inputScale

The input scale factor, which needs to be in the range 0 < x <= 1. Defaults to 1.0, resulting in no scaling.

The content will be scaled by this value in both the x and y dimensions, allowing the blur effect to be potentially applied over scaled-down content, before being scaled back up and drawn at the original size.

Using a value less than 1.0 may improve performance, at the sacrifice of quality and crispness. As always, run your own benchmarks as to whether this compromise is worth it.

If you're looking for a good value to experiment with, 0.8 results in a reduction in total resolution of ~35%, while being visually imperceptible to most people (probably).

The minimum value I would realistically use is somewhere in the region of 0.5, which results in the total pixel count being only 25% of the original content. This will likely be visually perceptible different to no scaling, but depending on the styling parameters will still look pleasing to the user.

This feature is experimental as it's unclear how much gain it provides. It may be removed some point in the future.