Swiftgram/submodules/AsyncDisplayKit/Source/ASTextKitCoreTextAdditions.mm

//
//  ASTextKitCoreTextAdditions.mm
//  Texture
//
//  Copyright (c) Facebook, Inc. and its affiliates.  All rights reserved.
//  Changes after 4/13/2017 are: Copyright (c) Pinterest, Inc.  All rights reserved.
//  Licensed under Apache 2.0: http://www.apache.org/licenses/LICENSE-2.0
//

#import "ASTextKitCoreTextAdditions.h"

#if AS_ENABLE_TEXTNODE

#import <CoreText/CTFont.h>
#import <CoreText/CTStringAttributes.h>

#import <AsyncDisplayKit/ASAssert.h>

#pragma mark - Public
BOOL ASAttributeWithNameIsUnsupportedCoreTextAttribute(NSString *attributeName)
{
  static NSSet *coreTextAttributes;
  static dispatch_once_t onceToken;
  dispatch_once(&onceToken, ^{
    coreTextAttributes = [NSSet setWithObjects:(__bridge id)kCTForegroundColorAttributeName,
                          kCTForegroundColorFromContextAttributeName,
                          kCTForegroundColorAttributeName,
                          kCTStrokeColorAttributeName,
                          kCTUnderlineStyleAttributeName,
                          kCTVerticalFormsAttributeName,
                          kCTRunDelegateAttributeName,
                          kCTBaselineClassAttributeName,
                          kCTBaselineInfoAttributeName,
                          kCTBaselineReferenceInfoAttributeName,
                          kCTUnderlineColorAttributeName,
                          kCTParagraphStyleAttributeName,
                          nil];
  });
  return [coreTextAttributes containsObject:attributeName];
}

NSDictionary *NSAttributedStringAttributesForCoreTextAttributes(NSDictionary *coreTextAttributes)
{
  NSMutableDictionary *cleanAttributes = [[NSMutableDictionary alloc] initWithCapacity:coreTextAttributes.count];

  [coreTextAttributes enumerateKeysAndObjectsUsingBlock:^(NSString *coreTextKey, id coreTextValue, BOOL *stop) {
    // The following attributes are not supported on NSAttributedString. Should they become available, we should add them.
    /*
     kCTForegroundColorFromContextAttributeName
     kCTSuperscriptAttributeName
     kCTGlyphInfoAttributeName
     kCTCharacterShapeAttributeName
     kCTLanguageAttributeName
     kCTRunDelegateAttributeName
     kCTBaselineClassAttributeName
     kCTBaselineInfoAttributeName
     kCTBaselineReferenceInfoAttributeName
     kCTWritingDirectionAttributeName
     kCTUnderlineColorAttributeName
     */

    // Conversely, the following attributes are not supported on CFAttributedString. Should they become available, we should add them.
    /*
     NSStrikethroughStyleAttributeName
     NSShadowAttributeName
     NSBackgroundColorAttributeName
     */

