* Take two: Delay reading image back from render backend using `SyncHandle`
This allows us to avoid blocking immediately after a `BitmapData.draw` call.
Instead, we only attempt to use the `SyncHandle` when performing an operation
that requires the CPU-side pixels (e.g. BitmapData.getPixel or BitmapData.setPixel).
In the best case, the SWF will never explicitly access the pixels of
the target BitmapData, removing the need to ever copy back the render backend
image to our BitmapData. If the SWF doesn't require access to the pixels immediately,
we can delay copying the pixels until they're actually needed, hopefully allowing
the render backend to finish processing the BitmapData.draw operation in
the backenground before we need the result.
Now that the CPU and GPU pixels can be intentionally out of sync with
each other, we need to ensure that we don't accidentally expose 'stale'
CPU-side pixels to ActionScript (which needs to remain unaware of
our internal laziness). We now use a wrapper type `BitmapDataWrapper`
to enforce that the `SyncHandle` is consumed before accessing the
underlying `BitmapData.
* core: Skip GPU->CPU sync for source and target BitmapData during draw
* Introduce DirtyState enum
This change makes it so that if there is a goto to a specific frame,
then a frame script is registered for that frame, and then a goto to the
same frame again, the frame script will not be skipped. At least one movie
appears to depend on this behaviour.
Now that a `Bitmap` always stores a `BitmapData`, we can read the pixels
directly from the `BitmapData`, instead of duplicating them in an
`initial_data` field
This makes `Bitmap` delegate to `BitmapData` for
all of the bitmap-related information (handle, width, and height).
As a result, we now unconditionally store a `BitmapData` in `Bitmap`.
As a result, swapping the underling `BitmapData` instance will
automatically change the properties (and rendered image) of a `Bitmap`.
This required some refactoring in the render backends in order to
get access to a `BitmapHandle` through `BitmapData`.
In future versions of `gc-arena`, the `Debug` impl. of `Gc`
and `GcCell` will print the pointed-to value, which will cause
derived `Debug` impls. to enter an infinite recursion.
As such, this manually implements `Debug` on types wrapping a
`Gc/GcCell` to maintain the current behavior.
Previous behaviour defaulted to undefined and applied the format to the
range [0,0) instead of defaulting to -1 and applying the format to the
full length of the TextField.
MartySVK