Autolayout Gists

RotationResistantView.h

//
//  RotationResistantView.h
//
//  Created by Steve Sparks on 1/24/15.
//

#import <UIKit/UIKit.h>


typedef NS_ENUM(NSInteger, RRLayoutAttribute) {
    RRLayoutAttributeLeft = 1,
    RRLayoutAttributeRight,
    RRLayoutAttributeTop,
    RRLayoutAttributeBottom,
    RRLayoutAttributeLeading,
    RRLayoutAttributeTrailing,
    RRLayoutAttributeWidth,
    RRLayoutAttributeHeight,
    RRLayoutAttributeCenterX,
    RRLayoutAttributeCenterY,
    RRLayoutAttributeBaseline,
    RRLayoutAttributeLastBaseline = RRLayoutAttributeBaseline,
    RRLayoutAttributeFirstBaseline NS_ENUM_AVAILABLE_IOS(8_0),
    RRLayoutAttributeLeftMargin NS_ENUM_AVAILABLE_IOS(8_0),
    RRLayoutAttributeRightMargin NS_ENUM_AVAILABLE_IOS(8_0),
    RRLayoutAttributeTopMargin NS_ENUM_AVAILABLE_IOS(8_0),
    RRLayoutAttributeBottomMargin NS_ENUM_AVAILABLE_IOS(8_0),
    RRLayoutAttributeLeadingMargin NS_ENUM_AVAILABLE_IOS(8_0),
    RRLayoutAttributeTrailingMargin NS_ENUM_AVAILABLE_IOS(8_0),
    RRLayoutAttributeCenterXWithinMargins NS_ENUM_AVAILABLE_IOS(8_0),
    RRLayoutAttributeCenterYWithinMargins NS_ENUM_AVAILABLE_IOS(8_0),
    RRLayoutAttributeNotAnAttribute = 0
};

#define RRReversedAttr     @{\
@(NSLayoutAttributeNotAnAttribute) : @(NSLayoutAttributeNotAnAttribute),\
@(NSLayoutAttributeLeft) : @(NSLayoutAttributeRight),\
@(NSLayoutAttributeRight) : @(NSLayoutAttributeLeft),\
@(NSLayoutAttributeTop) : @(NSLayoutAttributeBottom),\
@(NSLayoutAttributeBottom) : @(NSLayoutAttributeTop),\
@(NSLayoutAttributeLeading) : @(NSLayoutAttributeTrailing),\
@(NSLayoutAttributeTrailing) : @(NSLayoutAttributeLeading),\
@(NSLayoutAttributeWidth) : @(NSLayoutAttributeWidth),\
@(NSLayoutAttributeHeight) : @(NSLayoutAttributeHeight),\
@(NSLayoutAttributeCenterX) : @(NSLayoutAttributeCenterX),\
@(NSLayoutAttributeCenterY) : @(NSLayoutAttributeCenterY),\
@(NSLayoutAttributeBaseline) : @(NSLayoutAttributeFirstBaseline),\
@(NSLayoutAttributeLastBaseline) : @(NSLayoutAttributeFirstBaseline),\
@(NSLayoutAttributeFirstBaseline) : @(NSLayoutAttributeLastBaseline),\
@(NSLayoutAttributeLeftMargin) : @(NSLayoutAttributeRightMargin),\
@(NSLayoutAttributeRightMargin) : @(NSLayoutAttributeLeftMargin),\
@(NSLayoutAttributeTopMargin) : @(NSLayoutAttributeBottomMargin),\
@(NSLayoutAttributeBottomMargin) : @(NSLayoutAttributeTopMargin),\
@(NSLayoutAttributeLeadingMargin) : @(NSLayoutAttributeTrailingMargin),\
@(NSLayoutAttributeTrailingMargin) : @(NSLayoutAttributeLeadingMargin),\
@(NSLayoutAttributeCenterXWithinMargins) : @(NSLayoutAttributeCenterXWithinMargins),\
@(NSLayoutAttributeCenterYWithinMargins) : @(NSLayoutAttributeCenterYWithinMargins),\
}


