Previously, when previewing a filter on a layer with some transparency or a filter that changes the alpha, the preview was rendered on top of the layer. The preview blended with the layer, which isn't right.
In this change, the layer is hidden during the preview, and when the filter finishes (having been applied or canceled - the two possible paths), the layer is shown.
Technically, we are hiding and showing the layer's object renderer's konva group, which contains the layer's "real" data.
Another small change was made to prevent a flash of empty layer, by waiting to destroy a previous filter preview image until the new preview image is ready to display.
Due to the limited floating point precision, and konva's `scale` properties, it is possible for the relative rect of an object to have non-integer coordinates and dimensions.
When we go to rasterize and otherwise export images, the HTML canvas API truncates these numbers.
So, we can end up with situations where the relative width and height of a layer are very close to the "real" value, but slightly off.
For example, width and height might be 512px, but the relative rect is calculated to be something like 512.000000003 or 511.9999999997.
In the first case, the truncation results in 512x512 for the dimensions - which is correct. But in the second case, it results in 511x511!
One place where this causes issues is the image action `New Canvas from image -> As Raster Layer (resize)`. For certain input image sizes, this results in an incorrectly resized image. For example, a 1496x1946 input image is resized to 511x511 pixels when the bbox is 512x512.
To fix this, we can round both coords and dimensions of rects when rasterizing.
I've thought through the implications and done some testing. I believe this change will not cause any regressions and only fix edge cases. But, it's possible that something was inadvertently relying on the old behavior.
There's a bug where preset image tooltips get stuck open in the list.
After much fiddling, debugging, and review of upstream dependencies, I have determined that this is bug in Chakra-UI v2.
Specifically, it appears to be a race condition related to the Tooltip component's internal use of the `useDisclosure` hook to manage tooltip open state, and the react render cycle.
Unfortunately, Chakra v2 is no longer being updated, and it's a pain in the butt to vendor and fix that component given its dependencies. Not 100% sure I could easily fix it, anyways.
Fortunately, there is a workaround - reduce the tooltip openDelay to 0ms. I prefer the current 500ms delay but I think it's preferable to have too-quick tooltips than too-sticky tooltips...
