From 7fc9c134b0e1750cd65e4f9e7a30c58fee8d0525 Mon Sep 17 00:00:00 2001
From: milarin <milaring@proton.me>
Date: Mon, 24 Apr 2023 16:41:36 +0200
Subject: [PATCH] fixed unicode characters on last column

---
 draw_buffer.go              | 24 +++++++++++++++---------
 go.mod                      |  1 +
 go.sum                      |  2 ++
 layouts/layout_separator.go |  1 +
 screen.go                   | 33 ++++++++++++++++++++++++++-------
 tests/screen_test.go        |  4 ++--
 6 files changed, 47 insertions(+), 18 deletions(-)

diff --git a/draw_buffer.go b/draw_buffer.go
index 999ea43..6586920 100644
--- a/draw_buffer.go
+++ b/draw_buffer.go
@@ -1,30 +1,36 @@
 package tui
 
 import (
+	"git.milar.in/milarin/slices"
 	"github.com/gdamore/tcell"
+	"github.com/mattn/go-runewidth"
 )
 
 func drawBuffer(scr tcell.Screen, buf *ViewBuffer) {
-	// buf.ForEach(func(x, y int, rn Rune) {
-	// 	scr.SetContent(x, y, rn.Rn, nil, rn.Style)
-	// })
-
-	// TODO use runewidth.RuneWidth(rn)?
 	buf.ForEachLine(func(y int, content []Rune) {
 		for x := 0; x < buf.Width(); x++ {
 			rn := content[x]
-			if rn.Rn >= '─' && rn.Rn <= '╿' {
-				scr.SetContent(x, y, rn.Rn, []rune{content[x+1].Rn}, rn.Style)
-				x++
+
+			extraRuneCount := runewidth.RuneWidth(rn.Rn) - 1
+			var extraRunes []Rune
+			if x+1+extraRuneCount < len(content) {
+				extraRunes = content[x+1 : x+1+extraRuneCount]
 			} else {
-				scr.SetContent(x, y, rn.Rn, nil, rn.Style)
+				extraRunes = content[x+1 : x+1]
 			}
+
+			scr.SetContent(x, y, rn.Rn, slices.Map(extraRunes, getRune), rn.Style)
+			x += extraRuneCount
 		}
 	})
 
 	scr.Show()
 }
 
+func getRune(rn Rune) rune {
+	return rn.Rn
+}
+
 func truncateBuffer(buf *ViewBuffer, w, h int) *ViewBuffer {
 	if w < 0 {
 		w = buf.Width()
diff --git a/go.mod b/go.mod
index 0b91197..a936826 100644
--- a/go.mod
+++ b/go.mod
@@ -7,6 +7,7 @@ require (
 	git.milar.in/milarin/buf2d v1.1.7
 	git.milar.in/milarin/ds v0.0.2
 	git.milar.in/milarin/gmath v0.0.3
+	git.milar.in/milarin/slices v0.0.8
 	github.com/gdamore/tcell v1.4.0
 	github.com/mattn/go-runewidth v0.0.7
 )
diff --git a/go.sum b/go.sum
index 71a932d..91a64dd 100644
--- a/go.sum
+++ b/go.sum
@@ -6,6 +6,8 @@ git.milar.in/milarin/ds v0.0.2 h1:vCA3mDxZUNfvHpzrdz7SeBUKiPn74NTopo915IUG7I0=
 git.milar.in/milarin/ds v0.0.2/go.mod h1:HJK7QERcRvV9j7xzEocrKUtW+1q4JB1Ly4Bj54chfwI=
 git.milar.in/milarin/gmath v0.0.3 h1:ii6rKNItS55O/wtIFhD1cTN2BMwDZjTBmiOocKURvxM=
 git.milar.in/milarin/gmath v0.0.3/go.mod h1:HDLftG5RLpiNGKiIWh+O2G1PYkNzyLDADO8Cd/1abiE=
+git.milar.in/milarin/slices v0.0.8 h1:qN9TE3tkArdTixMKSnwvNPcApwAjxpLVwA5a9k1rm2s=
+git.milar.in/milarin/slices v0.0.8/go.mod h1:qMhdtMnfWswc1rHpwgNw33lB84aNEkdBn5BDiYA+G3k=
 github.com/gdamore/encoding v1.0.0 h1:+7OoQ1Bc6eTm5niUzBa0Ctsh6JbMW6Ra+YNuAtDBdko=
 github.com/gdamore/encoding v1.0.0/go.mod h1:alR0ol34c49FCSBLjhosxzcPHQbf2trDkoo5dl+VrEg=
 github.com/gdamore/tcell v1.4.0 h1:vUnHwJRvcPQa3tzi+0QI4U9JINXYJlOz9yiaiPQ2wMU=
diff --git a/layouts/layout_separator.go b/layouts/layout_separator.go
index 0991647..c824b70 100644
--- a/layouts/layout_separator.go
+++ b/layouts/layout_separator.go
@@ -111,6 +111,7 @@ func (g *SeperatorLayout) OnKeyPressed(event *tui.KeyEvent) (consumed bool) {
 			return true
 		}
 	}
+
 	return false
 }
 
