CODEWITHSUNDEEP
iosnspredicatecgrectcgpoint
Hasib Samad
Hasib Samad

Reputation: 1081

NSPredicate on an NSArray of CGPoints

I have an NSArray of CGPoints.

I actually want to get the minimal CGRect that contains all the CGPoints in that array. Is there already any iOS function to do this?

Otherwise I will have to manually fetch minX, maxX, minY, maxY, and construct my CGRect this way:

CGrectMake(minX, minY, maxX-minX, maxY-minY);

For this I need to filter the NSArray with an NSPredicate.

(I know, I could filter the array manually, but come on!...)

Upvotes: 0

Views: 480

Answers (2)

Tark
Tark

Reputation: 5175

This question is very unclear. Do you mean you want to create a minimal CGRect that contains all the points you have in an array? If so, that is pretty simple, just iterate over the array of points keeping track of the minX, maxX, minY and maxY. eg

CGFloat minX = CGFLOAT_MAX;
CGFloat minY = CGFLOAT_MAX;
CGFloat maxX = -CGFLOAT_MAX;
CGFloat maxY = -CGFLOAT_MAX;

for (NSValue *v in pointsArray) {
    CGPoint p = [v CGPointValue];
    minX = fminf(minX, p.x);
    minY = fminf(minY, p.y);
    maxX = fmaxf(maxX, p.x);
    maxY = fmaxf(maxY, p.y);
}

CGRect r = CGRectMake(minX, minY, maxX - minX, maxY - minY);

Upvotes: 1

rob mayoff
rob mayoff

Reputation: 385970

There is no public API that does what you're asking. You'll have to write it yourself.

It wouldn't be appropriate for NSPredicate anyway. A predicate is for filtering values, not for constructing new values.

CGRect boundsOfPointArray(NSArray *array) {
    CGRect bounds = CGRectNull;
    for (NSValue *wrapper in array) {
        CGRect r = (CGRect){ wrapper.CGPointValue, CGSizeZero };
        bounds = CGRectUnion(bounds, r);
    }
}

Upvotes: 2

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