Add a command to switch display modes

This can be added as key binding. Helpful both for troubleshooting, and
as actual feature.

src/display/DisplayComponent.cpp

@@ -298,3 +298,90 @@ QString DisplayComponent::debugInformation()
   return debugInfo;
 }
 
+///////////////////////////////////////////////////////////////////////////////////////////////////
+static bool modeEqualsFuzzy(const DMVideoMode& m1, const DMVideoMode& m2, float tolerance)
+{
+  return m1.height == m2.height &&
+         m1.width == m2.width &&
+         fabs(m1.refreshRate - m2.refreshRate) < tolerance &&
+         m1.bitsPerPixel == m2.bitsPerPixel &&
+         m1.interlaced == m2.interlaced;
+}
+
+/////////////////////////////////////////////////////////////////////////////////////////
+void DisplayComponent::switchCommand(QString command)
+{
+  if (!m_displayManager)
+    return;
+
+  int currentDisplay = getApplicationDisplay();
+  if (currentDisplay < 0)
+    return;
+  int id = m_displayManager->getCurrentDisplayMode(currentDisplay);
+  if (id < 0)
+    return;
+  DMVideoMode current_mode = *m_displayManager->displays[currentDisplay]->videoModes[id];
+  DMVideoMode mode = current_mode;
+
+  foreach (QString a, command.split(" "))
+  {
+    a = a.trimmed();
+    if (a == "p")
+    {
+      mode.interlaced = false;
+    }
+    else if (a == "i")
+    {
+      mode.interlaced = true;
+    }
+    else if (a.endsWith("hz"))
+    {
+      a = a.mid(0, a.size() - 2);
+      bool ok;
+      float rate = a.toFloat(&ok);
+      if (ok)
+        mode.refreshRate = rate;
+    }
+    else if (a.indexOf("x") >= 0)
+    {
+      QStringList sub = a.split("x");
+      if (sub.size() != 2)
+        continue;
+      bool ok;
+      int w = sub[0].toInt(&ok);
+      if (!ok)
+        continue;
+      int h = sub[1].toInt(&ok);
+      if (!ok)
+        continue;
+      mode.width = w;
+      mode.height = h;
+    }
+  }
+
+  QLOG_INFO() << "Current mode:" << current_mode.getPrettyName();
+  QLOG_INFO() << "Mode requestd by command:" << mode.getPrettyName();
+
+  foreach (auto cur, m_displayManager->displays[currentDisplay]->videoModes)
+  {
+    // Require matching one digit before the decimal point.
+    // This doesn't work if there are several modes that would match. To do
+    // this without requiring the user to give the refresh rate with full
+    // precision, we'd have to find a closest match instead.
+    if (modeEqualsFuzzy(*cur, mode, 0.1))
+    {
+      QLOG_INFO() << "Found mode to switch to:" << cur->getPrettyName();
+      if (m_displayManager->setDisplayMode(currentDisplay, cur->id))
+      {
+        m_lastDisplay = m_lastVideoMode = -1;
+      }
+      else
+      {
+        QLOG_INFO() << "Switching failed.";
+      }
+      return;
+    }
+  }
+
+  QLOG_INFO() << "Requested mode not found.";
+}

src/display/DisplayComponent.h

@@ -31,6 +31,15 @@ public:
   // Switch to best overall video mode. This will also switch the resolution.
   bool switchToBestOverallVideoMode(int display);
 
+  // The syntax is as follows: the command string consists of multiple arguments separated
+  // by spaces. Each argument can be one of the following:
+  //    <N>hz (e.g.: "24hz"): change the refresh rate
+  //    <W>x<H> (e.g.: "1280x720"): change the resolution
+  //    i: change to interlaced
+  //    p: change to progressive ("not interlaced")
+  // Example: "123x456 p 45hz"
+  void switchCommand(QString command);
+
   double currentRefreshRate();
 
   QString debugInformation();

src/ui/KonvergoWindow.cpp

@@ -348,6 +348,10 @@ void KonvergoWindow::handleHostCommand(QString hostCommand)
   {
     PlayerComponent::Get().userCommand(arguments);
   }
+  else if (hostCommand == "switch")
+  {
+    DisplayComponent::Get().switchCommand(arguments);
+  }
   else if (hostCommand == "toggleDebug")
   {
     if (property("showDebugLayer").toBool())