re-enable amd64 builds

.drone.yml

@@ -0,0 +1,99 @@
+kind: pipeline
+type: docker
+name: build
+
+steps:
+- name: build-deb-amd64
+  image: cache.coadcorp.com/library/buildpack-deps:jammy
+  environment:
+    DEBIAN_FRONTEND: noninteractive
+  commands:
+  - apt-get update
+  - apt-get install -y --no-install-recommends build-essential qt5-qmake qtbase5-dev qtbase5-dev-tools libexif-dev qt5-image-formats-plugins libmosquitto-dev dpkg-dev fakeroot ca-certificates
+  - ARCH=amd64 BUILD_DIR=build-amd64 bash sbin/build_deb.sh "${DRONE_TAG:-${DRONE_COMMIT_SHA:0:8}}"
+  - ls -la dist
+
+- name: build-deb-armhf
+  image: cache.coadcorp.com/library/buildpack-deps:jammy
+  environment:
+    DEBIAN_FRONTEND: noninteractive
+    ARM_CFLAGS: -march=armv6 -mfpu=vfp -mfloat-abi=hard -marm
+  commands:
+  - dpkg --add-architecture armhf
+  - |
+    cat > /etc/apt/sources.list <<'EOF'
+    deb [arch=amd64] http://archive.ubuntu.com/ubuntu jammy main restricted universe multiverse
+    deb [arch=amd64] http://archive.ubuntu.com/ubuntu jammy-updates main restricted universe multiverse
+    deb [arch=amd64] http://archive.ubuntu.com/ubuntu jammy-backports main restricted universe multiverse
+    deb [arch=amd64] http://security.ubuntu.com/ubuntu jammy-security main restricted universe multiverse
+    deb [arch=armhf] http://ports.ubuntu.com/ubuntu-ports jammy main restricted universe multiverse
+    deb [arch=armhf] http://ports.ubuntu.com/ubuntu-ports jammy-updates main restricted universe multiverse
+    deb [arch=armhf] http://ports.ubuntu.com/ubuntu-ports jammy-backports main restricted universe multiverse
+    deb [arch=armhf] http://ports.ubuntu.com/ubuntu-ports jammy-security main restricted universe multiverse
+    EOF
+  - apt-get update
+  - apt-get install -y --no-install-recommends build-essential qt5-qmake qtbase5-dev qtbase5-dev-tools libexif-dev qt5-image-formats-plugins libmosquitto-dev dpkg-dev fakeroot ca-certificates gcc-arm-linux-gnueabihf g++-arm-linux-gnueabihf qtbase5-dev:armhf libqt5core5a:armhf libqt5gui5:armhf libqt5widgets5:armhf libqt5network5:armhf libexif-dev:armhf libmosquitto-dev:armhf qt5-image-formats-plugins:armhf
+  - ARCH=armhf BUILD_DIR=build-armhf QMAKESPEC=$PWD/mkspecs/linux-armhf-g++ QMAKE_QTCONF=$PWD/mkspecs/qt-armhf.conf QMAKE_CFLAGS="$ARM_CFLAGS" QMAKE_CXXFLAGS="$ARM_CFLAGS" bash sbin/build_deb.sh "${DRONE_TAG:-${DRONE_COMMIT_SHA:0:8}}"
+  - ls -la dist
+
+- name: build-deb-arm64
+  image: cache.coadcorp.com/library/buildpack-deps:jammy
+  environment:
+    DEBIAN_FRONTEND: noninteractive
+    ARM64_CFLAGS: -march=armv8-a
+  commands:
+  - dpkg --add-architecture arm64
+  - |
+    cat > /etc/apt/sources.list <<'EOF'
+    deb [arch=amd64] http://archive.ubuntu.com/ubuntu jammy main restricted universe multiverse
+    deb [arch=amd64] http://archive.ubuntu.com/ubuntu jammy-updates main restricted universe multiverse
+    deb [arch=amd64] http://archive.ubuntu.com/ubuntu jammy-backports main restricted universe multiverse
+    deb [arch=amd64] http://security.ubuntu.com/ubuntu jammy-security main restricted universe multiverse
+    deb [arch=arm64] http://ports.ubuntu.com/ubuntu-ports jammy main restricted universe multiverse
+    deb [arch=arm64] http://ports.ubuntu.com/ubuntu-ports jammy-updates main restricted universe multiverse
+    deb [arch=arm64] http://ports.ubuntu.com/ubuntu-ports jammy-backports main restricted universe multiverse
