所有文本的 attributes 枚举，NSAttributedString

// Predefined character attributes for text. If the key is not in the dictionary, then use the default values as described below.
UIKIT_EXTERN NSString * const NSFontAttributeName NS_AVAILABLE(10_0, 6_0);                // UIFont, default Helvetica(Neue) 12
UIKIT_EXTERN NSString * const NSParagraphStyleAttributeName NS_AVAILABLE(10_0, 6_0);      // NSParagraphStyle, default defaultParagraphStyle
UIKIT_EXTERN NSString * const NSForegroundColorAttributeName NS_AVAILABLE(10_0, 6_0);     // UIColor, default blackColor
UIKIT_EXTERN NSString * const NSBackgroundColorAttributeName NS_AVAILABLE(10_0, 6_0);     // UIColor, default nil: no background
UIKIT_EXTERN NSString * const NSLigatureAttributeName NS_AVAILABLE(10_0, 6_0);            // NSNumber containing integer, default 1: default ligatures, 0: no ligatures
UIKIT_EXTERN NSString * const NSKernAttributeName NS_AVAILABLE(10_0, 6_0);                // NSNumber containing floating point value, in points; amount to modify default kerning. 0 means kerning is disabled.
UIKIT_EXTERN NSString * const NSStrikethroughStyleAttributeName NS_AVAILABLE(10_0, 6_0);  // NSNumber containing integer, default 0: no strikethrough
UIKIT_EXTERN NSString * const NSUnderlineStyleAttributeName NS_AVAILABLE(10_0, 6_0);      // NSNumber containing integer, default 0: no underline
UIKIT_EXTERN NSString * const NSStrokeColorAttributeName NS_AVAILABLE(10_0, 6_0);         // UIColor, default nil: same as foreground color
UIKIT_EXTERN NSString * const NSStrokeWidthAttributeName NS_AVAILABLE(10_0, 6_0);         // NSNumber containing floating point value, in percent of font point size, default 0: no stroke; positive for stroke alone, negative for stroke and fill (a typical value for outlined text would be 3.0)
UIKIT_EXTERN NSString * const NSShadowAttributeName NS_AVAILABLE(10_0, 6_0);              // NSShadow, default nil: no shadow
UIKIT_EXTERN NSString *const NSTextEffectAttributeName NS_AVAILABLE(10_10, 7_0);          // NSString, default nil: no text effect

UIKIT_EXTERN NSString * const NSAttachmentAttributeName NS_AVAILABLE(10_0, 7_0);          // NSTextAttachment, default nil
UIKIT_EXTERN NSString * const NSLinkAttributeName NS_AVAILABLE(10_0, 7_0);                // NSURL (preferred) or NSString
UIKIT_EXTERN NSString * const NSBaselineOffsetAttributeName NS_AVAILABLE(10_0, 7_0);      // NSNumber containing floating point value, in points; offset from baseline, default 0
UIKIT_EXTERN NSString * const NSUnderlineColorAttributeName NS_AVAILABLE(10_0, 7_0);      // UIColor, default nil: same as foreground color
UIKIT_EXTERN NSString * const NSStrikethroughColorAttributeName NS_AVAILABLE(10_0, 7_0);  // UIColor, default nil: same as foreground color
UIKIT_EXTERN NSString * const NSObliquenessAttributeName NS_AVAILABLE(10_0, 7_0);         // NSNumber containing floating point value; skew to be applied to glyphs, default 0: no skew
UIKIT_EXTERN NSString * const NSExpansionAttributeName NS_AVAILABLE(10_0, 7_0);           // NSNumber containing floating point value; log of expansion factor to be applied to glyphs, default 0: no expansion

UIKIT_EXTERN NSString * const NSWritingDirectionAttributeName NS_AVAILABLE(10_6, 7_0);    // NSArray of NSNumbers representing the nested levels of writing direction overrides as defined by Unicode LRE, RLE, LRO, and RLO characters.  The control characters can be obtained by masking NSWritingDirection and NSTextWritingDirection values.  LRE: NSWritingDirectionLeftToRight|NSWritingDirectionEmbedding, RLE: NSWritingDirectionRightToLeft|NSWritingDirectionEmbedding, LRO: NSWritingDirectionLeftToRight|NSWritingDirectionOverride, RLO: NSWritingDirectionRightToLeft|NSWritingDirectionOverride,

UIKIT_EXTERN NSString * const NSVerticalGlyphFormAttributeName NS_AVAILABLE(10_7, 6_0);   // An NSNumber containing an integer value.  0 means horizontal text.  1 indicates vertical text.  If not specified, it could follow higher-level vertical orientation settings.  Currently on iOS, it's always horizontal.  The behavior for any other value is undefined.