#define RRClockwiseAttr     @{\
@(NSLayoutAttributeNotAnAttribute) : @(NSLayoutAttributeNotAnAttribute),\
@(NSLayoutAttributeLeft) : @(NSLayoutAttributeTop),\
@(NSLayoutAttributeTop) : @(NSLayoutAttributeRight),\
@(NSLayoutAttributeRight) : @(NSLayoutAttributeBottom),\
@(NSLayoutAttributeBottom) : @(NSLayoutAttributeLeft),\
@(NSLayoutAttributeLeading) : @(NSLayoutAttributeTop),\
@(NSLayoutAttributeTrailing) : @(NSLayoutAttributeBottom),\
@(NSLayoutAttributeWidth) : @(NSLayoutAttributeHeight),\
@(NSLayoutAttributeHeight) : @(NSLayoutAttributeWidth),\
@(NSLayoutAttributeCenterX) : @(NSLayoutAttributeCenterY),\
@(NSLayoutAttributeCenterY) : @(NSLayoutAttributeCenterX),\
@(NSLayoutAttributeBaseline) : @(NSLayoutAttributeFirstBaseline),\
@(NSLayoutAttributeLastBaseline) : @(NSLayoutAttributeFirstBaseline),\
@(NSLayoutAttributeFirstBaseline) : @(NSLayoutAttributeLastBaseline),\
@(NSLayoutAttributeLeftMargin) : @(NSLayoutAttributeTopMargin),\
@(NSLayoutAttributeTopMargin) : @(NSLayoutAttributeRightMargin),\
@(NSLayoutAttributeRightMargin) : @(NSLayoutAttributeBottomMargin),\
@(NSLayoutAttributeBottomMargin) : @(NSLayoutAttributeLeftMargin),\
@(NSLayoutAttributeLeadingMargin) : @(NSLayoutAttributeTrailingMargin),\
@(NSLayoutAttributeTrailingMargin) : @(NSLayoutAttributeLeadingMargin),\
@(NSLayoutAttributeCenterXWithinMargins) : @(NSLayoutAttributeCenterYWithinMargins),\
@(NSLayoutAttributeCenterYWithinMargins) : @(NSLayoutAttributeCenterXWithinMargins),\
}

#define RRCounterclockwiseAttr     @{\
@(NSLayoutAttributeNotAnAttribute) : @(NSLayoutAttributeNotAnAttribute),\
@(NSLayoutAttributeLeft) : @(NSLayoutAttributeBottom),\
@(NSLayoutAttributeBottom) : @(NSLayoutAttributeRight),\
@(NSLayoutAttributeRight) : @(NSLayoutAttributeTop),\
@(NSLayoutAttributeTop) : @(NSLayoutAttributeLeft),\
@(NSLayoutAttributeLeading) : @(NSLayoutAttributeBottom),\
@(NSLayoutAttributeTrailing) : @(NSLayoutAttributeTop),\
@(NSLayoutAttributeWidth) : @(NSLayoutAttributeHeight),\
@(NSLayoutAttributeHeight) : @(NSLayoutAttributeWidth),\
@(NSLayoutAttributeCenterX) : @(NSLayoutAttributeCenterY),\
@(NSLayoutAttributeCenterY) : @(NSLayoutAttributeCenterX),\
@(NSLayoutAttributeBaseline) : @(NSLayoutAttributeFirstBaseline),\
@(NSLayoutAttributeLastBaseline) : @(NSLayoutAttributeFirstBaseline),\
@(NSLayoutAttributeFirstBaseline) : @(NSLayoutAttributeLastBaseline),\
@(NSLayoutAttributeLeftMargin) : @(NSLayoutAttributeBottomMargin),\
@(NSLayoutAttributeTopMargin) : @(NSLayoutAttributeLeftMargin),\
@(NSLayoutAttributeRightMargin) : @(NSLayoutAttributeTopMargin),\
@(NSLayoutAttributeBottomMargin) : @(NSLayoutAttributeRightMargin),\
@(NSLayoutAttributeLeadingMargin) : @(NSLayoutAttributeTopMargin),\
@(NSLayoutAttributeTrailingMargin) : @(NSLayoutAttributeBottomMargin),\
@(NSLayoutAttributeCenterXWithinMargins) : @(NSLayoutAttributeCenterYWithinMargins),\
@(NSLayoutAttributeCenterYWithinMargins) : @(NSLayoutAttributeCenterXWithinMargins),\
}