+    deb [arch=arm64] http://ports.ubuntu.com/ubuntu-ports jammy-security main restricted universe multiverse
+    EOF
+  - apt-get update
+  - apt-get install -y --no-install-recommends build-essential qt5-qmake qtbase5-dev qtbase5-dev-tools libexif-dev qt5-image-formats-plugins libmosquitto-dev dpkg-dev fakeroot ca-certificates gcc-aarch64-linux-gnu g++-aarch64-linux-gnu qtbase5-dev:arm64 libqt5core5a:arm64 libqt5gui5:arm64 libqt5widgets5:arm64 libqt5network5:arm64 libexif-dev:arm64 libmosquitto-dev:arm64 qt5-image-formats-plugins:arm64
+  - ARCH=arm64 BUILD_DIR=build-arm64 QMAKESPEC=$PWD/mkspecs/linux-arm64-g++ QMAKE_QTCONF=$PWD/mkspecs/qt-arm64.conf QMAKE_CFLAGS="$ARM64_CFLAGS" QMAKE_CXXFLAGS="$ARM64_CFLAGS" bash sbin/build_deb.sh "${DRONE_TAG:-${DRONE_COMMIT_SHA:0:8}}"
+  - ls -la dist
+
+- name: build-deps-image
+  image: cache.coadcorp.com/plugins/docker
+  settings:
+    registry: registry.coadcorp.com
+    repo: slide/build-deps
+    dockerfile: Dockerfile.builddeps
+    username:
+      from_secret: REGISTRY_USER
+    password:
+      from_secret: REGISTRY_PASS
+    tags:
+    - latest
+    - ${DRONE_COMMIT_SHA}
+  when:
+    event:
+    - promote
+    target:
+    - build-deps
+
+- name: gitea-release
+  image: cache.coadcorp.com/plugins/gitea-release
+  depends_on:
+  - build-deb-amd64
+  - build-deb-armhf
+  - build-deb-arm64
+  settings:
+    api_key:
+      from_secret: GITEA_TOKEN
+    base_url: https://git.coadcorp.com
+    files:
+    - dist/*.deb
+    draft: false
+    prerelease: false
+    title: ${DRONE_TAG}
+    note: Automated release for ${DRONE_TAG}
+  when:
+    event:
+    - tag

Dockerfile.builddeps

@@ -0,0 +1,17 @@
+FROM cache.coadcorp.com/library/ubuntu:22.04
+
+ENV DEBIAN_FRONTEND=noninteractive
+
+RUN apt-get update \
+  && apt-get install -y --no-install-recommends \
+    build-essential \
+    qt5-qmake \
+    qtbase5-dev \
+    qtbase5-dev-tools \
+    libexif-dev \
+    qt5-image-formats-plugins \
+    libmosquitto-dev \
+    dpkg-dev \
+    fakeroot \
+    ca-certificates \
+  && rm -rf /var/lib/apt/lists/*

Makefile

@@ -7,7 +7,7 @@ all: build
 
 .PHONY: install-deps-deb
 install-deps-deb:
-	apt install qt5-qmake libexif12 qt5-default libexif-dev qt5-image-formats-plugins
+	apt install qt5-qmake libexif12 qt5-default libexif-dev qt5-image-formats-plugins libmosquitto-dev
 
 check-deps-deb:
 	dpkg -l | grep qt5-qmake
@@ -15,6 +15,7 @@ check-deps-deb:
 	dpkg -l | grep libexif-dev
 	dpkg -l | grep qt5-default
 	dpkg -l | grep qt5-image-formats-plugins
+	dpkg -l | grep libmosquitto-dev
 
 .PHONY: clean
 clean:

README.md

@@ -117,6 +117,7 @@ Supported keys and values in the JSON configuration are:
 * `opacity` : the same as the command line `-o` argument
 * `blur` : the same as the command line `-b` argument
 * `debug` : set to true to enable verbose output from the program
+* `mqtt` : MQTT playback control (see below)
 * `immich` : connect to an Immich server instead of a local path (see below)
 * `scheduler` : this entry is an array of possible path values and associated settings. This key lets you manage display times/settings for a collection of paths. In the example above the top entry shows ONLY files from a Redit feed between 2 and 4pm, ONLY files from the `show_peak_times` folder from 8am to 10am and then 4pm to 7pm. At all other times it alternates displaying files in the `always_show_1` and `always_show_2` folder.
