qt_dev_tools.md

+# developer tools
+
+## debugging QML javascript
+
+Qt Creator as a qml debuger which is helpful to debug js.
+
+* To enable this, vlc must be compiled with --enable-qt-qml-debug
+
+* to start the debugger vlc must be started with something like:
+  --qt-qmljsdebugger=port:4242,block
+
+* in qt creator "debug" > "start debugging" > "attach to QML port"
+
+refer to [qt
+documentation](https://doc.qt.io/qt-5/qtquick-debugging.html#starting-applications)
+for more details
+
+## QML caching
+
+you can activate QML caching at compilation by passing the option
+
+## inspecting QML objects live
+
+there is a tool named GammaRay (https://github.com/KDAB/GammaRay/) which is
+helpful to debug layout. It is dependent from the version of Qt, the best is
+usually to compile it manually rather than using the version provided by your
+distribution
+
+# testing with software rendering
+
+```export QT_QUICK_BACKEND=software```
+
+# developer pitfalls
+
+some common issue made by newcomer (everyone actually ^_^):
+
+* beware of scaling issue, common sizes are defined in VLSStyle.qml and new ones
+   should be defined using dp() for proper scaling
+
+* beware of translated strings, you should use `i18n.qtr` in qml and `qtr` in C++
+
+* beware of theming colors, most colors are available in VLCStyle.colors. You
+  should test your code with light/dark/system theme.
+
+* beware of the keyboard navigation system, don't break it.
+
+# QML coding convention
+
+As usual, the convention is to follow the convention used in the file you edit,
+tough following guides are worth reading to have best practices in mind.
+
+* https://doc.qt.io/qt-5/qml-codingconventions.html
+
+* https://github.com/Furkanzmc/QML-Coding-Guide