Better deadzones (#19)

Reviewed-on: #19
Co-authored-by: Anna Rose Wiggins <annabunches@gmail.com>
Co-committed-by: Anna Rose Wiggins <annabunches@gmail.com>

internal/mappingrules/deadzone.go

@@ -0,0 +1,99 @@
+package mappingrules
+
+import (
+	"errors"
+	"fmt"
+
+	"git.annabunches.net/annabunches/joyful/internal/configparser"
+	"github.com/holoplot/go-evdev"
+)
+
+// TODO: need tests for multiple deadzones
+// TODO: need tests for emitting deadzones
+
+type Deadzone struct {
+	Start     int32
+	End       int32
+	Size      int32
+	Emit      bool
+	EmitValue int32
+}
+
+// DeadzoneState indicates whether a value is in a Deadzone and, if it is, whether the deadzone
+// should emit an event
+type DeadzoneState int
+
+const (
+	// DeadzoneClear indicates the value is *not* in the deadzone.
+	DeadzoneClear DeadzoneState = iota
+	DeadzoneEmit
+	DeadzoneNoEmit
+)
+
+// calculateDeadzones produces the deadzone start and end values in absolute terms
+func NewDeadzoneFromConfig(dzConfig configparser.DeadzoneConfig, device Device, axis evdev.EvCode) (Deadzone, error) {
+	dz := Deadzone{}
+	dz.Emit = dzConfig.Emit
+	dz.EmitValue = dzConfig.Value
+	fmt.Printf("DEBUG: %d, %d\n", dzConfig.Value, dz.EmitValue)
+
+	var min, max int32
+	absInfoMap, err := device.AbsInfos()
+
+	if err != nil {
+		return dz, err
+	} else {
+		absInfo := absInfoMap[axis]
+		min = absInfo.Minimum
+		max = absInfo.Maximum
+	}
+
+	if dzConfig.Start != 0 || dzConfig.End != 0 {
+		dz.Start = Clamp(dzConfig.Start, min, max)
+		dz.End = Clamp(dzConfig.End, min, max)
+		if dz.Start > dz.End {
+			return dz, errors.New("deadzone end must be greater than deadzone start")
+		}
+	} else {
+		center := Clamp(dzConfig.Center, min, max)
+		var deadzoneSize int32
+
+		switch {
+		case dzConfig.Size != 0:
+			deadzoneSize = dzConfig.Size
+		case dzConfig.SizePercent != 0:
+			deadzoneSize = (max - min) / dzConfig.SizePercent
+		default:
+			return dz, fmt.Errorf("deadzone configured incorrectly; must define start and end or center and size")
+		}
+
+		dz.Start = center - deadzoneSize/2
+		dz.End = center + deadzoneSize/2
+		dz.Start, dz.End = clampAndShift(dz.Start, dz.End, min, max)
+	}
+
+	dz.Size = dz.End - dz.Start
+	return dz, nil
+}
+
+func CalculateDeadzoneSize(dzs []Deadzone) int32 {
+	var size int32
+
+	for _, dz := range dzs {
+		size += dz.Size
+	}
+
+	return size
+}
+
+// Match checks whether the target value is inside the deadzone.
+// It returns a DeadzoneState enum and possibly an int32.
+func (dz Deadzone) Match(value int32) (DeadzoneState, int32) {
+	if value < dz.Start || value > dz.End {
+		return DeadzoneClear, value
+	}
+	if dz.Emit {
+		return DeadzoneEmit, dz.EmitValue
+	}
+	return DeadzoneNoEmit, value
+}