added files via upload

Tweaks/FLEX/Core/Views/Carousel/FLEXCarouselCell.h

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+//
+//  FLEXCarouselCell.h
+//  FLEX
+//
+//  Created by Tanner Bennett on 7/17/19.
+//  Copyright © 2020 FLEX Team. All rights reserved.
+//
+
+#import <UIKit/UIKit.h>
+
+@interface FLEXCarouselCell : UICollectionViewCell
+
+@property (nonatomic, copy) NSString *title;
+
+@end

Tweaks/FLEX/Core/Views/Carousel/FLEXCarouselCell.m

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+//
+//  FLEXCarouselCell.m
+//  FLEX
+//
+//  Created by Tanner Bennett on 7/17/19.
+//  Copyright © 2020 FLEX Team. All rights reserved.
+//
+
+#import "FLEXCarouselCell.h"
+#import "FLEXColor.h"
+#import "UIView+FLEX_Layout.h"
+
+@interface FLEXCarouselCell ()
+@property (nonatomic, readonly) UILabel *titleLabel;
+@property (nonatomic, readonly) UIView *selectionIndicatorStripe;
+@property (nonatomic) BOOL constraintsInstalled;
+@end
+
+@implementation FLEXCarouselCell
+
+- (instancetype)initWithFrame:(CGRect)frame {
+    self = [super initWithFrame:frame];
+    if (self) {
+        _titleLabel = [UILabel new];
+        _selectionIndicatorStripe = [UIView new];
+
+        self.titleLabel.font = [UIFont preferredFontForTextStyle:UIFontTextStyleBody];
+        self.selectionIndicatorStripe.backgroundColor = self.tintColor;
+        if (@available(iOS 10, *)) {
+            self.titleLabel.adjustsFontForContentSizeCategory = YES;
+        }
+
+        [self.contentView addSubview:self.titleLabel];
+        [self.contentView addSubview:self.selectionIndicatorStripe];
+
+        [self installConstraints];
+
+        [self updateAppearance];
+    }
+
+    return self;
+}
+
+- (void)updateAppearance {
+    self.selectionIndicatorStripe.hidden = !self.selected;
+
+    if (self.selected) {
+        self.titleLabel.textColor = self.tintColor;
+    } else {
+        self.titleLabel.textColor = FLEXColor.deemphasizedTextColor;
+    }
+}
+
+#pragma mark Public
+
+- (NSString *)title {
+    return self.titleLabel.text;
+}
+
+- (void)setTitle:(NSString *)title {
+    self.titleLabel.text = title;
+    [self.titleLabel sizeToFit];
+    [self setNeedsLayout];
+}
+
+#pragma mark Overrides
+
+- (void)prepareForReuse {
+    [super prepareForReuse];
+    [self updateAppearance];
+}
+
+- (void)installConstraints {
+    CGFloat stripeHeight = 2;
+
+    self.titleLabel.translatesAutoresizingMaskIntoConstraints = NO;
+    self.selectionIndicatorStripe.translatesAutoresizingMaskIntoConstraints = NO;
+
+    UIView *superview = self.contentView;
+    [self.titleLabel flex_pinEdgesToSuperviewWithInsets:UIEdgeInsetsMake(10, 15, 8 + stripeHeight, 15)];
+
+    [self.selectionIndicatorStripe.leadingAnchor constraintEqualToAnchor:superview.leadingAnchor].active = YES;
+    [self.selectionIndicatorStripe.bottomAnchor constraintEqualToAnchor:superview.bottomAnchor].active = YES;
+    [self.selectionIndicatorStripe.trailingAnchor constraintEqualToAnchor:superview.trailingAnchor].active = YES;
+    [self.selectionIndicatorStripe.heightAnchor constraintEqualToConstant:stripeHeight].active = YES;
+}
+
+- (void)setSelected:(BOOL)selected {
+    super.selected = selected;
+    [self updateAppearance];
+}
+
+@end

Tweaks/FLEX/Core/Views/Carousel/FLEXScopeCarousel.h

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+//
+//  FLEXScopeCarousel.h
+//  FLEX
+//
+//  Created by Tanner Bennett on 7/17/19.
+//  Copyright © 2020 FLEX Team. All rights reserved.
+//
+
+#import <UIKit/UIKit.h>
+
+/// Only use on iOS 10 and up. Requires iOS 10 APIs for calculating row sizes.
+@interface FLEXScopeCarousel : UIControl
+
+@property (nonatomic, copy) NSArray<NSString *> *items;
+@property (nonatomic) NSInteger selectedIndex;
+@property (nonatomic) void(^selectedIndexChangedAction)(NSInteger idx);
+
+- (void)registerBlockForDynamicTypeChanges:(void(^)(FLEXScopeCarousel *))handler;
+
+@end

