The font I'm using in my iOS app has an unfortunate quality: its characters are unusually small, and as a result, if a user types in a string which includes emoji (or possibly other characters not included in the font? Haven't tested that), when iOS draws those glyphs in the AppleColorEmoji font they come out huge relative to the other glyphs.
This is of course complicated by the fact that emoji are "two-part" glyphs so I can't just do a simple for-each-character-in-the-string loop.
What I need is a method along the lines of
-(NSAttributedString *)attributedStringByAddingAttributes:(NSArray *)attrs toString:(NSString*)myString forCharactersNotInFont:(UIFont *)font
... Or failing that, at least
-(NSAttributedString *)attributedStringByAddingAttributes:(NSArray *)attrs toStringForEmoji:(NSString*)myString
...or something.
Not sure of the best way to do this.
Code I ended up with, using code adapted from here:
- (BOOL)isEmoji:(NSString *)str {
const unichar high = [str characterAtIndex: 0];
// Surrogate pair (U+1D000-1F77F)
if (0xd800 <= high && high <= 0xdbff) {
const unichar low = [str characterAtIndex: 1];
const int codepoint = ((high - 0xd800) * 0x400) + (low - 0xdc00) + 0x10000;
return (0x1d000 <= codepoint && codepoint <= 0x1f77f);
// Not surrogate pair (U+2100-27BF)
} else {
return (0x2100 <= high && high <= 0x27bf);
}
}
// The following takes a string s and returns an attributed string where all the "special characters" contain the provided attributes
- (NSAttributedString *)attributedStringForString:(NSString *)s withAttributesForEmoji:(NSDictionary *)attrs {
NSMutableAttributedString *as = [[NSMutableAttributedString alloc] initWithString:#""];
NSRange fullRange = NSMakeRange(0, [s length]);
[s enumerateSubstringsInRange:fullRange
options:NSStringEnumerationByComposedCharacterSequences
usingBlock:^(NSString *substring, NSRange substringRange,
NSRange enclosingRange, BOOL *stop)
{
if ([self isEmoji:substring]) {
[as appendAttributedString:[[NSAttributedString alloc] initWithString:substring
attributes:attrs]];
} else {
[as appendAttributedString:[[NSAttributedString alloc] initWithString:substring]];
}
}];
return as;
}
So far, seems to work quite nicely!
Related
Apples documentation says:
[...] current file systems such as HFS+ (used by Mac OS X) allow you to create filenames with a 255-character limit [...] symbols may actually take up to the equivalent of nine English characters to store [...] This should be considered when attempting to create longer names.
How do I limit the length of a NSString in a way that it is truly shorter than 255 characters, even when it includes symbols that might take more than one character to store?
I add my current implementation below. If i add e.g. emojis to the string, while length answers the resulting string would be by far smaller than 255, it is still too long to be accepted by a NSSavePanel as file name.
NSRange stringRange = {0, MIN([fileName length], 255)};
stringRange = [fileName rangeOfComposedCharacterSequencesForRange:stringRange];
fileName = [fileName substringWithRange:stringRange];
As suggested by #JoshCaswell, I did modify this answer to a similar question. It apparently does work (I wrote several tests), but it seems strange to me. Such an obvious task cannot be so complicated to achieve?
// filename contains the NSString that should be shortened
NSMutableString *truncatedString = [NSMutableString string];
NSUInteger bytesRead = 0;
NSUInteger charIdx = 0;
while (bytesRead < 250 && charIdx < [fileName length])
{
NSRange range = [fileName rangeOfComposedCharacterSequencesForRange:NSMakeRange(charIdx, 1)];
NSString *character = [fileName substringWithRange:NSMakeRange(charIdx, range.length)];
bytesRead += [character lengthOfBytesUsingEncoding:NSUTF8StringEncoding];
charIdx = charIdx + range.length;
if (bytesRead <= 250)
[truncatedString appendString:character];
}
rangeOfComposedCharacterSequencesForRange: is basically doing the opposite of what you want: you give it a range that counts 255 composed characters, and it gives you the byte range that encompasses those, which might end up being much more than you want.
