Theme Engine in Qt C++ | Media Player Project Tutorial – Part 3b

Welcome back to the Ultimate Qt + C++ Media Player Tutorial Series! In this episode, we take our theme engine to the next level — building runtime theme switching from the GUI and dynamically loading font families directly from JSON. Whether you're designing dark, bright, or funky theme variants — this system makes it effortless to load full themes (including fonts, colors, and typography) just by switching a name. All theme data is driven through clean JSON, with support for multiple font families, file paths, weights, and a completely flattened palette structure that works seamlessly in QML and C++. This is production-ready styling built right into your media player. 🔍 What You'll Learn in This Part: 🔸 How to load .ttf font files dynamically using QFontDatabase 🔸 Registering custom font families and weights for QML/C++ usage 🔸 Theme JSON structure that supports font families and typography scaling 🔸 Flattening and exposing theme data via a QVariantMap 🔸 How to switch full themes at runtime via the App bridge class 🔸 Runtime reload of theme colors and fonts without restarting the app 📂 GitHub Project Code (LUNARA Media Player): 🔗 https://github.com/kaustuvpokharel/LUNARA_MediaPlayer_CPP_QT ☕ If you enjoy the series or want to support this journey as an international student, feel free to buy me a coffee 💛 https://buymeacoffee.com/k.a.l.i 🎮 Game Dev Qt Playlist: https://youtube.com/playlist?list=PLeYV3WjZWmHyYUe-BElUVNeFYTmpOQ9Xq&si=QXh5lNo6N-HBu7gh 🔗 My LinkedIn: https://www.linkedin.com/in/kaustuvpokharel/ 📘 Useful Qt Links: 📖 Official Qt Docs: https://doc.qt.io 🛠️ Qt Installation: https://www.qt.io/download #Qt #C++ #VideoPlayer #ThemeManager #RuntimeTheming #QFontDatabase #QML #CMake #QtDesignSystem #DynamicStyling #LUNARA #cppqt #qt6 #UIdesign #themeengine