2D and 3D GRAPHICS - Drawing port classes

Drawing port classes

Figure 228 shows the drawing port class architecture. The drawing port knows a graphics device and graphic state. A graphics device is an instance of the TGrafDevice class, and is described in the briefly under the heading "Graphics devices" on page 372. The graphic state is an instance of the TGrafState class. It contains the complete data set that defines the graphic state. See the heading "Graphic state" on page 360.

NOTE Picture and image graphics have a GetGrafPort function that returns a drawing port that draws to an offscreen graphics device. This drawing port is for drawing graphics into the picture or geometries into the image. See Chapter 6 and Chapter 10, respectively, for information on how to draw image and picture graphics.

TRootGrafPort: This class provides the default graphic state, which consists of an identity matrix, an infinite clipping area, and default 2D and 3D bundle attributes.

TLinkedGrafPort: This abstract base class is for concatenating graphic attributes to the graphic state of the parent. See the heading "Linked ports" on page 368 for more information.

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