core text attribute string miss last line fix

p.m

    - (NSMutableAttributedString*)fixLastLineMissBugWhenDrawWithCoreText:(NSMutableAttributedString*)content
    {
        //段落
        //line break
        CTParagraphStyleSetting lineBreakMode;
        CTLineBreakMode lineBreak = kCTLineBreakByCharWrapping; //换行模式
        lineBreakMode.spec = kCTParagraphStyleSpecifierLineBreakMode;
        lineBreakMode.value = &lineBreak;
        lineBreakMode.valueSize = sizeof(CTLineBreakMode);
        //行间距
        CTParagraphStyleSetting LineSpacing;
        CGFloat spacing = 0.0;  //指定间距
        LineSpacing.spec = kCTParagraphStyleSpecifierLineSpacingAdjustment;
        LineSpacing.value = &spacing;
        LineSpacing.valueSize = sizeof(CGFloat);
        
        CTParagraphStyleSetting settings[] = {lineBreakMode,LineSpacing};
        CTParagraphStyleRef paragraphStyle = CTParagraphStyleCreate(settings, 2);   //第二个参数为settings的长度
        [content addAttribute:(NSString *)kCTParagraphStyleAttributeName
                        value:(__bridge id)paragraphStyle
                        range:NSMakeRange(0, content.length)];
        
        CFRelease(paragraphStyle);
        return content;
        
    }

use.md

// 生成ctFrame
NSMutableAttributedString *attributeStringText = self.attributeStringText;
attributeStringText = [self fixLastLineMissBugWhenDrawWithCoreText:attributeStringText];
CTFramesetterRef framesetter = CTFramesetterCreateWithAttributedString((CFAttributedStringRef)attributeStringText);