Functions Reference


                    
                    
                    MMMCenterMultiplierForRatio

Suppose you need to contrain a view so its center divides its container in certain ratio different from 1:1 (e.g. golden section):

┌─────────┐ ◆ │ │ │ │ │ │ a │┌───────┐│ │ ─│┼ ─ ─ ─ ┼│─◆ ratio = a / b │└───────┘│ │ │ │ │ │ │ │ │ │ │ b │ │ │ │ │ │ │ │ │ └─────────┘ ◆

You cannot put this ratio directly into the multiplier parameter of the corresponding NSLayoutConstraints relating the centers of the views, because the multiplier would be the ratio between the distance to the center of the view (h) and the distance to the center of the container (H) instead:

◆ ┌─────────┐ ◆ │ │ │ │ │ │ │ │ a = h H │ │┌───────┐│ │ │ │├ ─ ─ ─ ┼│─◆ multiplier = h / H │ │└───────┘│ │ ratio = a / b = h / (2 * H - h) ◆─│─ ─ ─ ─ ─│ │ │ │ │ │ │ │ b = 2 * H - h │ │ │ │ │ │ │ │ │ └─────────┘ ◆

I.e. the multiplier is h / H (assuming the view is the first in the definition of the constraint), but the ratio we are interested would be h / (2 * H - h) if expressed in the distances to centers.

If you have a desired ratio and want to get a multiplier, which when applied, results in the layout dividing the container in this ratio, then you can use this function as shortcut.

Detailed calculations: ratio = h / (2 * H - h) ==> 2 * H * ratio - h * ratio = h ==> 2 * H * ratio / h - ratio = 1 ==> 1 + ratio = 2 * H * ratio / h ==> (1 + ratio) / (2 * ratio) = H / h where H / h is the inverse of our multiplier, so the actual multiplier is (2 * ratio) / (1 + ratio).

Declaration

Objective-C

static inline CGFloat MMMCenterMultiplierForRatio(CGFloat ratio)

Swift

class func centerMultiplier(forRatio ratio: CGFloat) -> CGFloat


                    
                    
                    MMMReverseAnimationCurve

Animation curve opposite to the given one, e.g. EaseIn for EaseOut.

Declaration

Objective-C

extern MMMAnimationCurve MMMReverseAnimationCurve(MMMAnimationCurve curve)

Swift

func MMMReverseAnimationCurve(_ curve: MMMAnimationCurve) -> MMMAnimationCurve


                    
                    
                    MMMLayoutAlignmentFromHorizontalAlignment

Undocumented

Declaration

Objective-C

static inline MMMLayoutAlignment MMMLayoutAlignmentFromHorizontalAlignment(MMMLayoutHorizontalAlignment alignment) {
	return (MMMLayoutAlignment)alignment;
}

Swift

func MMMLayoutAlignmentFromHorizontalAlignment(_ alignment: MMMLayoutHorizontalAlignment) -> MMMLayoutAlignment


                    
                    
                    MMMLayoutAlignmentFromVerticalAlignment

Undocumented

Declaration

Objective-C

static inline MMMLayoutAlignment MMMLayoutAlignmentFromVerticalAlignment(MMMLayoutVerticalAlignment alignment) {
	return (MMMLayoutAlignment)alignment;
}

Swift

func MMMLayoutAlignmentFromVerticalAlignment(_ alignment: MMMLayoutVerticalAlignment) -> MMMLayoutAlignment


                    
                    
                    MMMDictionaryFromUIEdgeInsets

A dictionary built from UIEdgeInsets suitable for AutoLayout metrics. The dictionary will have 4 values under the keys named “Top”, “Left”, “Bottom”, “Right”.

Declaration

Objective-C

extern NSDictionary<NSString *, NSNumber *>
    *_Nonnull MMMDictionaryFromUIEdgeInsets(NSString *_Nonnull prefix,
                                            UIEdgeInsets insets)

Swift

func MMMDictionaryFromUIEdgeInsets(_ prefix: String, _ insets: UIEdgeInsets) -> [String : NSNumber]