Unfortunately to do the reverse, you have to count the bytes manually. This isn't too hard, however, with enumerateSubstringsInRange:options:usingBlock:. Passing NSStringEnumerationByComposedCharacterSequences for the options gives you exactly what it says: each composed character in turn. You can then count the size of each with lengthOfBytesUsingEncoding:, passing the final encoding you'll be using (presumably UTF-8). Add up the bytes, keeping track of the character-based index, and stop when you've seen too many.
NSString * s = /* String containing multibyte characters */;
NSUInteger maxBytes = ...;
__block NSUInteger seenBytes = 0;
__block NSUInteger truncLength = 0;
NSRange fullLength = (NSRange){0, [s length]};
[s enumerateSubstringsInRange:fullLength
options:NSStringEnumerationByComposedCharacterSequences
usingBlock:
^(NSString *substring, NSRange substringRange,
NSRange _, BOOL *stop)
{
seenBytes += [substring lengthOfBytesUsingEncoding:NSUTF8StringEncoding];
if( seenBytes > maxBytes ){
*stop = YES;
return;
}
else {
truncLength += substringRange.length;
}
}];
NSString * truncS = [s substringToIndex:truncLength];
If I have a string like this.
NSString *string = #"😀1😀3😀5😀7😀"
To get a substring like #"3😀5" you have to account for the fact the smiley face character take two bytes.
NSString *substring = [string substringWithRange:NSMakeRange(5, 4)];
Is there a way to get the same substring by using the actual character index so NSMakeRange(3, 3) in this case?
Thanks to #Joe's link I was able to create a solution that works.
This still seems like a lot of work for just trying to create a substring at unicode character ranges for an NSString. Please post if you have a simpler solution.
#implementation NSString (UTF)
- (NSString *)substringWithRangeOfComposedCharacterSequences:(NSRange)range
{
NSUInteger codeUnit = 0;
NSRange result;
NSUInteger start = range.location;
NSUInteger i = 0;
while(i <= start)
{
result = [self rangeOfComposedCharacterSequenceAtIndex:codeUnit];
codeUnit += result.length;
i++;
}
NSRange substringRange;
substringRange.location = result.location;
NSUInteger end = range.location + range.length;
while(i <= end)
{
result = [self rangeOfComposedCharacterSequenceAtIndex:codeUnit];
codeUnit += result.length;
i++;
}
substringRange.length = result.location - substringRange.location;
return [self substringWithRange:substringRange];
}
#end
Example:
NSString *string = #"😀1😀3😀5😀7😀";
NSString *result = [string substringWithRangeOfComposedCharacterSequences:NSMakeRange(3, 3)];
NSLog(#"%#", result); // 3😀5
Make a swift extension of NSString and use new swift String struct. Has a beautifull String.Index that uses glyphs for counting characters and range selecting. Very usefull is cases like yours with emojis envolved
There is a textView in which I can enter Characters. characters can be a,b,c,d etc or a smiley face added using emoji keyboard.
-(void)textFieldDidEndEditing:(UITextField *)textField{
NSLog(#"len:%lu",textField.length);
NSLog(#"char:%c",[textField.text characterAtIndex:0]);
}
Currently , The above function gives following outputs
if textField.text = #"qq"
len:2
char:q
if textField.text = #"😄q"
len:3
char:=
What I need is
if textField.text = #"qq"
len:2
char:q
if textField.text = #"😄q"
len:2
char:😄
Any clue how to do this ?
Since Apple screwed up emoji (actually Unicode planes above 0) this becomes difficult. It seems it is necessary to enumerate through the composed character to get the actual length.
Note: The NSString method length does not return the number of characters but the number of code units (not characters) in unichars. See NSString and Unicode - Strings - objc.io issue #9.
