CT_EXPORT const CFStringRef kCTFontAttributeName;
CT_EXPORT const CFStringRef kCTForegroundColorFromContextAttributeName;
CT_EXPORT const CFStringRef kCTKernAttributeName;
CT_EXPORT const CFStringRef kCTLigatureAttributeName;
CT_EXPORT const CFStringRef kCTForegroundColorAttributeName;
CT_EXPORT const CFStringRef kCTBackgroundColorAttributeName;
CT_EXPORT const CFStringRef kCTParagraphStyleAttributeName;
CT_EXPORT const CFStringRef kCTStrokeWidthAttributeName;
CT_EXPORT const CFStringRef kCTStrokeColorAttributeName;
CT_EXPORT const CFStringRef kCTUnderlineStyleAttributeName;
CT_EXPORT const CFStringRef kCTSuperscriptAttributeName;
CT_EXPORT const CFStringRef kCTUnderlineColorAttributeName;
CT_EXPORT const CFStringRef kCTVerticalFormsAttributeName;
CT_EXPORT const CFStringRef kCTHorizontalInVerticalFormsAttributeName;
CT_EXPORT const CFStringRef kCTGlyphInfoAttributeName;
CT_EXPORT const CFStringRef kCTCharacterShapeAttributeName;
CT_EXPORT const CFStringRef kCTLanguageAttributeName;
CT_EXPORT const CFStringRef kCTRunDelegateAttributeName;
CT_EXPORT const CFStringRef kCTBaselineClassAttributeName;
CT_EXPORT const CFStringRef kCTBaselineInfoAttributeName;
CT_EXPORT const CFStringRef kCTBaselineReferenceInfoAttributeName;
CT_EXPORT const CFStringRef kCTWritingDirectionAttributeName;
CT_EXPORT const CFStringRef kCTRubyAnnotationAttributeName;


typedef CF_OPTIONS(int32_t, CTUnderlineStyle) {
    kCTUnderlineStyleNone           = 0x00,
    kCTUnderlineStyleSingle         = 0x01,
    kCTUnderlineStyleThick          = 0x02,
    kCTUnderlineStyleDouble         = 0x09
};

enum {
    kCTWritingDirectionEmbedding = (0 << 1),
    kCTWritingDirectionOverride = (1 << 1)
};

typedef CF_OPTIONS(int32_t, CTUnderlineStyleModifiers) {
    kCTUnderlinePatternSolid        = 0x0000,
    kCTUnderlinePatternDot          = 0x0100,
    kCTUnderlinePatternDash         = 0x0200,
    kCTUnderlinePatternDashDot      = 0x0300,
    kCTUnderlinePatternDashDotDot   = 0x0400
};