Cocoa Drawing Guide: Manipulating Geometric Types

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Manipulating Geometric Types

The Foundation framework includes numerous functions for manipulating geometric values and for performing various calculations using those values. In addition to basic equality checks, you can perform more complex operations, such as the union and intersection of rectangles or the inclusion of a point in a rectangle’s boundaries.

Table 5-3 lists some of the more commonly used functions and their behaviors. The function syntax is provided in a shorthand notation, with parameter types omitted to demonstrate the calling convention. For a complete list of available functions, and their full syntax, see the Functions section in Foundation Framework Reference.

**Table 5-3** Commonly used geometry functions
Operation	Function	Description
Creation	`NSPoint NSMakePoint(x, y)`	Returns a properly formatted `NSPoint` data structure with the specified x and y values.
	`NSSize NSMakeSize(w, h)`	Returns a properly formatted `NSSize` data structure with the specified width and height.
	`NSRect NSMakeRect(x, y, w, h)`	Returns a properly formatted `NSRect` data structure with the specified origin (x, y) and size (width, height).
Equality	`BOOL NSEqualPoints(p1, p2)`	Returns `YES` if the two points are the same.
	`BOOL NSEqualSizes(s1, s2)`	Returns `YES` if the two size types have identical widths and heights.
	`BOOL NSEqualRects(r1, r2)`	Returns `YES`, if the two rectangles have the same origins and the same widths and heights.
Rectangle manipulations	`BOOL NSContainsRect(r1, r2)`	Returns `YES` if rectangle 1 completely encloses rectangle 2.
	`NSRect NSInsetRect(r, dX, dY)`	Returns a copy of the specified rectangle with its sides moved inward by the specified delta values. Negative delta values move the sides outward. Does not modify the original rectangle.
	`NSRect NSIntersectionRect(r1, r2)`	Returns the intersection of the two rectangles.
	`NSRect NSUnionRect(r1, r2)`	Returns the union of the two rectangles.
	`BOOL NSMouseInRect(p, r, flipped)`	Tests whether the point lies within the specified view rectangle. Adjusts the hit-detection algorithm to provide consistent behavior from the user’s perspective.
	`BOOL NSPointInRect(p, r)`	Tests whether the point lies within the specified rectangle. This is a basic mathematical comparison.

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Last updated: 2007-10-31

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