1 files changed, 73 insertions, 0 deletions
diff --git a/lib/ui/borders.go b/lib/ui/borders.go
new file mode 100644
index 00000000..08071ad0
--- /dev/null
+++ b/lib/ui/borders.go
@@ -0,0 +1,73 @@
+package ui
+
+import (
+	tb "github.com/nsf/termbox-go"
+)
+
+const (
+	BORDER_LEFT   = 1 << iota
+	BORDER_TOP    = 1 << iota
+	BORDER_RIGHT  = 1 << iota
+	BORDER_BOTTOM = 1 << iota
+)
+
+type Bordered struct {
+	borders      uint
+	content      Drawable
+	onInvalidate func(d Drawable)
+}
+
+func NewBordered(content Drawable, borders uint) *Bordered {
+	b := &Bordered{
+		borders: borders,
+		content: content,
+	}
+	content.OnInvalidate(b.contentInvalidated)
+	return b
+}
+
+func (bordered *Bordered) contentInvalidated(d Drawable) {
+	bordered.Invalidate()
+}
+
+func (bordered *Bordered) Invalidate() {
+	if bordered.onInvalidate != nil {
+		bordered.onInvalidate(bordered)
+	}
+}
+
+func (bordered *Bordered) OnInvalidate(onInvalidate func(d Drawable)) {
+	bordered.onInvalidate = onInvalidate
+}
+
+func (bordered *Bordered) Draw(ctx *Context) {
+	x := 0
+	y := 0
+	width := ctx.Width()
+	height := ctx.Height()
+	cell := tb.Cell{
+		Ch: ' ',
+		Fg: tb.ColorBlack,
+		Bg: tb.ColorWhite,
+	}
+	if bordered.borders&BORDER_LEFT != 0 {
+		ctx.Fill(0, 0, 1, ctx.Height(), cell)
+		x += 1
+		width -= 1
+	}
+	if bordered.borders&BORDER_TOP != 0 {
+		ctx.Fill(0, 0, ctx.Width(), 1, cell)
+		y += 1
+		height -= 1
+	}
+	if bordered.borders&BORDER_RIGHT != 0 {
+		ctx.Fill(ctx.Width()-1, 0, 1, ctx.Height(), cell)
+		width -= 1
+	}
+	if bordered.borders&BORDER_BOTTOM != 0 {
+		ctx.Fill(0, ctx.Height()-1, ctx.Width(), 1, cell)
+		height -= 1
+	}
+	subctx := ctx.Subcontext(x, y, width, height)
+	bordered.content.Draw(subctx)
+}