make boxes cover anything behind them

ui/ui.go

@@ -193,6 +193,7 @@ type Box struct {
 	style       tcell.Style
 	cascade     bool
 	visible     bool
+	transparent bool
 }
 
 func NewBox(title string, menuItems []string, contents Contents, initialStyle tcell.Style, cascade bool) *Box {
@@ -203,6 +204,7 @@ func NewBox(title string, menuItems []string, contents Contents, initialStyle tc
 		style:       initialStyle,
 		cascade:     cascade,
 		visible:     true,
+		transparent: false,
 	}
 }
 
@@ -223,6 +225,15 @@ func (b *Box) Draw(s tcell.Screen) {
 	if !b.visible {
 		return
 	}
+	// blank out inner area
+	if !b.transparent {
+		for m := b.x + 1; m < b.x+b.w-1; m++ {
+			for n := b.y + 1; n < b.y+b.h-1; n++ {
+				s.SetContent(m, n, ' ', nil, b.style)
+			}
+		}
+	}
+	// draw outside bars
 	for m := b.x + 1; m < b.x+b.w-1; m++ {
 		s.SetContent(m, b.y, tcell.RuneHLine, nil, b.style)
 		s.SetContent(m, b.y+b.h-1, tcell.RuneHLine, nil, b.style)
@@ -262,6 +273,10 @@ func (b *Box) SetVisible(v bool) {
 	b.visible = v
 }
 
+func (b *Box) SetTransparent(v bool) {
+	b.transparent = v
+}
+
 func (b *Box) Contents() Contents {
 	return b.contents
 }