v0.1.4 tui uniform transparent background policy, tui example added

tui/pane.go

@@ -28,9 +28,7 @@ func (r Region) Pane(opts PaneOpts) Region {
 	r.Box(opts.Border, opts.BorderFg)
 
 	// Title on top edge
-	headerH := 0
 	if opts.Title != "" {
-		headerH = 1
 		title := " " + opts.Title + " "
 		if RuneLen(title) > r.W-4 {
 			title = Truncate(title, r.W-4)
@@ -44,8 +42,8 @@ func (r Region) Pane(opts PaneOpts) Region {
 		}
 	}
 
-	// Return content region (inside border, below title)
-	return r.Sub(1, 1+headerH, r.W-2, r.H-2-headerH)
+	// Content region is everything inside the border. The title sits ON the border row.
+	return r.Sub(1, 1, r.W-2, r.H-2)
 }
 
 // TitledPane fills region with background, draws centered title at top, returns content region
@@ -68,4 +66,3 @@ func (r Region) TitledPaneFocused(title string, titleFg, bg, focusBg color.RGB,
 	}
 	return r.TitledPane(title, titleFg, bg)
 }
-

tui/region.go

@@ -65,7 +65,11 @@ func (r Region) Inset(n int) Region {
 	return r.Sub(n, n, r.W-2*n, r.H-2*n)
 }
 
-// Cell sets a single cell with bounds checking
+// Cell sets a single cell with bounds checking.
+// A zero-value bg (color.RGB{}) is transparent: the existing cell's
+// background is preserved. Establish a base background first (Fill, or
+// pre-initialized cell buffer). For a literal black background use
+// CellOpaque or Fill(color.RGB{}).
 func (r Region) Cell(x, y int, ch rune, fg, bg color.RGB, attr terminal.Attr) {
 	if x < 0 || x >= r.W || y < 0 || y >= r.H {
 		return
@@ -81,15 +85,39 @@ func (r Region) Cell(x, y int, ch rune, fg, bg color.RGB, attr terminal.Attr) {
 	idx := absY*r.TotalW + absX
 	// Single bounds check for the backing slice
 	if uint(idx) < uint(len(r.Cells)) {
+		if bg == (color.RGB{}) {
+			bg = r.Cells[idx].Bg // transparent: inherit current background
+		}
 		r.Cells[idx] = terminal.Cell{Rune: ch, Fg: fg, Bg: bg, Attrs: attr}
 	}
 }
 
-// Fill fills entire region with background color
+// CellOpaque sets a single cell writing bg verbatim, including zero (black).
+// Used by base-layer operations (Fill) that must be able to write any color.
+func (r Region) CellOpaque(x, y int, ch rune, fg, bg color.RGB, attr terminal.Attr) {
+	if x < 0 || x >= r.W || y < 0 || y >= r.H {
+		return
+	}
+	absX := r.X + x
+	absY := r.Y + y
+
+	if uint(absX) >= uint(r.TotalW) {
+		return
+	}
+
+	idx := absY*r.TotalW + absX
+	if uint(idx) < uint(len(r.Cells)) {
+		r.Cells[idx] = terminal.Cell{Rune: ch, Fg: fg, Bg: bg, Attrs: attr}
+	}
+}
+
+// Fill fills entire region with background color.
+// Opaque by definition: Fill establishes the base layer, so bg is written
+// verbatim (including zero/black) rather than treated as transparent.
 func (r Region) Fill(bg color.RGB) {
 	for y := 0; y < r.H; y++ {
 		for x := 0; x < r.W; x++ {
-			r.Cell(x, y, ' ', color.RGB{}, bg, terminal.AttrNone)
+			r.CellOpaque(x, y, ' ', color.RGB{}, bg, terminal.AttrNone)
 		}
 	}
 }
@@ -113,4 +141,3 @@ func (r Region) Height() int {
 func (r Region) Bounds() (x, y, w, h int) {
 	return r.X, r.Y, r.W, r.H
 }
-

tui/table.go

@@ -129,7 +129,15 @@ func (r Region) Table(headers []string, rows [][]string, opts TableOpts) {
 }
 
 // renderTableRow renders a single table row
+// The row is cleared to style.Bg across the full region width first, so
+// alternating-row backgrounds render as continuous bands rather than only
+// under glyphs. A zero style.Bg inherits the underlying background.
 func (r Region) renderTableRow(y int, cells []string, widths []int, aligns []Align, sep rune, style Style) {
+	// Clear row with row background (full width, List-consistent banding)
+	for cx := 0; cx < r.W; cx++ {
+		r.Cell(cx, y, ' ', style.Fg, style.Bg, terminal.AttrNone)
+	}
+
 	x := 0
 	for i, w := range widths {
 		if x >= r.W {
@@ -177,4 +185,5 @@ func (r Region) renderTableRow(y int, cells []string, widths []int, aligns []Ali
 			x++
 		}
 	}
-}
+}
+