v0.2.1 tui enhancement and better narrow layouts

tui/field.go

@@ -36,36 +36,49 @@ type Field struct {
 
 // Field draws a form row at y: the focus mark, the label in a column labelW
 // wide with the required mark, and below, the error, or the help while
-// focused. It returns the region for the value beside the label, where the
-// caller draws a TextInput, Choice or Toggle, and the rows it used.
+// focused, wrapped. The label column leaves the value half the row; labelW 0
+// stacks the label on its own row and the value under it, indented. It
+// returns the region for the value, where the caller draws a TextInput,
+// Radio or Toggle, and the rows it used.
 func (r Region) Field(y, labelW int, f Field, focused bool, th Theme) (Region, int) {
 	label := th.Muted
 	if focused {
 		label = th.Text
 		r.TextStyled(0, y, string(th.Glyphs.Focus), th.Accent)
 	}
+	x, rows := 4, 2 // stacked: the label's own row, the value under it
+	if labelW > 0 {
+		labelW = min(labelW, max(1, (r.W-3)/2))
+		x, rows = 2+labelW+1, 1
+	} else {
+		labelW = r.W - 2
+	}
 	name := f.Label
 	if f.Required {
 		name = Truncate(name, labelW-2)
 		r.TextStyled(2+RuneLen(name)+1, y, string(th.Glyphs.Required), th.Accent)
 	}
 	r.TextStyled(2, y, Truncate(name, labelW), label)
+	value := r.Sub(x, y+rows-1, r.W-x, 1)
 
-	x := 2 + labelW + 1
 	note, style := f.Error, th.Error
 	if note == "" && focused {
 		note, style = f.Help, th.Muted
 	}
 	if note == "" {
-		return r.Sub(x, y, r.W-x, 1), 1
+		return value, rows
 	}
-	r.TextStyled(x, y+1, Truncate(note, r.W-x), style)
-	return r.Sub(x, y, r.W-x, 1), 2
+	lines := WrapText(note, r.W-x)
+	for i, l := range lines {
+		r.TextStyled(x, y+rows+i, l, style)
+	}
+	return value, rows + len(lines)
 }
 
 // TextInput draws state's text on r's first row, or, empty, the placeholder
 // muted: a default shows what an empty value means. Focused, it draws on the
-// Input background with the cursor, scrolling to keep the cursor in view.
+// Input background with the cursor, scrolling to keep the cursor in view; a
+// muted '…' marks text out of view.
 func (r Region) TextInput(state *TextFieldState, placeholder string, focused bool, th Theme) {
 	if r.W < 1 || r.H < 1 {
 		return
@@ -75,7 +88,7 @@ func (r Region) TextInput(state *TextFieldState, placeholder string, focused boo
 		bg = th.Input
 	}
 	state.AdjustScroll(r.W)
-	text, style := []rune(placeholder), th.Muted.On(bg)
+	text, style := []rune(Truncate(placeholder, r.W)), th.Muted.On(bg)
 	if len(state.Text) > 0 {
 		text, style = state.Text[state.Scroll:], th.Text.On(bg)
 	}
@@ -86,6 +99,14 @@ func (r Region) TextInput(state *TextFieldState, placeholder string, focused boo
 		}
 		r.Cell(x, 0, ch, style.Fg, style.Bg, style.Attr)
 	}
+	// Text scrolled out of view on either side is marked, never under the cursor
+	hidden := th.Muted.On(bg)
+	if state.Scroll > 0 && (state.Cursor != state.Scroll || !focused) {
+		r.Cell(0, 0, '…', hidden.Fg, hidden.Bg, hidden.Attr)
+	}
+	if end := r.W - 1; len(text) > r.W && (state.Cursor-state.Scroll != end || !focused) {
+		r.Cell(end, 0, '…', hidden.Fg, hidden.Bg, hidden.Attr)
+	}
 	if focused {
 		x, ch := state.Cursor-state.Scroll, ' '
 		if x < len(text) {