Use scrolling UITextView for captions

Example/NYTPhotoViewer/NYTViewController.m

@@ -11,6 +11,7 @@
 #import "NYTExamplePhoto.h"
 
 static const NSUInteger NYTViewControllerCustomEverythingPhotoIndex = 1;
+static const NSUInteger NYTViewControllerLongCaptionPhotoIndex = 2;
 static const NSUInteger NYTViewControllerDefaultLoadingSpinnerPhotoIndex = 3;
 static const NSUInteger NYTViewControllerNoReferenceViewPhotoIndex = 4;
 static const NSUInteger NYTViewControllerCustomMaxZoomScalePhotoIndex = 5;
@@ -62,10 +63,28 @@ + (NSArray *)newTestPhotos {
         if (i == NYTViewControllerCustomEverythingPhotoIndex) {
             photo.placeholderImage = [UIImage imageNamed:@"NYTimesBuildingPlaceholder"];
         }
+
+        NSString *caption = @"summary";
+        if (i == NYTViewControllerCustomEverythingPhotoIndex) {
+            caption = @"photo with custom everything";
+        }
+        else if (i == NYTViewControllerLongCaptionPhotoIndex) {
+            caption = @"photo with long caption. Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vestibulum maximus laoreet vehicula. Maecenas elit quam, pellentesque at tempor vel, tempus non sem. Vestibulum ut aliquam elit. Vivamus rhoncus sapien turpis, at feugiat augue luctus id. Nulla mi urna, viverra sed augue malesuada, bibendum bibendum massa. Cras urna nibh, lacinia vitae feugiat eu, consectetur a tellus. Morbi venenatis nunc sit amet varius pretium. Duis eget sem nec nulla lobortis finibus. Nullam pulvinar gravida est eget tristique. Curabitur faucibus nisl eu diam ullamcorper, at pharetra eros dictum. Suspendisse nibh urna, ultrices a augue a, euismod mattis felis. Ut varius tortor ac efficitur pellentesque. Mauris sit amet rhoncus dolor. Proin vel porttitor mi. Pellentesque lobortis interdum turpis, vitae tincidunt purus vestibulum vel. Phasellus tincidunt vel mi sit amet congue.";
+        }
+        else if (i == NYTViewControllerDefaultLoadingSpinnerPhotoIndex) {
+            caption = @"photo with loading spinner";
+        }
+        else if (i == NYTViewControllerNoReferenceViewPhotoIndex) {
+            caption = @"photo without reference view";
+        }
+        else if (i == NYTViewControllerCustomMaxZoomScalePhotoIndex) {
+            caption = @"photo with custom maximum zoom scale";
+        }
 
-        photo.attributedCaptionTitle = [[NSAttributedString alloc] initWithString:@(i + 1).stringValue attributes:@{NSForegroundColorAttributeName: [UIColor whiteColor]}];
-        photo.attributedCaptionSummary = [[NSAttributedString alloc] initWithString:@"summary" attributes:@{NSForegroundColorAttributeName: [UIColor grayColor]}];
-        photo.attributedCaptionCredit = [[NSAttributedString alloc] initWithString:@"credit" attributes:@{NSForegroundColorAttributeName: [UIColor darkGrayColor]}];
+        photo.attributedCaptionTitle = [[NSAttributedString alloc] initWithString:@(i + 1).stringValue attributes:@{NSForegroundColorAttributeName: [UIColor whiteColor], NSFontAttributeName: [UIFont preferredFontForTextStyle:UIFontTextStyleBody]}];
+        photo.attributedCaptionSummary = [[NSAttributedString alloc] initWithString:caption attributes:@{NSForegroundColorAttributeName: [UIColor lightGrayColor], NSFontAttributeName: [UIFont preferredFontForTextStyle:UIFontTextStyleBody]}];
+        photo.attributedCaptionCredit = [[NSAttributedString alloc] initWithString:@"credit" attributes:@{NSForegroundColorAttributeName: [UIColor grayColor], NSFontAttributeName: [UIFont preferredFontForTextStyle:UIFontTextStyleCaption1]}];
+
         [photos addObject:photo];
     }
 

Pod/Classes/ios/NYTPhotoCaptionView.h

@@ -7,16 +7,12 @@
 //
 
 @import UIKit;
-
-/**
- *  The left and right margin around the content.
- */
-extern const CGFloat NYTPhotoCaptionViewHorizontalMargin;
+#import "NYTPhotoCaptionViewLayoutWidthHinting.h"
 
 /**
  *  A view used to display the caption for a photo.
  */
-@interface NYTPhotoCaptionView : UIView
+@interface NYTPhotoCaptionView : UIView <NYTPhotoCaptionViewLayoutWidthHinting>
 
 /**
  *  Designated initializer that takes all the caption attributed strings as arguments.