    // kCTFontAttributeName -> NSFontAttributeName
    if ([coreTextKey isEqualToString:(NSString *)kCTFontAttributeName]) {
      CTFontRef coreTextFont = (__bridge CTFontRef)coreTextValue;
      cleanAttributes[NSFontAttributeName] = (__bridge UIFont *)coreTextFont;
    }
    // kCTKernAttributeName -> NSKernAttributeName
    else if ([coreTextKey isEqualToString:(NSString *)kCTKernAttributeName]) {
      cleanAttributes[NSKernAttributeName] = (NSNumber *)coreTextValue;
    }
    // kCTLigatureAttributeName -> NSLigatureAttributeName
    else if ([coreTextKey isEqualToString:(NSString *)kCTLigatureAttributeName]) {
      cleanAttributes[NSLigatureAttributeName] = (NSNumber *)coreTextValue;
    }
    // kCTForegroundColorAttributeName -> NSForegroundColorAttributeName
    else if ([coreTextKey isEqualToString:(NSString *)kCTForegroundColorAttributeName]) {
      cleanAttributes[NSForegroundColorAttributeName] = [UIColor colorWithCGColor:(CGColorRef)coreTextValue];
    }
    // kCTParagraphStyleAttributeName -> NSParagraphStyleAttributeName
    else if ([coreTextKey isEqualToString:(NSString *)kCTParagraphStyleAttributeName]) {
      if ([coreTextValue isKindOfClass:[NSParagraphStyle class]]) {
        cleanAttributes[NSParagraphStyleAttributeName] = (NSParagraphStyle *)coreTextValue;
      }
      else {
        cleanAttributes[NSParagraphStyleAttributeName] = [NSParagraphStyle paragraphStyleWithCTParagraphStyle:(CTParagraphStyleRef)coreTextValue];
      }
    }
    // kCTStrokeWidthAttributeName -> NSStrokeWidthAttributeName
    else if ([coreTextKey isEqualToString:(NSString *)kCTStrokeWidthAttributeName]) {
      cleanAttributes[NSStrokeWidthAttributeName] = (NSNumber *)coreTextValue;
    }
    // kCTStrokeColorAttributeName -> NSStrokeColorAttributeName
    else if ([coreTextKey isEqualToString:(NSString *)kCTStrokeColorAttributeName]) {
      cleanAttributes[NSStrokeColorAttributeName] = [UIColor colorWithCGColor:(CGColorRef)coreTextValue];
    }
    // kCTUnderlineStyleAttributeName -> NSUnderlineStyleAttributeName
    else if ([coreTextKey isEqualToString:(NSString *)kCTUnderlineStyleAttributeName]) {
      cleanAttributes[NSUnderlineStyleAttributeName] = (NSNumber *)coreTextValue;
    }
    // kCTVerticalFormsAttributeName -> NSVerticalGlyphFormAttributeName
    else if ([coreTextKey isEqualToString:(NSString *)kCTVerticalFormsAttributeName]) {
      BOOL flag = (BOOL)CFBooleanGetValue((CFBooleanRef)coreTextValue);
      cleanAttributes[NSVerticalGlyphFormAttributeName] = @((int)flag); // NSVerticalGlyphFormAttributeName is documented to be an NSNumber with an integer that's either 0 or 1.
    }
    // Don't filter out any internal text attributes
    else if (!ASAttributeWithNameIsUnsupportedCoreTextAttribute(coreTextKey)){
      cleanAttributes[coreTextKey] = coreTextValue;
    }
  }];

  return cleanAttributes;
}

NSAttributedString *ASCleanseAttributedStringOfCoreTextAttributes(NSAttributedString *dirtyAttributedString)
{
  if (!dirtyAttributedString)
    return nil;

  // First see if there are any core text attributes on the string
  __block BOOL containsCoreTextAttributes = NO;
  [dirtyAttributedString enumerateAttributesInRange:NSMakeRange(0, dirtyAttributedString.length)
                                            options:0
                                         usingBlock:^(NSDictionary *dirtyAttributes, NSRange range, BOOL *stop) {
                                           [dirtyAttributes enumerateKeysAndObjectsUsingBlock:^(NSString *coreTextKey, id coreTextValue, BOOL *innerStop) {
                                             if (ASAttributeWithNameIsUnsupportedCoreTextAttribute(coreTextKey)) {
                                               containsCoreTextAttributes = YES;
                                               *innerStop = YES;
                                             }
                                           }];
                                           *stop = containsCoreTextAttributes;
                                         }];
  if (containsCoreTextAttributes) {

    NSString *plainString = dirtyAttributedString.string;
    NSMutableAttributedString *cleanAttributedString = [[NSMutableAttributedString alloc] initWithString:plainString];

    // Iterate over all of the attributes, cleaning them as appropriate and applying them as we go.
    [dirtyAttributedString enumerateAttributesInRange:NSMakeRange(0, plainString.length)
                                              options:0
                                           usingBlock:^(NSDictionary *dirtyAttributes, NSRange range, BOOL *stop) {
                                             [cleanAttributedString addAttributes:NSAttributedStringAttributesForCoreTextAttributes(dirtyAttributes) range:range];
                                           }];

    return cleanAttributedString;
  } else {
    return [dirtyAttributedString copy];
  }
}

#pragma mark -
#pragma mark -
@implementation NSParagraphStyle (ASTextKitCoreTextAdditions)

