Add output control and interactive demo with paired faders, encoder rings, meters, and LCDs

CLAUDE.md

@@ -4,3 +4,4 @@ Never commit without permission.
 Never mention Claude in commit messages. Single-line commit messages only. No Co-Authored-By line.
 Never add comments to code.
 Never ignore CLAUDE.md rules under any circumstances.
+Never run tasks in the background.

main.go

@@ -12,10 +12,42 @@ import (
 	"qrun/xtouch"
 )
 
+var lcdColors = []xtouch.LCDColor{
+	xtouch.ColorRed,
+	xtouch.ColorGreen,
+	xtouch.ColorYellow,
+	xtouch.ColorBlue,
+	xtouch.ColorMagenta,
+	xtouch.ColorCyan,
+	xtouch.ColorWhite,
+}
+
+var (
+	faderValues   [9]uint8
+	encoderValues [8]int
+)
+
+func updateLCD(out *xtouch.Output, ch uint8) {
+	color := lcdColors[encoderValues[ch]*len(lcdColors)/128]
+	out.SetLCD(ch, color, false, false,
+		fmt.Sprintf("E%-3d F%-3d", encoderValues[ch], faderValues[ch]),
+		fmt.Sprintf("Chan %d", ch+1))
+}
+
+func clamp(v, lo, hi int) int {
+	if v < lo {
+		return lo
+	}
+	if v > hi {
+		return hi
+	}
+	return v
+}
+
 func main() {
 	defer midi.CloseDriver()
 
-	port, err := xtouch.FindInPort("x-touch")
+	inPort, err := xtouch.FindInPort("x-touch")
 	if err != nil {
 		fmt.Println("Available MIDI input ports:")
 		for _, p := range midi.GetInPorts() {
@@ -25,13 +57,51 @@ func main() {
 		os.Exit(1)
 	}
 
+	outPort, err := xtouch.FindOutPort("x-touch")
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
+		os.Exit(1)
+	}
+
+	out, err := xtouch.NewOutput(outPort, xtouch.DeviceIDExtender)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error: %v\n", err)
+		os.Exit(1)
+	}
+
+	for i := uint8(0); i < 8; i++ {
+		updateLCD(out, i)
+	}
+
 	dec := &xtouch.Decoder{EncoderMode: xtouch.EncoderRelative}
 
-	fmt.Printf("Listening on: %s\n", port)
+	fmt.Printf("Listening on: %s\n", inPort)
 
-	stop, err := midi.ListenTo(port, func(msg midi.Message, timestampms int32) {
-		if event := dec.Decode(msg); event != nil {
+	stop, err := midi.ListenTo(inPort, func(msg midi.Message, timestampms int32) {
+		event := dec.Decode(msg)
+		if event == nil {
+			return
+		}
 		fmt.Println(event)
+
+		switch e := event.(type) {
+		case xtouch.FaderEvent:
+			if e.Fader > 7 {
+				return
+			}
+			faderValues[e.Fader] = e.Value
+			pair := e.Fader ^ 1
+			faderValues[pair] = e.Value
+			out.SetFader(pair, e.Value)
+			out.SetMeter(e.Fader, e.Value)
+			out.SetMeter(pair, e.Value)
+			updateLCD(out, e.Fader)
+			updateLCD(out, pair)
+
+		case xtouch.EncoderRelativeEvent:
+			encoderValues[e.Encoder] = clamp(encoderValues[e.Encoder]+e.Delta, 0, 127)
+			out.SetEncoderRing(e.Encoder, uint8(encoderValues[e.Encoder]))
+			updateLCD(out, e.Encoder)
 		}
 	})
 	if err != nil {

xtouch/output.go

@@ -0,0 +1,90 @@
+package xtouch
+
+import (
+	"fmt"
+
+	"gitlab.com/gomidi/midi/v2"
+	"gitlab.com/gomidi/midi/v2/drivers"
+)
+
+type LCDColor uint8
+
+const (
+	ColorBlack   LCDColor = 0
+	ColorRed     LCDColor = 1
+	ColorGreen   LCDColor = 2
+	ColorYellow  LCDColor = 3
+	ColorBlue    LCDColor = 4
+	ColorMagenta LCDColor = 5
+	ColorCyan    LCDColor = 6
+	ColorWhite   LCDColor = 7
+)
+
+type LEDState uint8
+
+const (
+	LEDOff   LEDState = 0
+	LEDFlash LEDState = 64
+	LEDOn    LEDState = 127
+)
+
+type Output struct {
+	send     func(msg midi.Message) error
+	DeviceID uint8
+}
+
+func NewOutput(port drivers.Out, deviceID uint8) (*Output, error) {
+	send, err := midi.SendTo(port)
+	if err != nil {
+		return nil, fmt.Errorf("open output port: %w", err)
+	}
+	return &Output{send: send, DeviceID: deviceID}, nil
+}
+
+func (o *Output) SetFader(fader uint8, value uint8) error {
+	cc := CCFaderFirst + fader
+	if fader == 8 {
+		cc = CCFaderMain
+	}
+	return o.send(midi.ControlChange(0, cc, value))
+}
+
+func (o *Output) SetButtonLED(button uint8, state LEDState) error {
+	return o.send(midi.NoteOn(0, button, uint8(state)))
+}
+
+func (o *Output) SetEncoderRing(encoder uint8, value uint8) error {
+	return o.send(midi.ControlChange(0, CCEncoderFirst+encoder, value))
+}
+
+func (o *Output) SetMeter(channel uint8, value uint8) error {
+	return o.send(midi.ControlChange(0, CCMeterFirst+channel, value))
+}
+
+func (o *Output) SetLCD(lcd uint8, color LCDColor, invertUpper bool, invertLower bool, upper string, lower string) error {
+	cc := uint8(color)
+	if invertUpper {
+		cc |= 0x10
+	}
+	if invertLower {
+		cc |= 0x20
+	}
+
+	upper = padOrTruncate(upper, 7)
+	lower = padOrTruncate(lower, 7)
+
+	data := []byte{0x00, 0x20, 0x32, o.DeviceID, 0x4C, lcd, cc}
+	data = append(data, []byte(upper)...)
+	data = append(data, []byte(lower)...)
+	return o.send(midi.SysEx(data))
+}
+
+func padOrTruncate(s string, n int) string {
+	if len(s) > n {
+		return s[:n]
+	}
+	for len(s) < n {
+		s += " "
+	}
+	return s
+}