What does Qt uses to render GUI ?

adnan

Is it that qtcore and qtgui have been written using X11 API or they use GTK+ framework at the backend.

andre

They use X11 directly (or, in Qt 5, Wayland) on the systems where that is the window system. GTK+ is a competing framework. On Windows, Mac OS, and the many other platforms, Qt obviously uses other systems.

adnan

1-What is difference b/w X11 and wayland. Is wayland better? And you mean to say that Qt gui is different than GTK+ framework. But they look exactly similar, i mean widgets.

2- X11 is the default windowing system for Linux, so does this mean Qt5 apps will have additional dependency of downloading and installing wayland. Does Qt-Wayland has similar look of widgets as GTK+ as GTK+ uses X11, or they will look different.
Perhaps i asked too many questions!

mlong

Qt doesn't wrap up other toolkits' widgets. It generates and uses its own widgets by drawing at the lowest level of the graphics system of whatever platform it is running on. The widgets are styled by Qt's QStyle mechanism.

andre

Note that there is a Qt GTK style, to make Qt applications look like GTK applications. I believe there is a similar idea the other way around, a GTK style that mimics the default Qt style.

For information about Wayland, you could "start":http://en.wikipedia.org/wiki/Wayland_(display_server_protocol) at wikipedia.

dbzhang800

Old X11 backend (aka. Xlib) has been dropped in Qt5, the default backend for linux is XCB, and wayland can be selected if your OS support it.

Both Qt and GTK+ are ui toolkit, they are independent. GTK is now porting to wayland too.