Create luma thumbs at startup in a thread, so we don't freeeze for a few...

Create luma thumbs at startup in a thread, so we don't freeeze for a few seconds on first composition insertion

src/assets/view/widgets/listparamwidget.cpp

@@ -117,11 +117,9 @@ void ListParamWidget::slotRefresh()
             const QString &entry = values.at(j);
             m_list->addItem(values.at(j).section(QLatin1Char('/'), -1), entry);
             if (!entry.isEmpty() && (entry.endsWith(QLatin1String(".png")) || entry.endsWith(QLatin1String(".pgm")))) {
-                if (!MainWindow::m_lumacache.contains(entry)) {
-                    QImage pix(entry);
-                    MainWindow::m_lumacache.insert(entry, pix.scaled(50, 30, Qt::KeepAspectRatio, Qt::SmoothTransformation));
+                if (MainWindow::m_lumacache.contains(entry)) {
+                    m_list->setItemIcon(j + 1, QPixmap::fromImage(MainWindow::m_lumacache.value(entry)));
                 }
-                m_list->setItemIcon(j + 1, QPixmap::fromImage(MainWindow::m_lumacache.value(entry)));
             }
         }
         if (!value.isEmpty() && values.contains(value)) {

src/assets/view/widgets/listparamwidget.h

@@ -82,6 +82,7 @@ public slots:
     /** @brief refresh the properties to reflect changes in the model
      */
     void slotRefresh() override;
+
 };
 
 #endif

src/core.cpp

@@ -201,6 +201,19 @@ void Core::initGUI(const QUrl &Url)
     QThreadPool::globalInstance()->setMaxThreadCount(qMin(4, QThreadPool::globalInstance()->maxThreadCount()));
 }
 
+void Core::buildLumaThumbs(const QStringList &values)
+{
+    for (auto &entry : values) {
+        if (MainWindow::m_lumacache.contains(entry)) {
+            continue;
+        }
+        QImage pix(entry);
+        if (!pix.isNull()) {
+            MainWindow::m_lumacache.insert(entry, pix.scaled(50, 30, Qt::KeepAspectRatio, Qt::SmoothTransformation));
+        }
+    }
+}
+
 std::unique_ptr<Core> &Core::self()
 {
     if (!m_self) {

src/core.h

@@ -233,6 +233,8 @@ public slots:
     /** @brief display a user info/warning message in the project bin */
     void displayBinMessage(const QString &text, int type, const QList<QAction *> &actions = QList<QAction *>());
     void displayBinLogMessage(const QString &text, int type, const QString &logInfo);
+    /** @brief Create small thumbnails for luma used in compositions */
+    void buildLumaThumbs(const QStringList &values);
 
 signals:
     void coreIsReady();

src/mltconnection.cpp

@@ -17,6 +17,7 @@ the Free Software Foundation, either version 3 of the License, or
 #include <KUrlRequesterDialog>
 #include <config-kdenlive.h>
 #include <klocalizedstring.h>
+#include <QtConcurrent>
 
 #include "kdenlive_debug.h"
 #include <QFile>
@@ -181,6 +182,7 @@ void MltConnection::refreshLumas()
     fileFilters << QStringLiteral("*.png") << QStringLiteral("*.pgm");
     QStringList customLumas = QStandardPaths::locateAll(QStandardPaths::AppDataLocation, QStringLiteral("lumas"), QStandardPaths::LocateDirectory);
     customLumas.append(QString(mlt_environment("MLT_DATA")) + QStringLiteral("/lumas"));
+    QStringList allImagefiles;
     for (const QString &folder : customLumas) {
         QDir topDir(folder);
         QStringList folders = topDir.entryList(QDir::AllDirs | QDir::NoDotAndDotDot);
@@ -201,6 +203,9 @@ void MltConnection::refreshLumas()
                 imagefiles.append(dir.absoluteFilePath(fname));
             }
             MainWindow::m_lumaFiles.insert(format, imagefiles);
+            allImagefiles << imagefiles;
         }
     }
+    allImagefiles.removeDuplicates();
+    QtConcurrent::run(pCore.get(), &Core::buildLumaThumbs, allImagefiles);
 }