v0.2.0 16 colors, default colors, /dev/tty, bracketed paste, themed form controls

tui/field.go

@@ -0,0 +1,115 @@
+package tui
+
+import (
+	"github.com/lixenwraith/terminal"
+)
+
+// Focus is a focus ring over a form's controls, numbered 0 to Len-1
+type Focus struct {
+	Index, Len int
+}
+
+// HandleKey moves focus on Tab and Shift+Tab, wrapping, and reports whether
+// it moved
+func (f *Focus) HandleKey(key terminal.Key, mod terminal.Modifier) bool {
+	if f.Len < 1 {
+		return false
+	}
+	switch {
+	case key == terminal.KeyTab && mod&terminal.ModShift == 0:
+		f.Index = (f.Index + 1) % f.Len
+	case key == terminal.KeyTab || key == terminal.KeyBacktab:
+		f.Index = (f.Index - 1 + f.Len) % f.Len
+	default:
+		return false
+	}
+	return true
+}
+
+// Field labels one form row
+type Field struct {
+	Label    string
+	Required bool
+	Help     string // shown under the field while it has focus
+	Error    string // shown under the field, in place of Help
+}
+
+// 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.
+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)
+	}
+	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)
+
+	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
+	}
+	r.TextStyled(x, y+1, Truncate(note, r.W-x), style)
+	return r.Sub(x, y, r.W-x, 1), 2
+}
+
+// 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.
+func (r Region) TextInput(state *TextFieldState, placeholder string, focused bool, th Theme) {
+	if r.W < 1 || r.H < 1 {
+		return
+	}
+	var bg Style
+	if focused {
+		bg = th.Input
+	}
+	state.AdjustScroll(r.W)
+	text, style := []rune(placeholder), th.Muted.On(bg)
+	if len(state.Text) > 0 {
+		text, style = state.Text[state.Scroll:], th.Text.On(bg)
+	}
+	for x := 0; x < r.W; x++ {
+		ch := ' '
+		if x < len(text) {
+			ch = text[x]
+		}
+		r.Cell(x, 0, ch, style.Fg, style.Bg, style.Attr)
+	}
+	if focused {
+		x, ch := state.Cursor-state.Scroll, ' '
+		if x < len(text) {
+			ch = text[x]
+		}
+		r.Cell(x, 0, ch, th.Cursor.Fg, th.Cursor.Bg, th.Cursor.Attr)
+	}
+}
+
+// Group draws a foldable group's header at y: the focus mark, the Folded or
+// Unfolded glyph and the title, and while folded, a muted summary of what
+// it holds
+func (r Region) Group(y int, title, summary string, open, focused bool, th Theme) {
+	mark, style := th.Glyphs.Folded, th.Muted
+	if open {
+		mark = th.Glyphs.Unfolded
+	}
+	if focused {
+		style = th.Text
+		r.TextStyled(0, y, string(th.Glyphs.Focus), th.Accent)
+	}
+	r.TextStyled(2, y, string(mark)+" "+title, style)
+	if !open && summary != "" {
+		x := 2 + 2 + RuneLen(title) + 2
+		r.TextStyled(x, y, Truncate(summary, r.W-x), th.Muted)
+	}
+}