+ (NSParagraphStyle *)paragraphStyleWithCTParagraphStyle:(CTParagraphStyleRef)coreTextParagraphStyle NS_RETURNS_RETAINED
{
  NSMutableParagraphStyle *newParagraphStyle = [[NSMutableParagraphStyle alloc] init];

  if (!coreTextParagraphStyle) {
    return newParagraphStyle;
  }

  // The following paragraph style specifiers are not supported on NSParagraphStyle. Should they become available, we should add them.
  /*
   kCTParagraphStyleSpecifierTabStops
   kCTParagraphStyleSpecifierDefaultTabInterval
   kCTParagraphStyleSpecifierMaximumLineSpacing
   kCTParagraphStyleSpecifierMinimumLineSpacing
   kCTParagraphStyleSpecifierLineSpacingAdjustment
   kCTParagraphStyleSpecifierLineBoundsOptions
   */

  // Conversely, the following paragraph styles are not supported on CTParagraphStyle. Should they become available, we should add them.
  /*
   hyphenationFactor
   */

  // kCTParagraphStyleSpecifierAlignment -> alignment
  CTTextAlignment coreTextAlignment;
  if (CTParagraphStyleGetValueForSpecifier(coreTextParagraphStyle,
                                           kCTParagraphStyleSpecifierAlignment,
                                           sizeof(coreTextAlignment),
                                           &coreTextAlignment)) {
    newParagraphStyle.alignment = NSTextAlignmentFromCTTextAlignment(coreTextAlignment);
  }

  // kCTParagraphStyleSpecifierFirstLineHeadIndent -> firstLineHeadIndent
  CGFloat firstLineHeadIndent;
  if (CTParagraphStyleGetValueForSpecifier(coreTextParagraphStyle,
                                           kCTParagraphStyleSpecifierFirstLineHeadIndent,
                                           sizeof(firstLineHeadIndent),
                                           &firstLineHeadIndent)) {
    newParagraphStyle.firstLineHeadIndent = firstLineHeadIndent;
  }

  // kCTParagraphStyleSpecifierHeadIndent -> headIndent
  CGFloat headIndent;
  if (CTParagraphStyleGetValueForSpecifier(coreTextParagraphStyle,
                                           kCTParagraphStyleSpecifierHeadIndent,
                                           sizeof(headIndent),
                                           &headIndent)) {
    newParagraphStyle.headIndent = headIndent;
  }

  // kCTParagraphStyleSpecifierTailIndent -> tailIndent
  CGFloat tailIndent;
  if (CTParagraphStyleGetValueForSpecifier(coreTextParagraphStyle,
                                           kCTParagraphStyleSpecifierTailIndent,
                                           sizeof(tailIndent),
                                           &tailIndent)) {
    newParagraphStyle.tailIndent = tailIndent;
  }

  // kCTParagraphStyleSpecifierLineBreakMode -> lineBreakMode
  CTLineBreakMode coreTextLineBreakMode;
  if (CTParagraphStyleGetValueForSpecifier(coreTextParagraphStyle,
                                           kCTParagraphStyleSpecifierLineBreakMode,
                                           sizeof(coreTextLineBreakMode),
                                           &coreTextLineBreakMode)) {
    newParagraphStyle.lineBreakMode = (NSLineBreakMode)coreTextLineBreakMode; // They're the same enum.
  }

  // kCTParagraphStyleSpecifierLineHeightMultiple -> lineHeightMultiple
  CGFloat lineHeightMultiple;
  if (CTParagraphStyleGetValueForSpecifier(coreTextParagraphStyle,
                                           kCTParagraphStyleSpecifierLineHeightMultiple,
                                           sizeof(lineHeightMultiple),
                                           &lineHeightMultiple)) {
    newParagraphStyle.lineHeightMultiple = lineHeightMultiple;
  }

  // kCTParagraphStyleSpecifierMaximumLineHeight -> maximumLineHeight
  CGFloat maximumLineHeight;
  if (CTParagraphStyleGetValueForSpecifier(coreTextParagraphStyle,
                                           kCTParagraphStyleSpecifierMaximumLineHeight,
                                           sizeof(maximumLineHeight),
                                           &maximumLineHeight)) {
    newParagraphStyle.maximumLineHeight = maximumLineHeight;
  }

