Split into category packages; module github.com/ZacharyZhang-NY/MujicaUI

overlay/tooltip.go

@@ -0,0 +1,84 @@
+package overlay
+
+import (
+	"log/slog"
+	"time"
+
+	"github.com/egoist/mygo/ui"
+
+	"github.com/ZacharyZhang-NY/MujicaUI/core"
+	"github.com/ZacharyZhang-NY/MujicaUI/theme"
+)
+
+// TooltipOptions configure a Tooltip.
+type TooltipOptions struct {
+	// Delay is how long hover or focus rests before the tip shows: 500 ms when zero.
+	Delay time.Duration
+}
+
+// TooltipState tracks when the anchor became hot and whether Escape hid the tip.
+type TooltipState struct {
+	Since     time.Time
+	Dismissed bool
+}
+
+const tooltipMaxWidth = 240
+
+// Tooltip shows a non-interactive tip by anchor after hover or keyboard focus rests on it for Delay.
+func Tooltip(c *ui.Context, anchor *ui.Element, text string, opts TooltipOptions) *ui.Element {
+	if anchor == nil {
+		panic("mujica: Tooltip needs an anchor")
+	}
+	if opts.Delay < 0 {
+		panic("mujica: Tooltip Delay is negative")
+	}
+	if text == "" {
+		return anchor
+	}
+	anchor.Description(text)
+	st := ui.Local(anchor, "mujica.tooltip", func() TooltipState { return TooltipState{} })
+	hot := anchor.Hovered() || anchor.FocusVisible()
+	if !hot {
+		st.Since, st.Dismissed = time.Time{}, false
+		return anchor
+	}
+	if st.Dismissed {
+		return anchor
+	}
+	if st.Since.IsZero() {
+		st.Since = c.Now()
+	}
+	delay := opts.Delay
+	if delay == 0 {
+		delay = 500 * time.Millisecond
+	}
+	if wait := delay - c.Now().Sub(st.Since); wait > 0 {
+		c.After(wait)
+		return anchor
+	}
+	if core.OverlayEscape(c, st) {
+		slog.Debug("mujica: tooltip dismiss")
+		st.Dismissed = true
+		return anchor
+	}
+	tooltipShow(c, anchor.Bounds(), text)
+	return anchor
+}
+
+// tooltipShow draws the tip below a, or above it when there is no room.
+func tooltipShow(c *ui.Context, a ui.Rect, text string) {
+	k := core.Tokens(c)
+	u := core.Density(c).Unit()
+	size := core.FontSize(c, theme.CaptionSize+1)
+	tw, th := c.MeasureText(tooltipMaxWidth, ui.Span{Text: text, Size: size, Font: c.Theme().Font})
+	padX, padY := u*2.5, u*1.5
+	w, h := tw+2*(padX+theme.BorderWidth)+1, th+2*(padY+theme.BorderWidth)
+	x, y := core.PlaceOverlay(c, ui.Rect{X: a.X + a.W/2 - w/2, Y: a.Y, W: w, H: a.H}, w, h, 6)
+	ui.Overlay(c, func() {
+		ui.Box(c).Absolute().Left(x).Top(y).Width(w).Padding(padY, padX).Radius(theme.ControlRadius).
+			Background(k.Text).TextColor(k.Background).Border(theme.BorderWidth, k.Text).
+			PassThrough().Role(ui.RoleTooltip).Children(func() {
+			ui.Text(c, text).FontSize(size)
+		})
+	})
+}