About Geometric Shapes (IM: XG)

Inside Macintosh: QuickDraw GX Graphics /: Chapter 2 - Geometric Shapes

About Geometric Shapes
QuickDraw GX represents shapes in memory using a shape object and an associated style, ink, and transform object. QuickDraw GX uses these same objects to represent all types of shapes--graphic as well as typographic.
A shape object has nine properties, which are like fields of a data structure with one important exception: you cannot directly examine or change the information stored in a property. Instead, you must use QuickDraw GX functions to examine or alter the value of a property.
Figure 2-1 shows a graphic representation of a shape object and its nine properties.
Figure 2-1 A shape object

The first three properties of a shape object--the shape type, shape geometry, and shape fill--are called the geometric shape properties. These properties are examined in detail in "The Geometric Properties of Shape Objects" beginning on page 2-7. In particular, that section describes how these three properties are used by geometric shapes.
The next three properties of a shape object--the style, ink, and transform properties--are references to the style, ink, and transform objects associated with the shape. Each of these objects contains information that modifies the way QuickDraw GX draws the shape. You can find more information about these objects in Inside Macintosh: QuickDraw GX Objects. In addition, you can find specific information about how style objects affect geometric shapes in Chapter 3, "Geometric Styles," in this book.
The final three properties of a shape object--the shape attributes, the owner count, and the tag list--are the object-related shape properties. You can find information about these properties, and how they affect all types of shapes, in the chapter "Shape Objects" in Inside Macintosh: QuickDraw GX Objects.
QuickDraw GX provides six basic types of geometric shapes and two special types. The six basic types include points, lines, curves, rectangles, polygons, and paths; the two special types include empty shapes and full shapes.
Each of these shape types is examined in detail in "The Geometric Shape Types" beginning on page 2-16. In particular, that section analyzes how each type of geometric shape uses its shape geometry and shape fill, and also discusses the default geometric shapes.

Subtopics

The Geometric Properties of Shape Objects

The Geometric Shape Types