Example code:
NSString *text = #"qqq😄rrr";
int maxCharacters = 4;
__block NSInteger unicharCount = 0;
__block NSInteger charCount = 0;
[text enumerateSubstringsInRange:NSMakeRange(0, text.length)
options:NSStringEnumerationByComposedCharacterSequences
usingBlock:^(NSString *substring, NSRange substringRange, NSRange enclosingRange, BOOL *stop) {
unicharCount += substringRange.length;
if (++charCount >= maxCharacters)
*stop = YES;
}];
NSString *textStart = [text substringToIndex: unicharCount];
NSLog(#"textStart: '%#'", textStart);
textStart: 'qqq😄'
An alternative approach is to use utf32 encoding:
int byteCount = maxCharacters*4; // 4 utf32 characters
char buffer[byteCount];
NSUInteger usedBufferCount;
[text getBytes:buffer maxLength:byteCount usedLength:&usedBufferCount encoding:NSUTF32StringEncoding options:0 range:NSMakeRange(0, text.length) remainingRange:NULL];
NSString * textStart = [[NSString alloc] initWithBytes:buffer length:usedBufferCount encoding:NSUTF32LittleEndianStringEncoding];
There is some rational for this in Session 128 - Advance Text Processing from 2011 WWDC.
This is what i did to cut a string with emoji characters
+(NSUInteger)unicodeLength:(NSString*)string{
return [string lengthOfBytesUsingEncoding:NSUTF32StringEncoding]/4;
}
+(NSString*)unicodeString:(NSString*)string toLenght:(NSUInteger)len{
if (len >= string.length){
return string;
}
NSInteger charposition = 0;
for (int i = 0; i < len; i++){
NSInteger remainingChars = string.length-charposition;
if (remainingChars >= 2){
NSString* s = [string substringWithRange:NSMakeRange(charposition,2)];
if ([self unicodeLength:s] == 1){
charposition++;
}
}
charposition++;
}
return [string substringToIndex:charposition];
}
Hey everybody :) i have one method, which cuts a long text after a given number of words. It looks like this:
NSString *trimString(NSString *string, int length, Boolean soft) {
if(string == Nil || string.length == 0){
return string;
}
NSMutableString *sb = [[NSMutableString alloc]init];
int actualLength = length - 3;
if(string.length > actualLength){
// -3 because we add 3 dots at the end. Returned string length has to be length including the dots.
if(!soft) {
[sb appendString:[string substringToIndex:actualLength - 3]];
[sb appendString:#"..."];
return sb;
} else {
NSRange r = NSMakeRange(0, actualLength);
//NSRange range = [string rangeOfString:#" " options:NSBackwardsSearch range:r];
NSRange range = [string rangeOfCharacterFromSet:[NSCharacterSet characterSetWithCharactersInString:#" \n\r\t"] options:NSBackwardsSearch range:r];
[sb appendString:[string substringToIndex:range.location]];
[sb appendString:#"..."];
return sb;
}
}
return string;
}
My Problem is that i have to change everything to NSAttributedString, but there are no things like "substringToIndex:" so that i can change it....
Is it even possible to change it?
Thanks!
You can do anything to an NSAttributedString that NSString supports by referencing the string property on the attributed string. This is the underlying NSString that you may do whatever you like with.
If you are just looking for string clipping (substringToIndex:) you can use:
- (NSAttributedString *)attributedSubstringFromRange:(NSRange)aRange
Create the proper range and that will give you the functionality you are "missing".
Source.
Assuming that you're working with an NSMutableAttributedString, you need to call your function on NSAttributedString's string property, and you can use the returned string as a parameter to replaceCharactersInRange:withString:
If I were you, I would change the prototype of the function to return an NSRange value, this way you could use it in a more general way with strings and AttributedStrings (with functions such as stringWithRange)
How can I activate automatic hyphenation in iOS?
I have tried to set the hyphenation factor to 1 in the attributed text options of an UILabel, however I don't get any hyphens though.
The iOS 7 way. Use an UITextView instead of an UILabel. The hyphenationFactor (either as a NSParagraphStyle attribute or as a NSLayoutManager property) should work then (thanks to the new TextKit).