    * `exclusive` : When set to `true` only this entry will be used when it is in its valid time window. 
@@ -124,9 +125,36 @@ Supported keys and values in the JSON configuration are:
    * `path` : the path to image files
    * `stretch` : as above
 
+### MQTT control
+
+Add an `mqtt` block to control playback remotely. Publish one of the commands below to the configured topic.
+
+Example:
+```
+{
+  "mqtt": {
+    "host": "mqtt.local",
+    "port": 1883,
+    "topic": "slide/control",
+    "clientId": "slide-frame",
+    "username": "slide",
+    "password": "secret",
+    "keepAlive": 30,
+    "qos": 0
+  }
+}
+```
+
+Commands:
+* `play` / `resume` — resume slideshow
+* `pause` — pause slideshow
+* `next` / `next-image` — advance to next image
+* `next-folder` — jump to next configured path (if multiple paths are configured)
+* `restart` / `reset` — recreate the selector and restart playback
+
 ### Immich configuration (lightweight + low power)
 
-Immich uses an API key and a `/api` base path. This integration requests the asset search endpoint and downloads thumbnail images into a local cache before displaying them. That keeps bandwidth and power usage low while still letting `slide` do its normal scaling and transitions.
+Immich uses an API key and a `/api` base path. This integration requests the asset search endpoint and downloads the configured image size into a local cache before displaying them. That keeps bandwidth and power usage low while still letting `slide` do its normal scaling and transitions.
 
 Example (single source):
 ```
@@ -171,7 +199,7 @@ Immich settings:
 * `order`: `"asc"` or `"desc"` ordering for asset search.
 * `pageSize`: assets fetched per page.
 * `maxAssets`: cap on total assets fetched (0 means no cap).
-* `cachePath`: local cache directory for downloaded thumbnails.
+* `cachePath`: local cache directory for downloaded images.
 * `cacheMaxMB`: maximum cache size in MB (0 disables cleanup).
 * `includeArchived`: include archived assets in search results.
 When `immich` is set on an entry, `path` and `imageList` are ignored.
@@ -205,6 +233,7 @@ See the `Configuration File` section for details of each setting.
 * qt5
 * qt5-image-formats-plugins
 * libexif
+* libmosquitto-dev
 
 Ubuntu/Raspbian:
 

mkspecs/linux-arm64-g++/qmake.conf

@@ -0,0 +1,21 @@
+exists(/usr/lib/x86_64-linux-gnu/qt5/mkspecs/linux-g++/qmake.conf) {
+  include(/usr/lib/x86_64-linux-gnu/qt5/mkspecs/linux-g++/qmake.conf)
+} else: exists(/usr/share/qt5/mkspecs/linux-g++/qmake.conf) {
+  include(/usr/share/qt5/mkspecs/linux-g++/qmake.conf)
+} else: exists($$[QT_HOST_DATA]/mkspecs/linux-g++/qmake.conf) {
+  include($$[QT_HOST_DATA]/mkspecs/linux-g++/qmake.conf)
+} else {
+  include($$[QT_INSTALL_DATA]/mkspecs/linux-g++/qmake.conf)
