Swiftgram/AsyncDisplayKit/Details/ASTextNodeTextKitHelpers.mm
2015-01-25 16:27:01 -08:00

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/* Copyright (c) 2014-present, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
#import "ASTextNodeTextKitHelpers.h"
@interface ASTextKitComponents ()
// read-write redeclarations
@property (nonatomic, strong, readwrite) NSTextStorage *textStorage;
@property (nonatomic, strong, readwrite) NSTextContainer *textContainer;
@property (nonatomic, strong, readwrite) NSLayoutManager *layoutManager;
@end
@implementation ASTextKitComponents
+ (ASTextKitComponents *)componentsWithAttributedSeedString:(NSAttributedString *)attributedSeedString
textContainerSize:(CGSize)textContainerSize
{
ASTextKitComponents *components = [[ASTextKitComponents alloc] init];
// Create the TextKit component stack with our default configuration.
components.textStorage = (attributedSeedString ? [[NSTextStorage alloc] initWithAttributedString:attributedSeedString] : [[NSTextStorage alloc] init]);
components.layoutManager = [[NSLayoutManager alloc] init];
[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, FLT_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;
}
@end