Aha… I figured it out.
IMO this is a bit non-obvious but the empty_value field can be used provided that your source has an ‘alpha’ parameter.
The documentation sort of describes this, but it’s a bit obtuse. Perhaps the example could be expanded to show this a few different ways? (default color, default alpha, etc.).
The one example that does exist sets this value to “1” and it wasn’t at all clear to me that this was why my rectangles were opaque, despite having read the documentation.
On Thu, Mar 15, 2018 at 11:34 PM, Terry Simons [email protected] wrote:
I’d like to use the BoxEditTool, but I want to set its alpha value… I don’t see an obvious way to do that.
The BoxEditTool example in the documentation sets alphas on the pre-drawn rectangles, but the BoxEditTool, which uses the same data source, draws opaque rectangles.