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

tui/optionlist.go

@@ -0,0 +1,116 @@
+package tui
+
+import (
+	"strings"
+
+	"github.com/lixenwraith/terminal"
+)
+
+// Option is one entry of an option list
+type Option struct {
+	Name string // what is chosen
+	Hint string // a line about it
+}
+
+// OptionListState filters options by the text typed into it, matching name
+// or hint regardless of case, and keeps a cursor on the matches
+type OptionListState struct {
+	Options []Option
+	Filter  TextFieldState
+	Cursor  int // index into Matches
+	Scroll  int // first match shown
+}
+
+// NewOptionListState creates a list showing every option
+func NewOptionListState(options []Option) *OptionListState {
+	return &OptionListState{Options: options}
+}
+
+// Matches returns the indices of the options the filter matches, in order,
+// keeping the cursor on one of them
+func (s *OptionListState) Matches() []int {
+	filter := strings.ToLower(s.Filter.Value())
+	var m []int
+	for i, o := range s.Options {
+		if strings.Contains(strings.ToLower(o.Name), filter) || strings.Contains(strings.ToLower(o.Hint), filter) {
+			m = append(m, i)
+		}
+	}
+	s.Cursor = max(0, min(s.Cursor, len(m)-1))
+	return m
+}
+
+// Chosen returns the index in Options of the option under the cursor, and
+// false when nothing matches
+func (s *OptionListState) Chosen() (int, bool) {
+	m := s.Matches()
+	if len(m) == 0 {
+		return 0, false
+	}
+	return m[s.Cursor], true
+}
+
+// HandleKey moves the cursor on Up and Down, or edits the filter, and
+// reports whether anything changed
+func (s *OptionListState) HandleKey(key terminal.Key, r rune, mod terminal.Modifier) bool {
+	filter := s.Filter.Value()
+	switch {
+	case key == terminal.KeyUp:
+		s.Cursor--
+	case key == terminal.KeyDown:
+		s.Cursor++
+	case !s.Filter.HandleKey(key, r, mod):
+		return false
+	case s.Filter.Value() != filter:
+		s.Cursor = 0
+	}
+	s.Matches() // keeps the cursor on a match
+	return true
+}
+
+// Paste adds pasted text to the filter
+func (s *OptionListState) Paste(text string) bool {
+	if !s.Filter.Paste(text) {
+		return false
+	}
+	s.Cursor = 0
+	return true
+}
+
+// OptionList draws the filter on the first row and the matches below it,
+// the cursor row marked with the pointer on the Selected background, each
+// hint muted in a column after the names
+func (r Region) OptionList(s *OptionListState, th Theme) {
+	if r.W < 4 || r.H < 2 {
+		return
+	}
+	r.TextStyled(0, 0, "/", th.Muted)
+	r.Sub(2, 0, r.W-2, 1).TextInput(&s.Filter, "type to filter", true, th)
+
+	m := s.Matches()
+	rows := r.H - 1
+	if len(m) == 0 {
+		r.TextStyled(2, 1, "no match", th.Muted)
+		return
+	}
+	s.Scroll = max(0, min(s.Scroll, s.Cursor, len(m)-rows))
+	s.Scroll = max(s.Scroll, s.Cursor-rows+1)
+
+	nameW := 0
+	for _, i := range m {
+		nameW = max(nameW, RuneLen(s.Options[i].Name))
+	}
+	nameW = min(nameW, r.W/2)
+	for y := 0; y < rows && s.Scroll+y < len(m); y++ {
+		o := s.Options[m[s.Scroll+y]]
+		row := r.Sub(0, 1+y, r.W, 1)
+		var bg Style
+		if s.Scroll+y == s.Cursor {
+			bg = th.Selected
+			row.FillStyle(th.Text.On(bg))
+			row.TextStyled(0, 0, string(th.Glyphs.Pointer), th.Accent.On(bg))
+		}
+		row.TextStyled(2, 0, Truncate(o.Name, nameW), th.Text.On(bg))
+		row.TextStyled(2+nameW+2, 0, Truncate(o.Hint, r.W-nameW-4), th.Muted.On(bg))
+	}
+}