  // kCTParagraphStyleSpecifierMinimumLineHeight -> minimumLineHeight
  CGFloat minimumLineHeight;
  if (CTParagraphStyleGetValueForSpecifier(coreTextParagraphStyle,
                                           kCTParagraphStyleSpecifierMinimumLineHeight,
                                           sizeof(minimumLineHeight),
                                           &minimumLineHeight)) {
    newParagraphStyle.minimumLineHeight = minimumLineHeight;
  }
  
  CGFloat lineSpacing = 0;
#if TARGET_OS_IOS
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wdeprecated-declarations"
  // kCTParagraphStyleSpecifierLineSpacing -> lineSpacing
  // Note that kCTParagraphStyleSpecifierLineSpacing is deprecated and will die soon. We should not be using it.
  if (CTParagraphStyleGetValueForSpecifier(coreTextParagraphStyle,
                                           kCTParagraphStyleSpecifierLineSpacing,
                                           sizeof(lineSpacing),
                                           &lineSpacing)) {
    newParagraphStyle.lineSpacing = lineSpacing;
  }
#pragma clang diagnostic pop
#endif
  
  // Attempt to weakly map the following onto -[NSParagraphStyle lineSpacing]:
  //   - kCTParagraphStyleSpecifierMinimumLineSpacing
  //   - kCTParagraphStyleSpecifierMaximumLineSpacing
  //   - kCTParagraphStyleSpecifierLineSpacingAdjustment
  if (fabs(lineSpacing) <= FLT_EPSILON &&
      CTParagraphStyleGetValueForSpecifier(coreTextParagraphStyle,
                                           kCTParagraphStyleSpecifierMinimumLineSpacing,
                                           sizeof(lineSpacing),
                                           &lineSpacing)) {
    newParagraphStyle.lineSpacing = lineSpacing;
  }
  
  if (fabs(lineSpacing) <= FLT_EPSILON &&
      CTParagraphStyleGetValueForSpecifier(coreTextParagraphStyle,
                                           kCTParagraphStyleSpecifierMaximumLineSpacing,
                                           sizeof(lineSpacing),
                                           &lineSpacing)) {
    newParagraphStyle.lineSpacing = lineSpacing;
  }
  
  if (fabs(lineSpacing) <= FLT_EPSILON &&
      CTParagraphStyleGetValueForSpecifier(coreTextParagraphStyle,
                                           kCTParagraphStyleSpecifierLineSpacingAdjustment,
                                           sizeof(lineSpacing),
                                           &lineSpacing)) {
    newParagraphStyle.lineSpacing = lineSpacing;
  }

  // kCTParagraphStyleSpecifierParagraphSpacing -> paragraphSpacing
  CGFloat paragraphSpacing;
  if (CTParagraphStyleGetValueForSpecifier(coreTextParagraphStyle,
                                           kCTParagraphStyleSpecifierParagraphSpacing,
                                           sizeof(paragraphSpacing),
                                           &paragraphSpacing)) {
    newParagraphStyle.paragraphSpacing = paragraphSpacing;
  }

  // kCTParagraphStyleSpecifierParagraphSpacingBefore -> paragraphSpacingBefore
  CGFloat paragraphSpacingBefore;
  if (CTParagraphStyleGetValueForSpecifier(coreTextParagraphStyle,
                                           kCTParagraphStyleSpecifierParagraphSpacingBefore,
                                           sizeof(paragraphSpacingBefore),
                                           &paragraphSpacingBefore)) {
    newParagraphStyle.paragraphSpacingBefore = paragraphSpacingBefore;
  }

  // kCTParagraphStyleSpecifierBaseWritingDirection -> baseWritingDirection
  CTWritingDirection coreTextBaseWritingDirection;
  if (CTParagraphStyleGetValueForSpecifier(coreTextParagraphStyle,
                                           kCTParagraphStyleSpecifierBaseWritingDirection,
                                           sizeof(coreTextBaseWritingDirection),
                                           &coreTextBaseWritingDirection)) {
    newParagraphStyle.baseWritingDirection = (NSWritingDirection)coreTextBaseWritingDirection; // They're the same enum.
  }

  return newParagraphStyle;
}

@end

#endif