gui: show tracking hasn't started in preview area instead of "no video"

"no video" wasn't clearly indicating that no tracking was done. Some first
time users had hard times figuring out tracking had to be started.
@sthalik: I've put an image mimicking what you did for "no video", feel
free to change it or switch to plain text instead.

4 files changed, 73 insertions, 2 deletions

diff --git a/gui/images/tracking-not-started.png b/gui/images/tracking-not-started.png
new file mode 100644
index 000000000..5069e268d
--- /dev/null
+++ b/gui/images/tracking-not-started.png
diff --git a/gui/main.ui b/gui/main.ui
index 3a034ab0f..ca189a62e 100644
--- a/gui/main.ui
+++ b/gui/main.ui
@@ -152,15 +152,67 @@
                 <height>240</height>
                </size>
               </property>
+              <property name="palette">
+               <palette>
+                <active>
+                 <colorrole role="WindowText">
+                  <brush brushstyle="SolidPattern">
+                   <color alpha="255">
+                    <red>104</red>
+                    <green>104</green>
+                    <blue>104</blue>
+                   </color>
+                  </brush>
+                 </colorrole>
+                </active>
+                <inactive>
+                 <colorrole role="WindowText">
+                  <brush brushstyle="SolidPattern">
+                   <color alpha="255">
+                    <red>104</red>
+                    <green>104</green>
+                    <blue>104</blue>
+                   </color>
+                  </brush>
+                 </colorrole>
+                </inactive>
+                <disabled>
+                 <colorrole role="WindowText">
+                  <brush brushstyle="SolidPattern">
+                   <color alpha="255">
+                    <red>120</red>
+                    <green>120</green>
+                    <blue>120</blue>
+                   </color>
+                  </brush>
+                 </colorrole>
+                </disabled>
+               </palette>
+              </property>
+              <property name="font">
+               <font>
+                <family>Candara</family>
+                <pointsize>37</pointsize>
+                <weight>50</weight>
+                <bold>false</bold>
+                <kerning>true</kerning>
+               </font>
+              </property>
               <property name="text">
                <string/>
               </property>
               <property name="pixmap">
-               <pixmap resource="ui-res.qrc">:/images/no-feed.png</pixmap>
+               <pixmap resource="ui-res.qrc">:/images/tracking-not-started.png</pixmap>
               </property>
               <property name="scaledContents">
                <bool>false</bool>
               </property>
+              <property name="alignment">
+               <set>Qt::AlignCenter</set>
+              </property>
+              <property name="wordWrap">
+               <bool>true</bool>
+              </property>
              </widget>
             </widget>
            </widget>
@@ -1008,6 +1060,12 @@
                     <verstretch>0</verstretch>
                    </sizepolicy>
                   </property>
+                  <property name="font">
+                   <font>
+                    <weight>75</weight>
+                    <bold>true</bold>
+                   </font>
+                  </property>
                   <property name="text">
                    <string>Start</string>
                   </property>
@@ -1024,6 +1082,12 @@
                     <verstretch>0</verstretch>
                    </sizepolicy>
                   </property>
+                  <property name="font">
+                   <font>
+                    <weight>75</weight>
+                    <bold>true</bold>
+                   </font>
+                  </property>
                   <property name="text">
                    <string>Stop</string>
                   </property>
diff --git a/gui/ui-res.qrc b/gui/ui-res.qrc
index 030a61536..7b7fee54e 100644
--- a/gui/ui-res.qrc
+++ b/gui/ui-res.qrc
@@ -6,5 +6,6 @@
         <file>images/facetracknoir.png</file>
         <file>images/no-feed.png</file>
         <file>images/filter-16.png</file>
+        <file>images/tracking-not-started.png</file>
     </qresource>
 </RCC>
diff --git a/gui/ui.cpp b/gui/ui.cpp
index ffdbf8677..a136f2aa8 100755
--- a/gui/ui.cpp
+++ b/gui/ui.cpp
@@ -280,8 +280,14 @@ void MainWindow::updateButtonState(bool running, bool inertialp)
     ui.iconcomboProtocol->setEnabled ( not_running );
     ui.iconcomboFilter->setEnabled ( not_running );
     ui.iconcomboTrackerSource->setEnabled(not_running);
-    ui.video_frame_label->setVisible(not_running || inertialp);
     ui.profile_button->setEnabled(not_running);
+    ui.video_frame_label->setVisible(not_running || inertialp);
+    if(not_running) {
+        ui.video_frame_label->setPixmap(QPixmap(":/images/tracking-not-started.png"));
+    }
+    else {
+        ui.video_frame_label->setPixmap(QPixmap(":/images/no-feed.png"));
+    }
 }
 
 void MainWindow::reload_options()