#define RRReversedConstantMult     @{\
@(NSLayoutAttributeNotAnAttribute) : @(0),\
@(NSLayoutAttributeLeft) : @(-1),\
@(NSLayoutAttributeRight) : @(-1),\
@(NSLayoutAttributeTop) : @(-1),\
@(NSLayoutAttributeBottom) : @(-1),\
@(NSLayoutAttributeLeading) : @(-1),\
@(NSLayoutAttributeTrailing) : @(-1),\
@(NSLayoutAttributeWidth) : @(1),\
@(NSLayoutAttributeHeight) : @(1),\
@(NSLayoutAttributeCenterX) : @(-1),\
@(NSLayoutAttributeCenterY) : @(-1),\
@(NSLayoutAttributeBaseline) : @(-1),\
@(NSLayoutAttributeLastBaseline) : @(-1),\
@(NSLayoutAttributeFirstBaseline) : @(-1),\
@(NSLayoutAttributeLeftMargin) : @(-1),\
@(NSLayoutAttributeRightMargin) : @(-1),\
@(NSLayoutAttributeTopMargin) : @(-1),\
@(NSLayoutAttributeBottomMargin) : @(-1),\
@(NSLayoutAttributeLeadingMargin) : @(-1),\
@(NSLayoutAttributeTrailingMargin) : @(-1),\
@(NSLayoutAttributeCenterXWithinMargins) : @(-1),\
@(NSLayoutAttributeCenterYWithinMargins) : @(-1),\
}

#define RRClockwiseConstantMult     @{\
@(NSLayoutAttributeNotAnAttribute) : @(0),\
@(NSLayoutAttributeLeft) : @(1),\
@(NSLayoutAttributeRight) : @(1),\
@(NSLayoutAttributeTop) : @(-1),\
@(NSLayoutAttributeBottom) : @(-1),\
@(NSLayoutAttributeLeading) : @(1),\
@(NSLayoutAttributeTrailing) : @(1),\
@(NSLayoutAttributeWidth) : @(1),\
@(NSLayoutAttributeHeight) : @(1),\
@(NSLayoutAttributeCenterX) : @(-1),\
@(NSLayoutAttributeCenterY) : @(1),\
@(NSLayoutAttributeBaseline) : @(-1),\
@(NSLayoutAttributeLastBaseline) : @(-1),\
@(NSLayoutAttributeFirstBaseline) : @(-1),\
@(NSLayoutAttributeLeftMargin) : @(1),\
@(NSLayoutAttributeRightMargin) : @(1),\
@(NSLayoutAttributeTopMargin) : @(-1),\
@(NSLayoutAttributeBottomMargin) : @(-1),\
@(NSLayoutAttributeLeadingMargin) : @(1),\
@(NSLayoutAttributeTrailingMargin) : @(1),\
@(NSLayoutAttributeCenterXWithinMargins) : @(-1),\
@(NSLayoutAttributeCenterYWithinMargins) : @(1)\
}

#define RRCounterclockwiseConstantMult     @{\
@(NSLayoutAttributeNotAnAttribute) : @(0),\
@(NSLayoutAttributeLeft) : @(-1),\
@(NSLayoutAttributeRight) : @(-1),\
@(NSLayoutAttributeTop) : @(1),\
@(NSLayoutAttributeBottom) : @(1),\
@(NSLayoutAttributeLeading) : @(-1),\
@(NSLayoutAttributeTrailing) : @(-1),\
@(NSLayoutAttributeWidth) : @(1),\
@(NSLayoutAttributeHeight) : @(1),\
@(NSLayoutAttributeCenterX) : @(-1),\
@(NSLayoutAttributeCenterY) : @(1),\
@(NSLayoutAttributeBaseline) : @(-1),\
@(NSLayoutAttributeLastBaseline) : @(-1),\
@(NSLayoutAttributeFirstBaseline) : @(-1),\
@(NSLayoutAttributeLeftMargin) : @(-1),\
@(NSLayoutAttributeRightMargin) : @(-1),\
@(NSLayoutAttributeTopMargin) : @(1),\
@(NSLayoutAttributeBottomMargin) : @(1),\
@(NSLayoutAttributeLeadingMargin) : @(-1),\
@(NSLayoutAttributeTrailingMargin) : @(-1),\
@(NSLayoutAttributeCenterXWithinMargins) : @(-1),\
@(NSLayoutAttributeCenterYWithinMargins) : @(1),\
}


