Radio buttons in generated filter (GEGL) UI
Description: In certain cases, a set of radio buttons would work better for some enum properties of GEGL-based filters, rather than the drop-down lists that are currently used universally in the generated UIs.
Rationale: Over drop-down lists, radio buttons can offer a number of usability improvements, including discoverability at a glance, a further emphasis on the different choices available, and smooth interaction with one click of the mouse (rather than the usual two clicks used for a drop-down)
Implementation: GEGL operations should be able to set explicitly whether to use radio buttons or drop-downs through GUM. In addition, radio buttons could be automatically used if a parameter has few options (four or fewer, perhaps) and if the generated UI has the space to accommodate. Putting the radio buttons into columns as space permits might be nice.