v0.1.0 initial commit

tui/region.go

@@ -0,0 +1,112 @@
+package tui
+
+import "github.com/lixenwraith/terminal"
+
+// Region represents a rectangular area within a cell buffer
+// All coordinates are relative to the region's origin
+type Region struct {
+	Cells  []terminal.Cell
+	TotalW int // Total width of the underlying cell buffer
+	X, Y   int // Absolute position in cell buffer
+	W, H   int // Region dimensions
+}
+
+// NewRegion creates a region referencing a cell slice with bounds
+func NewRegion(cells []terminal.Cell, totalW, x, y, w, h int) Region {
+	return Region{
+		Cells:  cells,
+		TotalW: totalW,
+		X:      x,
+		Y:      y,
+		W:      w,
+		H:      h,
+	}
+}
+
+// Sub returns a nested region with coordinates relative to parent, result is clipped to parent bounds
+func (r Region) Sub(x, y, w, h int) Region {
+	// Clip to parent bounds
+	if x < 0 {
+		w += x
+		x = 0
+	}
+	if y < 0 {
+		h += y
+		y = 0
+	}
+	if x+w > r.W {
+		w = r.W - x
+	}
+	if y+h > r.H {
+		h = r.H - y
+	}
+	if w < 0 {
+		w = 0
+	}
+	if h < 0 {
+		h = 0
+	}
+
+	return Region{
+		Cells:  r.Cells,
+		TotalW: r.TotalW,
+		X:      r.X + x,
+		Y:      r.Y + y,
+		W:      w,
+		H:      h,
+	}
+}
+
+// Inset returns a region shrunk by n cells on all sides
+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
+func (r Region) Cell(x, y int, ch rune, fg, bg terminal.RGB, attr terminal.Attr) {
+	if x < 0 || x >= r.W || y < 0 || y >= r.H {
+		return
+	}
+	absX := r.X + x
+	absY := r.Y + y
+
+	// Bounds check against the physical buffer dimensions
+	if uint(absX) >= uint(r.TotalW) {
+		return
+	}
+
+	idx := absY*r.TotalW + absX
+	// Single bounds check for the backing slice
+	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
+func (r Region) Fill(bg terminal.RGB) {
+	for y := 0; y < r.H; y++ {
+		for x := 0; x < r.W; x++ {
+			r.Cell(x, y, ' ', terminal.RGB{}, bg, terminal.AttrNone)
+		}
+	}
+}
+
+// Clear fills region with spaces and zero colors
+func (r Region) Clear() {
+	r.Fill(terminal.RGB{})
+}
+
+// Width returns region width
+func (r Region) Width() int {
+	return r.W
+}
+
+// Height returns region height
+func (r Region) Height() int {
+	return r.H
+}
+
+// Bounds returns absolute position and dimensions
+func (r Region) Bounds() (x, y, w, h int) {
+	return r.X, r.Y, r.W, r.H
+}