The Web way. Use an UIWebView and the -webkit-hyphens CSS properties.
The Core Text or the hard way. Use the CFStringGetHyphenationLocationBeforeIndex() function that you mentioned in a comment. This function only gives you a hint about where to put hyphens in a string for a specific language. Then you have to break your lines of text yourself using the Core Text functions (like CTLineCreateWithAttributedString() and all). See Getting to Know TextKit (the paragraph called Hyphenation explains the logic of the Core Text process, with no code) and Hyphenation with Core Text on the iPad (gives some code sample, but the website seems to be down right now). It's probably going to be more work than you want!
CoreText or TextKit
You need to add "soft hyphenation" to the string. These are "-" which is not visible when rendered, but instead merely queues for CoreText or UITextKit to know how to break up words.
The soft hyphen sign which you should place in the text is:
unichar const kTextDrawingSoftHyphenUniChar = 0x00AD;
NSString * const kTextDrawingSoftHyphenToken = #"Â"; // NOTE: UTF-8 soft hyphen!
Example code
NSString *string = #"accessibility tests and frameworks checking";
NSLocale *locale = [NSLocale localeWithLocaleIdentifier:#"en_US"];
NSString *hyphenatedString = [string softHyphenatedStringWithLocale:locale error:nil];
NSLog(#"%#", hyphenatedString);
Outputs ac-ces-si-bil-i-ty tests and frame-works check-ing
NSString+SoftHyphenation.h
typedef enum {
NSStringSoftHyphenationErrorNotAvailableForLocale
} NSStringSoftHyphenationError;
extern NSString * const NSStringSoftHyphenationErrorDomain;
#interface NSString (SoftHyphenation)
- (NSString *)softHyphenatedStringWithLocale:(NSLocale *)locale error:(out NSError **)error;
#end
NSString+SoftHyphenation.m
NSString * const NSStringSoftHyphenationErrorDomain = #"NSStringSoftHyphenationErrorDomain";
#implementation NSString (SoftHyphenation)
- (NSError *)hyphen_createOnlyError
{
NSDictionary *userInfo = #{
NSLocalizedDescriptionKey: #"Hyphenation is not available for given locale",
NSLocalizedFailureReasonErrorKey: #"Hyphenation is not available for given locale",
NSLocalizedRecoverySuggestionErrorKey: #"You could try using a different locale even though it might not be 100% correct"
};
return [NSError errorWithDomain:NSStringSoftHyphenationErrorDomain code:NSStringSoftHyphenationErrorNotAvailableForLocale userInfo:userInfo];
}
- (NSString *)softHyphenatedStringWithLocale:(NSLocale *)locale error:(out NSError **)error
{
CFLocaleRef localeRef = (__bridge CFLocaleRef)(locale);
if(!CFStringIsHyphenationAvailableForLocale(localeRef))
{
if(error != NULL)
{
*error = [self hyphen_createOnlyError];
}
return [self copy];
}
else
{
NSMutableString *string = [self mutableCopy];
unsigned char hyphenationLocations[string.length];
memset(hyphenationLocations, 0, string.length);
CFRange range = CFRangeMake(0, string.length);
for(int i = 0; i < string.length; i++)
{
CFIndex location = CFStringGetHyphenationLocationBeforeIndex((CFStringRef)string,
i,
range,
0,
localeRef,
NULL);
if(location >= 0 && location < string.length)
{
hyphenationLocations[location] = 1;
}
}
for(int i = string.length - 1; i > 0; i--)
{
if(hyphenationLocations[i])
{
[string insertString:#"-" atIndex:i];
}
}
if(error != NULL) { *error = nil;}
return string;
}
}
#end
Swift version:
let paragraphStyle = NSMutableParagraphStyle()
paragraphStyle.hyphenationFactor = 1
paragraphStyle.alignment = .center
let string = NSAttributedString(string: "wyindywidualizowany indywidualista".uppercased(),
attributes: [NSParagraphStyleAttributeName : paragraphStyle])
myLabel.attributedText = string