Files
MujicaUI/mic_level_meter.go
T

102 lines
2.7 KiB
Go

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)
}