Update go.mod

buffer.go

@@ -7,6 +7,7 @@ import (
 // Buffer is a 2-dimensional buffer
 type Buffer[T any] struct {
 	data       [][]T
+	x, y       int
 	width      int
 	height     int
 	parent     *Buffer[T]
@@ -24,6 +25,7 @@ func NewBuffer[T any](width, height int, defaultValue T) *Buffer[T] {
 	}
 
 	return &Buffer[T]{
+		x: 0, y: 0,
 		data:       b,
 		width:      width,
 		height:     height,
@@ -32,18 +34,18 @@ func NewBuffer[T any](width, height int, defaultValue T) *Buffer[T] {
 	}
 }
 
-func (b *Buffer[T]) x(x int) int {
+func (b *Buffer[T]) limX(x int) int {
 	return limit(x, 0, b.width-1)
 }
 
-func (b *Buffer[T]) y(y int) int {
+func (b *Buffer[T]) limY(y int) int {
 	return limit(y, 0, b.height-1)
 }
 
 // Set sets the value at position (x,y) to c
 func (b *Buffer[T]) Set(x, y int, v T) {
 	if b.width > 0 && b.height > 0 {
-		b.data[b.y(y)][b.x(x)] = v
+		b.data[b.limY(y)][b.limX(x)] = v
 	}
 }
 
@@ -67,14 +69,32 @@ func (b *Buffer[T]) Height() int {
 	return b.height
 }
 
-// ForEach calls f for every value in this buffer
+// Offset returns the offset of b relative to its parent buffer.
+// Offset returns zeros if b has no parent
+func (b *Buffer[T]) Offset() (x, y int) {
+	return b.x, b.y
+}
+
+// OffsetX returns the horizontal offset of b relative to its parent buffer.
+// OffsetX returns 0 if b has no parent
+func (b *Buffer[T]) OffsetX() int {
+	return b.x
+}
+
+// OffsetY returns the vertical offset of b relative to its parent buffer.
+// OffsetY returns 0 if b has no parent
+func (b *Buffer[T]) OffsetY() int {
+	return b.y
+}
+
+// ForEachLine calls f for each line in b
 func (b *Buffer[T]) ForEachLine(f func(line int, content []T)) {
 	for line, content := range b.data {
 		f(line, content)
 	}
 }
 
-// ForEach calls f for every value in this buffer
+// ForEach calls f for every value in b
 func (b *Buffer[T]) ForEach(f func(x, y int, v T)) {
 	for y, col := range b.data {
 		for x, v := range col {
@@ -116,6 +136,7 @@ func (b *Buffer[T]) Sub(x, y, w, h int) *Buffer[T] {
 
 	// make buffer
 	return &Buffer[T]{
+		x: x, y: y,
 		data:       data,
 		width:      w,
 		height:     h,

buffer_test.go

@@ -22,3 +22,9 @@ func TestSet(t *testing.T) {
 	b := NewBuffer(0, 0, ' ')
 	b.Set(0, 0, 'a')
 }
+
+func TestOffset(t *testing.T) {
+	b := NewBuffer(10, 10, ' ')
+	b = b.Sub(3, 3, 3, 3)
+	fmt.Println(b.OffsetX(), b.OffsetY())
+}

go.mod

@@ -1,3 +1,7 @@
-module git.tordarus.net/Tordarus/buf2d
+module git.tordarus.net/tordarus/buf2d
 
 go 1.18
+
+require github.com/mattn/go-runewidth v0.0.14
+
+require github.com/rivo/uniseg v0.2.0 // indirect

go.sum

@@ -0,0 +1,4 @@
+github.com/mattn/go-runewidth v0.0.14 h1:+xnbZSEeDbOIg5/mE6JF0w6n9duR1l3/WmbinWVwUuU=
+github.com/mattn/go-runewidth v0.0.14/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=

write_string.go

@@ -2,19 +2,23 @@ package buf2d
 
 import (
 	"strings"
+
+	"github.com/mattn/go-runewidth"
 )
 
-// WriteString writes a whole string to the buffer at position (x,y)
-// no word wrap is applied at all. If the string does not fit, it will be truncated
-func WriteString(b *Buffer[rune], str string, x, y int) {
+// WriteString writes a whole string to the buffer at position (x,y).
+// no word wrap is applied at all. If the string does not fit, it will be truncated.
+// It returns the amount of runes in str
+func WriteString(b *Buffer[rune], str string, x, y int) (width int) {
 	dx := x
 	for _, r := range str {
-		if dx >= b.width {
+		if dx >= b.Width() {
 			return
 		}
 		b.Set(dx, y, r)
-		dx++
+		dx += runewidth.RuneWidth(r)
 	}
+	return dx - x
 }
 
 // WriteMultiLineString writes a multi-line string to the buffer at position (x,y)