Make the central part of Cyrillic Twe to follow lowercase Tau variants (

#2122).

changes/28.0.1.md

@@ -1,2 +1,3 @@
 * Add italic form of CYRILLIC SMALL LETTER TE WITH MIDDLE HOOK (`U+A68B`) (#2119).
 * Add missing feature tag to chaining plus ligation (#2118).
+* Make the central part of Cyrillic Twe to follow lowercase Tau variants (#2122).

packages/font-glyphs/src/letter/latin/lower-il.ptl

@@ -130,10 +130,12 @@ glyph-block Letter-Latin-Lower-I : begin
 			set-base-anchor 'trailing' (xMiddle + [HSwToV : 0.75 * df.mvs]) 0
 			set-base-anchor 'palatalHookMask' currentGlyph.baseAnchors.trailing.x (HalfStroke + O)
 
+			local depth : [DiagTail.StdDepth df df.mvs] * (df.rightSB - xMiddle) / (df.rightSB - [XMiddle.FlatTailed df])
+
 			include : dispiro
 				widths.center df.mvs
 				flat xMiddle top [heading Downward]
-				DiagTail.R xMiddle 0 [DiagTail.StdDepth df df.mvs] df.mvs
+				DiagTail.R xMiddle 0 depth df.mvs
 
 		export : define [PhoneticLeft df top xMiddle] : glyph-proc
 			include : dispiro
@@ -282,6 +284,18 @@ glyph-block Letter-Latin-Lower-I : begin
 
 			currentGlyph.deleteBaseAnchor 'trailing'
 
+		create-glyph "cyrl/Twe/middle.\(suffix)" : glyph-proc
+			local df : include : DivFrame div
+			include : Body df CAP [XMiddle.Center df]
+			currentGlyph.deleteBaseAnchor 'trailing'
+			set-mark-anchor 'cvDecompose' (df.width / 2) CAP
+
+		create-glyph "cyrl/twe/middle.\(suffix)" : glyph-proc
+			local df : include : DivFrame div
+			include : Body df XH  [XMiddle.Center df]
+			currentGlyph.deleteBaseAnchor 'trailing'
+			set-mark-anchor 'cvDecompose' (df.width / 2) XH
+
 	do "i glyphs"
 		select-variant 'dotlessi' 0x131
 		link-reduced-variant 'dotlessi/sansSerif' 'dotlessi' MathSansSerif
@@ -397,6 +411,8 @@ glyph-block Letter-Latin-Lower-I : begin
 
 	do "Tau"
 		select-variant 'grek/tau' 0x3C4
+		select-variant 'cyrl/Twe/middle' (follow -- 'grek/tau/tailed')
+		select-variant 'cyrl/twe/middle' (follow -- 'grek/tau/tailed')
 
 	do "Blackboard"
 		glyph-block-import Letter-Blackboard : BBS BBD BBBarCenter

packages/font-glyphs/src/letter/latin/upper-t.ptl

@@ -16,7 +16,7 @@ glyph-block Letter-Latin-Upper-T : begin
 	define [TLeftX df]  : df.leftSB  + 0.75 * OX
 	define [TRightX df] : df.rightSB - 0.75 * OX
 	define [TShape df top doTopSerifs doBottomSerifs] : glyph-proc
-		include : VBar.m df.middle 0 top
+		include : tagged 'strokeV' : VBar.m df.middle 0 top
 		local l : TLeftX df
 		local r : TRightX df
 		include : tagged 'strokeLT' : HBar.t l df.middle top
@@ -53,18 +53,9 @@ glyph-block Letter-Latin-Upper-T : begin
 		local sf2 : [SerifFrame.fromDf df (top / 2) 0].slice 1 2
 		if SLAB : include sf2.rt.full
 
