fix unicode display

go.mod

@@ -14,7 +14,7 @@ require (
 	github.com/kr/pretty v0.3.0 // indirect
 	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
 	github.com/mattn/go-isatty v0.0.14 // indirect
-	github.com/mattn/go-runewidth v0.0.13 // indirect
+	github.com/mattn/go-runewidth v0.0.15 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/rivo/uniseg v0.2.0 // indirect
 	github.com/rogpeppe/go-internal v1.8.1 // indirect

go.sum

@@ -22,6 +22,8 @@ github.com/mattn/go-isatty v0.0.14 h1:yVuAays6BHfxijgZPzw+3Zlu5yQgKGP2/hcQbHb7S9
 github.com/mattn/go-isatty v0.0.14/go.mod h1:7GGIvUiUoEMVVmxf/4nioHXj79iQHKdU27kJ6hsGG94=
 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/mattn/go-runewidth v0.0.15 h1:UNAjwbU9l54TA3KzvqLGxwWjHmMgBUVhBiTjelZgg3U=
+github.com/mattn/go-runewidth v0.0.15/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
 github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=

state_model.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"github.com/gdamore/tcell/v2"
+	"github.com/mattn/go-runewidth"
 	"github.com/viktomas/godu/commands"
 	"github.com/viktomas/godu/interactive"
 )
@@ -48,8 +49,17 @@ func (vs visualState) GetCell(x, y int) (rune, tcell.Style, []rune, int) {
 	if line.IsMarked {
 		style = style.Foreground(tcell.ColorGreen)
 	}
-	if x < len(vs.folders[shiftedIndex].Text) {
-		return line.Text[x], style, nil, 1
+
+	visualIndex := 0
+	for _, r := range line.Text {
+		width := runewidth.RuneWidth(r)
+		if visualIndex == x {
+			return r, style, nil, width
+		}
+		visualIndex += width
+		if visualIndex > x {
+			break
+		}
 	}
 	return ' ', style, nil, 1
 }

state_model_test.go

@@ -0,0 +1,47 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/gdamore/tcell/v2"
+	"github.com/viktomas/godu/interactive"
+)
+
+func TestGetCell(t *testing.T) {
+	vs := visualState{
+		folders: []interactive.Line{
+			{Text: []rune("Hello"), IsMarked: false},
+			{Text: []rune("你好"), IsMarked: true},
+		},
+		selected:     1,
+		screenHeight: 5,
+	}
+
+	tests := []struct {
+		x, y          int
+		expectedRune  rune
+		expectedStyle tcell.Style
+		expectedWidth int
+	}{
+		{0, 0, 'H', tcell.StyleDefault, 1},
+		{1, 0, 'e', tcell.StyleDefault, 1},
+		{0, 1, '你', tcell.StyleDefault.Reverse(true).Foreground(tcell.ColorGreen), 2},
+		{1, 1, ' ', tcell.StyleDefault.Reverse(true).Foreground(tcell.ColorGreen), 1},
+		{2, 1, '好', tcell.StyleDefault.Reverse(true).Foreground(tcell.ColorGreen), 2},
+		{0, 2, ' ', tcell.StyleDefault, 1}, // out of bounds y
+		{6, 0, ' ', tcell.StyleDefault, 1}, // out of bounds x
+	}
+
+	for _, tt := range tests {
+		r, style, _, width := vs.GetCell(tt.x, tt.y)
+		if r != tt.expectedRune {
+			t.Errorf("GetCell(%d, %d) = %c; want %c", tt.x, tt.y, r, tt.expectedRune)
+		}
+		if style != tt.expectedStyle {
+			t.Errorf("GetCell(%d, %d) style = %+v; want %+v", tt.x, tt.y, style, tt.expectedStyle)
+		}
+		if width != tt.expectedWidth {
+			t.Errorf("GetCell(%d, %d) width = %d; want %d", tt.x, tt.y, width, tt.expectedWidth)
+		}
+	}
+}