Qt: SeekPoints / Input Slider: fix behaviour for 0 timed seekpoint

(cherry picked from commit 76ab0c709e6cd45ffe8e0b6d12f437501c58b67c)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

modules/gui/qt4/adapters/seekpoints.cpp

@@ -53,10 +53,15 @@ void SeekPoints::update()
     /* lock here too, as update event is triggered by an external thread */
     if ( !access() ) return;
     pointsList.clear();
+    if ( p_title->i_seekpoint > 0 )
+    {
+        /* first check the last point to see if we have filled time offsets (> 0) */
+        if ( p_title->seekpoint[p_title->i_seekpoint - 1]->i_time_offset > 0 )
+        {
             for ( int i=0; i<p_title->i_seekpoint ; i++ )
-        if ( p_title->seekpoint[i]->i_time_offset > 0 )
                 pointsList << SeekPoint( p_title->seekpoint[i] );
-
+        }
+    }
     vlc_input_title_Delete( p_title );
     release();
 }

modules/gui/qt4/util/input_slider.cpp

@@ -200,6 +200,9 @@ void SeekSlider::mousePressEvent( QMouseEvent* event )
             {
                 QList<SeekPoint> points = chapters->getPoints();
                 int i_selected = -1;
+                bool b_startsnonzero = false; /* as we always starts at 1 */
+                if ( points.count() > 0 ) /* do we need an extra offset ? */
+                    b_startsnonzero = ( points.at(0).time > 0 );
                 int i_min_diff = i_width + 1;
                 for( int i = 0 ; i < points.count() ; i++ )
                 {
@@ -208,7 +211,7 @@ void SeekSlider::mousePressEvent( QMouseEvent* event )
                     if ( diff_x < i_min_diff )
                     {
                         i_min_diff = diff_x;
-                        i_selected = i;
+                        i_selected = i + ( ( b_startsnonzero )? 1 : 0 );
                     } else break;
                 }
                 if ( i_selected && i_min_diff < 4 ) // max 4px around mark
@@ -248,11 +251,14 @@ void SeekSlider::mouseMoveEvent( QMouseEvent *event )
         {
                 QList<SeekPoint> points = chapters->getPoints();
                 int i_selected = -1;
+                bool b_startsnonzero = false;
+                if ( points.count() > 0 )
+                    b_startsnonzero = ( points.at(0).time > 0 );
                 for( int i = 0 ; i < points.count() ; i++ )
                 {
                     int x = points.at(i).time / 1000000.0 / inputLength * size().width();
                     if ( event->x() >= x )
-                        i_selected = i;
+                        i_selected = i + ( ( b_startsnonzero )? 1 : 0 );
                 }
                 if ( i_selected >= 0 )
                     chapterLabel = points.at( i_selected ).name;