+}
+
+QMAKE_CC = aarch64-linux-gnu-gcc
+QMAKE_CXX = aarch64-linux-gnu-g++
+QMAKE_LINK = aarch64-linux-gnu-g++
+QMAKE_AR = aarch64-linux-gnu-ar cqs
+QMAKE_STRIP = aarch64-linux-gnu-strip
+
+QMAKE_INCDIR_QT = /usr/include/aarch64-linux-gnu/qt5
+QMAKE_LIBDIR_QT = /usr/lib/aarch64-linux-gnu
+QMAKE_INCDIR += /usr/include/aarch64-linux-gnu/qt5
+QMAKE_LIBDIR += /usr/lib/aarch64-linux-gnu
+QMAKE_LFLAGS += -Wl,-rpath-link,/usr/lib/aarch64-linux-gnu

mkspecs/linux-arm64-g++/qplatformdefs.h

@@ -0,0 +1 @@
+#include "/usr/lib/x86_64-linux-gnu/qt5/mkspecs/linux-g++/qplatformdefs.h"

mkspecs/linux-armhf-g++/qmake.conf

@@ -0,0 +1,21 @@
+exists(/usr/lib/x86_64-linux-gnu/qt5/mkspecs/linux-g++/qmake.conf) {
+  include(/usr/lib/x86_64-linux-gnu/qt5/mkspecs/linux-g++/qmake.conf)
+} else: exists(/usr/share/qt5/mkspecs/linux-g++/qmake.conf) {
+  include(/usr/share/qt5/mkspecs/linux-g++/qmake.conf)
+} else: exists($$[QT_HOST_DATA]/mkspecs/linux-g++/qmake.conf) {
+  include($$[QT_HOST_DATA]/mkspecs/linux-g++/qmake.conf)
+} else {
+  include($$[QT_INSTALL_DATA]/mkspecs/linux-g++/qmake.conf)
+}
+
+QMAKE_CC = arm-linux-gnueabihf-gcc
+QMAKE_CXX = arm-linux-gnueabihf-g++
+QMAKE_LINK = arm-linux-gnueabihf-g++
+QMAKE_AR = arm-linux-gnueabihf-ar cqs
+QMAKE_STRIP = arm-linux-gnueabihf-strip
+
+QMAKE_INCDIR_QT = /usr/include/arm-linux-gnueabihf/qt5
+QMAKE_LIBDIR_QT = /usr/lib/arm-linux-gnueabihf
+QMAKE_INCDIR += /usr/include/arm-linux-gnueabihf/qt5
+QMAKE_LIBDIR += /usr/lib/arm-linux-gnueabihf
+QMAKE_LFLAGS += -Wl,-rpath-link,/usr/lib/arm-linux-gnueabihf

mkspecs/linux-armhf-g++/qplatformdefs.h

@@ -0,0 +1 @@
+#include "/usr/lib/x86_64-linux-gnu/qt5/mkspecs/linux-g++/qplatformdefs.h"

mkspecs/qt-arm64.conf

@@ -0,0 +1,11 @@
+[Paths]
+Prefix=/usr
+Headers=/usr/include/aarch64-linux-gnu/qt5
+Libraries=/usr/lib/aarch64-linux-gnu
+ArchData=/usr/lib/aarch64-linux-gnu/qt5
+Data=/usr/lib/aarch64-linux-gnu/qt5
+Plugins=/usr/lib/aarch64-linux-gnu/qt5/plugins
+HostPrefix=/usr
+HostData=/usr/lib/x86_64-linux-gnu/qt5
+HostBinaries=/usr/lib/qt5/bin
+HostLibraries=/usr/lib/x86_64-linux-gnu

mkspecs/qt-armhf.conf

@@ -0,0 +1,11 @@
+[Paths]
+Prefix=/usr
+Headers=/usr/include/arm-linux-gnueabihf/qt5
+Libraries=/usr/lib/arm-linux-gnueabihf
+ArchData=/usr/lib/arm-linux-gnueabihf/qt5
+Data=/usr/lib/arm-linux-gnueabihf/qt5
+Plugins=/usr/lib/arm-linux-gnueabihf/qt5/plugins
+HostPrefix=/usr
+HostData=/usr/lib/x86_64-linux-gnu/qt5
+HostBinaries=/usr/lib/qt5/bin
+HostLibraries=/usr/lib/x86_64-linux-gnu

sbin/build_deb.sh

@@ -5,15 +5,49 @@ set -euo pipefail
 ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
 VERSION="${1:-${VERSION:-0.0.0}}"
 VERSION="${VERSION#v}"
+# Debian versions must start with a digit; fall back to 0.0.0+<sha/tag>.
