feat: add ability to disable units temporarily

Quite often the user wants to experiment what particular unit(s) add
to the sound. This commit adds ability to disable any set of units
temporarily, without actually deleting them. Ctrl-D disables and
re-enables the units. Disabled units are considered non-existent in
the patch.

Closes #116.

tracker/bool.go

@@ -19,6 +19,7 @@ type (
 	CommentExpanded Model
 	NoteTracking    Model
 	UnitSearching   Model
+	UnitDisabled    Model
 )
 
 func (v Bool) Toggle() {
@@ -41,6 +42,7 @@ func (m *Model) Effect() *Effect                   { return (*Effect)(m) }
 func (m *Model) CommentExpanded() *CommentExpanded { return (*CommentExpanded)(m) }
 func (m *Model) NoteTracking() *NoteTracking       { return (*NoteTracking)(m) }
 func (m *Model) UnitSearching() *UnitSearching     { return (*UnitSearching)(m) }
+func (m *Model) UnitDisabled() *UnitDisabled       { return (*UnitDisabled)(m) }
 
 // Panic methods
 
@@ -126,3 +128,36 @@ func (m *UnitSearching) setValue(val bool) {
 	}
 }
 func (m *UnitSearching) Enabled() bool { return true }
+
+// UnitDisabled methods
+
+func (m *UnitDisabled) Bool() Bool { return Bool{m} }
+func (m *UnitDisabled) Value() bool {
+	if m.d.InstrIndex < 0 || m.d.InstrIndex >= len(m.d.Song.Patch) {
+		return false
+	}
+	if m.d.UnitIndex < 0 || m.d.UnitIndex >= len(m.d.Song.Patch[m.d.InstrIndex].Units) {
+		return false
+	}
+	return m.d.Song.Patch[m.d.InstrIndex].Units[m.d.UnitIndex].Disabled
+}
+func (m *UnitDisabled) setValue(val bool) {
+	if m.d.InstrIndex < 0 || m.d.InstrIndex >= len(m.d.Song.Patch) {
+		return
+	}
+	l := ((*Model)(m)).Units().List()
+	a, b := l.listRange()
+	defer (*Model)(m).change("UnitDisabledSet", PatchChange, MajorChange)()
+	for i := a; i <= b; i++ {
+		m.d.Song.Patch[m.d.InstrIndex].Units[i].Disabled = val
+	}
+}
+func (m *UnitDisabled) Enabled() bool {
+	if m.d.InstrIndex < 0 || m.d.InstrIndex >= len(m.d.Song.Patch) {
+		return false
+	}
+	if len(m.d.Song.Patch[m.d.InstrIndex].Units) == 0 {
+		return false
+	}
+	return true
+}

tracker/gioui/instrument_editor.go

@@ -7,6 +7,7 @@ import (
 	"strconv"
 	"strings"
 
+	"gioui.org/font"
 	"gioui.org/io/clipboard"
 	"gioui.org/io/key"
 	"gioui.org/layout"
@@ -343,6 +344,7 @@ func (ie *InstrumentEditor) layoutUnitList(gtx C, t *Tracker) D {
 		}
 		u := units[i]
 		var color color.NRGBA = white
+		f := labelDefaultFont
 
 		var stackText string
 		stackText = strconv.FormatInt(int64(u.StackAfter), 10)
@@ -353,6 +355,10 @@ func (ie *InstrumentEditor) layoutUnitList(gtx C, t *Tracker) D {
 			color = warningColor
 			(*tracker.Alerts)(t.Model).AddNamed("InstrumentLeavesSignals", fmt.Sprintf("Instrument leaves %v signal(s) on the stack", u.StackAfter), tracker.Warning)
 		}
+		if u.Disabled {
+			color = disabledTextColor
+			f.Style = font.Italic
+		}
 
 		stackLabel := LabelStyle{Text: stackText, ShadeColor: black, Color: mediumEmphasisTextColor, Font: labelDefaultFont, FontSize: unit.Sp(12), Shaper: t.Theme.Shaper}
 		rightMargin := layout.Inset{Right: unit.Dp(10)}
@@ -381,7 +387,7 @@ func (ie *InstrumentEditor) layoutUnitList(gtx C, t *Tracker) D {
 					editor.Color = color
 					editor.HintColor = instrumentNameHintColor
 					editor.TextSize = unit.Sp(12)
-					editor.Font = labelDefaultFont
+					editor.Font = f
 
 					defer clip.Rect(image.Rect(0, 0, gtx.Constraints.Max.X, gtx.Constraints.Max.Y)).Push(gtx.Ops).Pop()
 					key.InputOp{Tag: &ie.searchEditor, Keys: globalKeys}.Add(gtx.Ops)
@@ -399,7 +405,7 @@ func (ie *InstrumentEditor) layoutUnitList(gtx C, t *Tracker) D {
 					}
 					return ret
 				} else {
-					unitNameLabel := LabelStyle{Text: u.Type, ShadeColor: black, Color: color, Font: labelDefaultFont, FontSize: unit.Sp(12), Shaper: t.Theme.Shaper}
+					unitNameLabel := LabelStyle{Text: u.Type, ShadeColor: black, Color: color, Font: f, FontSize: unit.Sp(12), Shaper: t.Theme.Shaper}
 					if unitNameLabel.Text == "" {
 						unitNameLabel.Text = "---"
 					}

