//

// ASTextNode.mm

// AsyncDisplayKit

//

// 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 "ASTextNode.h"

#import "ASTextNode+Beta.h"

#include <mutex>

#import <tgmath.h>

#import "_ASDisplayLayer.h"

#import "ASDisplayNode+Subclasses.h"

#import "ASDisplayNodeInternal.h"

#import "ASHighlightOverlayLayer.h"

#import "ASDisplayNodeExtras.h"

#import "ASTextKitCoreTextAdditions.h"

#import "ASTextKitRenderer+Positioning.h"

#import "ASTextKitShadower.h"

#import "ASInternalHelpers.h"

#import "ASLayout.h"

#import "CGRect+ASConvenience.h"

#import "ASObjectDescriptionHelpers.h"

/**

* If set, we will record all values set to attributedText into an array

* and once we get 2000, we'll write them all out into a plist file.

*

* This is useful for gathering realistic text data sets from apps for performance

* testing.

*/

#define AS_TEXTNODE_RECORD_ATTRIBUTED_STRINGS 0

static const NSTimeInterval ASTextNodeHighlightFadeOutDuration = 0.15;

static const NSTimeInterval ASTextNodeHighlightFadeInDuration = 0.1;

static const CGFloat ASTextNodeHighlightLightOpacity = 0.11;

static const CGFloat ASTextNodeHighlightDarkOpacity = 0.22;

static NSString *ASTextNodeTruncationTokenAttributeName = @"ASTextNodeTruncationAttribute";

#pragma mark - ASTextKitRenderer

// Not used at the moment but handy to have

/*ASDISPLAYNODE_INLINE NSUInteger ASHashFromCGRect(CGRect rect)

{

return ((*(NSUInteger *)&rect.origin.x << 10 ^ *(NSUInteger *)&rect.origin.y) + (*(NSUInteger *)&rect.size.width << 10 ^ *(NSUInteger *)&rect.size.height));

}*/

ASDISPLAYNODE_INLINE NSUInteger ASHashFromCGSize(CGSize size)

{

return ((*(NSUInteger *)&size.width << 10 ^ *(NSUInteger *)&size.height));

}

@interface ASTextNodeRendererKey : NSObject

@property (assign, nonatomic) ASTextKitAttributes attributes;

@property (assign, nonatomic) CGSize constrainedSize;

@end

@implementation ASTextNodeRendererKey

- (NSUInteger)hash

{

return _attributes.hash() ^ ASHashFromCGSize(_constrainedSize);

}

- (BOOL)isEqual:(ASTextNodeRendererKey *)object

{

if (self == object) {

return YES;

}

return _attributes == object.attributes

&& CGSizeEqualToSize(_constrainedSize, object.constrainedSize);

}

@end

static NSCache *sharedRendererCache()

{

static dispatch_once_t onceToken;

static NSCache *__rendererCache = nil;

dispatch_once(&onceToken, ^{

__rendererCache = [[NSCache alloc] init];

__rendererCache.totalCostLimit = 500; // 500 renders cache

});

return __rendererCache;

}

/**

The concept here is that neither the node nor layout should ever have a strong reference to the renderer object.

This is to reduce memory load when loading thousands and thousands of text nodes into memory at once. Instead

we maintain a LRU renderer cache that is queried via stack-allocated keys.

*/

static ASTextKitRenderer *rendererForAttributes(ASTextKitAttributes attributes, CGSize constrainedSize)

{

NSCache *cache = sharedRendererCache();

ASTextNodeRendererKey *key = [[ASTextNodeRendererKey alloc] init];

key.attributes = attributes;

key.constrainedSize = constrainedSize;

ASTextKitRenderer *renderer = [cache objectForKey:key];

if (renderer == nil) {

renderer = [[ASTextKitRenderer alloc] initWithTextKitAttributes:attributes constrainedSize:constrainedSize];

[cache setObject:renderer forKey:key cost:1];

}

return renderer;

}

#pragma mark - ASTextNode

struct ASTextNodeDrawParameter {

CGRect bounds;

UIColor *backgroundColor;

};

@interface ASTextNode () <UIGestureRecognizerDelegate>

@end

@implementation ASTextNode {

CGSize _shadowOffset;

CGColorRef _shadowColor;

UIColor *_cachedShadowUIColor;

CGFloat _shadowOpacity;

CGFloat _shadowRadius;

UIEdgeInsets _textContainerInset;

NSArray *_exclusionPaths;

NSAttributedString *_composedTruncationText;

