UIView+LayoutConstraints.h

//
//  UIView+LayoutConstraints.h
//  UIView+LayoutConstraints
//
//  Created by Dylan Gyesbreghs on 02/02/2018.
//

#import <PureLayout.h>

typedef NS_ENUM(NSInteger, ALAnchor) {
    ALAnchorLeft = NSLayoutAttributeLeft,             // the left edge of the view
    ALAnchorRight = NSLayoutAttributeRight,           // the right edge of the view
    ALAnchorTop = NSLayoutAttributeTop,               // the top edge of the view
    ALAnchorBottom = NSLayoutAttributeBottom,         // the bottom edge of the view
    ALAnchorLeading = NSLayoutAttributeLeading,       // the leading edge of the view (left edge for left-to-right languages like English, right edge for right-to-left languages like Arabic)
    ALAnchorTrailing = NSLayoutAttributeTrailing      // the trailing edge of the view (right edge for left-to-right languages like English, left edge for right-to-left languages like Arabic)
};

static inline ALEdge convertAnchor(ALAnchor anchor) {
    switch (anchor) {
            case ALAnchorLeft:
                return ALEdgeLeft;
            case ALAnchorRight:
                return ALEdgeRight;
            case ALAnchorTop:
                return ALEdgeTop;
            case ALAnchorBottom:
                return ALEdgeBottom;
            case ALAnchorLeading:
                return ALEdgeLeading;
            case ALAnchorTrailing:
                return ALEdgeTrailing;
    }
}

@interface UIView (LayoutConstraints)

//** Pins the left and right edge depending on the orientation so everything is correct for iPhone X
- (void)createLandscapePhoneConstraintWithArray:(NSMutableArray *)constraints;

#pragma mark - Superview Helpers

/** Pins the given edge of the view to the same edge of the superview with an inset. */
- (NSLayoutConstraint *)autoPinAnchorToSuperviewAnchor:(ALAnchor)anchor withConstant:(CGFloat)constant;

/** Pins the edges of the view to the edges of its superview with edge insets zero. */
- (NSArray *)autoPinAnchorsToSuperviewAnchors;

/** Pins 3 of the 4 edges of the view to the edges of its superview with the given edge insets, excluding one edge. */
- (NSArray *)autoPinAnchorsToSuperviewAnchorsWithExcludingAnchor:(ALAnchor)anchor;

/** Pins the edges of the view to the edges of its superview with the given edge insets. */
- (NSArray *)autoPinAnchorsToSuperviewAnchorsWithInsets:(UIEdgeInsets)insets;

/** Pins 3 of the 4 edges of the view to the edges of its superview with the given edge insets, excluding one edge. */
- (NSArray *)autoPinAnchorsToSuperviewAnchorsWithInsets:(UIEdgeInsets)insets excludingAnchor:(ALAnchor)anchor;

#pragma mark - Dimensions Helpers

/** Sets the view to a specific size. */
- (NSArray *)autoSetDimensionsToSize:(CGSize)size;

/** Sets the given dimension of the view to a specific size. */
- (NSLayoutConstraint *)autoSetDimension:(ALDimension)dimension toSize:(CGFloat)size;

/** Matches a dimension of the view to a given dimension of another view. */
- (NSLayoutConstraint *)autoMatchDimension:(ALDimension)dimension ofView:(UIView *)peerView;

///** Matches a dimension of the view to a given dimension of another view with an offset. */
- (NSLayoutConstraint *)autoMatchDimension:(ALDimension)dimension ofView:(UIView *)peerView withOffset:(CGFloat)offset;

/** Return the layoutGuide for the correct iOS Version
 < iOS 11 -> Margin Area Guide
 >= iOS 11 -> Safe Area Guide
 */
- (UILayoutGuide *)layoutGuide;

@end

UIView+LayoutConstraints.m

//
//  UIView+LayoutConstraints.m
//  UIView+LayoutConstraints
//
//  Created by Dylan Gyesbreghs on 02/02/2018.
//

#import "UIView+LayoutConstraints.h"

@implementation UIView (LayoutConstraints)

- (void)createLandscapePhoneConstraintWithArray:(NSMutableArray *)constraints {
    if (constraints == nil) {
        constraints = [NSMutableArray arrayWithCapacity:2];
    }
    
    [NSLayoutConstraint deactivateConstraints:constraints];
    [constraints removeAllObjects];
    
    if ([UIApplication sharedApplication].statusBarOrientation == UIInterfaceOrientationLandscapeRight) {
        [constraints addObjectsFromArray:@[[self autoPinEdgeToSuperviewEdge:ALEdgeRight withInset:0],[self autoPinAnchorToSuperviewAnchor:ALAnchorLeft withConstant:0]]];
    } else if ([UIApplication sharedApplication].statusBarOrientation == UIInterfaceOrientationLandscapeLeft){
        [constraints addObjectsFromArray:@[[self autoPinEdgeToSuperviewEdge:ALEdgeLeft withInset:0],[self autoPinAnchorToSuperviewAnchor:ALAnchorRight withConstant:0]]];
    } else {
        [constraints addObjectsFromArray:@[[self autoPinAnchorToSuperviewAnchor:ALAnchorRight withConstant:0], [self autoPinAnchorToSuperviewAnchor:ALAnchorLeft withConstant:0]]];
    }
}

#pragma mark - Superview Helpers

- (NSLayoutConstraint *)autoPinAnchorToSuperviewAnchor:(ALAnchor)anchor withConstant:(CGFloat)constant;
{
    if (![self respondsToSelector:@selector(safeAreaLayoutGuide)]) {
        return [self autoPinEdgeToSuperviewEdge:convertAnchor(anchor) withInset:constant];
    }
    