+if [[ ! "$VERSION" =~ ^[0-9] ]]; then
+  VERSION="0.0.0+${VERSION}"
+fi
 ARCH="${ARCH:-$(dpkg --print-architecture)}"
-
-PACKAGE_NAME="slide"
-BUILD_DIR="$ROOT_DIR/build"
+BUILD_DIR="${BUILD_DIR:-$ROOT_DIR/build-$ARCH}"
 DIST_DIR="$ROOT_DIR/dist"
 STAGE_DIR="$BUILD_DIR/deb"
+QMAKE_BIN="${QMAKE_BIN:-qmake}"
+MAKE_JOBS="${MAKE_JOBS:-2}"
+
+QMAKE_ARGS=()
+if [[ -n "${QMAKESPEC:-}" ]]; then
+  QMAKE_ARGS+=("-spec" "$QMAKESPEC")
+fi
+if [[ -n "${QMAKE_QTCONF:-}" ]]; then
+  QMAKE_ARGS+=("-qtconf" "$QMAKE_QTCONF")
+fi
+if [[ -n "${QMAKE_CC:-}" ]]; then
+  QMAKE_ARGS+=("QMAKE_CC=$QMAKE_CC")
+fi
+if [[ -n "${QMAKE_CXX:-}" ]]; then
+  QMAKE_ARGS+=("QMAKE_CXX=$QMAKE_CXX")
+fi
+if [[ -n "${QMAKE_LINK:-}" ]]; then
+  QMAKE_ARGS+=("QMAKE_LINK=$QMAKE_LINK")
+fi
+if [[ -n "${QMAKE_CFLAGS:-}" ]]; then
+  QMAKE_ARGS+=("QMAKE_CFLAGS=$QMAKE_CFLAGS")
+fi
+if [[ -n "${QMAKE_CXXFLAGS:-}" ]]; then
+  QMAKE_ARGS+=("QMAKE_CXXFLAGS=$QMAKE_CXXFLAGS")
+fi
+if [[ -n "${QMAKE_LFLAGS:-}" ]]; then
+  QMAKE_ARGS+=("QMAKE_LFLAGS=$QMAKE_LFLAGS")
+fi
+
+PACKAGE_NAME="slide"
 
 cd "$ROOT_DIR"
-make build
+mkdir -p "$BUILD_DIR"
+"$QMAKE_BIN" "${QMAKE_ARGS[@]}" "$ROOT_DIR/src/slide.pro" -o "$BUILD_DIR/Makefile"
+make -C "$BUILD_DIR" -j"$MAKE_JOBS"
 
 rm -rf "$STAGE_DIR"
 mkdir -p "$STAGE_DIR/DEBIAN" "$STAGE_DIR/usr/local/bin" "$DIST_DIR"
@@ -27,7 +61,7 @@ Section: graphics
 Priority: optional
 Architecture: ${ARCH}
 Maintainer: slide build
-Depends: libqt5core5a, libqt5gui5, libqt5widgets5, libqt5network5, libexif12, qt5-image-formats-plugins
+Depends: libqt5core5a, libqt5gui5, libqt5widgets5, libqt5network5, libexif12, qt5-image-formats-plugins, libmosquitto1
 Description: Lightweight slideshow for photo frames
  Simple, lightweight slideshow designed for low power devices.
 EOF

src/appconfig.cpp

@@ -112,6 +112,39 @@ ImmichConfig ParseImmichConfigObject(QJsonObject immichJson) {
   return config;
 }
 
+MqttConfig ParseMqttConfigObject(QJsonObject mqttJson) {
+  MqttConfig config;
+
+  std::string host = ParseJSONString(mqttJson, "host");
+  if(!host.empty())
+    config.host = host;
+
+  std::string topic = ParseJSONString(mqttJson, "topic");
+  if(!topic.empty())
+    config.topic = topic;
+
+  std::string clientId = ParseJSONString(mqttJson, "clientId");
+  if(!clientId.empty())
+    config.clientId = clientId;
+
+  std::string username = ParseJSONString(mqttJson, "username");
+  if(!username.empty())
+    config.username = username;
+
+  std::string password = ParseJSONString(mqttJson, "password");
+  if(!password.empty())
+    config.password = password;
+
+  SetJSONInt(config.port, mqttJson, "port");
+  SetJSONInt(config.keepAlive, mqttJson, "keepAlive");
+  SetJSONInt(config.qos, mqttJson, "qos");
+
+  if(!config.host.empty() && !config.topic.empty())
+    config.enabled = true;
+
+  return config;
+}
+
 Config loadConfiguration(const std::string &configFilePath, const Config &currentConfig) {
   if(configFilePath.empty())
   {
@@ -327,6 +360,11 @@ AppConfig loadAppConfiguration(const AppConfig &commandLineConfig) {
     loadedConfig.overlay = overlayString;
   }
 
+  if(jsonDoc.contains("mqtt") && jsonDoc["mqtt"].isObject())
+  {
+    loadedConfig.mqtt = ParseMqttConfigObject(jsonDoc["mqtt"].toObject());
+  }
+
   loadedConfig.paths = parsePathEntry(jsonDoc, baseRecursive, baseShuffle, baseSorted);
   if(loadedConfig.paths.count() <= 0)