@interface RotationResistantView : UIView
- (void)rr_preserveConstraints;

@end

RotationResistantView.m

//
//  RotationResistantView.m
//
//  Created by Steve Sparks on 1/24/15.
//

#import "RotationResistantView.h"
#import "Pannr.h"

@interface RRLayoutConstraint : NSObject
@property (nonatomic) id firstItem;
@property (nonatomic) RRLayoutAttribute firstAttribute;
@property (nonatomic) NSLayoutRelation relation;
@property (nonatomic) id secondItem;
@property (nonatomic) RRLayoutAttribute secondAttribute;
@property (nonatomic) CGFloat multiplier;
@property (nonatomic) CGFloat constant;
@property (weak, nonatomic) NSLayoutConstraint *currentConstraint;
- (instancetype) initWithConstraint:(NSLayoutConstraint*)constraint inOrientation:(UIDeviceOrientation)orientation;
@end


@implementation RRLayoutConstraint

- (instancetype)initWithConstraint:(NSLayoutConstraint *)constraint inOrientation:(UIDeviceOrientation)orientation {
    self = [super init];
    if(self) {
        self.currentConstraint = constraint;
        self.firstItem = constraint.firstItem;
        self.secondItem = constraint.secondItem;
        self.constant = constraint.constant;
        self.multiplier = constraint.multiplier;
        self.relation = constraint.relation;


        // We need to save constraints relative to portrait, so right here,
        // we unroll whatever orientation they have applied, and see what
        // the constraints are w/r/t portrait.
        switch([UIDevice currentDevice].orientation) {
            case UIDeviceOrientationLandscapeLeft:
                self.firstAttribute = [RRClockwiseAttr[@(constraint.firstAttribute)] integerValue];
                self.secondAttribute = [RRClockwiseAttr[@(constraint.secondAttribute)] integerValue];
                break;
            case UIDeviceOrientationLandscapeRight:
                self.firstAttribute = [RRCounterclockwiseAttr[@(constraint.firstAttribute)] integerValue];
                self.secondAttribute = [RRCounterclockwiseAttr[@(constraint.secondAttribute)] integerValue];
                break;
            case UIDeviceOrientationPortraitUpsideDown:
                self.firstAttribute = [RRReversedAttr[@(constraint.firstAttribute)] integerValue];
                self.secondAttribute = [RRReversedAttr[@(constraint.secondAttribute)] integerValue];
                break;
            default:
                self.firstAttribute = (RRLayoutAttribute)constraint.firstAttribute;
                self.secondAttribute = (RRLayoutAttribute)constraint.secondAttribute;
                break;
        }
    }
    return self;
}

- (NSLayoutConstraint *) constraintForOrientation:(UIDeviceOrientation)orientation {
    NSLayoutAttribute newFirst = (NSLayoutAttribute)self.firstAttribute;
    NSLayoutAttribute newSecond = (NSLayoutAttribute)self.secondAttribute;

    CGFloat newConstant = self.constant;

    switch(orientation) {
        case UIDeviceOrientationLandscapeLeft:
            newFirst = [RRCounterclockwiseAttr[@(self.firstAttribute)] integerValue];
            newSecond = [RRCounterclockwiseAttr[@(self.secondAttribute)] integerValue];
            newConstant = newConstant * [RRCounterclockwiseConstantMult[@(self.firstAttribute)] doubleValue];
            break;
        case UIDeviceOrientationLandscapeRight:
            newFirst = [RRClockwiseAttr[@(self.firstAttribute)] integerValue];
            newSecond = [RRClockwiseAttr[@(self.secondAttribute)] integerValue];
            newConstant = newConstant * [RRClockwiseConstantMult[@(self.firstAttribute)] doubleValue];
            break;
        case UIDeviceOrientationPortraitUpsideDown:
            newConstant = newConstant * [RRReversedConstantMult[@(self.firstAttribute)] doubleValue];
        case UIDeviceOrientationFaceDown:
        case UIDeviceOrientationFaceUp:
        case UIDeviceOrientationPortrait:
        default:
            ;
    }

