, bounds coordinates, anchor point coordinates, anchor point visibility

Graphic Annotation objects do not have a color property. Instead, Graphic Layer has "Recommended Display Grayscale Value" property. ImageGear converts the color of the first mark in the ART group to grayscale and uses this value to initialize the "Recommended Display Grayscale Value" property of the layer.