Inside Macintosh: QuickDraw GX Objects /

Chapter 2 - Shape Objects / Shape Objects Reference

Functions / Creating and Manipulating Shape Objects

GXEqualShape

You can use the GXEqualShape function to determine if two shapes are equal.

boolean GXEqualShape(gxShape one, gxShape two);

one

A reference to one of the shapes to test for equality.

two

A reference to the other shape to test for equality.

function result

true if the shape specified by the one parameter is equal to the shape specified by the two parameter; false otherwise.

DESCRIPTION

The GXEqualShape function returns as its function result a Boolean value indicating whether the two QuickDraw GX shapes are equal. For two QuickDraw GX shapes to be equal, they must satisfy these requirements:

• They must have the same shape type and fill, but they do not need to have the same attributes, owner count, or tag list.
• Their geometries must have identical values; geometries that are equivalent but not identical are not considered to be equal. To eliminate false rejection of equivalent geometries, call the GXSimplifyShape function to simplify both shapes before you call GXEqualShape.

ERRORS, WARNINGS, AND NOTICES

Errors
out_of_memory
shape_is_nil

SEE ALSO

Equivalent geometries are described in the section "Copying, Comparing, and Cloning Shape Objects" beginning on page 2-25. The GXSimplifyShape function is described in the geometric shapes chapter of Inside Macintosh: QuickDraw GX Graphics.

To make a copy of a shape object that is equal by the criteria of this function, use the GXCopyToShape function, described on page 2-57.