    if(newFirst && newSecond) {
        return [NSLayoutConstraint constraintWithItem:self.firstItem attribute:newFirst relatedBy:self.relation toItem:self.secondItem attribute:newSecond multiplier:self.multiplier constant:newConstant];
    }
    return nil;
}

@end



@interface RotationResistantView ()
@property (nonatomic) NSArray *preservedConstraints;
@property (nonatomic) UIDeviceOrientation previousOrientation;

@end

@implementation RotationResistantView

- (void)layoutSubviews {
    if(self.preservedConstraints.count) {
        [self rr_removeAndApplyConstraints];
    }
    [super layoutSubviews];
}

- (void)rr_preserveConstraints {
    NSMutableArray *newConstraints = [[NSMutableArray alloc] initWithCapacity:self.constraints.count];

    UIDeviceOrientation o = [UIDevice currentDevice].orientation;

    for(NSLayoutConstraint *c in self.constraints) {
        if(c.secondAttribute != NSLayoutAttributeNotAnAttribute) {
            RRLayoutConstraint *lc = [[RRLayoutConstraint alloc] initWithConstraint:c inOrientation:o];
            [newConstraints addObject:lc];
        }
    }
    self.preservedConstraints = [newConstraints copy];
}

- (void)rr_removeAndApplyConstraints {
    UIDeviceOrientation o = [UIDevice currentDevice].orientation;

    for(RRLayoutConstraint *localConstraint in self.preservedConstraints) {
        NSLayoutConstraint *oldC = constraint.currentConstraint;
        [self removeConstraint:oldC];

        NSLayoutConstraint *newC = [localConstraint constraintForOrientation:o];
        localConstraint.currentConstraint = newC;
        [self addConstraint:newC];
    }
}

@end

UIViewController+RotationAware.h

//
//  UIViewController+RotationAware.h
//
//  Created by Steve Sparks on 12/27/14.
//

#import <UIKit/UIKit.h>

@interface UIViewController(RotationAware)

- (void)ltc_addViewToRotationGroup:(UIView *)view;
- (void)ltc_removeViewFromRotationGroup:(UIView *)view;
- (CGAffineTransform)ltc_currentTransform;
- (void)ltc_updateOrientation;

@end

UIViewController+RotationAware.m

//
//  UIViewController+RotationAware.m
//
//  Created by Steve Sparks on 12/27/14.
//

#import "UIViewController+RotationAware.h"
#import <objc/runtime.h>

@implementation UIViewController(RotationAware)

const void *currentTransformKey = &currentTransformKey;
const void *rotationGroupKey = &rotationGroupKey;

- (NSMutableArray*)rotationGroup {
    NSMutableArray *ret = objc_getAssociatedObject(self, rotationGroupKey);
    if(!ret) {
        ret = [[NSMutableArray alloc] init];
        objc_setAssociatedObject(self, rotationGroupKey, ret, OBJC_ASSOCIATION_RETAIN);
    }
    return ret;
}

- (CGAffineTransform)ltc_currentTransform {
    return [self currentTransform];
}

- (CGAffineTransform)currentTransform {
    CGAffineTransform ret = CGAffineTransformIdentity;
    NSValue *v = objc_getAssociatedObject(self, currentTransformKey);
    if(v) {
        ret = [v CGAffineTransformValue];
    } else {
        ret = [self transformForCurrentOrientation];
        [self setCurrentTransform:ret];
    }
    return ret;
}

- (void)setCurrentTransform:(CGAffineTransform)currentTransform {
    objc_setAssociatedObject(self, currentTransformKey, [NSValue valueWithCGAffineTransform:currentTransform], OBJC_ASSOCIATION_RETAIN);
}

