NSParagraphStyle - 段落设置

偶尔用到了一下，顺便做个笔记。

    NSMutableParagraphStyle *paragraphStyle = [NSMutableParagraphStyle new];
    
    paragraphStyle.lineSpacing = 20.;// 行间距
    paragraphStyle.lineHeightMultiple = 1.5;// 行高倍数（1.5倍行高）
    paragraphStyle.firstLineHeadIndent = 30.0f;//首行缩进
    paragraphStyle.minimumLineHeight = 10;//最低行高
    paragraphStyle.maximumLineHeight = 20;//最大行高(会影响字体)
    
    paragraphStyle.alignment = NSTextAlignmentLeft;// 对齐方式
    paragraphStyle.defaultTabInterval = 144;// 默认Tab 宽度
    paragraphStyle.headIndent = 20;// 起始 x位置
    paragraphStyle.tailIndent = 320;// 结束 x位置（不是右边间距，与inset 不一样）
    
    paragraphStyle.paragraphSpacing = 44.;// 段落间距
    paragraphStyle.paragraphSpacingBefore = 44.;// 段落头部空白(实测与上边的没差啊？)
    

    paragraphStyle.lineBreakMode = NSLineBreakByWordWrapping;// 分割模式
    /*
     NSLineBreakByWordWrapping = 0,      // Wrap at word boundaries, default
     NSLineBreakByCharWrapping,  // Wrap at character boundaries
     NSLineBreakByClipping,  // Simply clip
     NSLineBreakByTruncatingHead, // Truncate at head of line: "...wxyz"
     NSLineBreakByTruncatingTail, // Truncate at tail of line: "abcd..."
     NSLineBreakByTruncatingMiddle // Truncate middle of line:  "ab...yz"
     */

    
    paragraphStyle.baseWritingDirection = NSWritingDirectionRightToLeft;// 段落方向
    /*
     NSWritingDirectionNatural       = -1,    // Determines direction using the Unicode Bidi Algorithm rules P2 and P3
     NSWritingDirectionLeftToRight   =  0,    // Left to right writing direction
     NSWritingDirectionRightToLeft   =  1
     */