Remove repeated pixmap updates when idle in Watch Recordings

[kuphal@…]

Currently, mythfrontend updates the pixmap when you have a recording selected in the Watch Recordings screen every 500ms by querying the backend if the pixmap has changed. This is done in the code that is meant to update the preview window when using video preview. It has the side effect of sending a great deal of chatter back and forth between the frontend and backend when sitting idle.

This patch updates the videoRect in the 500ms timer only when we are expecting there to be a preview video. The other screen updates when selecting and deselecting recordings handles the pixmap updating just fine without it.

Index: programs/mythfrontend/playbackbox.cpp
===================================================================
--- programs/mythfrontend/playbackbox.cpp       (revision 7235)
+++ programs/mythfrontend/playbackbox.cpp       (working copy)
@@ -3254,7 +3254,8 @@
     if (titleList.count() <= 1)
         return;

-    update(videoRect);
+    if (playbackPreview)
+        update(videoRect);
 }

 void PlaybackBox::keyPressEvent(QKeyEvent *e)

[cpinkham]

(In [7359]) "Remove repeated pixmap updates when idle in Watch Recordings"

Patch by Kevin Kuphal. Closes #392.