Fix mix crossfade sometimes using wrong order (starting at 100% and ending at...

Fix mix crossfade sometimes using wrong order (starting at 100% and ending at 0%) instead of reverse

src/timeline2/model/trackmodel.cpp

@@ -1881,9 +1881,6 @@ bool TrackModel::requestClipMix(std::pair<int, int> clipIds, int mixDuration, bo
                 t->set("kdenlive:mixcut", secondClipCut);
                 t->set("start", -1);
                 t->set("accepts_blanks", 1);
-                if (dest_track == 0) {
-                    t->set("reverse", 1);
-                }
                 m_track->plant_transition(*t.get(), 0, 1);
                 assetName = QStringLiteral("mix");
             } else {
@@ -1891,13 +1888,16 @@ bool TrackModel::requestClipMix(std::pair<int, int> clipIds, int mixDuration, bo
                 t->set_in_and_out(mixPosition, mixPosition + mixDuration);
                 t->set("kdenlive:mixcut", secondClipCut);
                 t->set("kdenlive_id", "luma");
+                m_track->plant_transition(*t.get(), 0, 1);
                 if (dest_track == 0) {
                     t->set("reverse", 1);
                 }
-                m_track->plant_transition(*t.get(), 0, 1);
                 assetName = QStringLiteral("luma");
             }
             QDomElement xml = TransitionsRepository::get()->getXml(assetName);
+            if (dest_track == 0 && Xml::hasXmlParameter(xml, QStringLiteral("reverse"))) {
+                Xml::setXmlParameter(xml, QStringLiteral("reverse"), QStringLiteral("1"));
+            }
             std::shared_ptr<AssetParameterModel> asset(new AssetParameterModel(std::move(t), xml, assetName, {ObjectType::TimelineMix, clipIds.second}, QString()));
             m_sameCompositions[clipIds.second] = asset;
             m_mixList.insert(clipIds.first, clipIds.second);

src/xml/xml.cpp

@@ -134,6 +134,33 @@ void Xml::setXmlProperty(QDomElement element, const QString &propertyName, const
     }
 }
 
+void Xml::setXmlParameter(QDomElement element, const QString &propertyName, const QString &value)
+{
+    QDomNodeList params = element.elementsByTagName(QStringLiteral("parameter"));
+    // Update property if it already exists
+    bool found = false;
+    for (int i = 0; i < params.count(); ++i) {
+        QDomElement e = params.item(i).toElement();
+        if (e.attribute(QStringLiteral("name")) == propertyName) {
+            e.setAttribute(QStringLiteral("value"), value);
+            found = true;
+            break;
+        }
+    }
+}
+
+bool Xml::hasXmlParameter(QDomElement element, const QString &propertyName)
+{
+    QDomNodeList params = element.elementsByTagName(QStringLiteral("parameter"));
+    for (int i = 0; i < params.count(); ++i) {
+        QDomElement e = params.item(i).toElement();
+        if (e.attribute(QStringLiteral("name")) == propertyName) {
+            return true;
+        }
+    }
+    return false;
+}
+
 bool Xml::hasXmlProperty(QDomElement element, const QString &propertyName)
 {
     QDomNodeList params = element.elementsByTagName(QStringLiteral("property"));

src/xml/xml.hpp

@@ -64,6 +64,7 @@ QString getXmlParameter(const QDomElement &element, const QString &propertyName,
 /** @brief Returns true if the element contains a named property
 */
 bool hasXmlProperty(QDomElement element, const QString &propertyName);
+bool hasXmlParameter(QDomElement element, const QString &propertyName);
 
 /** @brief Add properties to the given xml element
    For each element (n, v) in the properties map, it creates a sub element of the form : <property name="n">v</property>
@@ -75,6 +76,7 @@ void addXmlProperties(QDomElement &producer, const QMap<QString, QString> &prope
 /** @brief Edit or add a property
  */
 void setXmlProperty(QDomElement element, const QString &propertyName, const QString &value);
+void setXmlParameter(QDomElement element, const QString &propertyName, const QString &value);
 /** @brief Remove a property
  */
 void removeXmlProperty(QDomElement effect, const QString &name);