Summary of Style Run and Text Layout Attribute Tag Information

This appendix provides tabular summaries of the Apple-defined style run and text layout attribute tags and the data type, size, and default values of the attributes they identify. Table 1 summarizes this information for style run attribute tags.

Table C-1 Style run attribute tags and the data type, size, and default values of the style run attributes they identify

Style run attribute tag	Corresponding data type and size (in bytes)		Corresponding default value
`kATSUQDBoldfaceTag`	`Boolean`	1	`false`; plain text
`kATSUQDItalicTag`	`Boolean`	1	`false`; plain text
`kATSUQDUnderlineTag`	`Boolean`	1	`false`; plain text
`kATSUQDCondensedTag`	`Boolean`	1	`false`; plain text
`kATSUQDExtendedTag`	`Boolean`	1	`false`; plain text
`kATSUFontTag`	`ATSUFontID`	4	the application font for the current script system; you can determine this value by calling `GetScriptVariable(smSystemScript,smScriptAppFond)`. If the application font cannot be rendered with ATSUI, the default font is Helvetica.
`kATSUSizeTag`	`Fixed`	4	the size of the application font for the current script system; you can determine this value by calling `GetScriptVariable(smSystemScript,smScriptAppFondSize)` and examining the low word of the return value
`kATSUColorTag`	`RGBColor`	6	`(0, 0, 0)`; black text
`kATSULanguageTag`	`RegionCode`	2	the `RegionCode` of the system script; you can determine this value by calling `GetScriptVariable(smSystemScript,smScriptLang)`
`kATSUVerticalCharacterTag`	`ATSUVerticalCharacterType`	2	`kATSUStronglyHorizontal`; horizontally-oriented glyphs
`kATSUImposeWidthTag`	`ATSUTextMeasurement`	4	`kATSUNoImposedWidth`; use font-defined character width default value
`kATSUBeforeWithStreamShiftTag`	`Fixed`	4	0; use the font-defined with-stream shift default value before glyphs
`kATSUAfterWithStreamShiftTag`	`Fixed`	4	0; use the font-defined with-stream shift default value after glyphs
`kATSUCrossStreamShiftTag`	`Fixed`	4	0; use the font-defined cross-stream shift default value
`kATSUTrackingTag`	`Fixed`	4	0; use the font-defined tracking default value
`kATSUHangingInhibitFactorTag`	`Fract`	4	0; use the font-defined hanging glyph default value
`kATSUKerningInhibitFactorTag`	`Fract`	4	0; use the font-defined default kerning value
`kATSUDecompositionFactorTag`	`Fixed`	4	0; use the font-defined ligature decomposition default value
`kATSUBaselineClassTag`	`ATSUFontID`	4	`kBSLNRomanBaseline`; Roman baseline
`kATSUPriorityJustOverrideTag`	`ATSJustWidthDeltaEntryOverride` structure	20	0's in all fields; apply the font-defined justification priority behavior default values
`kATSUNoLigatureSplitTag`	`Boolean`	1	false; treat ligatures as divisible
`kATSUNoCaretAngleTag`	`Boolean`	1	false; use inherent angle of text to draw caret and highlighting
`kATSUSuppressCrossKerningTag`	`Boolean`	1	`false`; use the font-defined cross kerning default value
`kATSUNoOpticalAlignmentTag`	`Boolean`	1	`false`; use the font-defined optical alignment default value
`kATSUForceHangingTag`	`Boolean`	1	`false`; glyphs will not extend into the margin, even if they would normally do so
`kATSUNoSpecialJustificationTag`	`Boolean`	1	`false`; post compensation actions will occur if they are needed
`kATSUMaxStyleTag`			the maximum Apple-defined style run attribute tag value
`kATSUMaxATSUITagValue`			No Apple-defined tags may exceed this value. Apple-defined values between kATSUMaxStyleTag and kATSUMaxATSUITagValue are reserved. You can create you own attribute tags with any greater value.

Table C-2 summarizes the Apple-defined text layout attribute tags and their corresponding data type, size, and default values.

Table C-2 Text layout attribute tags and the data type, size, and default value of the attributes they identify

Text layout attribute tag	Corresponding data type and size (in bytes)		Corresponding default value
`kATSULineWidthTag`	`ATSUTextMeasurement`	4	0; no imposed line width
`kATSULineRotationTag`	`Fixed`	4	0; no line rotation
`kATSULineDirectionTag`	`Boolean`	1	derived from the system script; you can determine this value by calling the function `GetSysDirection`
`kATSULineJustificationFactorTag`	`Fract`	4	kATSUNoJustification; no line justification
`kATSULineFlushFactorTag`	`Fract`	4	kATSUStartAlignment; text is drawn to the right of the left margin
`kATSULineBaselineValuesTag`	`BslnBaselineRecord`	4	all 0's; no baseline deltas are applied to the cross-stream shifting of glyphs
`kATSULineLayoutOptionsTag`	`UInt32`	4	`kATSUNoLayoutOptions`; no special line layout options are set
`kATSULineAscentTag`	`ATSUTextMeasurement`	4	`kATSUseLineHeight`; use the maximum line ascent of all the style runs in a line <<is this right?>>
`kATSULineDescentTag`	`ATSUTextMeasurement`	4	`kATSUseLineHeight`; use the maximum line descent of all the style runs in a line
`kATSULineLanguageTag`	`RegionCode`	2	0; no language variation specified
`kATSULineTextLocatorTag`	TextBreakLocatorRef	4	`NULL`; language specified locator or the default Text Utilities locator