NSString *_highlightedLinkAttributeName;

id _highlightedLinkAttributeValue;

ASTextNodeHighlightStyle _highlightStyle;

NSRange _highlightRange;

ASHighlightOverlayLayer *_activeHighlightLayer;

CGSize _constrainedSize;

ASTextNodeDrawParameter _drawParameter;

UILongPressGestureRecognizer *_longPressGestureRecognizer;

}

@dynamic placeholderEnabled;

#pragma mark - NSObject

+ (void)initialize

{

[super initialize];

if (self != [ASTextNode class]) {

// Prevent custom drawing in subclasses

ASDisplayNodeAssert(!ASSubclassOverridesClassSelector([ASTextNode class], self, @selector(drawRect:withParameters:isCancelled:isRasterizing:)), @"Subclass %@ must not override drawRect:withParameters:isCancelled:isRasterizing: method. Custom drawing in %@ subclass is not supported.", NSStringFromClass(self), NSStringFromClass([ASTextNode class]));

}

}

static NSArray *DefaultLinkAttributeNames = @[ NSLinkAttributeName ];

- (instancetype)init

{

if (self = [super init]) {

// Load default values from superclass.

_shadowOffset = [super shadowOffset];

CGColorRef superColor = [super shadowColor];

if (superColor != NULL) {

_shadowColor = CGColorRetain(superColor);

}

_shadowOpacity = [super shadowOpacity];

_shadowRadius = [super shadowRadius];

// Disable user interaction for text node by default.

self.userInteractionEnabled = NO;

self.needsDisplayOnBoundsChange = YES;

_truncationMode = NSLineBreakByWordWrapping;

_composedTruncationText = DefaultTruncationAttributedString();

// The common case is for a text node to be non-opaque and blended over some background.

self.opaque = NO;

self.backgroundColor = [UIColor clearColor];

self.linkAttributeNames = DefaultLinkAttributeNames;

// Accessibility

self.isAccessibilityElement = YES;

self.accessibilityTraits = UIAccessibilityTraitStaticText;

_constrainedSize = CGSizeMake(-INFINITY, -INFINITY);

// Placeholders

// Disabled by default in ASDisplayNode, but add a few options for those who toggle

// on the special placeholder behavior of ASTextNode.

_placeholderColor = ASDisplayNodeDefaultPlaceholderColor();

_placeholderInsets = UIEdgeInsetsMake(1.0, 0.0, 1.0, 0.0);

}

return self;

}

- (void)dealloc

{

if (_shadowColor != NULL) {

CGColorRelease(_shadowColor);

}

if (_longPressGestureRecognizer) {

_longPressGestureRecognizer.delegate = nil;

[_longPressGestureRecognizer removeTarget:nil action:NULL];

[self.view removeGestureRecognizer:_longPressGestureRecognizer];

}

}

#pragma mark - Description

- (NSString *)_plainStringForDescription

{

NSString *plainString = [[self.attributedText string] stringByTrimmingCharactersInSet:[NSCharacterSet newlineCharacterSet]];

if (plainString.length > 50) {

plainString = [[plainString substringToIndex:50] stringByAppendingString:@"\u2026"];

}

return plainString;

}

- (NSMutableArray<NSDictionary *> *)propertiesForDescription

{

NSMutableArray *result = [super propertiesForDescription];

NSString *plainString = [self _plainStringForDescription];

if (plainString.length > 0) {

[result insertObject:@{ @"text" : ASStringWithQuotesIfMultiword(plainString) } atIndex:0];

}

return result;

}

- (NSMutableArray<NSDictionary *> *)propertiesForDebugDescription

{

NSMutableArray *result = [super propertiesForDebugDescription];

NSString *plainString = [self _plainStringForDescription];

if (plainString.length > 0) {

[result insertObject:@{ @"text" : ASStringWithQuotesIfMultiword(plainString) } atIndex:0];

}

return result;

}

#pragma mark - ASDisplayNode

- (void)didLoad

{

[super didLoad];

// If we are view-backed and the delegate cares, support the long-press callback.

