add mqtt control

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;
+}