Add simple border

border.go

@@ -0,0 +1,75 @@
+package tui
+
+const (
+	runeMinus      = '-'
+	runePlusSmall  = '+'
+	runeVLineSmall = '|'
+
+	runePlus     = '┼'
+	runeHLine    = '─'
+	runeVLine    = '│'
+	runeTTee     = '┬'
+	runeRTee     = '┤'
+	runeLTee     = '├'
+	runeBTee     = '┴'
+	runeULCorner = '┌'
+	runeURCorner = '┐'
+	runeLLCorner = '└'
+	runeLRCorner = '┘'
+)
+
+var runeFallbacks = map[rune]rune{}
+
+func init() {
+	defaultBorder()
+}
+
+// default
+//	┌──────────────────┐
+//	│┌────────┬───────┐│
+//	││A       │apple  ││
+//	│└────────┴───────┘│
+//	└──────────────────┘
+func defaultBorder() {
+	runeFallbacks = map[rune]rune{
+		runePlus:     runePlus,
+		runeHLine:    runeHLine,
+		runeVLine:    runeVLine,
+		runeTTee:     runeTTee,
+		runeRTee:     runeRTee,
+		runeLTee:     runeLTee,
+		runeBTee:     runeBTee,
+		runeULCorner: runeULCorner,
+		runeURCorner: runeURCorner,
+		runeLLCorner: runeLLCorner,
+		runeLRCorner: runeLRCorner,
+	}
+}
+
+// small
+//	+------------------+
+//	|+--------+-------+|
+//	||A       |apple  ||
+//	|+--------+-------+|
+//	+------------------+
+func simpleBorder() {
+	runeFallbacks = map[rune]rune{
+		runeHLine: runeMinus,
+		runeVLine: runeVLineSmall,
+
+		runePlus:     runePlusSmall,
+		runeLLCorner: runePlusSmall,
+		runeLRCorner: runePlusSmall,
+		runeTTee:     runePlusSmall,
+		runeRTee:     runePlusSmall,
+		runeLTee:     runePlusSmall,
+		runeBTee:     runePlusSmall,
+		runeULCorner: runePlusSmall,
+		runeURCorner: runePlusSmall,
+	}
+}
+
+// GetBorder get a simple or default border in a compatible way
+func GetBorder(k rune) rune {
+	return runeFallbacks[k]
+}

grid.go

@@ -49,8 +49,8 @@ func (g *Grid) Draw(p *Painter) {
 		for i := 0; i < g.cols-1; i++ {
 			x := g.colWidths[i] + coloff + border
 			p.DrawVerticalLine(x, 0, s.Y-1)
-			p.DrawRune(x, 0, '┬')
-			p.DrawRune(x, s.Y-1, '┴')
+			p.DrawRune(x, 0, GetBorder('┬'))
+			p.DrawRune(x, s.Y-1, GetBorder('┴'))
 			coloff = x
 		}
 
@@ -59,8 +59,8 @@ func (g *Grid) Draw(p *Painter) {
 		for j := 0; j < g.rows-1; j++ {
 			y := g.rowHeights[j] + rowoff + border
 			p.DrawHorizontalLine(0, s.X-1, y)
-			p.DrawRune(0, y, '├')
-			p.DrawRune(s.X-1, y, '┤')
+			p.DrawRune(0, y, GetBorder('├'))
+			p.DrawRune(s.X-1, y, GetBorder('┤'))
 			rowoff = y
 		}
 
@@ -71,7 +71,7 @@ func (g *Grid) Draw(p *Painter) {
 			coloff = 0
 			for i := 0; i < g.cols-1; i++ {
 				x := g.colWidths[i] + coloff + border
-				p.DrawRune(x, y, '┼')
+				p.DrawRune(x, y, GetBorder('┼'))
 				coloff = x
 			}
 			rowoff = y
@@ -409,6 +409,16 @@ func (g *Grid) SetBorder(enabled bool) {
 	g.hasBorder = enabled
 }
 
