WIP essentials 5

vertical_slider.go

@@ -0,0 +1,98 @@
+package mujica
+
+import (
+	"cmp"
+	"log/slog"
+	"math"
+
+	"github.com/egoist/mygo/ui"
+
+	"mujicaui/theme"
+)
+
+// VerticalSliderOptions configure a VerticalSlider. Min and Max both zero mean 0 to 100.
+type VerticalSliderOptions struct {
+	Min, Max float64
+	// Step snaps the value; zero is continuous.
+	Step  float64
+	Marks []SliderMark
+	// Height is the track length; zero is 160.
+	Height float32
+	// ShowValue shows the value beside the thumb while hovered, dragged or focused.
+	ShowValue bool
+	Format    func(float64) string
+	Disabled  bool
+	Label     string
+}
+
+// VerticalSlider is a Slider standing up: max at the top, Up and Right raise it.
+func VerticalSlider(c *ui.Context, value *float64, opts VerticalSliderOptions) ChoiceResult {
+	if value == nil {
+		panic("mujica: VerticalSlider needs a value")
+	}
+	if !(opts.Height >= 0) || math.IsInf(float64(opts.Height), 1) {
+		panic("mujica: VerticalSlider Height must be finite and >= 0")
+	}
+	g, _ := sliderSetup(opts.Min, opts.Max, opts.Step, opts.Marks, false, c)
+	format := sliderFormat(opts.Format, g)
+	k := Tokens(c)
+	size := FontSize(c, theme.CaptionSize)
+	h := cmp.Or(opts.Height, 160)
+	old := g.snap(*value)
+	*value = old
+	var s *ui.Element
+	var next float64
+	var held bool
+	wrap := ui.Column(c).Disabled(opts.Disabled)
+	wrap.Children(func() { s, next, held = sliderControl(c, old, g, g.lo, g.hi) })
+	// The base maps the pointer across; here the height decides.
+	y := func(r ui.Rect, v float64) float32 {
+		return r.Y + r.H - sliderThumb/2 - (r.H-sliderThumb)*float32((v-g.lo)/(g.hi-g.lo))
+	}
+	if held {
+		if _, py, _ := s.PointerPosition(); s.Bounds().H > sliderThumb {
+			f := 1 - float64((py-sliderThumb/2)/(s.Bounds().H-sliderThumb))
+			next = g.snap(g.lo + max(0, min(1, f))*(g.hi-g.lo))
+		}
+	}
+	w := Density(c).ControlHeight()
+	for _, m := range opts.Marks {
+		if m.Label != "" {
+			w += 40
+			break
+		}
+	}
+	s.Size(w, h).PaddingY(sliderThumb / 2).FocusRing(false).Cursor(ui.CursorPointer)
+	if opts.Label != "" {
+		s.Label(opts.Label)
+	}
+	if !wrap.IsDisabled() {
+		*value = next
+	}
+	changed := *value != old
+	if changed {
+		slog.Debug("mujica: vertical_slider changed", "label", opts.Label, "value", *value)
+	}
+	hot := s.Hovered() || held
+	v := *value
+	s.Draw(func(p *ui.Painter, r ui.Rect) {
+		x := r.X + Density(c).ControlHeight()/2
+		top, bot := y(r, g.hi), y(r, g.lo)
+		p.Fill(ui.Rect{X: x - sliderTrack/2, Y: top, W: sliderTrack, H: bot - top}, k.Border, 0)
+		p.Stroke(ui.Rect{X: x - sliderTrack/2, Y: top, W: sliderTrack, H: bot - top}, k.ControlBorder, 0, 1)
+		p.Fill(ui.Rect{X: x - sliderTrack/2, Y: y(r, v), W: sliderTrack, H: bot - y(r, v)}, k.AccentText, 0)
+		for _, m := range opts.Marks {
+			my := y(r, m.Value)
+			p.Fill(ui.Rect{X: x + sliderTrack/2 + 2, Y: my - 0.5, W: 5, H: 1}, k.TextMuted, 0)
+			if m.Label != "" {
+				_, th := p.MeasureText(1000, ui.Span{Text: m.Label, Size: size})
+				p.Text(x+sliderTrack/2+10, my-th/2, m.Label, size, k.TextMuted)
+			}
+		}
+		sliderThumbPaint(p, k, x, y(r, v), hot, s.FocusVisible())
+		if opts.ShowValue && (hot || s.Focused()) {
+			sliderBubblePaint(p, k, x, y(r, v), format(v), size)
+		}
+	})
+	return ChoiceResult{wrap, changed}
+}