Pod/Classes/ios/NYTPhotoCaptionView.m

@@ -8,8 +8,8 @@
 
 #import "NYTPhotoCaptionView.h"
 
-const CGFloat NYTPhotoCaptionViewHorizontalMargin = 16.0;
-static const CGFloat NYTPhotoCaptionViewVerticalMargin = 12.0;
+static const CGFloat NYTPhotoCaptionViewHorizontalMargin = 8.0;
+static const CGFloat NYTPhotoCaptionViewVerticalMargin = 7.0;
 
 @interface NYTPhotoCaptionView ()
 
@@ -19,13 +19,15 @@ - (instancetype)initWithCoder:(NSCoder *)aDecoder NS_DESIGNATED_INITIALIZER;
 @property (nonatomic, readonly) NSAttributedString *attributedSummary;
 @property (nonatomic, readonly) NSAttributedString *attributedCredit;
 
-@property (nonatomic) UILabel *textLabel;
+@property (nonatomic) UITextView *textView;
 @property (nonatomic) CAGradientLayer *gradientLayer;
 
 @end
 
 @implementation NYTPhotoCaptionView
 
+@synthesize preferredMaxLayoutWidth = _preferredMaxLayoutWidth;
+
 #pragma mark - UIView
 
 - (instancetype)initWithFrame:(CGRect)frame {
@@ -42,10 +44,42 @@ - (instancetype)initWithCoder:(NSCoder *)aDecoder {
     return self;
 }
 
++ (BOOL)requiresConstraintBasedLayout {
+    return YES;
+}
+
+- (void)didMoveToSuperview {
+    [super didMoveToSuperview];
+
+    NSLayoutConstraint *maxHeightConstraint = [NSLayoutConstraint constraintWithItem:self attribute:NSLayoutAttributeHeight relatedBy:NSLayoutRelationLessThanOrEqual toItem:self.superview attribute:NSLayoutAttributeHeight multiplier:0.3f constant:0.0f];
+    [self.superview addConstraint:maxHeightConstraint];
+}
+
 - (void)layoutSubviews {
     [super layoutSubviews];
-
-    self.gradientLayer.frame = self.layer.bounds;
+
+    // On iOS 8.x, when this view is height-constrained, neither `self.bounds` nor `self.layer.bounds` reflects the new layout height immediately after `[super layoutSubviews]`. Both of those properties appear correct in the next runloop.
+    // This problem doesn't affect iOS 9 and there may be a better solution; PRs welcome.
+    dispatch_async(dispatch_get_main_queue(), ^{
+        self.gradientLayer.frame = self.layer.bounds;
+    });
+}
+
+- (CGSize)intrinsicContentSize {
+    CGSize contentSize = [self.textView sizeThatFits:CGSizeMake(self.preferredMaxLayoutWidth, CGFLOAT_MAX)];
+    CGFloat width = (CGFloat)self.preferredMaxLayoutWidth;
+    CGFloat height = (CGFloat)ceil(contentSize.height);
+
+    return CGSizeMake(width, height);
+}
+
+- (void)setPreferredMaxLayoutWidth:(CGFloat)preferredMaxLayoutWidth {
+    preferredMaxLayoutWidth = (CGFloat)ceil(preferredMaxLayoutWidth);
+
+    if (ABS(_preferredMaxLayoutWidth - preferredMaxLayoutWidth) > 0.1) {
+        _preferredMaxLayoutWidth = preferredMaxLayoutWidth;
+        [self invalidateIntrinsicContentSize];
+    }
 }
 
 #pragma mark - NYTPhotoCaptionView
@@ -67,21 +101,25 @@ - (instancetype)initWithAttributedTitle:(NSAttributedString *)attributedTitle at
 - (void)commonInit {
     self.translatesAutoresizingMaskIntoConstraints = NO;
 
-    [self setupTextLabel];
-    [self updateTextLabelAttributedText];
+    [self setupTextView];
+    [self updateTextViewAttributedText];
     [self setupGradient];
 }
 