-	define [TweShape df top doTopSerifs] : glyph-proc
-		local hd : FlatHookDepth df
-		include : difference
-			TShape df top doTopSerifs false
-			MaskBelow hd.y
-
-		include : dispiro
-			widths.center
-			straight.down.start df.middle hd.y [heading Downward]
-			arcvh.superness DesignParameters.tightHookSuperness
-			flat (df.middle + hd.x - [HSwToV HalfStroke]) HalfStroke
-			curl (df.middle + [Math.max (hd.x - [HSwToV HalfStroke] + 1) (LongJut * 1.05)] + HalfStroke * TanSlope) HalfStroke
+	define [TweUpperShape df top doTopSerifs] : glyph-proc
+		include : TShape df top doTopSerifs false
+		eject-contour 'strokeV'
 
 	define [CyrlTallTeShape df top doTopSerifs doBottomSerifs] : glyph-proc
 		local xRight : df.width - 1.5 * df.leftSB
@@ -120,15 +111,17 @@ glyph-block Letter-Latin-Upper-T : begin
 			set-base-anchor 'bottomRight' (df.middle + [HSwToV HalfStroke]) 0
 			include : TShape df XH doST doSB
 
-		create-glyph "cyrl/Twe.\(suffix)" : glyph-proc
+		create-glyph "cyrl/Twe/upper.\(suffix)" : glyph-proc
 			set-width df.width
 			include : df.markSet.capital
-			include : TweShape df CAP doST doSB
+			include : TweUpperShape df CAP doST doSB
+			set-base-anchor 'cvDecompose' (df.width / 2) CAP
 
-		create-glyph "cyrl/twe.\(suffix)" : glyph-proc
+		create-glyph "cyrl/twe/upper.\(suffix)" : glyph-proc
 			set-width df.width
 			include : df.markSet.e
-			include : TweShape df XH doST doSB
+			include : TweUpperShape df XH doST doSB
+			set-base-anchor 'cvDecompose' (df.width / 2) XH
 
 		create-glyph "currency/tengeSign.\(suffix)" : glyph-proc
 			set-width df.width
@@ -187,8 +180,10 @@ glyph-block Letter-Latin-Upper-T : begin
 
 	select-variant 'cyrl/TjeKomi' 0x50E (follow -- 'T/rtailBase')
 	select-variant 'cyrl/tjeKomi.upright' null (follow -- 'T/rtailBase')
-	select-variant 'cyrl/Twe' 0xA68C (follow -- 'T/rtailBase')
-	select-variant 'cyrl/twe' 0xA68D (follow -- 'T/rtailBase')
+	select-variant 'cyrl/Twe/upper' (follow -- 'T/rtailBase')
+	select-variant 'cyrl/twe/upper' (follow -- 'T/rtailBase')
+	derive-composites 'cyrl/Twe' 0xA68C 'cyrl/Twe/upper' 'cyrl/Twe/middle'
+	derive-composites 'cyrl/twe' 0xA68D 'cyrl/twe/upper' 'cyrl/twe/middle'
 
 	select-variant 'currency/tengeSign' 0x20B8 (follow -- 'T')
 

params/variants.toml

@@ -5033,31 +5033,37 @@ tagKind = "letter"
 rank = 1
 description = "Greek lower Tau (`τ`) with a tailless shape"
 selector."grek/tau" = "tau/tailless"
+selector."grek/tau/tailed" = "tau/flatTailed"
 
 [prime.lower-tau.variants.short-tailed]
 rank = 2
 description = "Greek lower Tau (`τ`) with a very short tail"
 selector."grek/tau" = "tau/shortTailed"
+selector."grek/tau/tailed" = "tau/flatTailed"
 
 [prime.lower-tau.variants.tailed]
 rank = 3
 description = "Greek lower Tau (`τ`) with curly tail"
 selector."grek/tau" = "tau/tailed"
+selector."grek/tau/tailed" = "tau/tailed"
 
 [prime.lower-tau.variants.flat-tailed]
 rank = 4
 description = "Greek lower Tau (`τ`) with a flat tail"
 selector."grek/tau" = "tau/flatTailed"
+selector."grek/tau/tailed" = "tau/flatTailed"
 
 [prime.lower-tau.variants.diagonal-tailed]
 rank = 5
 description = "Greek lower Tau (`τ`) with a diagonal tail"
 selector."grek/tau" = "tau/diagonalTailed"
+selector."grek/tau/tailed" = "tau/diagonalTailed"
 
 [prime.lower-tau.variants.semi-tailed]
 rank = 6
 description = "Greek lower Tau (`τ`) with a slightly curly tail"
 selector."grek/tau" = "tau/semiTailed"
+selector."grek/tau/tailed" = "tau/semiTailed"