1 files changed, 108 insertions, 0 deletions
diff --git a/pkg/draw/buffer.go b/pkg/draw/buffer.go
new file mode 100644
index 0000000..9e18f58
--- /dev/null
+++ b/pkg/draw/buffer.go
@@ -0,0 +1,108 @@
+package draw
+
+import (
+	"io"
+)
+
+type Buffer struct {
+	Runes [][]rune
+	Box
+}
+
+func (b *Buffer) GetBuffer() *Buffer { return b }
+
+func NewBuffer(size Box) *Buffer {
+	r := make([][]rune, size.Height)
+	for i := range r {
+		r[i] = make([]rune, size.Width)
+	}
+	return &Buffer{
+		Runes: r,
+		Box:   size,
+	}
+}
+
+func (b *Buffer) Fill(r rune) {
+	for i := range b.Runes {
+		for j := range b.Runes[i] {
+			b.Runes[i][j] = r
+		}
+	}
+}
+
+func (b *Buffer) Get(y, x int) rune {
+	if y < 0 || y >= b.Height {
+		return 0
+	}
+	if x < 0 || x >= b.Width {
+		return 0
+	}
+	return b.Runes[y][x]
+}
+
+func (b *Buffer) Set(y, x int, r rune) {
+	if y < 0 || y >= b.Height {
+		return
+	}
+	if x < 0 || x >= b.Width {
+		return
+	}
+	b.Runes[y][x] = r
+}
+
+func (b *Buffer) SetRow(y, x1, x2 int, r rune) {
+	for i := x1; i < x2; i++ {
+		b.Set(y, i, r)
+	}
+}
+
+func (b *Buffer) SetColumn(y1, y2, x int, r rune) {
+	for i := y1; i < y2; i++ {
+		b.Set(i, x, r)
+	}
+}
+
+func (b *Buffer) SetOr(y, x int, r rune) {
+	if y < 0 || y >= b.Height {
+		return
+	}
+	if x < 0 || x >= b.Width {
+		return
+	}
+	b.Runes[y][x] |= r
+}
+
+func (b *Buffer) Write(y, x int, r []rune) {
+	if y < 0 || y >= b.Height {
+		return
+	}
+	for i := 0; i < len(r); i++ {
+		xi := x + i
+		if xi < 0 || xi >= b.Width {
+			continue
+		}
+		b.Runes[y][xi] = r[i]
+	}
+}
+
+func (b *Buffer) WriteLeft(y, x int, r []rune) {
+	b.Write(y, x-len(r), r)
+}
+
+func (b *Buffer) WriteRight(y, x int, r []rune) {
+	b.Write(y, x, r)
+}
+
+func (b *Buffer) WriteCenter(y, x int, r []rune) {
+	b.Write(y, x-len(r)/2, r)
+}
+
+func (b *Buffer) Render(w io.Writer) {
+	for i := range b.Runes {
+		row := b.Runes[b.Height-i-1]
+		w.Write([]byte(string(row)))
+		if i < b.Height-1 {
+			w.Write([]byte{'\n'})
+		}
+	}
+}