Tweaks/FLEX/Core/Views/Carousel/FLEXScopeCarousel.m

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+//
+//  FLEXScopeCarousel.m
+//  FLEX
+//
+//  Created by Tanner Bennett on 7/17/19.
+//  Copyright © 2020 FLEX Team. All rights reserved.
+//
+
+#import "FLEXScopeCarousel.h"
+#import "FLEXCarouselCell.h"
+#import "FLEXColor.h"
+#import "FLEXMacros.h"
+#import "UIView+FLEX_Layout.h"
+
+const CGFloat kCarouselItemSpacing = 0;
+NSString * const kCarouselCellReuseIdentifier = @"kCarouselCellReuseIdentifier";
+
+@interface FLEXScopeCarousel () <UICollectionViewDelegate, UICollectionViewDataSource, UICollectionViewDelegateFlowLayout>
+@property (nonatomic, readonly) UICollectionView *collectionView;
+@property (nonatomic, readonly) FLEXCarouselCell *sizingCell;
+
+@property (nonatomic, readonly) id dynamicTypeObserver;
+@property (nonatomic, readonly) NSMutableArray *dynamicTypeHandlers;
+
+@property (nonatomic) BOOL constraintsInstalled;
+@end
+
+@implementation FLEXScopeCarousel
+
+- (id)initWithFrame:(CGRect)frame {
+    self = [super initWithFrame:frame];
+    if (self) {
+        self.backgroundColor = FLEXColor.primaryBackgroundColor;
+        self.autoresizingMask = UIViewAutoresizingFlexibleWidth;
+        self.translatesAutoresizingMaskIntoConstraints = YES;
+        _dynamicTypeHandlers = [NSMutableArray new];
+        
+        CGSize itemSize = CGSizeZero;
+        if (@available(iOS 10.0, *)) {
+            itemSize = UICollectionViewFlowLayoutAutomaticSize;
+        }
+
+        // Collection view layout
+        UICollectionViewFlowLayout *layout = ({
+            UICollectionViewFlowLayout *layout = [UICollectionViewFlowLayout new];
+            layout.scrollDirection = UICollectionViewScrollDirectionHorizontal;
+            layout.sectionInset = UIEdgeInsetsZero;
+            layout.minimumLineSpacing = kCarouselItemSpacing;
+            layout.itemSize = itemSize;
+            layout.estimatedItemSize = itemSize;
+            layout;
+        });
+
+        // Collection view
+        _collectionView = ({
+            UICollectionView *cv = [[UICollectionView alloc]
+                initWithFrame:CGRectZero
+                collectionViewLayout:layout
+            ];
+            cv.showsHorizontalScrollIndicator = NO;
+            cv.backgroundColor = UIColor.clearColor;
+            cv.delegate = self;
+            cv.dataSource = self;
+            [cv registerClass:[FLEXCarouselCell class] forCellWithReuseIdentifier:kCarouselCellReuseIdentifier];
+
+            [self addSubview:cv];
+            cv;
+        });
+
+
+        // Sizing cell
+        _sizingCell = [FLEXCarouselCell new];
+        self.sizingCell.title = @"NSObject";
+
+        // Dynamic type
+        weakify(self);
+        _dynamicTypeObserver = [NSNotificationCenter.defaultCenter
+            addObserverForName:UIContentSizeCategoryDidChangeNotification
+            object:nil queue:nil usingBlock:^(NSNotification *note) { strongify(self)
+                [self.collectionView setNeedsLayout];
+                [self setNeedsUpdateConstraints];
+
+                // Notify observers
+                for (void (^block)(FLEXScopeCarousel *) in self.dynamicTypeHandlers) {
+                    block(self);
+                }
+            }
+        ];
+    }
+
+    return self;
+}
+
+- (void)dealloc {
+    [NSNotificationCenter.defaultCenter removeObserver:self.dynamicTypeObserver];
+}
+
+#pragma mark - Overrides
+
+- (void)drawRect:(CGRect)rect {
+    [super drawRect:rect];
+
+    CGFloat width = 1.f / UIScreen.mainScreen.scale;
+
+    // Draw hairline
+    CGContextRef context = UIGraphicsGetCurrentContext();
