feat!: display the parameters as knobs in a grid

Also removed the negbandpass & neghighpass parameters
and replaced them with bandpass & highpass set to -1, to
fit the switches better to the GUI.

Closes #51, closes #173

tracker/gioui/signal_rail.go

@@ -0,0 +1,106 @@
+package gioui
+
+import (
+	"image"
+	"image/color"
+	"math"
+
+	"gioui.org/f32"
+	"gioui.org/op/clip"
+	"gioui.org/op/paint"
+	"gioui.org/unit"
+	"github.com/vsariola/sointu/tracker"
+)
+
+const maxSignalsDrawn = 16
+
+type (
+	RailStyle struct {
+		Color        color.NRGBA
+		LineWidth    unit.Dp
+		SignalWidth  unit.Dp
+		PortDiameter unit.Dp
+		PortColor    color.NRGBA
+	}
+
+	RailWidget struct {
+		Style  *RailStyle
+		Signal tracker.Rail
+		Height unit.Dp
+	}
+)
+
+func Rail(th *Theme, signal tracker.Rail) RailWidget {
+	return RailWidget{
+		Style:  &th.SignalRail,
+		Signal: signal,
+		Height: th.UnitEditor.Height,
+	}
+}
+
+func (s RailWidget) Layout(gtx C) D {
+	sw := gtx.Dp(s.Style.SignalWidth)
+	h := gtx.Dp(s.Height)
+	if s.Signal.PassThrough == 0 && len(s.Signal.StackUse.Inputs) == 0 && s.Signal.StackUse.NumOutputs == 0 {
+		return D{Size: image.Pt(sw, h)}
+	}
+	lw := gtx.Dp(s.Style.LineWidth)
+	pd := gtx.Dp(s.Style.PortDiameter)
+	center := sw / 2
+	var path clip.Path
+	path.Begin(gtx.Ops)
+	// Draw pass through signals
+	for i := range min(maxSignalsDrawn, s.Signal.PassThrough) {
+		x := float32(i*sw + center)
+		path.MoveTo(f32.Pt(x, 0))
+		path.LineTo(f32.Pt(x, float32(h)))
+	}
+	// Draw the routing of input signals
+	for i := range min(len(s.Signal.StackUse.Inputs), maxSignalsDrawn-s.Signal.PassThrough) {
+		input := s.Signal.StackUse.Inputs[i]
+		x1 := float32((i+s.Signal.PassThrough)*sw + center)
+		for _, link := range input {
+			x2 := float32((link+s.Signal.PassThrough)*sw + center)
+			path.MoveTo(f32.Pt(x1, 0))
+			path.LineTo(f32.Pt(x2, float32(h/2)))
+		}
+	}
+	if s.Signal.Send {
+		for i := range min(len(s.Signal.StackUse.Inputs), maxSignalsDrawn-s.Signal.PassThrough) {
+			d := gtx.Dp(8)
+			from := f32.Pt(float32((i+s.Signal.PassThrough)*sw+center), float32(h/2))
+			to := f32.Pt(float32(gtx.Constraints.Max.X), float32(h)-float32(d))
+			ctrl := f32.Pt(from.X, to.Y)
+			path.MoveTo(from)
+			path.QuadTo(ctrl, to)
+		}
+	}
+	// Draw the routing of output signals
+	for i := range min(s.Signal.StackUse.NumOutputs, maxSignalsDrawn-s.Signal.PassThrough) {
+		x := float32((i+s.Signal.PassThrough)*sw + center)
+		path.MoveTo(f32.Pt(x, float32(h/2)))
+		path.LineTo(f32.Pt(x, float32(h)))
+	}
+	// Signal paths finished
+	paint.FillShape(gtx.Ops, s.Style.Color,
+		clip.Stroke{
+			Path:  path.End(),
+			Width: float32(lw),
+		}.Op())
+	// Draw the circles on signals that get modified
+	var circle clip.Path
+	circle.Begin(gtx.Ops)
+	for i := range min(len(s.Signal.StackUse.Modifies), maxSignalsDrawn-s.Signal.PassThrough) {
+		if !s.Signal.StackUse.Modifies[i] {
+			continue
+		}
+		f := f32.Pt(float32((i+s.Signal.PassThrough)*sw+center), float32(h/2))
+		circle.MoveTo(f32.Pt(f.X-float32(pd/2), float32(h/2)))
+		circle.ArcTo(f, f, float32(2*math.Pi))
+	}
+	p := clip.Outline{Path: circle.End()}.Op().Push(gtx.Ops)
+	paint.ColorOp{Color: s.Style.PortColor}.Add(gtx.Ops)
+	paint.PaintOp{}.Add(gtx.Ops)
+	p.Pop()
+	return D{Size: image.Pt(sw, h)}
+}