上面说的是什么意思呢？

“给文本预定义的字符属性。如果键不在字典中，那就用下面描述的值。”

“

UIKIT_EXTERN NSString * const NSFontAttributeName NS_AVAILABLE(10_0, 6_0);

// 字体大小,默认的是 Helvetica(Neue) 12号 （PS：Helvetica（Neue）是一种西文字体，也是苹果电脑的默认字体，设计者：爱德华德·霍夫曼（Eduard Hoffmann）和马克斯·米耶丁格（Max Miedinger））

UIKIT_EXTERN NSString * const NSParagraphStyleAttributeName NS_AVAILABLE(10_0, 6_0);

// 段落样式，默认是 defaultParagraphStyle

UIKIT_EXTERN NSString * const NSForegroundColorAttributeName NS_AVAILABLE(10_0, 6_0);

// 颜色，默认识黑色

UIKIT_EXTERN NSString * const NSBackgroundColorAttributeName NS_AVAILABLE(10_0, 6_0);

// 颜色 默认是nil；没有背景色

UIKIT_EXTERN NSString * const NSLigatureAttributeName NS_AVAILABLE(10_0, 6_0);

// 包含integer的数字，默认为1；连字符数，默认为0:没有连字符数

UIKIT_EXTERN NSString * const NSKernAttributeName NS_AVAILABLE(10_0, 6_0);

// 包含在点中的浮点型指针值；类似于修改默认字间距。0代表字间距不可用.

UIKIT_EXTERN NSString * const NSStrikethroughStyleAttributeName NS_AVAILABLE(10_0, 6_0);  

//包含integer的数字, 默认是0: 没有删除线

UIKIT_EXTERN NSString * const NSUnderlineStyleAttributeName NS_AVAILABLE(10_0, 6_0);     

// 包含整型的数字，默认是0，没有下划线

UIKIT_EXTERN NSString * const NSStrikethroughStyleAttributeName NS_AVAILABLE(10_0, 6_0);

// 包含整型integer的数字, 默认为0: 无下划线

UIKIT_EXTERN NSString * const NSStrokeColorAttributeName NS_AVAILABLE(10_0, 6_0);

// 颜色，默认为nil:像前景色一样

UIKIT_EXTERN NSString * const NSStrokeWidthAttributeName NS_AVAILABLE(10_0, 6_0);

// 包含点值得浮点型, 点尺寸的百分比, 默认为0: 无描边;利于单独描边, 不利于描边和填充 (描述文本的一个典型值是3.0)

UIKIT_EXTERN NSString * const NSShadowAttributeName NS_AVAILABLE(10_0, 6_0);

// 阴影，默认为nil: 没有阴影

UIKIT_EXTERN NSString *const NSTextEffectAttributeName NS_AVAILABLE(10_10, 7_0);

// 字符串, 默认为nil: 没有文本效果

UIKIT_EXTERN NSString * const NSAttachmentAttributeName NS_AVAILABLE(10_0, 7_0);

// 富文本, 默认为nil

UIKIT_EXTERN NSString * const NSLinkAttributeName NS_AVAILABLE(10_0, 7_0);

// 网址 (倾向于)或者是字符串

UIKIT_EXTERN NSString * const NSBaselineOffsetAttributeName NS_AVAILABLE(10_0, 7_0);

// 包含点值的浮点型数字,在点中; 从基线偏移, 默认为0

UIKIT_EXTERN NSString * const NSUnderlineColorAttributeName NS_AVAILABLE(10_0, 7_0);

// 颜色, 默认为nil: 像前景色一样

UIKIT_EXTERN NSString * const NSStrikethroughColorAttributeName NS_AVAILABLE(10_0, 7_0);

// 颜色, 默认为nil: 像前景色一样

UIKIT_EXTERN NSString * const NSObliquenessAttributeName NS_AVAILABLE(10_0, 7_0);

// 包含点值得浮点型数字; 向实际应用的符号倾斜, 默认为0: 没有倾斜

UIKIT_EXTERN NSString * const NSExpansionAttributeName NS_AVAILABLE(10_0, 7_0);

// 包含点值得浮点型数字; 实际应用的符号的膨胀系数记录, 默认为0: 没有膨胀

UIKIT_EXTERN NSString * const NSWritingDirectionAttributeName NS_AVAILABLE(10_6, 7_0);

//数字数组代表书写方向的嵌套水平覆盖了Unicode 的LRE，RLE，LRO和RLO字符的定义

UIKIT_EXTERN NSString * const NSVerticalGlyphFormAttributeName NS_AVAILABLE(10_7, 6_0);

//包含integer值的数字，0意思是水平方向文本，1代表垂直方向文本，如果没有特殊指明，任何其他的值得行为都是未定义的

”

未完待续... ...