-- (void)setupTextLabel {
-    self.textLabel = [[UILabel alloc] init];
-    self.textLabel.numberOfLines = 0;
-    self.textLabel.translatesAutoresizingMaskIntoConstraints = NO;
-    [self addSubview:self.textLabel];
+- (void)setupTextView {
+    self.textView = [[UITextView alloc] initWithFrame:CGRectZero textContainer:nil];
+    self.textView.translatesAutoresizingMaskIntoConstraints = NO;
+    self.textView.editable = NO;
+    self.textView.dataDetectorTypes = UIDataDetectorTypeNone;
+    self.textView.backgroundColor = [UIColor clearColor];
+    self.textView.textContainerInset = UIEdgeInsetsMake(NYTPhotoCaptionViewVerticalMargin, NYTPhotoCaptionViewHorizontalMargin, NYTPhotoCaptionViewVerticalMargin, NYTPhotoCaptionViewHorizontalMargin);
+
+    [self addSubview:self.textView];
 
-    NSLayoutConstraint *topConstraint = [NSLayoutConstraint constraintWithItem:self.textLabel attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeTop multiplier:1.0 constant:NYTPhotoCaptionViewVerticalMargin];
-    NSLayoutConstraint *bottomConstraint = [NSLayoutConstraint constraintWithItem:self.textLabel attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeBottom multiplier:1.0 constant:-NYTPhotoCaptionViewVerticalMargin];
-    NSLayoutConstraint *widthConstraint = [NSLayoutConstraint constraintWithItem:self.textLabel attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeWidth multiplier:1.0 constant:-NYTPhotoCaptionViewHorizontalMargin * 2.0];
-    NSLayoutConstraint *horizontalPositionConstraint = [NSLayoutConstraint constraintWithItem:self.textLabel attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeCenterX multiplier:1.0 constant:0.0];
+    NSLayoutConstraint *topConstraint = [NSLayoutConstraint constraintWithItem:self.textView attribute:NSLayoutAttributeTop relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeTop multiplier:1.0 constant:0.0];
+    NSLayoutConstraint *bottomConstraint = [NSLayoutConstraint constraintWithItem:self.textView attribute:NSLayoutAttributeBottom relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeBottom multiplier:1.0 constant:0.0];
+    NSLayoutConstraint *widthConstraint = [NSLayoutConstraint constraintWithItem:self.textView attribute:NSLayoutAttributeWidth relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeWidth multiplier:1.0 constant:0.0];
+    NSLayoutConstraint *horizontalPositionConstraint = [NSLayoutConstraint constraintWithItem:self.textView attribute:NSLayoutAttributeCenterX relatedBy:NSLayoutRelationEqual toItem:self attribute:NSLayoutAttributeCenterX multiplier:1.0 constant:0.0];
 
     [self addConstraints:@[topConstraint, bottomConstraint, widthConstraint, horizontalPositionConstraint]];
 }
@@ -93,7 +131,7 @@ - (void)setupGradient {
     [self.layer insertSublayer:self.gradientLayer atIndex:0];
 }
 
-- (void)updateTextLabelAttributedText {
+- (void)updateTextViewAttributedText {
     NSMutableAttributedString *attributedLabelText = [[NSMutableAttributedString alloc] init];
 
     if (self.attributedTitle) {
@@ -116,7 +154,7 @@ - (void)updateTextLabelAttributedText {
         [attributedLabelText appendAttributedString:self.attributedCredit];
     }
 
-    self.textLabel.attributedText = attributedLabelText;
+    self.textView.attributedText = attributedLabelText;
 }
 
 @end

Pod/Classes/ios/NYTPhotosOverlayView.m

@@ -7,6 +7,7 @@
 //
 
 #import "NYTPhotosOverlayView.h"
+#import "NYTPhotoCaptionViewLayoutWidthHinting.h"
 
 @interface NYTPhotosOverlayView ()
 
@@ -49,6 +50,10 @@ - (void)layoutSubviews {
     }];
 
     [super layoutSubviews];
+
+    if ([self.captionView conformsToProtocol:@protocol(NYTPhotoCaptionViewLayoutWidthHinting)]) {
+        [(id<NYTPhotoCaptionViewLayoutWidthHinting>) self.captionView setPreferredMaxLayoutWidth:self.bounds.size.width];
+    }
 }
 
 #pragma mark - NYTPhotosOverlayView

Pod/Classes/ios/NYTPhotosViewController.h

@@ -1,6 +1,6 @@
 //
 //  NYTPhotosViewController.h
-//  NYTNewsReader
+//  NYTPhotoViewer
 //
 //  Created by Brian Capps on 2/10/15.
 //  Copyright (c) 2015 NYTimes. All rights reserved.

