Add input components 086-105; park focus off disabled controls

input/combobox.go

@@ -0,0 +1,156 @@
+package input
+
+import (
+	"log/slog"
+	"strings"
+
+	"github.com/egoist/mygo/ui"
+
+	"git.zacharyzhang.com/ZacharyZhang-NY/8bitMyGoUI/pixel"
+)
+
+type ComboboxOptions struct {
+	Placeholder string
+	// Width is in dots; zero means 120.
+	Width    int
+	Disabled bool
+}
+
+type ComboboxResult struct {
+	Element *ui.Element
+	// Changed reports a new *value; Chosen, an option taken.
+	Changed, Chosen bool
+}
+
+type comboKey struct{}
+
+type combo struct {
+	open, typed bool
+	// lit is the lit option; ptr, the last pointer spot.
+	lit int
+	ptr [2]float32
+	// top is the first row shown; wheel, unspent scroll.
+	top   int
+	wheel float32
+}
+
+// comboRows is how many options show at once.
+const comboRows = 8
+
+// Combobox lists matching options; Enter or a click takes one.
+func Combobox(c *ui.Context, text string, value *string, options []string, o ComboboxOptions) ComboboxResult {
+	k := pixel.K(c)
+	ed, e := field(c, value, pixel.EditorOptions{Label: text, Placeholder: o.Placeholder, Disabled: o.Disabled}, o.Width, nil, nil, nil)
+	ed.Input.Role(ui.RoleComboBox)
+	st := ui.Local(e, comboKey{}, func() combo { return combo{} })
+	res := ComboboxResult{Element: e, Changed: ed.Changed}
+	take := func(opt string) {
+		if *value != opt {
+			*value, res.Changed = opt, true
+		}
+		st.open, st.typed, res.Chosen = false, false, true
+	}
+	if ed.Changed {
+		st.open, st.typed, st.lit = true, true, 0
+	}
+	if e.Shortcut(0, ui.KeyDown) {
+		if st.open {
+			st.lit++
+		} else {
+			st.open, st.typed, st.lit = true, false, 0
+		}
+	}
+	if st.open && e.Shortcut(0, ui.KeyUp) {
+		st.lit--
+	}
+	shown := options
+	if st.typed {
+		shown = matching(options, *value)
+	}
+	st.lit = max(0, min(st.lit, len(shown)-1))
+	// The rows shown follow the lit option.
+	st.top = max(0, min(st.top, st.lit, len(shown)-comboRows), st.lit-comboRows+1)
+	if st.open && len(shown) > 0 && e.Shortcut(0, ui.KeyEnter) {
+		take(shown[st.lit])
+	}
+	show, held := st.open && len(shown) > 0, false
+	panel := ui.PopoverBase(c, e, &show, func(panel *ui.Element) {
+		panel.MinWidth(e.Bounds().W)
+		panel.HandleInput(func(ev ui.InputEvent) bool {
+			if ev.Kind != ui.InputScroll {
+				return false
+			}
+			st.wheel += ev.DY
+			turn(&st.wheel, k.D(pixel.LineHeight), func(d int) { st.lit = max(0, min(len(shown)-1, st.lit+d)) })
+			return true
+		})
+		end := min(len(shown), st.top+comboRows)
+		panel.DrawOver(func(p *ui.Painter, r ui.Rect) {
+			g := k.Canvas(p, r)
+			if st.top > 0 {
+				g.Sprite(g.W-8, 2, tinyUp, 0, pixel.Faint, 1)
+			}
+			if end < len(shown) {
+				g.Sprite(g.W-8, g.H-5, tinyDown, 0, pixel.Faint, 1)
+			}
+		})
+		// Only a pointer that moves lights the option under it.
+		px, py, over := panel.PointerPosition()
+		moved := over && [2]float32{px, py} != st.ptr
+		st.ptr = [2]float32{px, py}
+		menu(c, panel, func() {
+			items := make([]*ui.Element, len(shown))
+			for i := st.top; i < end; i++ {
+				opt := shown[i]
+				items[i] = ui.Row(c).Role(ui.RoleListItem).Label(opt)
+				if items[i].Hovered() && moved {
+					st.lit = i
+				}
+				if items[i].Pressed() {
+					held = true
+				}
+				if items[i].Clicked() {
+					take(opt)
+				}
+			}
+			for i := st.top; i < end; i++ {
+				row(k, items[i], shown[i], i == st.lit, shown[i] == *value)
+			}
+		})
+	})
+	if st.open && len(shown) > 0 && !show {
+		st.open = false
+	}
+	// Losing focus closes it, unless pressing on the list.
+	if panel != nil && panel.Pressed() {
+		held = true
+	}
+	if panel != nil && st.open && !ed.Focused && !held {
+		st.open = false
+		// This frame built the list: hide it, rebuild without it.
+		panel.Invisible()
+		c.Invalidate()
+	}
+	if res.Chosen {
+		slog.Debug("8bit: combobox chosen", "label", text, "value", *value)
+	}
+	return res
+}
+
+// matching are options holding q, prefix matches first.
+func matching(options []string, q string) []string {
+	q = strings.ToLower(strings.TrimSpace(q))
+	if q == "" {
+		return options
+	}
+	var starts, holds []string
+	for _, opt := range options {
+		switch l := strings.ToLower(opt); {
+		case strings.HasPrefix(l, q):
+			starts = append(starts, opt)
+		case strings.Contains(l, q):
+			holds = append(holds, opt)
+		}
+	}
+	return append(starts, holds...)
+}