Media: components 341-360

mic_level_meter.go

@@ -0,0 +1,101 @@
+package mujica
+
+import (
+	"fmt"
+	"math"
+	"time"
+
+	"github.com/egoist/mygo/ui"
+
+	"mujicaui/theme"
+)
+
+// MicLevelMeterOptions configure a MicLevelMeter.
+type MicLevelMeterOptions struct {
+	// Hold keeps the peak mark this long; zero is 1.5s.
+	Hold time.Duration
+	// Label names the meter for assistive technology.
+	Label string
+}
+
+const micSegments = 24
+
+type micPeak struct {
+	level float32
+	at    time.Time
+}
+
+// MicLevelMeter shows level as segments, held peak and dB.
+func MicLevelMeter(c *ui.Context, level float32, opts MicLevelMeterOptions) *ui.Element {
+	if level < 0 || level > 1 || math.IsNaN(float64(level)) || opts.Hold < 0 {
+		panic("mujica: MicLevelMeter needs level in 0..1 and Hold >= 0")
+	}
+	hold := opts.Hold
+	if hold == 0 {
+		hold = 1500 * time.Millisecond
+	}
+	k := Tokens(c)
+	label := opts.Label
+	if label == "" {
+		label = msg(c, "mic_level_meter.label")
+	}
+	row := ui.Row(c).Gap(Density(c).Unit() * 2).AlignItems(ui.Center).MinHeight(theme.MinHitSize)
+	pk := ui.Local(row, micPeak{}, func() micPeak { return micPeak{} })
+	now := c.Now()
+	switch {
+	case level >= pk.level:
+		*pk = micPeak{level, now}
+	case now.Sub(pk.at) >= hold:
+		*pk = micPeak{level, now}
+	default:
+		// Repaint once when the hold ends; nothing runs while idle.
+		c.After(hold - now.Sub(pk.at))
+	}
+	peak := pk.level
+	row.Role(ui.RoleMeter).Label(label).Description(micDB(level) + ", " + msg(c, "mic_level_meter.peak") + " " + micDB(peak))
+	row.Children(func() {
+		ui.Box(c).Height(12).MinWidth(120).Grow(1).Draw(func(p *ui.Painter, r ui.Rect) {
+			gap := float32(2)
+			w := (r.W - gap*(micSegments-1)) / micSegments
+			lit := int(math.Round(float64(level * micSegments)))
+			mark := int(math.Round(float64(peak*micSegments))) - 1
+			for i := range micSegments {
+				x := r.X + float32(i)*(w+gap)
+				seg := ui.Rect{X: x, Y: r.Y, W: w, H: r.H}
+				col := micZone(k, i)
+				switch {
+				case i < lit:
+					p.Fill(seg, col, 1)
+				case i == mark:
+					p.Fill(seg, col, 1)
+					p.Fill(ui.Rect{X: x + 1, Y: r.Y + 2, W: w - 2, H: r.H - 4}, k.Surface, 0)
+				default:
+					p.Stroke(seg, k.Border, 1, 1)
+				}
+			}
+		})
+		ui.Text(c, micDB(level)).FontSize(FontSize(c, theme.CaptionSize)).FontFeatures("tnum").
+			TextColor(k.TextMuted).MinWidth(56).TextAlign(ui.End).SingleLine()
+	})
+	return row
+}
+
+// micZone colors the safe, loud and clipping zones.
+func micZone(k theme.Tokens, i int) ui.Color {
+	switch {
+	case i >= micSegments*9/10:
+		return k.Danger
+	case i >= micSegments*7/10:
+		return k.Warning
+	}
+	return k.Success
+}
+
+// micDB writes a full-scale level in decibels.
+func micDB(v float32) string {
+	if v <= 0 {
+		return "-∞ dB"
+	}
+	// Adding 0 turns a rounded -0 into 0.
+	return fmt.Sprintf("%.0f dB", math.Round(20*math.Log10(float64(v)))+0)
+}