#pragma mark -

- (void)ltc_updateOrientation {
    [self noteOrientationChange:nil];
}

- (CGAffineTransform) transformForCurrentOrientation {
    UIDeviceOrientation deviceOrientation = [[UIDevice currentDevice] orientation];
    UIInterfaceOrientation statusBarOrientation = [[UIApplication sharedApplication] statusBarOrientation];

    UIDeviceOrientation final = UIDeviceOrientationPortrait;

    CGFloat angle = 0.0;

    switch (statusBarOrientation) {
        case UIInterfaceOrientationPortrait:
            final = deviceOrientation;
            break;
        case UIInterfaceOrientationLandscapeLeft:
            switch(deviceOrientation) {
                case UIDeviceOrientationPortrait:
                    final = UIDeviceOrientationLandscapeRight;
                    break;
                case UIDeviceOrientationLandscapeLeft:
                    final = UIDeviceOrientationPortrait;
                    break;
                case UIDeviceOrientationLandscapeRight:
                    final = UIDeviceOrientationPortraitUpsideDown;
                    break;
                case UIDeviceOrientationPortraitUpsideDown:
                    final = UIDeviceOrientationLandscapeRight;
                    break;
                default:
                    ;
            }
            break;
        case UIInterfaceOrientationLandscapeRight:
            switch(deviceOrientation) {
                case UIDeviceOrientationPortrait:
                    final = UIDeviceOrientationLandscapeLeft;
                    break;
                case UIDeviceOrientationLandscapeLeft:
                    final = UIDeviceOrientationPortraitUpsideDown;
                    break;
                case UIDeviceOrientationLandscapeRight:
                    final = UIDeviceOrientationPortrait;
                    break;
                case UIDeviceOrientationPortraitUpsideDown:
                    final = UIDeviceOrientationLandscapeRight;
                    break;
                default:
                    ;
            }
            break;
        case UIInterfaceOrientationPortraitUpsideDown: {
            switch(deviceOrientation) {
                case UIDeviceOrientationPortrait:
                    final = UIDeviceOrientationPortraitUpsideDown;
                    break;
                case UIDeviceOrientationLandscapeLeft:
                    final = UIDeviceOrientationLandscapeRight;
                    break;
                case UIDeviceOrientationLandscapeRight:
                    final = UIDeviceOrientationLandscapeLeft;
                    break;
                case UIDeviceOrientationPortraitUpsideDown:
                    final = UIDeviceOrientationPortrait;
                    break;
                default:
                    ;
            }
            break;

        }
        default:
            break;
    }

    switch (final) {
        case UIDeviceOrientationLandscapeLeft:
            angle = M_PI_2;
            break;
        case UIDeviceOrientationLandscapeRight:
            angle = 0 - M_PI_2;
            break;
        case UIDeviceOrientationPortraitUpsideDown:
            angle = M_PI;
            break;
        default:
            break;
    }
    CGAffineTransform transform = CGAffineTransformMakeRotation(angle);
    return transform;
}

- (void)noteOrientationChange:(NSNotification*)note { // UIDeviceOrientationDidChangeNotification
    CGAffineTransform transform = [self transformForCurrentOrientation];
    self.currentTransform = transform;
    [UIView animateWithDuration:0.25 animations:^{
        for(UIView *view in self.rotationGroup) {
            view.transform = transform;
        }
    }];
//    [self willAnimateRotationToInterfaceOrientation:(UIInterfaceOrientation)final duration:0.25];
}

#pragma mark -

- (void)ltc_addViewToRotationGroup:(UIView *)view {
    if([view isKindOfClass:[UIView class]]) {
        if(!self.rotationGroup.count) {
            [self noteOrientationChange:nil];
            [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(noteOrientationChange:) name:UIDeviceOrientationDidChangeNotification object:nil];
        }
        view.transform = self.currentTransform;
        [self.rotationGroup addObject:view];
    }
}

- (void)ltc_removeViewFromRotationGroup:(UIView *)view {
    [self.rotationGroup removeObject:view];
    if(!self.rotationGroup.count) {
        [[NSNotificationCenter defaultCenter] removeObserver:self name:UIDeviceOrientationDidChangeNotification object:nil];
    }
}
@end