+// SetSimpleBorder sets the border use [+ - |]. This is a global config.
+func (g *Grid) SetSimpleBorder() {
+	simpleBorder()
+}
+
+// SetDefaultBorder sets the border use [┼ ─ │ ┬ ┤ ├ ┴ ┌ ┐ └ ┘]. This is a global config.
+func (g *Grid) SetDefaultBorder() {
+	defaultBorder()
+}
+
 // AppendRow adds a new row at the end.
 func (g *Grid) AppendRow(row ...Widget) {
 	g.rows++

grid_test.go

@@ -221,6 +221,23 @@ var drawGridTests = []struct {
 ┌─┬─────────┬──────────────────┬─┐
 │f│bar......│baz...............│t│
 └─┴─────────┴──────────────────┴─┘
+`,
+	},
+	{
+		test: "Empty grid with simple border",
+		size: image.Point{15, 5},
+		setup: func() *Grid {
+			g := NewGrid(0, 0)
+			g.SetBorder(true)
+			g.SetSimpleBorder()
+			return g
+		},
+		want: `
++-------------+
+|.............|
+|.............|
+|.............|
++-------------+
 `,
 	},
 }
@@ -232,6 +249,8 @@ func TestGrid_Draw(t *testing.T) {
 			painter := NewPainter(surface, NewTheme())
 			painter.Repaint(tt.setup())
 
+			// Reset
+			tt.setup().SetDefaultBorder()
 			if diff := surfaceEquals(surface, tt.want); diff != "" {
 				t.Error(diff)
 			}

painter.go

@@ -106,14 +106,14 @@ func (p *Painter) DrawText(x, y int, text string) {
 // DrawHorizontalLine paints a horizontal line using box characters.
 func (p *Painter) DrawHorizontalLine(x1, x2, y int) {
 	for x := x1; x < x2; x++ {
-		p.DrawRune(x, y, '─')
+		p.DrawRune(x, y, GetBorder('─'))
 	}
 }
 
 // DrawVerticalLine paints a vertical line using box characters.
 func (p *Painter) DrawVerticalLine(x, y1, y2 int) {
 	for y := y1; y < y2; y++ {
-		p.DrawRune(x, y, '│')
+		p.DrawRune(x, y, GetBorder('│'))
 	}
 }
 
@@ -126,17 +126,17 @@ func (p *Painter) DrawRect(x, y, w, h int) {
 
 			switch {
 			case i == 0 && j == 0:
-				p.DrawRune(m, n, '┌')
+				p.DrawRune(m, n, GetBorder('┌'))
 			case i == w-1 && j == 0:
-				p.DrawRune(m, n, '┐')
+				p.DrawRune(m, n, GetBorder('┐'))
 			case i == 0 && j == h-1:
-				p.DrawRune(m, n, '└')
+				p.DrawRune(m, n, GetBorder('└'))
 			case i == w-1 && j == h-1:
-				p.DrawRune(m, n, '┘')
+				p.DrawRune(m, n, GetBorder('┘'))
 			case i == 0 || i == w-1:
-				p.DrawRune(m, n, '│')
+				p.DrawRune(m, n, GetBorder('│'))
 			case j == 0 || j == h-1:
-				p.DrawRune(m, n, '─')
+				p.DrawRune(m, n, GetBorder('─'))
 			}
 		}
 	}

table.go

@@ -35,8 +35,8 @@ func (t *Table) Draw(p *Painter) {
 		for i := 0; i < t.cols-1; i++ {
 			x := t.colWidths[i] + coloff + border
 			p.DrawVerticalLine(x, 0, s.Y-1)
-			p.DrawRune(x, 0, '┬')
-			p.DrawRune(x, s.Y-1, '┴')
+			p.DrawRune(x, 0, GetBorder('┬'))
+			p.DrawRune(x, s.Y-1, GetBorder('┴'))
 			coloff = x
 		}
 
@@ -45,8 +45,8 @@ func (t *Table) Draw(p *Painter) {
 		for j := 0; j < t.rows-1; j++ {
 			y := t.rowHeights[j] + rowoff + border
 			p.DrawHorizontalLine(0, s.X-1, y)
-			p.DrawRune(0, y, '├')
-			p.DrawRune(s.X-1, y, '┤')
+			p.DrawRune(0, y, GetBorder('├'))
+			p.DrawRune(s.X-1, y, GetBorder('┤'))
 			rowoff = y
 		}
 
@@ -57,7 +57,7 @@ func (t *Table) Draw(p *Painter) {
 			coloff = 0
 			for i := 0; i < t.cols-1; i++ {
 				x := t.colWidths[i] + coloff + border
-				p.DrawRune(x, y, '┼')
+				p.DrawRune(x, y, GetBorder('┼'))
 				coloff = x
 			}
 			rowoff = y