allow ~ in background pixmap path

ChangeLog

@@ -1,6 +1,8 @@
 (Format: Year/Month/Day)
 Changes for 0.9.16:
 *06/04/19:
+   * Allow ~ in "background" pixmap options (Simon + thanks_markt)
+     RootTheme.cc
    * Windows keep relative position in ArrangeWindows (Mathias)
      WorkspaceCmd.cc
    * Made fbgm more pure bourne-compatibel (Mathias)

src/RootTheme.cc

@@ -175,6 +175,7 @@ void RootTheme::reconfigTheme() {
         // if background argument is a file then
         // parse image options and call image setting 
         // command specified in the resources
+        filename = FbTk::StringUtil::expandFilename(filename);
         if (FbTk::FileUtil::isRegularFile(filename.c_str())) {
             // parse options
             std::string options;