SEL longPressCallback = @selector(textNode:longPressedLinkAttribute:value:atPoint:textRange:);

if (!self.isLayerBacked && [_delegate respondsToSelector:longPressCallback]) {

_longPressGestureRecognizer = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(_handleLongPress:)];

_longPressGestureRecognizer.cancelsTouchesInView = self.longPressCancelsTouches;

_longPressGestureRecognizer.delegate = self;

[self.view addGestureRecognizer:_longPressGestureRecognizer];

}

}

#pragma mark - Renderer Management

- (ASTextKitRenderer *)_renderer

{

return [self _rendererWithBounds:self.threadSafeBounds];

}

- (ASTextKitRenderer *)_rendererWithBounds:(CGRect)bounds

{

ASDN::MutexLocker l(__instanceLock__);

CGSize constrainedSize;

if (_constrainedSize.width != -INFINITY) {

constrainedSize = _constrainedSize;

} else {

constrainedSize = bounds.size;

constrainedSize.width -= (_textContainerInset.left + _textContainerInset.right);

constrainedSize.height -= (_textContainerInset.top + _textContainerInset.bottom);

}

return rendererForAttributes([self _rendererAttributes], constrainedSize);

}

- (ASTextKitAttributes)_rendererAttributes

{

ASDN::MutexLocker l(__instanceLock__);

return {

.attributedString = _attributedText,

.truncationAttributedString = _composedTruncationText,

.lineBreakMode = _truncationMode,

.maximumNumberOfLines = _maximumNumberOfLines,

.exclusionPaths = _exclusionPaths,

.shadowOffset = _shadowOffset,

.shadowColor = _cachedShadowUIColor,

.shadowOpacity = _shadowOpacity,

.shadowRadius = _shadowRadius,

// use the property getter so a subclass can provide these scale factors on demand if desired

.pointSizeScaleFactors = self.pointSizeScaleFactors

};

}

#pragma mark - Layout and Sizing

- (void)setTextContainerInset:(UIEdgeInsets)textContainerInset

{

ASDN::MutexLocker l(__instanceLock__);

BOOL needsUpdate = !UIEdgeInsetsEqualToEdgeInsets(textContainerInset, _textContainerInset);

if (needsUpdate) {

_textContainerInset = textContainerInset;

[self invalidateCalculatedLayout];

[self setNeedsLayout];

}

}

- (UIEdgeInsets)textContainerInset

{

ASDN::MutexLocker l(__instanceLock__);

return _textContainerInset;

}

- (void)calculatedLayoutDidChange

{

[super calculatedLayoutDidChange];

ASLayout *layout = self.calculatedLayout;

if (layout != nil) {

ASDN::MutexLocker l(__instanceLock__);

CGSize layoutSize = layout.size;

// Apply textContainerInset

layoutSize.width -= (_textContainerInset.left + _textContainerInset.right);

layoutSize.height -= (_textContainerInset.top + _textContainerInset.bottom);

if (CGSizeEqualToSize(_constrainedSize, layoutSize) == NO) {

_constrainedSize = layoutSize;

}

}

}

- (CGSize)calculateSizeThatFits:(CGSize)constrainedSize

{

ASDN::MutexLocker l(__instanceLock__);

ASDisplayNodeAssert(constrainedSize.width >= 0, @"Constrained width for text (%f) is too narrow", constrainedSize.width);

ASDisplayNodeAssert(constrainedSize.height >= 0, @"Constrained height for text (%f) is too short", constrainedSize.height);

// Cache the original constrained size for final size calculateion

CGSize originalConstrainedSize = constrainedSize;

// Adjust constrainedSize for textContainerInset before assigning it

constrainedSize.width -= (_textContainerInset.left + _textContainerInset.right);

constrainedSize.height -= (_textContainerInset.top + _textContainerInset.bottom);

_constrainedSize = constrainedSize;

ASTextKitRenderer *renderer = [self _renderer];

CGSize size = renderer.size;

if (_attributedText.length > 0) {

self.ascender = [[self class] ascenderWithAttributedString:_attributedText];

self.descender = [[_attributedText attribute:NSFontAttributeName atIndex:_attributedText.length - 1 effectiveRange:NULL] descender];

if (renderer.currentScaleFactor > 0 && renderer.currentScaleFactor < 1.0) {

// while not perfect, this is a good estimate of what the ascender of the scaled font will be.

self.ascender *= renderer.currentScaleFactor;

self.descender *= renderer.currentScaleFactor;

}

}

// Add textContainerInset to size

size.width += (_textContainerInset.left + _textContainerInset.right);

size.height += (_textContainerInset.top + _textContainerInset.bottom);

return CGSizeMake(std::fmin(size.width, originalConstrainedSize.width),

std::fmin(size.height, originalConstrainedSize.height));

}

#pragma mark - Modifying User Text

// Returns the ascender of the first character in attributedString by also including the line height if specified in paragraph style.