+    CGContextSetStrokeColorWithColor(context, FLEXColor.hairlineColor.CGColor);
+    CGContextSetLineWidth(context, width);
+    CGContextMoveToPoint(context, 0, rect.size.height - width);
+    CGContextAddLineToPoint(context, rect.size.width, rect.size.height - width);
+    CGContextStrokePath(context);
+}
+
++ (BOOL)requiresConstraintBasedLayout {
+    return YES;
+}
+
+- (void)updateConstraints {
+    if (!self.constraintsInstalled) {
+        self.collectionView.translatesAutoresizingMaskIntoConstraints = NO;
+        [self.collectionView flex_pinEdgesToSuperview];
+        
+        self.constraintsInstalled = YES;
+    }
+    
+    [super updateConstraints];
+}
+
+- (CGSize)intrinsicContentSize {
+    return CGSizeMake(
+        UIViewNoIntrinsicMetric,
+        [self.sizingCell systemLayoutSizeFittingSize:UILayoutFittingCompressedSize].height
+    );
+}
+
+#pragma mark - Public
+
+- (void)setItems:(NSArray<NSString *> *)items {
+    NSParameterAssert(items.count);
+
+    _items = items.copy;
+
+    // Refresh list, select first item initially
+    [self.collectionView reloadData];
+    self.selectedIndex = 0;
+}
+
+- (void)setSelectedIndex:(NSInteger)idx {
+    NSParameterAssert(idx < self.items.count);
+
+    _selectedIndex = idx;
+    NSIndexPath *path = [NSIndexPath indexPathForItem:idx inSection:0];
+    [self.collectionView selectItemAtIndexPath:path
+                                      animated:YES
+                                scrollPosition:UICollectionViewScrollPositionCenteredHorizontally];
+    [self collectionView:self.collectionView didSelectItemAtIndexPath:path];
+}
+
+- (void)registerBlockForDynamicTypeChanges:(void (^)(FLEXScopeCarousel *))handler {
+    [self.dynamicTypeHandlers addObject:handler];
+}
+
+#pragma mark - UICollectionView
+
+- (CGSize)collectionView:(UICollectionView *)collectionView layout:(UICollectionViewLayout *)collectionViewLayout sizeForItemAtIndexPath:(NSIndexPath *)indexPath {
+//    if (@available(iOS 10.0, *)) {
+//        return UICollectionViewFlowLayoutAutomaticSize;
+//    }
+    
+    self.sizingCell.title = self.items[indexPath.item];
+    return [self.sizingCell systemLayoutSizeFittingSize:UILayoutFittingCompressedSize];
+}
+
+- (NSInteger)collectionView:(UICollectionView *)collectionView numberOfItemsInSection:(NSInteger)section {
+    return self.items.count;
+}
+
+- (UICollectionViewCell *)collectionView:(UICollectionView *)collectionView
+                  cellForItemAtIndexPath:(NSIndexPath *)indexPath {
+    FLEXCarouselCell *cell = (id)[collectionView dequeueReusableCellWithReuseIdentifier:kCarouselCellReuseIdentifier
+                                                                           forIndexPath:indexPath];
+    cell.title = self.items[indexPath.row];
+    return cell;
+}
+
+- (void)collectionView:(UICollectionView *)collectionView didSelectItemAtIndexPath:(NSIndexPath *)indexPath {
+    _selectedIndex = indexPath.item; // In case self.selectedIndex didn't trigger this call
+
+    if (self.selectedIndexChangedAction) {
+        self.selectedIndexChangedAction(indexPath.row);
+    }
+
+    // TODO: dynamically choose a scroll position. Very wide items should
+    // get "Left" while smaller items should not scroll at all, unless
+    // they are only partially on the screen, in which case they
+    // should get "HorizontallyCentered" to bring them onto the screen.
+    // For now, everything goes to the left, as this has a similar effect.
+    [collectionView scrollToItemAtIndexPath:indexPath
+                           atScrollPosition:UICollectionViewScrollPositionLeft
+                                   animated:YES];
+    [self sendActionsForControlEvents:UIControlEventValueChanged];
+}
+
+@end