CODEWITHSUNDEEP
cocoacharacteruppercasensattributedstring
AmitSri
AmitSri

Reputation: 1225

how to change characters case to Upper in NSAttributedString

I want to convert NSAttributedString containing RTFD to uppercase without losing attributes of existing characters and graphics.

Thanks,

Upvotes: 11

Views: 8313

Answers (2)

hasancan85
hasancan85

Reputation: 21

When you uppercase German "ß" character, it becomes "SS"; therefore the range changes. This might cause crash in the accepted answer. Here's my proposal to cover this case as well:

extension NSAttributedString {
  func uppercased() -> NSAttributedString {
    // Original NSAttributedString
    let originalAttributedString = self
    // Convert the attributed string to a regular string
    let originalString = originalAttributedString.string
    // Uppercase the string
    let uppercasedString = originalString.uppercased()
    // Create a new mutable attributed string with the uppercased string
    let uppercasedAttributedString = NSMutableAttributedString(string: uppercasedString)
    // Track the difference in length due to character count changes
    var indexOffset = 0

    originalAttributedString.enumerateAttributes(in: NSRange(location: 0, length: originalAttributedString.length),
                                                 options: []) { attributes, range, _ in

      // Extract the substring from the original string for this range
      let originalSubstring = originalAttributedString.attributedSubstring(from: range).string

      // Uppercase the substring
      let uppercasedSubstring = originalSubstring.uppercased()

      // Calculate the difference in length between the original and uppercased substrings
      let lengthDifference = uppercasedSubstring.count - originalSubstring.count

      // Adjust the range for the uppercased string (apply indexOffset before adjustment)
      let adjustedRange = NSRange(location: range.location + indexOffset, length: uppercasedSubstring.count)

      // Apply attributes to the new range in the uppercased attributed string
      uppercasedAttributedString.addAttributes(attributes, range: adjustedRange)

      // Update the index offset for future ranges
      indexOffset += lengthDifference
    }

    return uppercasedAttributedString
  }
}

Upvotes: 0

spudwaffle
spudwaffle

Reputation: 2915

EDIT:

@fluidsonic Is correct that the original code is incorrect. Below is an updated version in Swift, that replaces the text in each attribute range with an uppercased version of the string in that range.

extension NSAttributedString {
    func uppercased() -> NSAttributedString {

        let result = NSMutableAttributedString(attributedString: self)

        result.enumerateAttributes(in: NSRange(location: 0, length: length), options: []) {_, range, _ in
            result.replaceCharacters(in: range, with: (string as NSString).substring(with: range).uppercased())
        }

        return result
    }
}

Original answer: 

- (NSAttributedString *)upperCaseAttributedStringFromAttributedString:(NSAttributedString *)inAttrString {
    // Make a mutable copy of your input string
    NSMutableAttributedString *attrString = [inAttrString mutableCopy];

    // Make an array to save the attributes in
    NSMutableArray *attributes = [NSMutableArray array];

    // Add each set of attributes to the array in a dictionary containing the attributes and range
    [attrString enumerateAttributesInRange:NSMakeRange(0, [attrString length]) options:0 usingBlock:^(NSDictionary *attrs, NSRange range, BOOL *stop) {
        [attributes addObject:@{@"attrs":attrs, @"range":[NSValue valueWithRange:range]}];
    }];

    // Make a plain uppercase string
    NSString *string = [[attrString string]uppercaseString];

    // Replace the characters with the uppercase ones
    [attrString replaceCharactersInRange:NSMakeRange(0, [attrString length]) withString:string];

    // Reapply each attribute
    for (NSDictionary *attribute in attributes) {
        [attrString setAttributes:attribute[@"attrs"] range:[attribute[@"range"] rangeValue]];
    }

    return attrString;
}

What this does:

  1. Makes a mutable copy of the input attributed string.
  2. Takes all the attributes from that string and puts them in an array so they can be used later.
  3. Makes an uppercase plain string using built-in NSString method.
  4. Re-applys all the attributes.

Upvotes: 13

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