   {

src/appconfig.h

@@ -49,6 +49,36 @@ struct ImmichConfig {
   }
 };
 
+struct MqttConfig {
+  bool enabled = false;
+  std::string host = "localhost";
+  int port = 1883;
+  std::string topic = "slide/control";
+  std::string clientId = "slide";
+  std::string username = "";
+  std::string password = "";
+  int keepAlive = 30;
+  int qos = 0;
+
+  bool operator==(const MqttConfig &b) const
+  {
+    return enabled == b.enabled &&
+           host == b.host &&
+           port == b.port &&
+           topic == b.topic &&
+           clientId == b.clientId &&
+           username == b.username &&
+           password == b.password &&
+           keepAlive == b.keepAlive &&
+           qos == b.qos;
+  }
+
+  bool operator!=(const MqttConfig &b) const
+  {
+    return !operator==(b);
+  }
+};
+
 // configuration options that apply to an image/folder of images
 struct Config {
   public:
@@ -106,6 +136,7 @@ struct AppConfig : public Config {
     std::string overlay = "";
     QString overlayHexRGB = "#FFFFFF";
     QVector<PathEntry> paths;
+    MqttConfig mqtt;
 
     bool debugMode = false;
 

src/imageswitcher.cpp

@@ -21,6 +21,8 @@ ImageSwitcher::ImageSwitcher(MainWindow& w, unsigned int timeoutMsec, std::uniqu
 
 void ImageSwitcher::updateImage()
 {
+    if (paused)
+      return;
     if(reloadConfigIfNeeded)
     {
       reloadConfigIfNeeded(window, this);
@@ -60,10 +62,64 @@ void ImageSwitcher::setConfigFileReloader(std::function<void(MainWindow &w, Imag
 void ImageSwitcher::setRotationTime(unsigned int timeoutMsecIn)
 {
   timeout = timeoutMsecIn;
-  timer.start(timeout);
+  if (!paused)
+    timer.start(timeout);
 }
 
 void ImageSwitcher::setImageSelector(std::unique_ptr<ImageSelector>& selectorIn)
 {
   selector = std::move(selectorIn);
 }
+
+void ImageSwitcher::pause()
+{
+  paused = true;
+  timer.stop();
+  timerNoContent.stop();
+}
+
+void ImageSwitcher::resume()
+{
+  if (!paused)
+    return;
+  paused = false;
+  timer.start(timeout);
+  scheduleImageUpdate();
+}
+
+void ImageSwitcher::stepOnce()
+{
+  bool wasPaused = paused;
+  if (wasPaused)
+    paused = false;
+  updateImage();
+  if (wasPaused)
+  {
+    paused = true;
+    timer.stop();
+    timerNoContent.stop();
+  }
+}
+
+void ImageSwitcher::restart(std::unique_ptr<ImageSelector>& selectorIn)
+{
+  paused = false;
+  timerNoContent.stop();
+  setImageSelector(selectorIn);
+  timer.start(timeout);
+  scheduleImageUpdate();
+}
+
+bool ImageSwitcher::skipToNextFolder()
+{
+  auto *listSelector = dynamic_cast<ListImageSelector*>(selector.get());
+  if (!listSelector)
+    return false;
+  stepOnce();
+  return true;
+}
+
+bool ImageSwitcher::isPaused() const
+{
+  return paused;
+}

src/imageswitcher.h

@@ -19,6 +19,12 @@ public:
     void setConfigFileReloader(std::function<void(MainWindow &w, ImageSwitcher *switcher)> reloadConfigIfNeededIn);
     void setRotationTime(unsigned int timeoutMsec);
     void setImageSelector(std::unique_ptr<ImageSelector>& selector);
+    void pause();
+    void resume();
+    void stepOnce();
+    void restart(std::unique_ptr<ImageSelector>& selector);
+    bool skipToNextFolder();
+    bool isPaused() const;
 
 public slots:
     void updateImage();
@@ -30,6 +36,7 @@ private:
     const unsigned int timeoutNoContent = 5 * 1000; // 5 sec
     QTimer timerNoContent;
