BugFix Seek OSC as percent of play duration

Response to issue #120

src/SourceCallback.cpp

@@ -655,11 +655,13 @@ void Seek::update(Source *s, float dt)
     // access media player if target source is a media source
     MediaSource *ms = dynamic_cast<MediaSource *>(s);
     if (ms != nullptr) {
-        // set target position
+        // get media info
         GstClockTime media_duration = ms->mediaplayer()->timeline()->duration();
-        GstClockTime t = (double) media_duration * (double) target_percent_;
-        if (target_time_ > 0)
-            t = target_time_;
+        // set target position
+        GstClockTime t = target_time_;
+        // set target as percent if not provided
+        if (t<1)
+            t = ms->mediaplayer()->timeline()->timeFromPercent(target_percent_);
 
         // perform seek
         if (GST_CLOCK_TIME_IS_VALID(t) && GST_CLOCK_TIME_IS_VALID(media_duration)

src/Timeline.cpp

@@ -78,7 +78,7 @@ void Timeline::reset()
     clearFading();
 }
 
-bool Timeline::is_valid()
+bool Timeline::is_valid() const
 {
     return timing_.is_valid() && step_ != GST_CLOCK_TIME_NONE;
 }
@@ -314,6 +314,32 @@ GstClockTime Timeline::sectionsTimeAt(GstClockTime t) const
     return d;
 }
 
+GstClockTime Timeline::timeFromPercent(const float p) const
+{
+    if (!is_valid())
+        return 0;
+
+    // compute time at p % of actural section duration
+    GstClockTime percent = (double) p * 100000;
+    GstClockTime d = (sectionsDuration() * percent ) / 100000;
+
+    // loop over gaps
+    for (auto g = gaps_.begin(); g != gaps_.end(); ++g) {
+        // gap before target?
+        if ( g->begin < d ) {
+            // jump over gap
+            d += g->duration();
+        }
+        else
+            // done
+            break;
+    }
+
+    // return time corresponding to p% of play duration
+    return d;
+}
+
+
 size_t Timeline::fillSectionsArrays( float* const gaps, float* const fading)
 {
     size_t arraysize = MAX_TIMELINE_ARRAY;

src/Timeline.h

@@ -100,7 +100,7 @@ public:
     ~Timeline();
     Timeline& operator = (const Timeline& b);
 
-    bool is_valid();
+    bool is_valid() const;
     void update();
     void refresh();
 
@@ -121,6 +121,7 @@ public:
     inline TimeInterval interval() const { return timing_; }
     GstClockTime next(GstClockTime time) const;
     GstClockTime previous(GstClockTime time) const;
+    GstClockTime timeFromPercent(const float p) const;
 
     // Manipulation of gaps
     inline TimeIntervalSet gaps() const { return gaps_; }