General Concepts of the ImageGear Vector API

Vector data is created when reading vector files such as DWF, DWG/DXF, DGN, CGM, HPGL, U3D as well as ASCII, PTOCA, WMF and some other. Vector data is attached to HIGEAR handle and draws its content itself during the display operations.

Vector API consists of constants, structures, handles and functions.

Constants define different flags, types and attributes.
Structures are opened data types that can be modified by the user directly
Handles are closed data types. They can be accessed using the functions.

Vector data (Drawing) is accessible via the handle HIG_VECT_DRWNG and the set of functions having the prefix IG_vect_drwng_... .

The content of the Drawing consists of vector primitives - Entities. The samples of the entities are: easy line, text, polyline, block and other. The Entity is created by the Drawing and accessible via the handle HIG_VECT_ENTITY.

Any Entity has some common attributes. They are: Identifier, type, Layer and some flags: Dirty, Selected, Deleted. Entity has also several optional attributes, which do not exist until they are created. These attributes are: draw color, fill color, line type, fill type, thickness, offset, rotation, scale and position. All common Entity features and attributes are accessible via HIG_VECT_ENTITY handle and functions with prefix IG_vect_ent_... .

There is a set of functions for access to the unique features of the entity. They all have the corresponding prefix. For example, the IG_vect_ellipse_get_radiusx function returns the radius along the x axes of the ellipse:

	Copy Code
IG_vect_ellipse_get_radiusx (HIG_VECT_ENTITY hEntity, float* lpRadiusx);

The Layer is an object that contains attributes, which can be applied to the group of the entities. The Layer is created by the Drawing and accessed by the handle HIG_VECT_LAYER and functions with the prefix IG_vect_layer_... .

Drawing can have several Views, that is, different points of view to the set of Entities. Every View is represented by its Camera attributes such as position, scale, rotation, focus. A View can be created and destroyed.

This section provides information about the following: