CODEWITHSUNDEEP
iosobjective-cswiftcgpoint
user6631314
user6631314

Reputation: 1976

Programmatically supply argument to cgpointmake or cgpoint to create cgpoints from coordinate pair

Please forgive this naive question, but is there any direct way to create a cgpoints from a coordinate pair without extracting the x and y value separately.

I know you can do:

CGPoint point = CGPointMake(2, 3);

or

float x = 2;
float y = 3;

CGPoint p  = CGPointMake(x,y);

Is there any way to create it a point directly from (2,3) without extracting each x and y separately?

The reason I'm asking is I have to create a lot of CGPoints from an array of coordinates that look like [(2,3),(4,5),(6,7)] etc.

Thanks in advance for any suggestions.

Upvotes: 1

Views: 160

Answers (4)

squ1dd13
squ1dd13

Reputation: 84

A solution for Objective C might look like this:

CGFloat pointValues[] = {
    2, 3,
    4, 5,
    6, 7
};

for(int i = 0; i < sizeof(pointValues) / sizeof(CGFloat); i += 2) {
    CGPoint p = CGPointMake(pointValues[i], pointValues[i + 1]);
    // Do something with 'p'...
}

The pointValues array is a 1D array of the x and y values of each point.

Alternatively, if you can use Objective C++, you can simply do this:

CGPoint points[] {
    { 2, 3 },
    { 4, 5 },
    { 6, 7 }
};

Upvotes: 0

Frankenstein
Frankenstein

Reputation: 16371

Use map and CGPoint init with x and y parameters.

let coordinates = [(2,3),(4,5),(6,7)]
let points = coordinates.map { CGPoint(x: $0, y: $1) }
print("\(type(of: points)): \(points)") // You'll get an `[CGPoint]` although they print as normal [(x, y)] tuples array.

Upvotes: 3

Leo Dabus
Leo Dabus

Reputation: 236538

Swift can infer the proper initializer if you map an array of tuples of the same types of an available initializer of the resulting type:

let points = [(2,3),(4,5),(6,7)].map(CGPoint.init)

Upvotes: 1

skaak
skaak

Reputation: 3018

Well, if you have a flair for the dramatic, maybe something like this

        // One big array
        float *   p1 = ( float [] ){ 1, 2, 3, 4, 5, 6, 7, 8 };
        float * end1 = p1 + 8;

        while ( p1 < end1 )
        {
            CGPoint point = CGPointMake ( * p1, * ( p1 + 1 ) );
            p1 += 2;

            NSLog ( @"Point ( %f, %f )", point.x, point.y );
        }

        // Array of 2D tuples
        // Not much difference though, maybe easier on the eyes?
        float *   p2 = ( float * )( float [][ 2 ] ){ { 1, 2 }, { 3, 4 }, { 5, 6 }, { 7, 8 } };
        float * end2 = p2 + 8;

        while ( p2 < end2 )
        {
            CGPoint point = CGPointMake( * p2, * ( p2 + 1 ) );
            p2 += 2;

            NSLog ( @"Point ( %f, %f )", point.x, point.y );
        }

Upvotes: 0

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