     std::function<void(MainWindow &w, ImageSwitcher *switcher)> reloadConfigIfNeeded;
+    bool paused = false;
 };
 
 #endif // IMAGESWITCHER_H

src/main.cpp

@@ -3,6 +3,7 @@
 #include "imageswitcher.h"
 #include "pathtraverser.h"
 #include "immichpathtraverser.h"
+#include "mqttcontroller.h"
 #include "overlay.h"
 #include "appconfig.h"
 #include "logger.h"
@@ -275,6 +276,24 @@ int main(int argc, char *argv[])
   w.setImageSwitcher(&switcher);
   std::function<void(MainWindow &w, ImageSwitcher *switcher)> reloader = [&appConfig](MainWindow &w, ImageSwitcher *switcher) { ReloadConfigIfNeeded(appConfig, w, switcher); };
   switcher.setConfigFileReloader(reloader);
+
+  std::unique_ptr<MqttController> mqttController;
+  if (appConfig.mqtt.enabled)
+  {
+    mqttController = std::unique_ptr<MqttController>(new MqttController(appConfig.mqtt, &a));
+    QObject::connect(mqttController.get(), &MqttController::play, [&switcher]() { switcher.resume(); });
+    QObject::connect(mqttController.get(), &MqttController::pause, [&switcher]() { switcher.pause(); });
+    QObject::connect(mqttController.get(), &MqttController::nextImage, [&switcher]() { switcher.stepOnce(); });
+    QObject::connect(mqttController.get(), &MqttController::nextFolder, [&switcher]() {
+      if (!switcher.skipToNextFolder())
+        switcher.stepOnce();
+    });
+    QObject::connect(mqttController.get(), &MqttController::restart, [&appConfig, &switcher]() {
+      std::unique_ptr<ImageSelector> newSelector = GetSelectorForApp(appConfig);
+      switcher.restart(newSelector);
+    });
+    mqttController->start();
+  }
   switcher.start();
   return a.exec();
 }

src/mqttcontroller.cpp

@@ -0,0 +1,152 @@
+#include "mqttcontroller.h"
+#include "logger.h"
+
+#include <QMetaObject>
+
+#include <mosquitto.h>
+
+namespace {
+bool g_mqttInitialized = false;
+}
+
+MqttController::MqttController(const MqttConfig &configIn, QObject *parent)
+  : QObject(parent),
+    config(configIn)
+{
+  if (!g_mqttInitialized)
+  {
+    mosquitto_lib_init();
+    g_mqttInitialized = true;
+  }
+}
+
+MqttController::~MqttController()
+{
+  if (client)
+  {
+    mosquitto_disconnect(client);
+    mosquitto_loop_stop(client, true);
+    mosquitto_destroy(client);
+    client = nullptr;
+  }
+}
+
+void MqttController::start()
+{
+  if (!config.enabled)
+  {
+    Log("MQTT disabled or missing host/topic.");
+    return;
+  }
+
+  QString clientId = QString::fromStdString(config.clientId);
+  if (clientId.isEmpty())
+    clientId = "slide";
+
+  client = mosquitto_new(clientId.toUtf8().constData(), true, this);
+  if (!client)
+  {
+    Log("MQTT: failed to create client.");
+    return;
+  }
+
+  mosquitto_connect_callback_set(client, &MqttController::HandleConnect);
+  mosquitto_message_callback_set(client, &MqttController::HandleMessage);
+
+  if (!config.username.empty())
+  {
+    mosquitto_username_pw_set(client, config.username.c_str(),
+                              config.password.empty() ? nullptr : config.password.c_str());
+  }
+
+  mosquitto_reconnect_delay_set(client, 2, 30, true);
+
+  int rc = mosquitto_connect_async(client, config.host.c_str(), config.port, config.keepAlive);
+  if (rc != MOSQ_ERR_SUCCESS)
+  {
+    Log("MQTT connect failed: ", mosquitto_strerror(rc));
+    return;
+  }
+
+  rc = mosquitto_loop_start(client);
+  if (rc != MOSQ_ERR_SUCCESS)
+  {