+ (CGFloat)ascenderWithAttributedString:(NSAttributedString *)attributedString

{

UIFont *font = [attributedString attribute:NSFontAttributeName atIndex:0 effectiveRange:NULL];

NSParagraphStyle *paragraphStyle = [attributedString attribute:NSParagraphStyleAttributeName atIndex:0 effectiveRange:NULL];

if (!paragraphStyle) {

return font.ascender;

}

CGFloat lineHeight = MAX(font.lineHeight, paragraphStyle.minimumLineHeight);

if (paragraphStyle.maximumLineHeight > 0) {

lineHeight = MIN(lineHeight, paragraphStyle.maximumLineHeight);

}

return lineHeight + font.descender;

}

- (void)setAttributedText:(NSAttributedString *)attributedText

{

if (attributedText == nil) {

attributedText = [[NSAttributedString alloc] initWithString:@"" attributes:nil];

}

// Don't hold textLock for too long.

{

ASDN::MutexLocker l(__instanceLock__);

if (ASObjectIsEqual(attributedText, _attributedText)) {

return;

}

_attributedText = ASCleanseAttributedStringOfCoreTextAttributes(attributedText);

#if AS_TEXTNODE_RECORD_ATTRIBUTED_STRINGS

[ASTextNode _registerAttributedText:_attributedText];

#endif

// Sync the truncation string with attributes from the updated _attributedString

// Without this, the size calculation of the text with truncation applied will

// not take into account the attributes of attributedText in the last line

[self _updateComposedTruncationText];

}

NSUInteger length = attributedText.length;

if (length > 0) {

self.ascender = [[self class] ascenderWithAttributedString:attributedText];

self.descender = [[attributedText attribute:NSFontAttributeName atIndex:attributedText.length - 1 effectiveRange:NULL] descender];

}

// Tell the display node superclasses that the cached layout is incorrect now

[self invalidateCalculatedLayout];

// Force display to create renderer with new size and redisplay with new string

[self setNeedsDisplay];

// Accessiblity

self.accessibilityLabel = attributedText.string;

self.isAccessibilityElement = (length != 0); // We're an accessibility element by default if there is a string.

}

#pragma mark - Text Layout

- (void)setExclusionPaths:(NSArray *)exclusionPaths

{

ASDN::MutexLocker l(__instanceLock__);

if (ASObjectIsEqual(exclusionPaths, _exclusionPaths)) {

return;

}

_exclusionPaths = [exclusionPaths copy];

[self invalidateCalculatedLayout];

[self setNeedsDisplay];

}

- (NSArray *)exclusionPaths

{

ASDN::MutexLocker l(__instanceLock__);

return _exclusionPaths;

}

#pragma mark - Drawing

- (NSObject *)drawParametersForAsyncLayer:(_ASDisplayLayer *)layer

{

ASDN::MutexLocker l(__instanceLock__);

_drawParameter = {

.backgroundColor = self.backgroundColor,

.bounds = self.bounds

};

return nil;

}

- (void)drawRect:(CGRect)bounds withParameters:(id <NSObject>)p isCancelled:(asdisplaynode_iscancelled_block_t)isCancelledBlock isRasterizing:(BOOL)isRasterizing;

{

ASDN::MutexLocker l(__instanceLock__);

ASTextNodeDrawParameter drawParameter = _drawParameter;

CGRect drawParameterBounds = drawParameter.bounds;

UIColor *backgroundColor = isRasterizing ? nil : drawParameter.backgroundColor;

CGContextRef context = UIGraphicsGetCurrentContext();

ASDisplayNodeAssert(context, @"This is no good without a context.");

CGContextSaveGState(context);

CGContextTranslateCTM(context, _textContainerInset.left, _textContainerInset.top);

ASTextKitRenderer *renderer = [self _rendererWithBounds:drawParameterBounds];

UIEdgeInsets shadowPadding = [self shadowPaddingWithRenderer:renderer];

CGPoint boundsOrigin = drawParameterBounds.origin;

CGPoint textOrigin = CGPointMake(boundsOrigin.x - shadowPadding.left, boundsOrigin.y - shadowPadding.top);

// Fill background

if (backgroundColor != nil) {

[backgroundColor setFill];

UIRectFillUsingBlendMode(CGContextGetClipBoundingBox(context), kCGBlendModeCopy);

}

// Draw shadow

[renderer.shadower setShadowInContext:context];

// Draw text

bounds.origin = textOrigin;

