New Stereo Panner GUI

Although the panning GUI in Ardour 2.X was very powerful and flexible, it made the most common operations with 2in/2out panning more cumbersome than they should be. In Ardour 3.0, the old panners are used for many I/O configurations, but the special case of 2in/2out ("stereo") is now handled by a more deliberately designed GUI element, shown below:

stereo panner

Dragging the top half of the widget will move the pan position within the stereo field. Dragging the lower half will adjust the width of the stereo field. You can drag to the center, collapsing the pan into a mono mix to both outputs, and keep going to invert the assignment of signals to outputs. Different color schemes (user configurable) are used to highlight the mono and inverted mix situations.

Obviously the mouse scroll wheel also works and the arrow keys can be used to adjust both position and width (Left/Right keys adjust position, Up/Down adjust width). Three more key bindings will reset the widget to 100%, 0%, and -100% (Shift-up, 0, Shift-down respectively). The tooltip will display numerical values for the pan position and field width.