diff --git a/screen.go b/screen.go
index be2e617..7e94389 100644
--- a/screen.go
+++ b/screen.go
@@ -23,6 +23,13 @@ type Screen struct {
 
 	// Root is the root view which is currently shown on screen
 	Root View
+
+	// Some unicode characters need more bytes than one. For these characters,
+	// an additional last column will be provided in the internal view buffer.
+	// That way, these characters can also be shown on the right most column.
+	//
+	// You should enable this flag if you have missing unicode characters in the last column.
+	UnicodeSupport bool
 }
 
 func NewScreen(root View) (*Screen, error) {
@@ -142,13 +149,7 @@ func (s *Screen) drawloop() {
 	defer s.handlePanic("panicked while redrawing")
 
 	for range s.redrawCh {
-		w, h := s.scr.Size()
-
-		if s.buf == nil || s.buf.Width() != w || s.buf.Height() != h {
-			s.buf = buf2d.NewBuffer(w, h, DefaultRune)
-		} else {
-			s.buf.Fill(DefaultRune)
-		}
+		s.prepareViewBuffer()
 
 		// draw root view
 		rw, rh := s.Root.Layout()
@@ -166,6 +167,24 @@ func (s *Screen) drawloop() {
 	}
 }
 
+func (s *Screen) prepareViewBuffer() {
+	w, h := s.scr.Size()
+
+	if s.UnicodeSupport {
+		if s.buf == nil || s.buf.Width() != w-1 || s.buf.Height() != h {
+			s.buf = buf2d.NewBuffer(w, h, DefaultRune).Sub(0, 0, w-1, h)
+		} else {
+			s.buf.Fill(DefaultRune)
+		}
+	} else {
+		if s.buf == nil || s.buf.Width() != w || s.buf.Height() != h {
+			s.buf = buf2d.NewBuffer(w, h, DefaultRune)
+		} else {
+			s.buf.Fill(DefaultRune)
+		}
+	}
+}
+
 func (s *Screen) handlePanic(msg string) {
 	if err := recover(); err != nil {
 		if e, ok := err.(error); ok {
diff --git a/tests/screen_test.go b/tests/screen_test.go
index 2011253..1683a6a 100644
--- a/tests/screen_test.go
+++ b/tests/screen_test.go
@@ -86,11 +86,11 @@ func TestScrollView(t *testing.T) {
 }
 
 func TestBorderView(t *testing.T) {
-	textView := views.NewTextView("hello world!")
+	textView := views.NewTextView("hello world! こんにちは！")
 	borderView := views.NewBorderView(textView)
 	//borderView2 := views.NewBorderView(borderView)
 
-	screen, err := tui.NewScreen(borderView)
+	screen, err := tui.NewScreen(views.NewGrowView(borderView))
 	if err != nil {
 		t.Error(err)
 		return