Ian Hickson

This is not working on the Flutter API docs. Any chance we could make it a high priority? We're about to have a significant branch cut, and this is a...

Yes, this was dependent on first removing SizeObserver.

The original context was that we had a RenderObject that, during layout, invoked a callback with its `size`, and people would, in that callback, call `setState` so that they could...

@Abhishek01039 By "during layout" you mean while handling a "performLayout" call in a RenderObject subclass?

That's during build, not layout. (You can tell because it says "The following assertion was thrown building..." and "the framework is already in the process of building widgets".)

for example, if a render object has a callback which is invoked during layout, and a State's build method uses such a render object and provides a callback that calls...

This is still valid but realistically we can't add asserts at this low level anymore without breaking tons of apps so I'm going to make a call that we're not...

This is normal behaviour. What's happening is that the boxes are not quite aligned with pixel boundaries, so there's some anti-aliasing happening on the boundaries, which involves transparency, which means...

@radzish what is Android doing to avoid the problem?

These comments have suggestions for things to put in documentation: https://github.com/flutter/flutter/issues/14288#issuecomment-361375791 https://github.com/flutter/flutter/issues/17084#issuecomment-385718108 https://github.com/flutter/flutter/issues/15035#issuecomment-370028740