[renderer drawInContext:context bounds:bounds];

CGContextRestoreGState(context);

}

#pragma mark - Attributes

- (id)linkAttributeValueAtPoint:(CGPoint)point

attributeName:(out NSString **)attributeNameOut

range:(out NSRange *)rangeOut

{

return [self _linkAttributeValueAtPoint:point

attributeName:attributeNameOut

range:rangeOut

inAdditionalTruncationMessage:NULL

forHighlighting:NO];

}

- (id)_linkAttributeValueAtPoint:(CGPoint)point

attributeName:(out NSString **)attributeNameOut

range:(out NSRange *)rangeOut

inAdditionalTruncationMessage:(out BOOL *)inAdditionalTruncationMessageOut

forHighlighting:(BOOL)highlighting

{

ASDisplayNodeAssertMainThread();

ASDN::MutexLocker l(__instanceLock__);

ASTextKitRenderer *renderer = [self _renderer];

NSRange visibleRange = renderer.firstVisibleRange;

NSAttributedString *attributedString = _attributedText;

NSRange clampedRange = NSIntersectionRange(visibleRange, NSMakeRange(0, attributedString.length));

// Check in a 9-point region around the actual touch point so we make sure

// we get the best attribute for the touch.

__block CGFloat minimumGlyphDistance = CGFLOAT_MAX;

// Final output vars

__block id linkAttributeValue = nil;

__block BOOL inTruncationMessage = NO;

[renderer enumerateTextIndexesAtPosition:point usingBlock:^(NSUInteger characterIndex, CGRect glyphBoundingRect, BOOL *stop) {

CGPoint glyphLocation = CGPointMake(CGRectGetMidX(glyphBoundingRect), CGRectGetMidY(glyphBoundingRect));

CGFloat currentDistance = std::sqrt(std::pow(point.x - glyphLocation.x, 2.f) + std::pow(point.y - glyphLocation.y, 2.f));

if (currentDistance >= minimumGlyphDistance) {

// If the distance computed from the touch to the glyph location is

// not the minimum among the located link attributes, we can just skip

// to the next location.

return;

}

// Check if it's outside the visible range, if so, then we mark this touch

// as inside the truncation message, because in at least one of the touch

// points it was.

if (!(NSLocationInRange(characterIndex, visibleRange))) {

inTruncationMessage = YES;

}

if (inAdditionalTruncationMessageOut != NULL) {

*inAdditionalTruncationMessageOut = inTruncationMessage;

}

// Short circuit here if it's just in the truncation message. Since the

// truncation message may be beyond the scope of the actual input string,

// we have to make sure that we don't start asking for attributes on it.

if (inTruncationMessage) {

return;

}

for (NSString *attributeName in _linkAttributeNames) {

NSRange range;

id value = [attributedString attribute:attributeName atIndex:characterIndex longestEffectiveRange:&range inRange:clampedRange];

NSString *name = attributeName;

if (value == nil || name == nil) {

// Didn't find anything

continue;

}

// If highlighting, check with delegate first. If not implemented, assume YES.

if (highlighting

&& [_delegate respondsToSelector:@selector(textNode:shouldHighlightLinkAttribute:value:atPoint:)]

&& ![_delegate textNode:self shouldHighlightLinkAttribute:name value:value atPoint:point]) {

value = nil;

name = nil;

}

if (value != nil || name != nil) {

// We found a minimum glyph distance link attribute, so set the min

// distance, and the out params.

minimumGlyphDistance = currentDistance;

if (rangeOut != NULL && value != nil) {

*rangeOut = range;

// Limit to only the visible range, because the attributed string will

// return values outside the visible range.

if (NSMaxRange(*rangeOut) > NSMaxRange(visibleRange)) {

(*rangeOut).length = MAX(NSMaxRange(visibleRange) - (*rangeOut).location, 0);

}

}

if (attributeNameOut != NULL) {

*attributeNameOut = name;

}

// Set the values for the next iteration

linkAttributeValue = value;

break;

}

}

}];

return linkAttributeValue;

}

#pragma mark - UIGestureRecognizerDelegate

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer

{

ASDisplayNodeAssertMainThread();

if (gestureRecognizer == _longPressGestureRecognizer) {

// Don't allow long press on truncation message

if ([self _pendingTruncationTap]) {

return NO;

