使用CoreText呈现字符串时的紧排问题

如果有人有同样的问题,我会在这里使用一种方法: https://github.com/MichMich/XMCircleType/blob/master/XMCircleType/Views/XMCircleTypeView.m

- (float)kerningForCharacter:(NSString *)currentCharacter afterCharacter:(NSString *)previousCharacter
{
    //Create a unique cache key
    NSString *kerningCacheKey = [NSString stringWithFormat:@"%@%@", previousCharacter, currentCharacter];

    //Look for kerning in the cache dictionary
    NSNumber *cachedKerning = [self.kerningCacheDictionary objectForKey:kerningCacheKey];

    //If kerning is found: return.
    if (cachedKerning) {
        return [cachedKerning floatValue];
    }

    //Otherwise, calculate.
    float totalSize = [[NSString stringWithFormat:@"%@%@", previousCharacter, currentCharacter] sizeWithAttributes:self.textAttributes].width;
    float currentCharacterSize = [currentCharacter sizeWithAttributes:self.textAttributes].width;
    float previousCharacterSize = [previousCharacter sizeWithAttributes:self.textAttributes].width;

    float kerning = (currentCharacterSize + previousCharacterSize) - totalSize;

    //Store kerning in cache.
    [self.kerningCacheDictionary setValue:@(kerning) forKey:kerningCacheKey];

    //Return kerning.
    return kerning;
}