Pod/Classes/ios/NYTPhotosViewController.m

@@ -1,6 +1,6 @@
 //
 //  NYTPhotosViewController.m
-//  NYTNewsReader
+//  NYTPhotoViewer
 //
 //  Created by Brian Capps on 2/10/15.
 //  Copyright (c) 2015 NYTimes. All rights reserved.
@@ -23,7 +23,7 @@
 
 static const CGFloat NYTPhotosViewControllerOverlayAnimationDuration = 0.2;
 static const CGFloat NYTPhotosViewControllerInterPhotoSpacing = 16.0;
-static const UIEdgeInsets NYTPhotosViewControllerCloseButtinImageInsets = {3, 0, -3, 0};
+static const UIEdgeInsets NYTPhotosViewControllerCloseButtonImageInsets = {3, 0, -3, 0};
 
 @interface NYTPhotosViewController () <UIPageViewControllerDataSource, UIPageViewControllerDelegate, NYTPhotoViewControllerDelegate>
 
@@ -171,10 +171,9 @@ - (void)commonInitWithPhotos:(NSArray *)photos initialPhoto:(id <NYTPhoto>)initi
     self.transitioningDelegate = _transitionController;
     self.modalPresentationCapturesStatusBarAppearance = YES;
 
-    // iOS 7 has an issue with constraints that could evaluate to be negative, so we set the width to the margins' size.
-    _overlayView = [[NYTPhotosOverlayView alloc] initWithFrame:CGRectMake(0, 0, NYTPhotoCaptionViewHorizontalMargin * 2.0, 0)];
+    _overlayView = [[NYTPhotosOverlayView alloc] initWithFrame:CGRectZero];
     _overlayView.leftBarButtonItem = [[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:@"NYTPhotoViewerCloseButtonX" inBundle:[NSBundle nyt_photoViewerResourceBundle] compatibleWithTraitCollection:nil] landscapeImagePhone:[UIImage imageNamed:@"NYTPhotoViewerCloseButtonXLandscape" inBundle:[NSBundle nyt_photoViewerResourceBundle] compatibleWithTraitCollection:nil] style:UIBarButtonItemStylePlain target:self action:@selector(doneButtonTapped:)];
-    _overlayView.leftBarButtonItem.imageInsets = NYTPhotosViewControllerCloseButtinImageInsets;
+    _overlayView.leftBarButtonItem.imageInsets = NYTPhotosViewControllerCloseButtonImageInsets;
     _overlayView.rightBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemAction target:self action:@selector(actionButtonTapped:)];
 
     _notificationCenter = [[NSNotificationCenter alloc] init];

Pod/Classes/ios/Protocols/NYTPhoto.h

@@ -1,6 +1,6 @@
 //
 //  NYTPhoto.h
-//  NYTNewsReader
+//  NYTPhotoViewer
 //
 //  Created by Brian Capps on 2/10/15.
 //  Copyright (c) 2015 NYTimes. All rights reserved.

Pod/Classes/ios/Protocols/NYTPhotoCaptionViewLayoutWidthHinting.h

@@ -0,0 +1,29 @@
+//
+//  NYTPhotoCaptionViewLayoutWidthHinting.h
+//  NYTPhotoViewer
+//
+//  Created by Chris Dzombak on 10/30/15.
+//
+//
+
+@import Foundation;
+@import UIKit;
+
+/**
+ *  Allows a view to opt-in to receiving a hint of its layout width. This aids in calculating an appropriate intrinsic content size.
+ */
+@protocol NYTPhotoCaptionViewLayoutWidthHinting <NSObject>
+
+/**
+ *  The preferred maximum width, in points, of this caption view.
+ *
+ *  This property works exactly as it does on `UILabel`.
+ *
+ *  This property affects the size of the view when layout constraints are applied to it. During layout, if the text extends beyond the width specified by this property, the additional text is flowed to one or more new lines, thereby increasing the height of the view.
+ */
+@property (nonatomic) CGFloat preferredMaxLayoutWidth;
+
+@end
+
+@interface UILabel (NYTPhotoCaptionViewLayoutWidthHinting) <NYTPhotoCaptionViewLayoutWidthHinting>
+@end

Pod/Classes/ios/Protocols/NYTPhotosViewControllerDataSource.h

@@ -1,6 +1,6 @@
 //
 //  NYTPhotosViewControllerDataSource.h
-//  NYTNewsReader
+//  NYTPhotoViewer
 //
 //  Created by Brian Capps on 2/10/15.
 //  Copyright (c) 2015 NYTimes. All rights reserved.