Previously, we cleared the canvas progress image when the canvas had no active generations. This allowed for a brief flash of canvas state between the last progress image for a given generation, and when the output image for that generation rendered. Here's the sequence:
- Progress images are received and rendered
- Generation completes - no active canvas generations
- Clear the progress image -> canvas layers visible unexpectedly, creating an awkward jarring change
- Generation output image is rendered -> output image overlaid on canvas layers
In 83538c4b2b I attempted to fix this by only clearing the progress image while we were not staging.
This isn't quite right, though. We are often staging with no active generations - for example, you have a few images completed and are waiting to choose one.
In this situation, if you cancel a pending generation, the logic to clear the progress image doesn't fire because it sees staging is in progress.
What we really need is:
- Staging area module clears the progress image once it has rendered an output image.
- Progress image module clears the progress image when a generation is canceled or failed, in which case there will be no output image.
To do this, we can add an event listener to the progress image module to listen for queue item status changes, and when we get a cancelation or failure, clear the progress image.
This feature involves a certain amount of extra work to ensure stroke and fill with partial opacity render correctly together. However, none of our shapes actually use that combination of attributes, so we can disable this for a minor perf boost.
- Canvas manages its own progress socket event listeners and progress event data.
- Remove cancellations listener jank.
- Dip into low-level redux subscription API to watch for queue status changes, clearing the last "global" progress event when the queue has nothing in progress. Could also do this in a useEffect I guess.
- Had to shuffle some things around to prevent circular imports, so there are a lot of tiny changes here.
Big cleanup. Makes these classes easier to implement, lots of comments and docstrings to clarify how it all works.
- Add default implementations for `destroy`, `repr` and `getLoggingContext`
- Tidy individual module configs
- Update `CanvasManager.buildLogger` to accept a canvas module as the arg
- Add `CanvasManager.buildPath`
