feat(input): add absolute pointer and scroll

gateway/input.go

@@ -15,6 +15,8 @@ const (
 	gatewayInputRelative   = 3
 	gatewayInputUTF8       = 4
 	gatewayInputController = 5
+	gatewayInputAbsolute   = 6
+	gatewayInputScroll     = 7
 )
 
 func EncodeInputEvent(event InputEvent) ([]byte, error) {
@@ -76,6 +78,24 @@ func EncodeInputEvent(event InputEvent) ([]byte, error) {
 		encoded[4], encoded[5], encoded[6] = gatewayInputController, 17, byte(event.Code)
 		copy(encoded[7:], event.Payload)
 		return encoded, nil
+	case "mouse-absolute":
+		if event.Pressed || event.Code != 0 || !validAbsolutePayload(event.Payload) {
+			return nil, ErrInputMalformed
+		}
+		encoded := make([]byte, gatewayInputHeaderSize+8)
+		copy(encoded, "VGI1")
+		encoded[4], encoded[5] = gatewayInputAbsolute, 8
+		copy(encoded[6:], event.Payload)
+		return encoded, nil
+	case "mouse-scroll":
+		if event.Pressed || event.Code != 0 || len(event.Payload) != 4 {
+			return nil, ErrInputMalformed
+		}
+		encoded := make([]byte, gatewayInputHeaderSize+4)
+		copy(encoded, "VGI1")
+		encoded[4], encoded[5] = gatewayInputScroll, 4
+		copy(encoded[6:], event.Payload)
+		return encoded, nil
 	default:
 		return nil, ErrInputMalformed
 	}
@@ -117,11 +137,30 @@ func DecodeInputEvent(data []byte) (InputEvent, error) {
 			return InputEvent{}, ErrInputMalformed
 		}
 		return InputEvent{Device: "controller", Code: int32(body[0]), Pressed: active != 0, Payload: payload}, nil
+	case gatewayInputAbsolute:
+		if !validAbsolutePayload(body) {
+			return InputEvent{}, ErrInputMalformed
+		}
+		return InputEvent{Device: "mouse-absolute", Payload: append([]byte(nil), body...)}, nil
+	case gatewayInputScroll:
+		if len(body) != 4 {
+			return InputEvent{}, ErrInputMalformed
+		}
+		return InputEvent{Device: "mouse-scroll", Payload: append([]byte(nil), body...)}, nil
 	default:
 		return InputEvent{}, ErrInputMalformed
 	}
 }
 
+func validAbsolutePayload(payload []byte) bool {
+	if len(payload) != 8 {
+		return false
+	}
+	x, y := binary.BigEndian.Uint16(payload[:2]), binary.BigEndian.Uint16(payload[2:4])
+	width, height := binary.BigEndian.Uint16(payload[4:6]), binary.BigEndian.Uint16(payload[6:8])
+	return width != 0 && height != 0 && x < width && y < height
+}
+
 func anyNonzero(data []byte) bool {
 	for _, value := range data {
 		if value != 0 {