}

// Ask our delegate if a long-press on an attribute is relevant

if ([_delegate respondsToSelector:@selector(textNode:shouldLongPressLinkAttribute:value:atPoint:)]) {

return [_delegate textNode:self

shouldLongPressLinkAttribute:_highlightedLinkAttributeName

value:_highlightedLinkAttributeValue

atPoint:[gestureRecognizer locationInView:self.view]];

}

// Otherwise we are good to go.

return YES;

}

if (([self _pendingLinkTap] || [self _pendingTruncationTap])

&& [gestureRecognizer isKindOfClass:[UITapGestureRecognizer class]]

&& CGRectContainsPoint(self.threadSafeBounds, [gestureRecognizer locationInView:self.view])) {

return NO;

}

return [super gestureRecognizerShouldBegin:gestureRecognizer];

}

#pragma mark - Highlighting

- (ASTextNodeHighlightStyle)highlightStyle

{

ASDN::MutexLocker l(__instanceLock__);

return _highlightStyle;

}

- (void)setHighlightStyle:(ASTextNodeHighlightStyle)highlightStyle

{

ASDN::MutexLocker l(__instanceLock__);

_highlightStyle = highlightStyle;

}

- (NSRange)highlightRange

{

ASDisplayNodeAssertMainThread();

return _highlightRange;

}

- (void)setHighlightRange:(NSRange)highlightRange

{

[self setHighlightRange:highlightRange animated:NO];

}

- (void)setHighlightRange:(NSRange)highlightRange animated:(BOOL)animated

{

[self _setHighlightRange:highlightRange forAttributeName:nil value:nil animated:animated];

}

- (void)_setHighlightRange:(NSRange)highlightRange forAttributeName:(NSString *)highlightedAttributeName value:(id)highlightedAttributeValue animated:(BOOL)animated

{

ASDisplayNodeAssertMainThread();

_highlightedLinkAttributeName = highlightedAttributeName;

_highlightedLinkAttributeValue = highlightedAttributeValue;

if (!NSEqualRanges(highlightRange, _highlightRange) && ((0 != highlightRange.length) || (0 != _highlightRange.length))) {

_highlightRange = highlightRange;

if (_activeHighlightLayer) {

if (animated) {

__weak CALayer *weakHighlightLayer = _activeHighlightLayer;

_activeHighlightLayer = nil;

weakHighlightLayer.opacity = 0.0;

CFTimeInterval beginTime = CACurrentMediaTime();

CABasicAnimation *possibleFadeIn = (CABasicAnimation *)[weakHighlightLayer animationForKey:@"opacity"];

if (possibleFadeIn) {

// Calculate when we should begin fading out based on the end of the fade in animation,

// Also check to make sure that the new begin time hasn't already passed

CGFloat newBeginTime = (possibleFadeIn.beginTime + possibleFadeIn.duration);

if (newBeginTime > beginTime) {

beginTime = newBeginTime;

}

}

CABasicAnimation *fadeOut = [CABasicAnimation animationWithKeyPath:@"opacity"];

fadeOut.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut];

fadeOut.fromValue = possibleFadeIn.toValue ? : @(((CALayer *)weakHighlightLayer.presentationLayer).opacity);

fadeOut.toValue = @0.0;

fadeOut.fillMode = kCAFillModeBoth;

fadeOut.duration = ASTextNodeHighlightFadeOutDuration;

fadeOut.beginTime = beginTime;

dispatch_block_t prev = [CATransaction completionBlock];

[CATransaction setCompletionBlock:^{

[weakHighlightLayer removeFromSuperlayer];

}];

[weakHighlightLayer addAnimation:fadeOut forKey:fadeOut.keyPath];

[CATransaction setCompletionBlock:prev];

} else {

[_activeHighlightLayer removeFromSuperlayer];

_activeHighlightLayer = nil;

}

}

if (0 != highlightRange.length) {

// Find layer in hierarchy that allows us to draw highlighting on.

CALayer *highlightTargetLayer = self.layer;

while (highlightTargetLayer != nil) {

if (highlightTargetLayer.as_allowsHighlightDrawing) {

break;

}

highlightTargetLayer = highlightTargetLayer.superlayer;

}

if (highlightTargetLayer != nil) {

ASDN::MutexLocker l(__instanceLock__);

ASTextKitRenderer *renderer = [self _renderer];

NSArray *highlightRects = [renderer rectsForTextRange:highlightRange measureOption:ASTextKitRendererMeasureOptionBlock];

NSMutableArray *converted = [NSMutableArray arrayWithCapacity:highlightRects.count];

for (NSValue *rectValue in highlightRects) {

UIEdgeInsets shadowPadding = renderer.shadower.shadowPadding;

