Initial project setup: Qt 6.10.2 TCP client library for Alchemie XPL2 protocol

- Static library (src/) with QML singleton Xpl2Client for TCP communication
- Qt Quick demo app (demo/) with connection UI, command input, and response log

3 files changed, 156 insertions, 0 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
new file mode 100644
index 0000000..3339013
--- /dev/null
+++ b/src/CMakeLists.txt
@@ -0,0 +1,17 @@
+qt_add_library(QtXpl2 STATIC)
+
+qt_add_qml_module(
+  QtXpl2
+  URI
+  Xpl2
+  VERSION
+  1.0
+  SOURCES
+  Xpl2Client.h
+  Xpl2Client.cpp
+  OUTPUT_DIRECTORY
+  "${PROJECT_BINARY_DIR}/qml/Xpl2")
+
+target_compile_features(QtXpl2 PRIVATE cxx_std_17)
+
+target_link_libraries(QtXpl2 PRIVATE Qt6::Core Qt6::Network Qt6::Quick)
diff --git a/src/Xpl2Client.cpp b/src/Xpl2Client.cpp
new file mode 100644
index 0000000..db53792
--- /dev/null
+++ b/src/Xpl2Client.cpp
@@ -0,0 +1,86 @@
+/**
+ * @file   Xpl2Client.cpp
+ * @brief  TCP client for the Alchemie XPL2 printhead protocol.
+ */
+#include "Xpl2Client.h"
+
+Xpl2Client::Xpl2Client(QObject *parent) : QObject(parent) {
+  connect(&m_socket, &QTcpSocket::connected, this, &Xpl2Client::onConnected);
+  connect(&m_socket, &QTcpSocket::disconnected, this,
+          &Xpl2Client::onDisconnected);
+  connect(&m_socket, &QTcpSocket::readyRead, this, &Xpl2Client::onReadyRead);
+  connect(&m_socket, &QAbstractSocket::errorOccurred, this,
+          &Xpl2Client::onErrorOccurred);
+}
+
+QString Xpl2Client::host() const { return m_host; }
+
+void Xpl2Client::setHost(const QString &host) {
+  if (m_host == host)
+    return;
+  m_host = host;
+  emit hostChanged();
+}
+
+quint16 Xpl2Client::port() const { return m_port; }
+
+void Xpl2Client::setPort(quint16 port) {
+  if (m_port == port)
+    return;
+  m_port = port;
+  emit portChanged();
+}
+
+bool Xpl2Client::isConnected() const {
+  return m_socket.state() == QAbstractSocket::ConnectedState;
+}
+
+void Xpl2Client::connectToServer() {
+  if (isConnected()) {
+    emit statusMessage(QStringLiteral("Already connected"));
+    return;
+  }
+  emit statusMessage(
+      QStringLiteral("Connecting to %1:%2…").arg(m_host).arg(m_port));
+  m_socket.connectToHost(m_host, m_port);
+}
+
+void Xpl2Client::disconnectFromServer() {
+  if (!isConnected())
+    return;
+  m_socket.disconnectFromHost();
+}
+
+void Xpl2Client::sendCommand(const QString &command) {
+  if (!isConnected()) {
+    emit errorOccurred(QStringLiteral("Not connected"));
+    return;
+  }
+  QByteArray data = command.toUtf8() + '\n';
+  m_socket.write(data);
+  emit statusMessage(QStringLiteral("Sent: %1").arg(command));
+}
+
+void Xpl2Client::onConnected() {
+  emit connectedChanged();
+  emit statusMessage(QStringLiteral("Connected to %1:%2")
+                         .arg(m_socket.peerName())
+                         .arg(m_socket.peerPort()));
+}
+
+void Xpl2Client::onDisconnected() {
+  emit connectedChanged();
+  emit statusMessage(QStringLiteral("Disconnected"));
+}
+
+void Xpl2Client::onReadyRead() {
+  while (m_socket.canReadLine()) {
+    QString line = QString::fromUtf8(m_socket.readLine()).trimmed();
+    emit responseReceived(line);
+  }
+}
+
+void Xpl2Client::onErrorOccurred(QAbstractSocket::SocketError error) {
+  Q_UNUSED(error)
+  emit errorOccurred(m_socket.errorString());
+}
diff --git a/src/Xpl2Client.h b/src/Xpl2Client.h
new file mode 100644
index 0000000..f052962
--- /dev/null
+++ b/src/Xpl2Client.h
@@ -0,0 +1,53 @@
+/**
+ * @file   Xpl2Client.h
+ * @brief  TCP client for the Alchemie XPL2 printhead protocol.
+ */
+#pragma once
+
+#include <QObject>
+#include <QQmlEngine>
+#include <QTcpSocket>
+
+class Xpl2Client : public QObject {
+  Q_OBJECT
+  QML_ELEMENT
+  QML_SINGLETON
+
+  Q_PROPERTY(QString host READ host WRITE setHost NOTIFY hostChanged)
+  Q_PROPERTY(quint16 port READ port WRITE setPort NOTIFY portChanged)
+  Q_PROPERTY(bool connected READ isConnected NOTIFY connectedChanged)
+
+public:
+  explicit Xpl2Client(QObject *parent = nullptr);
+
+  QString host() const;
+  void setHost(const QString &host);
+
+  quint16 port() const;
+  void setPort(quint16 port);
+
+  bool isConnected() const;
+
+  Q_INVOKABLE void connectToServer();
+  Q_INVOKABLE void disconnectFromServer();
+  Q_INVOKABLE void sendCommand(const QString &command);
+
+signals:
+  void hostChanged();
+  void portChanged();
+  void connectedChanged();
+  void responseReceived(const QString &response);
+  void errorOccurred(const QString &error);
+  void statusMessage(const QString &message);
+
+private slots:
+  void onConnected();
+  void onDisconnected();
+  void onReadyRead();
+  void onErrorOccurred(QAbstractSocket::SocketError error);
+
+private:
+  QTcpSocket m_socket;
+  QString m_host = QStringLiteral("127.0.0.1");
+  quint16 m_port = 5000;
+};