I'm seeing a couple of issues with SnapshotWidget and/or toImageSync under Impeller.

First, text is sometimes mangled in the image coming from toImageSync:

I've only been able to repro this on iOS hardware.

Second, using the result of toImageSync, specifically in the SnapshotWidget, as a sampler in a shader, gives all black.

Sorry for the large repro, but here is my fork of flutter/gallery.

https://github.com/zanderso/gallery/commits/impeller-tis-issue

The live implementation of snapshotPainter in there just draws the provided image to the canvas. The commented out code in snapshotPainter uses the custom shader.

@jonahwilliams @bdero @dnfield