CODEWITHSUNDEEP
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RobertL
RobertL

Reputation: 14894

How can CGRectEdge be used to establish the edges of a rectangle?

CGRectEdge is defined in CGGeometry.h like so:

enum CGRectEdge {
  CGRectMinXEdge, CGRectMinYEdge, CGRectMaxXEdge, CGRectMaxYEdge
};
typedef enum CGRectEdge CGRectEdge;

and the documentation (in CGGeometry Reference) says that CGRectEdge is "coordinates that establish the edges of a rectangle". So what is setting these values? Or how can these values be set? The individual values are read-only. It sounds potentially useful but I don't see how to use it for anything since I don't see how to set it. Nor how to relate it to a particular rectangle.

Upvotes: 3

Views: 878

Answers (2)

w0mbat
w0mbat

Reputation: 2459

The CGRectEdge enum is used to supply information to calls that divide rectangles into sub-rectangles, these two calls being CGRectDivide in <CoreGraphics/CGGeometry.h> and MKMapRectDivide in <MapKit/MKGeometry.h>.

/* Make two new rectangles, `slice' and `remainder', by dividing `rect' with
a line that's parallel to one of its sides, specified by `edge' -- either
`CGRectMinXEdge', `CGRectMinYEdge', `CGRectMaxXEdge', or
`CGRectMaxYEdge'. The size of `slice' is determined by `amount', which
 measures the distance from the specified edge. */

void CGRectDivide(CGRect rect, CGRect *slice, CGRect *remainder,
    CGFloat amount, CGRectEdge edge);

void MKMapRectDivide(MKMapRect rect, MKMapRect *slice, MKMapRect *remainder, double amount, CGRectEdge edge) NS_AVAILABLE(10_9, 4_0);

Upvotes: 3

gudatcomputers
gudatcomputers

Reputation: 2882

This is primarily used in CGRectDivide from what I can tell.

You would pass a type of CGRectEdge to the parameter edge

An edge value that specifies the side of the rectangle from which the distance passed in the amount parameter is measured. CGRectDivide produces a “slice” rectangle that contains the specified edge and extends amount distance beyond it.

Upvotes: 3

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