tracker/gioui/keyevent.go

@@ -64,6 +64,11 @@ func (t *Tracker) KeyEvent(e key.Event, o *op.Ops) {
 				t.Model.Redo().Do()
 				return
 			}
+		case "D":
+			if e.Modifiers.Contain(key.ModShortcut) {
+				t.Model.UnitDisabled().Bool().Toggle()
+				return
+			}
 		case "N":
 			if e.Modifiers.Contain(key.ModShortcut) {
 				t.NewSong().Do()

tracker/gioui/unit_editor.go

@@ -21,25 +21,27 @@ import (
 )
 
 type UnitEditor struct {
-	sliderList    *DragList
-	searchList    *DragList
-	Parameters    []*ParameterWidget
-	DeleteUnitBtn *ActionClickable
-	CopyUnitBtn   *TipClickable
-	ClearUnitBtn  *ActionClickable
-	SelectTypeBtn *widget.Clickable
-	tag           bool
-	caser         cases.Caser
+	sliderList     *DragList
+	searchList     *DragList
+	Parameters     []*ParameterWidget
+	DeleteUnitBtn  *ActionClickable
+	CopyUnitBtn    *TipClickable
+	ClearUnitBtn   *ActionClickable
+	DisableUnitBtn *BoolClickable
+	SelectTypeBtn  *widget.Clickable
+	tag            bool
+	caser          cases.Caser
 }
 
 func NewUnitEditor(m *tracker.Model) *UnitEditor {
 	ret := &UnitEditor{
-		DeleteUnitBtn: NewActionClickable(m.DeleteUnit()),
-		ClearUnitBtn:  NewActionClickable(m.ClearUnit()),
-		CopyUnitBtn:   new(TipClickable),
-		SelectTypeBtn: new(widget.Clickable),
-		sliderList:    NewDragList(m.Params().List(), layout.Vertical),
-		searchList:    NewDragList(m.SearchResults().List(), layout.Vertical),
+		DeleteUnitBtn:  NewActionClickable(m.DeleteUnit()),
+		ClearUnitBtn:   NewActionClickable(m.ClearUnit()),
+		DisableUnitBtn: NewBoolClickable(m.UnitDisabled().Bool()),
+		CopyUnitBtn:    new(TipClickable),
+		SelectTypeBtn:  new(widget.Clickable),
+		sliderList:     NewDragList(m.Params().List(), layout.Vertical),
+		searchList:     NewDragList(m.SearchResults().List(), layout.Vertical),
 	}
 	ret.caser = cases.Title(language.English)
 	return ret
@@ -114,6 +116,7 @@ func (pe *UnitEditor) layoutFooter(gtx C, t *Tracker) D {
 	}
 	copyUnitBtnStyle := TipIcon(t.Theme, pe.CopyUnitBtn, icons.ContentContentCopy, "Copy unit (Ctrl+C)")
 	deleteUnitBtnStyle := ActionIcon(t.Theme, pe.DeleteUnitBtn, icons.ActionDelete, "Delete unit (Ctrl+Backspace)")
+	disableUnitBtnStyle := ToggleIcon(t.Theme, pe.DisableUnitBtn, icons.AVVolumeUp, icons.AVVolumeOff, "Disable unit (Ctrl-D)", "Enable unit (Ctrl-D)")
 	text := t.Units().SelectedType()
 	if text == "" {
 		text = "Choose unit type"
@@ -124,6 +127,7 @@ func (pe *UnitEditor) layoutFooter(gtx C, t *Tracker) D {
 	return layout.Flex{Axis: layout.Horizontal, Alignment: layout.Middle}.Layout(gtx,
 		layout.Rigid(deleteUnitBtnStyle.Layout),
 		layout.Rigid(copyUnitBtnStyle.Layout),
+		layout.Rigid(disableUnitBtnStyle.Layout),
 		layout.Rigid(func(gtx C) D {
 			var dims D
 			if t.Units().SelectedType() != "" {

tracker/list.go

@@ -34,6 +34,7 @@ type (
 
 	UnitListItem struct {
 		Type                               string
+		Disabled                           bool
 		StackNeed, StackBefore, StackAfter int
 	}
 
@@ -323,7 +324,13 @@ func (v *Units) Iterate(yield UnitYieldFunc) {
 	stackBefore := 0
 	for _, unit := range v.d.Song.Patch[v.d.InstrIndex].Units {
 		stackAfter := stackBefore + unit.StackChange()
-		if !yield(UnitListItem{unit.Type, unit.StackNeed(), stackBefore, stackAfter}) {
+		if !yield(UnitListItem{
+			Type:        unit.Type,
+			Disabled:    unit.Disabled,
+			StackNeed:   unit.StackNeed(),
+			StackBefore: stackBefore,
+			StackAfter:  stackAfter,
+		}) {
 			break
 		}
 		stackBefore = stackAfter