iOS-NSMutableParagraphStyle

NSMutableParagraphStyle风格

// NSParagraphStyleAttributeName 段落的风格（设置首行，行间距，对齐方式什么的）看自己需要什么属性，写什么 

NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];

paragraphStyle.lineSpacing = 10; // 字体的行间距

paragraphStyle.firstLineHeadIndent = 20.0f; //首行缩进

paragraphStyle.alignment = NSTextAlignmentJustified; //（两端对齐的）文本对齐方式：（左，中，右，两端对齐，自然）

paragraphStyle.lineBreakMode = NSLineBreakByTruncatingTail; //结尾部分的内容以……方式省略 ( "...wxyz" ,"abcd..." ,"ab...yz")

paragraphStyle.headIndent = 20; //整体缩进(首行除外)

paragraphStyle.tailIndent = 20; //

paragraphStyle.minimumLineHeight = 10; //最低行高

paragraphStyle.maximumLineHeight = 20; //最大行高

paragraphStyle.paragraphSpacing = 15; //段与段之间的间距

paragraphStyle.paragraphSpacingBefore = 22.0f; //段首行空白空间/* Distance between the bottom of the previous paragraph (or the end of its paragraphSpacing, if any) and the top of this paragraph. */

paragraphStyle.baseWritingDirection = NSWritingDirectionLeftToRight; //从左到右的书写方向（一共➡️三种）

paragraphStyle.lineHeightMultiple = 15; /* Natural line height is multiplied by this factor (if positive) before being constrained by minimum and maximum line height. */

paragraphStyle.hyphenationFactor = 1; //连字属性 在iOS，唯一支持的值分别为0和1

计算段落高度

NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc] init];
style.lineSpacing = 10.f;
[contentStr addAttribute:NSParagraphStyleAttributeName value:style range:NSMakeRange(0, [contentStr length])];
CGSize size = [contentStr boundingRectWithSize:CGSizeMake(UI_SCREEN_WIDTH, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin context:nil].size;
CGFloat height = size.height;  

NSMutableParagraphStyle *style = [[NSMutableParagraphStyle alloc] init];
style.lineSpacing = 10.f;
CGRect rect = [contentStr boundingRectWithSize:CGSizeMake(UI_SCREEN_WIDTH, MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName : YXFontT04, NSParagraphStyleAttributeName : style} context:nil];
CGFloat height = rect.size.height;

添加行间距

@implementation NSMutableAttributedString (YXAdd)

/// 参考 font 设置行高
/// @param lineSpace 行高
/// @param font 字体
- (void)yx_addLineSpace:(CGFloat)lineSpace referentFont:(UIFont *)font {

    CGFloat similarLineHeight = font.ascender;
    CGFloat similarPadding = font.lineHeight - similarLineHeight;

    NSAssert(similarPadding < lineSpace, @"间隔太小");

    NSMutableParagraphStyle *style = [NSMutableParagraphStyle new];
    style.lineSpacing = lineSpace - similarPadding;

    [self addAttribute:NSParagraphStyleAttributeName value:style range:NSMakeRange(0, self.length)];
}

@end

@implementation UILabel (YXAdd)

/// 在限定宽度内设置文本的行间距
/// @param text 文本内容
/// @param lineSpacing 行间距
/// @param width 限定宽度
- (void)yx_setText:(NSString *)text lineSpacing:(CGFloat)lineSpacing width:(CGFloat)width {
    if (lineSpacing < 0.01 || !text) {
        self.text = text;
        return;
    }
    BOOL isOneLineNumber = YES;
    NSRange range = [text rangeOfString:@"\n"];
    if (text.length > (range.location + range.length)) {
        isOneLineNumber = NO;
    } else {
        CGSize textSize = [text sizeWithAttributes:@{NSFontAttributeName: self.font}];
        if (textSize.width > width) {
            isOneLineNumber = NO;
        }
    }
    NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:text];
    [attributedString addAttribute:NSFontAttributeName value:self.font range:NSMakeRange(0, [text length])];
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    paragraphStyle.lineSpacing = isOneLineNumber ? 0 : lineSpacing;
    [paragraphStyle setLineBreakMode:self.lineBreakMode];
    [paragraphStyle setAlignment:self.textAlignment];
    [attributedString addAttribute:NSParagraphStyleAttributeName
                             value:paragraphStyle
                             range:NSMakeRange(0, [text length])];
    self.attributedText = attributedString;
}

@end