Add fullscreen mode parameter

Before this commit, `FullScreen` and `FullScreenAllMonitors` could be
used to configure whether to use the current monitor in fullscreen,
or all monitors in fullscreen.

This commit deprecates `FullScreenAllMonitors` in favour of
`FullScreenMode` (which can either be `current` or `all`). This allows
for additional modes to be added, without the risk of having invalid
states (for example two activate two different fullscreen modes at the
same time).

A new concept has been added; read-only parameters. They are parameters
that will be read, but never written back. This allows for migration
paths to be constructed, where a parameter can be taken to consideration
but then for example be discarded, logged or changed into something else.

This has been used for `FullScreenAllMonitors` to provide a migration
path. On startup of vncviewer, if `FullScreenAllMonitors` is enabled,
`FullScreenMode=all` will be automatically enabled instead. The next
time the configuration file is written to disk, `FullScreenAllMonitors`
will then be removed.

1 files changed, 12 insertions, 0 deletions

diff --git a/vncviewer/vncviewer.cxx b/vncviewer/vncviewer.cxx
index bb41a2f7..6a84c7cb 100644
--- a/vncviewer/vncviewer.cxx
+++ b/vncviewer/vncviewer.cxx
@@ -435,6 +435,16 @@ potentiallyLoadConfigurationFile(char *vncServerName)
   }
 }
 
+static void
+migrateDeprecatedOptions()
+{
+  if (fullScreenAllMonitors) {
+    vlog.info(_("FullScreenAllMonitors is deprecated, set FullScreenMode to 'all' instead."));
+
+    fullScreenMode.setParam("all");
+  }
+}
+
 #ifndef WIN32
 static int
 interpretViaParam(char *remoteHost, int *remotePort, int localPort)
@@ -613,6 +623,8 @@ int main(int argc, char** argv)
   // Check if the server name in reality is a configuration file
   potentiallyLoadConfigurationFile(vncServerName);
 
+  migrateDeprecatedOptions();
+
   mkvnchomedir();
 
   CSecurity::upg = &dlg;