[sysui] Load UI in two stages to get a first frame drawn faster

Change-Id: Id43b25e3549e05c503619df086596b3789a730ea
Reviewed-by: Lukáš Tinkl <ltinkl@luxoft.com>
Reviewed-by: Bramastyo Harimukti Santoso <bramastyo.harimukti.santoso@pelagicore.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/Main.qml b/Main.qml
index 3f2756b8..91e60567 100644
--- a/Main.qml
+++ b/Main.qml
@@ -54,6 +54,24 @@ Window {
     readonly property real smallerDimension: isLandscape ? height : width
     readonly property real largerDimension: isLandscape ? width : height
 
+    // Load the full UI once a frame has been drawn with the ligth version of it
+    // The very first frame is a blank. Only the second one has actual content,
+    // hence the counter.
+    // FIXME: Find a better way of finding out when the first proper frame has been
+    //       rendered (scene no longer dirty. render thread idle)
+    Connections {
+        id: windowConns
+        property int frameCount: 0
+        target: root
+        onFrameSwapped: {
+            frameCount = frameCount + 1;
+            if (frameCount === 2) {
+                display.loadUI();
+                windowConns.enabled = false;
+            }
+        }
+    }
+
     Display {
         id: display