4 - Output

Abstract

This chapter discusses the concept of graphic objects as defined by the computer graphics interface (CGI) output functions. The CGI output functions create graphic objects that comprise the client application's pictures and control their appearance. Output functions establish the geometry and the visible properties of graphic objects. With these functions, the client can create standardized graphic objects using straight lines, arcs, elliptical arcs, markers, characters, polygons, rectangles, circles, ellipses, and images and can create non-standard graphic objects using generalized drawing primitives (GDPs). The functions can be used in conjunction with the CGI control, segments, input, and raster functions. The chapter discusses the four categories of output functions and provides an overview of the output state transitions. It also outlines the general concepts of graphic objects and explains how graphic objects relate to the CGI pipeline, and the primitives and the attributes used to create these objects. The chapter provides an overview of the CGFs output capabilities. It describes the details of creating each type of graphic object: line, marker, text, filled area, compound, image, and non-standard.