feat(tracker): move reset and load song into popup menu

tracker/popup.go

@@ -0,0 +1,72 @@
+package tracker
+
+import (
+	"image/color"
+
+	"gioui.org/f32"
+	"gioui.org/io/pointer"
+	"gioui.org/layout"
+	"gioui.org/op"
+	"gioui.org/op/clip"
+	"gioui.org/op/paint"
+	"gioui.org/unit"
+)
+
+type PopupStyle struct {
+	Visible        *bool
+	Contents       layout.Widget
+	SurfaceColor   color.NRGBA
+	SE, SW, NW, NE unit.Value
+}
+
+func Popup(visible *bool, contents layout.Widget) PopupStyle {
+	return PopupStyle{
+		Visible:      visible,
+		Contents:     contents,
+		SurfaceColor: popupSurfaceColor,
+		SE:           unit.Dp(6),
+		SW:           unit.Dp(6),
+		NW:           unit.Dp(6),
+		NE:           unit.Dp(6),
+	}
+}
+
+func (s PopupStyle) Layout(gtx C) D {
+	if !*s.Visible {
+		return D{}
+	}
+	for _, ev := range gtx.Events(s.Visible) {
+		e, ok := ev.(pointer.Event)
+		if !ok {
+			continue
+		}
+
+		switch e.Type {
+		case pointer.Press:
+			*s.Visible = false
+		}
+	}
+
+	bg := func(gtx C) D {
+		pointer.InputOp{Tag: s.Visible,
+			Types: pointer.Press,
+		}.Add(gtx.Ops)
+		rrect := clip.RRect{
+			Rect: f32.Rectangle{Max: f32.Pt(float32(gtx.Constraints.Min.X), float32(gtx.Constraints.Min.Y))},
+			SE:   float32(gtx.Px(s.SE)),
+			SW:   float32(gtx.Px(s.SW)),
+			NW:   float32(gtx.Px(s.NW)),
+			NE:   float32(gtx.Px(s.NE)),
+		}
+		paint.FillShape(gtx.Ops, s.SurfaceColor, rrect.Op(gtx.Ops))
+		return D{Size: gtx.Constraints.Min}
+	}
+	macro := op.Record(gtx.Ops)
+	dims := layout.Stack{}.Layout(gtx,
+		layout.Expanded(bg),
+		layout.Stacked(s.Contents),
+	)
+	callop := macro.Stop()
+	op.Defer(gtx.Ops, callop)
+	return dims
+}