#import @interface PGRectangle : NSObject @property (nonatomic, readonly) CGPoint topLeft; @property (nonatomic, readonly) CGPoint topRight; @property (nonatomic, readonly) CGPoint bottomLeft; @property (nonatomic, readonly) CGPoint bottomRight; - (PGRectangle *)transform:(CGAffineTransform)transform; - (PGRectangle *)rotate90; - (PGRectangle *)sort; - (PGRectangle *)cartesian:(CGFloat)height; @end @interface PGRectangleDetector : NSObject @property (nonatomic, copy) void(^update)(bool, PGRectangle *); - (void)detectRectangle:(CVPixelBufferRef)pixelBuffer; @end