feat(tracker): add button for deleting instrument

tracker/instruments.go

@@ -44,10 +44,41 @@ func (t *Tracker) layoutInstruments() layout.Widget {
 					}),
 				)
 			}),
+			layout.Rigid(t.layoutInstrumentHeader()),
 			layout.Flexed(1, t.layoutInstrumentEditor()))
 	}
 }
 
+func (t *Tracker) layoutInstrumentHeader() layout.Widget {
+	headerBg := func(gtx C) D {
+		paint.FillShape(gtx.Ops, trackMenuSurfaceColor, clip.Rect{
+			Max: gtx.Constraints.Min,
+		}.Op())
+		return layout.Dimensions{Size: gtx.Constraints.Min}
+	}
+	header := func(gtx C) D {
+		deleteInstrumentBtnStyle := material.IconButton(t.Theme, t.DeleteInstrumentBtn, deleteIcon)
+		deleteInstrumentBtnStyle.Background = transparent
+		deleteInstrumentBtnStyle.Inset = layout.UniformInset(unit.Dp(6))
+		if len(t.song.Patch.Instruments) > 1 {
+			deleteInstrumentBtnStyle.Color = primaryColor
+		} else {
+			deleteInstrumentBtnStyle.Color = disabledTextColor
+		}
+		return layout.Flex{Axis: layout.Horizontal}.Layout(gtx,
+			layout.Flexed(1, func(gtx C) D { return layout.Dimensions{Size: gtx.Constraints.Min} }),
+			layout.Rigid(deleteInstrumentBtnStyle.Layout))
+	}
+	for t.DeleteInstrumentBtn.Clicked() {
+		t.DeleteInstrument()
+	}
+	return func(gtx C) D {
+		return layout.Stack{Alignment: layout.Center}.Layout(gtx,
+			layout.Expanded(headerBg),
+			layout.Stacked(header))
+	}
+}
+
 func (t *Tracker) layoutInstrumentNames() layout.Widget {
 	return func(gtx C) D {
 		gtx.Constraints.Max.Y = gtx.Px(unit.Dp(36))

tracker/layout.go

@@ -22,6 +22,7 @@ var addIcon *widget.Icon
 var loadIcon *widget.Icon
 var saveIcon *widget.Icon
 var clearIcon *widget.Icon
+var deleteIcon *widget.Icon
 
 func init() {
 	var err error
@@ -49,6 +50,10 @@ func init() {
 	if err != nil {
 		log.Fatal(err)
 	}
+	deleteIcon, err = widget.NewIcon(icons.ActionDelete)
+	if err != nil {
+		log.Fatal(err)
+	}
 }
 
 func smallButton(icStyle material.IconButtonStyle) material.IconButtonStyle {

tracker/tracker.go

@@ -31,6 +31,7 @@ type Tracker struct {
 	BPM                   *NumberInput
 	NewTrackBtn           *widget.Clickable
 	NewInstrumentBtn      *widget.Clickable
+	DeleteInstrumentBtn   *widget.Clickable
 	LoadSongFileBtn       *widget.Clickable
 	NewSongFileBtn        *widget.Clickable
 	AddSemitoneBtn        *widget.Clickable
@@ -210,6 +211,17 @@ func (t *Tracker) AddInstrument() {
 	t.sequencer.SetPatch(t.song.Patch)
 }
 
+func (t *Tracker) DeleteInstrument() {
+	if len(t.song.Patch.Instruments) <= 1 {
+		return
+	}
+	t.SaveUndo()
+	t.song.Patch.Instruments = append(t.song.Patch.Instruments[:t.CurrentInstrument], t.song.Patch.Instruments[t.CurrentInstrument+1:]...)
+	if t.CurrentInstrument >= len(t.song.Patch.Instruments) {
+		t.CurrentInstrument = len(t.song.Patch.Instruments) - 1
+	}
+}
+
 // SetCurrentNote sets the (note) value in current pattern under cursor to iv
 func (t *Tracker) SetCurrentNote(iv byte) {
 	t.SaveUndo()
@@ -318,6 +330,7 @@ func New(audioContext sointu.AudioContext) *Tracker {
 		SongLength:            new(NumberInput),
 		NewTrackBtn:           new(widget.Clickable),
 		NewInstrumentBtn:      new(widget.Clickable),
+		DeleteInstrumentBtn:   new(widget.Clickable),
 		NewSongFileBtn:        new(widget.Clickable),
 		LoadSongFileBtn:       new(widget.Clickable),
 		SaveSongFileBtn:       new(widget.Clickable),