### Special Geometry

Special Geometry classes for making area geometry by concatenating different geometric shapes, used mostly for clipping.

### IGArea

The IGArea class is a device-independent specification of an arbitrarily-shaped area. An IGArea object (henceforth referred to as an area) is defined by performing binary constructive area geometry (CAG) operations on other area-defining geometries, such as rectangles, ellipses, and polygons.

The operations are shown below.

You can form a binary tree to describe the content of any area. For example, the following area is defined to be the rectangle plus the ellipse minus the polygon.

When the area above is filled, only the highlighted outline is filled. Similarly, when it is framed, the frame is drawn around the boundary of the filled area.

### Special Image: IGImage

IGImage is a special geometry. Even though it is a raster image, it does have geometric properties such as bounds and is transformable (by resampling if needed).

An image is a device-independent, pixel-based graphic that lets you work in pixels. You create an image by drawing graphics into it. The graphics are converted from coordinate units to pixels.

IGImage also encapsulates image data. Image data is normally stored in different file formats. These formats include bitmap(.BMP), GIF, PCX, and TIFF.