[yoz-y]

Is it better to write one own's GUI in this case? I believe most toolkits have a way to add new controls, so it should be less work to add a knob to GtK, Qt or any other toolkit.

[fasterdom]

True, you could write a new Qt control.

Then you hit the second requirement: complete bitmap theming, many times of a skeuomorphic kind. This is extremely difficult to do in something like Gtk/Qt.

[torarnv]

Behold, in all its skeuomorphic glory, the Qt styles example:

https://doc.qt.io/qt-5/qtwidgets-widgets-styles-example.html

[kazinator]

That looks almost exactly like Motif from 1991, but superimposed with a wood grain pattern.

[Narishma]

Looks more like Windows 9x than Motif to me.

[kazinator]

1. Motif came first. Among people who knew what Motif is, the look of Windows 95 was widely recognized as being very similar to Motif to the point of being a knock-off.

2. See the diamond-shaped radio buttons in the second example. :)

3. 3D embossed arrows on scroll bars.

[Narishma]

Oh, I didn't see the second screenshot. Yeah that one is more like what I remember Motif looking like. The first one though is definitely going for the Windows 95 look.

[jcelerier]

Qt has the following style that you can use, where you just have to ship the bitmaps for your controls in a predefined naming scheme : https://doc.qt.io/qt-5/qtquickcontrols2-imagine.html