CGRect rendererRect = ASTextNodeAdjustRenderRectForShadowPadding(rectValue.CGRectValue, shadowPadding);

// The rects returned from renderer don't have `textContainerInset`,

// as well as they are using the `constrainedSize` for layout,

// so we can simply increase the rect by insets to get the full blown layout.

rendererRect.size.width += _textContainerInset.left + _textContainerInset.right;

rendererRect.size.height += _textContainerInset.top + _textContainerInset.bottom;

CGRect highlightedRect = [self.layer convertRect:rendererRect toLayer:highlightTargetLayer];

// We set our overlay layer's frame to the bounds of the highlight target layer.

// Offset highlight rects to avoid double-counting target layer's bounds.origin.

highlightedRect.origin.x -= highlightTargetLayer.bounds.origin.x;

highlightedRect.origin.y -= highlightTargetLayer.bounds.origin.y;

[converted addObject:[NSValue valueWithCGRect:highlightedRect]];

}

ASHighlightOverlayLayer *overlayLayer = [[ASHighlightOverlayLayer alloc] initWithRects:converted];

overlayLayer.highlightColor = [[self class] _highlightColorForStyle:self.highlightStyle];

overlayLayer.frame = highlightTargetLayer.bounds;

overlayLayer.masksToBounds = NO;

overlayLayer.opacity = [[self class] _highlightOpacityForStyle:self.highlightStyle];

[highlightTargetLayer addSublayer:overlayLayer];

if (animated) {

CABasicAnimation *fadeIn = [CABasicAnimation animationWithKeyPath:@"opacity"];

fadeIn.fromValue = @0.0;

fadeIn.toValue = @(overlayLayer.opacity);

fadeIn.duration = ASTextNodeHighlightFadeInDuration;

fadeIn.beginTime = CACurrentMediaTime();

[overlayLayer addAnimation:fadeIn forKey:fadeIn.keyPath];

}

[overlayLayer setNeedsDisplay];

_activeHighlightLayer = overlayLayer;

}

}

}

}

- (void)_clearHighlightIfNecessary

{

ASDisplayNodeAssertMainThread();

if ([self _pendingLinkTap] || [self _pendingTruncationTap]) {

[self setHighlightRange:NSMakeRange(0, 0) animated:YES];

}

}

+ (CGColorRef)_highlightColorForStyle:(ASTextNodeHighlightStyle)style

{

return [UIColor colorWithWhite:(style == ASTextNodeHighlightStyleLight ? 0.0 : 1.0) alpha:1.0].CGColor;

}

+ (CGFloat)_highlightOpacityForStyle:(ASTextNodeHighlightStyle)style

{

return (style == ASTextNodeHighlightStyleLight) ? ASTextNodeHighlightLightOpacity : ASTextNodeHighlightDarkOpacity;

}

#pragma mark - Text rects

static CGRect ASTextNodeAdjustRenderRectForShadowPadding(CGRect rendererRect, UIEdgeInsets shadowPadding) {

rendererRect.origin.x -= shadowPadding.left;

rendererRect.origin.y -= shadowPadding.top;

return rendererRect;

}

- (NSArray *)rectsForTextRange:(NSRange)textRange

{

return [self _rectsForTextRange:textRange measureOption:ASTextKitRendererMeasureOptionCapHeight];

}

- (NSArray *)highlightRectsForTextRange:(NSRange)textRange

{

return [self _rectsForTextRange:textRange measureOption:ASTextKitRendererMeasureOptionBlock];

}

- (NSArray *)_rectsForTextRange:(NSRange)textRange measureOption:(ASTextKitRendererMeasureOption)measureOption

{

ASDN::MutexLocker l(__instanceLock__);

NSArray *rects = [[self _renderer] rectsForTextRange:textRange measureOption:measureOption];

NSMutableArray *adjustedRects = [NSMutableArray array];

for (NSValue *rectValue in rects) {

CGRect rect = [rectValue CGRectValue];

rect = ASTextNodeAdjustRenderRectForShadowPadding(rect, self.shadowPadding);

NSValue *adjustedRectValue = [NSValue valueWithCGRect:rect];

[adjustedRects addObject:adjustedRectValue];

}

return adjustedRects;

}

- (CGRect)trailingRect

{

ASDN::MutexLocker l(__instanceLock__);

