#import "ASTextKitComponents.h"

@interface ASTextKitComponents ()

@property (nonatomic, strong, readwrite) NSTextStorage *textStorage;

@property (nonatomic, strong, readwrite) NSTextContainer *textContainer;

@property (nonatomic, strong, readwrite) NSLayoutManager *layoutManager;

@implementation ASTextKitComponents

+ (instancetype)componentsWithAttributedSeedString:(NSAttributedString *)attributedSeedString

textContainerSize:(CGSize)textContainerSize

{

NSTextStorage *textStorage = attributedSeedString ? [[NSTextStorage alloc] initWithAttributedString:attributedSeedString] : [[NSTextStorage alloc] init];

return [self componentsWithTextStorage:textStorage

textContainerSize:textContainerSize

layoutManager:[[NSLayoutManager alloc] init]];

}

+ (instancetype)componentsWithTextStorage:(NSTextStorage *)textStorage

textContainerSize:(CGSize)textContainerSize

layoutManager:(NSLayoutManager *)layoutManager

{

ASTextKitComponents *components = [[self alloc] init];

components.textStorage = textStorage;

components.layoutManager = layoutManager;

[components.textStorage addLayoutManager:components.layoutManager];

components.textContainer = [[NSTextContainer alloc] initWithSize:textContainerSize];

components.textContainer.lineFragmentPadding = 0.0; // We want the text laid out up to the very edges of the text-view.

[components.layoutManager addTextContainer:components.textContainer];

return components;

}

- (CGSize)sizeForConstrainedWidth:(CGFloat)constrainedWidth

{

ASTextKitComponents *components = self;

// If our text-view's width is already the constrained width, we can use our existing TextKit stack for this sizing calculation.

// Otherwise, we create a temporary stack to size for `constrainedWidth`.

if (CGRectGetWidth(components.textView.bounds) != constrainedWidth) {

components = [ASTextKitComponents componentsWithAttributedSeedString:components.textStorage textContainerSize:CGSizeMake(constrainedWidth, CGFLOAT_MAX)];

}

// Force glyph generation and layout, which may not have happened yet (and isn't triggered by -usedRectForTextContainer:).

[components.layoutManager ensureLayoutForTextContainer:components.textContainer];

CGSize textSize = [components.layoutManager usedRectForTextContainer:components.textContainer].size;

return textSize;

}