Upgraded to new rivo/uniseg version.

go.mod

@@ -6,7 +6,7 @@ require (
 	github.com/gdamore/tcell/v2 v2.4.1-0.20210905002822-f057f0a857a1
 	github.com/lucasb-eyer/go-colorful v1.2.0
 	github.com/mattn/go-runewidth v0.0.13
-	github.com/rivo/uniseg v0.2.0
+	github.com/rivo/uniseg v0.3.0
 	golang.org/x/sys v0.0.0-20210309074719-68d13333faf2 // indirect
 	golang.org/x/term v0.0.0-20210220032956-6a3ed077a48d // indirect
 )

go.sum

@@ -6,8 +6,9 @@ github.com/lucasb-eyer/go-colorful v1.2.0 h1:1nnpGOrhyZZuNyfu1QjKiUICQ74+3FNCN69
 github.com/lucasb-eyer/go-colorful v1.2.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
 github.com/mattn/go-runewidth v0.0.13 h1:lTGmDsbAYt5DmK6OnoV7EuIF1wEIFAcxld6ypU4OSgU=
 github.com/mattn/go-runewidth v0.0.13/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
-github.com/rivo/uniseg v0.2.0 h1:S1pD9weZBuJdFmowNwbpi7BJ8TNftyUImj/0WQi72jY=
 github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
+github.com/rivo/uniseg v0.3.0 h1:eyC18g7xB83Dv/xlJXLgNkRidVoR7nqFZBJvqo/K188=
+github.com/rivo/uniseg v0.3.0/go.mod h1:FN3SvrM+Zdj16jyLfmOkMNblXMcoc8DfTHruCPUcx88=
 golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210309074719-68d13333faf2 h1:46ULzRKLh1CwgRq2dC5SlBzEqqNCi8rreOZnNrbqcIY=
 golang.org/x/sys v0.0.0-20210309074719-68d13333faf2/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=

textview.go

@@ -807,10 +807,7 @@ func (t *TextView) reindexBuffer(width int) {
 				extract := runewidth.Truncate(str, width, "")
 				if len(extract) == 0 {
 					// We'll extract at least one grapheme cluster.
-					gr := uniseg.NewGraphemes(str)
-					gr.Next()
-					_, to := gr.Positions()
-					extract = str[:to]
+					extract, _, _ = uniseg.FirstGraphemeClusterInString(str, -1)
 				}
 				if t.wordWrap && len(extract) < len(str) {
 					// Add any spaces from the next line.

util.go

@@ -445,10 +445,14 @@ func TaggedStringWidth(text string) int {
 // text. It splits the text into its grapheme clusters, calculates each
 // cluster's width, and adds them up to a total.
 func stringWidth(text string) (width int) {
-	g := uniseg.NewGraphemes(text)
-	for g.Next() {
-		var chWidth int
-		for _, r := range g.Runes() {
+	state := -1
+	for len(text) > 0 {
+		var (
+			chWidth int
+			cl      string
+		)
+		cl, text, state = uniseg.FirstGraphemeClusterInString(text, state)
+		for _, r := range cl {
 			chWidth = runewidth.RuneWidth(r)
 			if chWidth > 0 {
 				break // Our best guess at this point is to use the width of the first non-zero-width rune.
@@ -582,23 +586,34 @@ func Escape(text string) string {
 // returns true. This function returns true if the iteration was stopped before
 // the last character.
 func iterateString(text string, callback func(main rune, comb []rune, textPos, textWidth, screenPos, screenWidth int) bool) bool {
-	var screenPos int
+	var screenPos, textPos int
+
+	state := -1
+	for len(text) > 0 {
+		var cluster string
+		cluster, text, state = uniseg.FirstGraphemeClusterInString(text, state)
+
+		var width int
+		runes := make([]rune, 0, len(cluster))
+		for _, r := range cluster {
+			runes = append(runes, r)
+			w := runewidth.RuneWidth(r)
+			if width == 0 && w > 0 {
+				width = w // Our best guess at this point is to use the width of the first non-zero-width rune.
+			}
+		}
 
-	gr := uniseg.NewGraphemes(text)
-	for gr.Next() {
-		r := gr.Runes()
-		from, to := gr.Positions()
-		width := stringWidth(gr.Str())
 		var comb []rune
-		if len(r) > 1 {
-			comb = r[1:]
+		if len(runes) > 1 {
+			comb = runes[1:]
 		}
 
-		if callback(r[0], comb, from, to-from, screenPos, width) {
+		if callback(runes[0], comb, textPos, len(cluster), screenPos, width) {
 			return true
 		}
 
 		screenPos += width
+		textPos += len(cluster)
 	}
 
 	return false