    NSLayoutConstraint *constraint;
    
    if (anchor == ALAnchorBottom || anchor == ALAnchorRight || anchor == ALAnchorTrailing) {
            // The bottom, right, and trailing insets (and relations, if an inequality) are inverted to become offsets
        constant = -constant;
    }
    
    UILayoutGuide *layoutGuide = self.superview.layoutGuide;
    switch (anchor) {
        case ALAnchorTop:
            constraint = [self.topAnchor constraintEqualToAnchor:layoutGuide.topAnchor
                                                        constant:constant];
            break;
        case ALAnchorBottom:
            constraint = [self.bottomAnchor constraintEqualToAnchor:layoutGuide.bottomAnchor
                                                           constant:constant];
            break;
        case ALAnchorLeading:
            constraint = [self.leadingAnchor constraintEqualToAnchor:layoutGuide.leadingAnchor
                                                            constant:constant];
            break;
        case ALAnchorTrailing:
            constraint = [self.trailingAnchor constraintEqualToAnchor:layoutGuide.trailingAnchor
                                                             constant:constant];
            break;
        case ALAnchorLeft:
            constraint = [self.leftAnchor constraintEqualToAnchor:layoutGuide.leftAnchor
                                                            constant:constant];
            break;
        case ALAnchorRight:
            constraint = [self.rightAnchor constraintEqualToAnchor:layoutGuide.rightAnchor
                                                          constant:constant];
            break;
    }
    
    constraint.active = YES;
    
    return constraint;
}

- (NSArray *)autoPinAnchorsToSuperviewAnchors
{
    return [self autoPinAnchorsToSuperviewAnchorsWithInsets:UIEdgeInsetsZero];
}


- (NSArray *)autoPinAnchorsToSuperviewAnchorsWithExcludingAnchor:(ALAnchor)anchor
{
    return [self autoPinAnchorsToSuperviewAnchorsWithInsets:UIEdgeInsetsZero excludingAnchor:anchor];
}

- (NSArray *)autoPinAnchorsToSuperviewAnchorsWithInsets:(UIEdgeInsets)insets
{
    NSMutableArray *constraints = [NSMutableArray new];
    [constraints addObject:[self autoPinAnchorToSuperviewAnchor:ALAnchorTop withConstant:insets.top]];
    [constraints addObject:[self autoPinAnchorToSuperviewAnchor:ALAnchorLeading withConstant:insets.left]];
    [constraints addObject:[self autoPinAnchorToSuperviewAnchor:ALAnchorBottom withConstant:insets.bottom]];
    [constraints addObject:[self autoPinAnchorToSuperviewAnchor:ALAnchorTrailing withConstant:insets.right]];
    return constraints;
}

- (NSArray *)autoPinAnchorsToSuperviewAnchorsWithInsets:(UIEdgeInsets)insets excludingAnchor:(ALAnchor)anchor
{
    NSMutableArray *constraints = [NSMutableArray new];
    if (anchor != ALAnchorTop) {
        [constraints addObject:[self autoPinAnchorToSuperviewAnchor:ALAnchorTop withConstant:insets.top]];
    }
    if (anchor != ALAnchorLeading && anchor != ALAnchorLeft) {
        [constraints addObject:[self autoPinAnchorToSuperviewAnchor:ALAnchorLeading withConstant:insets.left]];
    }
    if (anchor != ALAnchorBottom) {
        [constraints addObject:[self autoPinAnchorToSuperviewAnchor:ALAnchorBottom withConstant:insets.bottom]];
    }
    if (anchor != ALAnchorTrailing && anchor != ALAnchorRight) {
        [constraints addObject:[self autoPinAnchorToSuperviewAnchor:ALAnchorTrailing withConstant:insets.right]];
    }
    return constraints;
}

#pragma mark - Dimensions

- (NSArray *)autoSetDimensionsToSize:(CGSize)size
{
    NSMutableArray *constraints = [NSMutableArray new];
    [constraints addObject:[self autoSetDimension:ALDimensionWidth toSize:size.width]];
    [constraints addObject:[self autoSetDimension:ALDimensionHeight toSize:size.height]];
    return constraints;
}

- (NSLayoutConstraint *)autoSetDimension:(ALDimension)dimension toSize:(CGFloat)size
{
    NSLayoutConstraint *constraint;
    
    switch (dimension) {
        case ALDimensionWidth:
            constraint = [self.widthAnchor constraintEqualToConstant:size];
            break;
        case ALDimensionHeight:
            constraint = [self.heightAnchor constraintEqualToConstant:size];
            break;
    }
    
    constraint.active = YES;
    
    return constraint;
}

- (NSLayoutConstraint *)autoMatchDimension:(ALDimension)dimension ofView:(UIView *)peerView
{
    return [self autoMatchDimension:dimension ofView:peerView withOffset:0];
}

- (NSLayoutConstraint *)autoMatchDimension:(ALDimension)dimension ofView:(UIView *)peerView withOffset:(CGFloat)offset
{
    NSLayoutConstraint *constraint;
    
    switch (dimension) {
        case ALDimensionWidth:
            constraint = [self.widthAnchor constraintEqualToAnchor:peerView.layoutGuide.widthAnchor
                                                     constant:offset];
            break;
        case ALDimensionHeight:
            constraint = [self.heightAnchor constraintEqualToAnchor:peerView.layoutGuide.heightAnchor
                                                      constant:offset];
            break;
    }
    
    constraint.active = YES;
    
    return constraint;
}

- (UILayoutGuide *)layoutGuide
{
    if (@available(iOS 11, *)) {
        return self.safeAreaLayoutGuide;
    }
    return self.layoutMarginsGuide;
}

@end