Improve maximum width of characters in a string (#257)

The function `maxRuneWidth` was using a flawed approach by only
evaluating strings based on each rune. The `uniseg` package provides a
more accurate method based on grapheme clusters.

This change switches over to the improved implementation which should
achieve better results when determining the maximum width of all
grapheme clusters in a string.

Signed-off-by: Michael Lorant <michael.lorant@nine.com.au>

.github/workflows/build.yml

@@ -4,7 +4,7 @@ jobs:
   test:
     strategy:
       matrix:
-        go-version: [~1.17, ^1]
+        go-version: [~1.18, ^1]
         os: [ubuntu-latest, macos-latest, windows-latest]
     runs-on: ${{ matrix.os }}
     env:

borders.go

@@ -3,9 +3,9 @@ package lipgloss
 import (
 	"strings"
 
-	"github.com/mattn/go-runewidth"
 	"github.com/muesli/reflow/ansi"
 	"github.com/muesli/termenv"
+	"github.com/rivo/uniseg"
 )
 
 // Border contains a series of values which comprise the various parts of a
@@ -423,13 +423,18 @@ func (s Style) styleBorder(border string, fg, bg TerminalColor) string {
 	return style.Styled(border)
 }
 
-func maxRuneWidth(str string) (width int) {
-	for _, r := range str {
-		w := runewidth.RuneWidth(r)
+func maxRuneWidth(str string) int {
+	var width int
+
+	state := -1
+	for len(str) > 0 {
+		var w int
+		_, str, w, state = uniseg.FirstGraphemeClusterInString(str, state)
 		if w > width {
 			width = w
 		}
 	}
+
 	return width
 }
 

go.mod

@@ -2,19 +2,19 @@ module github.com/charmbracelet/lipgloss
 
 retract v0.7.0 // v0.7.0 introduces a bug that causes some apps to freeze.
 
-go 1.17
+go 1.18
 
 require (
 	github.com/acarl005/stripansi v0.0.0-20180116102854-5a71ef0e047d
 	github.com/mattn/go-runewidth v0.0.15
 	github.com/muesli/reflow v0.3.0
 	github.com/muesli/termenv v0.15.2
+	github.com/rivo/uniseg v0.4.6
 )
 
 require (
 	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
 	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
 	github.com/mattn/go-isatty v0.0.18 // indirect
-	github.com/rivo/uniseg v0.2.0 // indirect
 	golang.org/x/sys v0.12.0 // indirect
 )

go.sum

@@ -7,17 +7,16 @@ github.com/lucasb-eyer/go-colorful v1.2.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i
 github.com/mattn/go-isatty v0.0.18 h1:DOKFKCQ7FNG2L1rbrmstDN4QVRdS89Nkh85u68Uwp98=
 github.com/mattn/go-isatty v0.0.18/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
 github.com/mattn/go-runewidth v0.0.12/go.mod h1:RAqKPSqVFrSLVXbA8x7dzmKdmGzieGRCM46jaSJTDAk=
-github.com/mattn/go-runewidth v0.0.14/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
 github.com/mattn/go-runewidth v0.0.15 h1:UNAjwbU9l54TA3KzvqLGxwWjHmMgBUVhBiTjelZgg3U=
 github.com/mattn/go-runewidth v0.0.15/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
 github.com/muesli/reflow v0.3.0 h1:IFsN6K9NfGtjeggFP+68I4chLZV2yIKsXJFNZ+eWh6s=
 github.com/muesli/reflow v0.3.0/go.mod h1:pbwTDkVPibjO2kyvBQRBxTWEEGDGq0FlB1BIKtnHY/8=
 github.com/muesli/termenv v0.15.2 h1:GohcuySI0QmI3wN8Ok9PtKGkgkFIk7y6Vpb5PvrY+Wo=
 github.com/muesli/termenv v0.15.2/go.mod h1:Epx+iuz8sNs7mNKhxzH4fWXGNpZwUaJKRS1noLXviQ8=
 github.com/rivo/uniseg v0.1.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
-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 v0.4.6 h1:Sovz9sDSwbOz9tgUy8JpT+KgCkPYJEN/oYzlJiYTNLg=
+github.com/rivo/uniseg v0.4.6/go.mod h1:FN3SvrM+Zdj16jyLfmOkMNblXMcoc8DfTHruCPUcx88=
 golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.7.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.12.0 h1:CM0HF96J0hcLAwsHPJZjfdNzs0gftsLfgKt57wWHJ0o=
 golang.org/x/sys v0.12.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=