CGRect rect = [[self _renderer] trailingRect];

return ASTextNodeAdjustRenderRectForShadowPadding(rect, self.shadowPadding);

}

- (CGRect)frameForTextRange:(NSRange)textRange

{

ASDN::MutexLocker l(__instanceLock__);

CGRect frame = [[self _renderer] frameForTextRange:textRange];

return ASTextNodeAdjustRenderRectForShadowPadding(frame, self.shadowPadding);

}

#pragma mark - Placeholders

- (void)setPlaceholderColor:(UIColor *)placeholderColor

{

ASDN::MutexLocker l(__instanceLock__);

_placeholderColor = placeholderColor;

// prevent placeholders if we don't have a color

self.placeholderEnabled = placeholderColor != nil;

}

- (UIImage *)placeholderImage

{

// FIXME: Replace this implementation with reusable CALayers that have .backgroundColor set.

// This would completely eliminate the memory and performance cost of the backing store.

CGSize size = self.calculatedSize;

if ((size.width * size.height) < CGFLOAT_EPSILON) {

return nil;

}

ASDN::MutexLocker l(__instanceLock__);

UIGraphicsBeginImageContext(size);

[self.placeholderColor setFill];

ASTextKitRenderer *renderer = [self _renderer];

NSRange visibleRange = renderer.firstVisibleRange;

// cap height is both faster and creates less subpixel blending

NSArray *lineRects = [self _rectsForTextRange:visibleRange measureOption:ASTextKitRendererMeasureOptionLineHeight];

// fill each line with the placeholder color

for (NSValue *rectValue in lineRects) {

CGRect lineRect = [rectValue CGRectValue];

CGRect fillBounds = CGRectIntegral(UIEdgeInsetsInsetRect(lineRect, self.placeholderInsets));

if (fillBounds.size.width > 0.0 && fillBounds.size.height > 0.0) {

UIRectFill(fillBounds);

}

}

UIImage *image = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return image;

}

#pragma mark - Touch Handling

- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event

{

ASDisplayNodeAssertMainThread();

if (!_passthroughNonlinkTouches) {

return [super pointInside:point withEvent:event];

}

NSRange range = NSMakeRange(0, 0);

NSString *linkAttributeName = nil;

BOOL inAdditionalTruncationMessage = NO;

id linkAttributeValue = [self _linkAttributeValueAtPoint:point

attributeName:&linkAttributeName

range:&range

inAdditionalTruncationMessage:&inAdditionalTruncationMessage

forHighlighting:YES];

NSUInteger lastCharIndex = NSIntegerMax;

BOOL linkCrossesVisibleRange = (lastCharIndex > range.location) && (lastCharIndex < NSMaxRange(range) - 1);

if (inAdditionalTruncationMessage) {

return YES;

} else if (range.length && !linkCrossesVisibleRange && linkAttributeValue != nil && linkAttributeName != nil) {

return YES;

} else {

return NO;

}

}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event

{

ASDisplayNodeAssertMainThread();

[super touchesBegan:touches withEvent:event];

CGPoint point = [[touches anyObject] locationInView:self.view];

NSRange range = NSMakeRange(0, 0);

NSString *linkAttributeName = nil;

BOOL inAdditionalTruncationMessage = NO;

id linkAttributeValue = [self _linkAttributeValueAtPoint:point

attributeName:&linkAttributeName

range:&range

inAdditionalTruncationMessage:&inAdditionalTruncationMessage

forHighlighting:YES];

NSUInteger lastCharIndex = NSIntegerMax;

BOOL linkCrossesVisibleRange = (lastCharIndex > range.location) && (lastCharIndex < NSMaxRange(range) - 1);

if (inAdditionalTruncationMessage) {

NSRange visibleRange = NSMakeRange(0, 0);

{

ASDN::MutexLocker l(__instanceLock__);

visibleRange = [self _renderer].firstVisibleRange;

}

NSRange truncationMessageRange = [self _additionalTruncationMessageRangeWithVisibleRange:visibleRange];

[self _setHighlightRange:truncationMessageRange forAttributeName:ASTextNodeTruncationTokenAttributeName value:nil animated:YES];

} else if (range.length && !linkCrossesVisibleRange && linkAttributeValue != nil && linkAttributeName != nil) {

[self _setHighlightRange:range forAttributeName:linkAttributeName value:linkAttributeValue animated:YES];

}

}

- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event

{

ASDisplayNodeAssertMainThread();

[super touchesCancelled:touches withEvent:event];

[self _clearHighlightIfNecessary];

}