Inside Macintosh: QuickDraw GX Graphics /

Chapter 4 - Geometric Operations / Geometric Operations Reference

Functions

Performing Geometric Arithmetic With Shapes

QuickDraw GX provides six arithmetic operations you can apply to geometric shapes: intersection, union, difference, reverse difference, exclusion, and inversion.

The GXIntersectRectangle and GXUnionRectangle perform the intersection and union operations on rectangle structures.

The other functions described in this section perform the arithmetic operations on shapes:

• The GXIntersectShape function finds the area common to the shapes.
• The GXUnionShape function finds the smallest area that contains both the shapes.
• The GXDifferenceShape function finds the area covered by the first shape that is not covered by the second shape.
• The GXReverseDifferenceShape function finds the area covered by the second shape that is not covered by the first shape.
• The GXExcludeShape fucntion finds the area covered by one shape or the other, but not by both.
• The GXInvertShape function finds the area not covered by a shape.

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Subtopics

GXIntersectRectangle

GXUnionRectangle

GXIntersectShape

GXUnionShape

GXDifferenceShape

GXReverseDifferenceShape

GXExcludeShape

GXInvertShape

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