+    Log("MQTT loop start failed: ", mosquitto_strerror(rc));
+    return;
+  }
+}
+
+void MqttController::HandleConnect(struct mosquitto *mosq, void *userdata, int rc)
+{
+  auto *self = static_cast<MqttController *>(userdata);
+  if (!self || !mosq)
+    return;
+  if (rc != 0)
+  {
+    Log("MQTT connect error: ", mosquitto_strerror(rc));
+    return;
+  }
+  self->connected = true;
+  self->subscribe();
+}
+
+void MqttController::subscribe()
+{
+  if (!client || !connected)
+    return;
+  int rc = mosquitto_subscribe(client, nullptr, config.topic.c_str(), config.qos);
+  if (rc != MOSQ_ERR_SUCCESS)
+  {
+    Log("MQTT subscribe failed: ", mosquitto_strerror(rc));
+  }
+  else
+  {
+    Log("MQTT subscribed to ", config.topic);
+  }
+}
+
+void MqttController::HandleMessage(struct mosquitto *mosq, void *userdata, const struct mosquitto_message *message)
+{
+  Q_UNUSED(mosq);
+  auto *self = static_cast<MqttController *>(userdata);
+  if (!self || !message || !message->payload)
+    return;
+
+  QString payload = QString::fromUtf8(static_cast<const char *>(message->payload), message->payloadlen);
+  QMetaObject::invokeMethod(self, "handleCommand", Qt::QueuedConnection, Q_ARG(QString, payload));
+}
+
+void MqttController::handleCommand(const QString &payload)
+{
+  QString cmd = payload.trimmed().toLower();
+  if (cmd.isEmpty())
+    return;
+
+  if (cmd == "play" || cmd == "resume")
+  {
+    emit play();
+    return;
+  }
+  if (cmd == "pause")
+  {
+    emit pause();
+    return;
+  }
+  if (cmd == "next" || cmd == "skip" || cmd == "next-image")
+  {
+    emit nextImage();
+    return;
+  }
+  if (cmd == "next-folder" || cmd == "folder-next" || cmd == "skip-folder")
+  {
+    emit nextFolder();
+    return;
+  }
+  if (cmd == "restart" || cmd == "reset")
+  {
+    emit restart();
+    return;
+  }
+
+  Log("MQTT unknown command: ", cmd.toStdString());
+}

src/mqttcontroller.h

@@ -0,0 +1,42 @@
+#ifndef MQTTCONTROLLER_H
+#define MQTTCONTROLLER_H
+
+#include <QObject>
+#include <QString>
+
+#include "appconfig.h"
+
+struct mosquitto;
+struct mosquitto_message;
+
+class MqttController : public QObject
+{
+  Q_OBJECT
+public:
+  explicit MqttController(const MqttConfig &config, QObject *parent = nullptr);
+  ~MqttController();
+
+  void start();
+
+signals:
+  void play();
+  void pause();
+  void nextImage();
+  void nextFolder();
+  void restart();
+
+private slots:
+  void handleCommand(const QString &payload);
+
+private:
+  static void HandleConnect(struct mosquitto *mosq, void *userdata, int rc);
+  static void HandleMessage(struct mosquitto *mosq, void *userdata, const struct mosquitto_message *message);
+
+  void subscribe();
+
+  MqttConfig config;
+  struct mosquitto *client = nullptr;
+  bool connected = false;
+};
+
+#endif // MQTTCONTROLLER_H

src/slide.pro

@@ -37,6 +37,7 @@ SOURCES += \
         pathtraverser.cpp \
         immichpathtraverser.cpp \
         immichclient.cpp \
+        mqttcontroller.cpp \
         overlay.cpp \
         imageselector.cpp \
         appconfig.cpp \
@@ -49,6 +50,7 @@ HEADERS += \
         pathtraverser.h \
         immichpathtraverser.h \
         immichclient.h \
+        mqttcontroller.h \
         overlay.h \
         imageswitcher.h \
         imagestructs.h \
@@ -62,3 +64,4 @@ target.path = /usr/local/bin/
 INSTALLS += target
 
 unix|win32: LIBS += -lexif
+unix|win32: LIBS += -lmosquitto