We currently choose to set the animation parameters (blend method, blend
rect, disposal method, timeout) in imgFrame::Finish instead of
imgFrame::InitForDecoder. The decoders themselves already have access to
the necessary information at the time InitForDecoder is called, so there
is no reason to do this. Moving the configuration to initialization will
allow us to relax the mutex protection on these parameters.
This part simply reorganizes imgFrame, and subsequent parts will
introduce the necessary changes to SurfacePipe and decoders.
This creates a number of stubs and leaves some surrounding code that may be irrelevant (eg. recorded time stamps, status variables).
Stub resolution/removal should be a follow-up to this.
A dimension of 3000 largest size x or y should cover all common caching cases for SVG icons and web app elements, but not caching large vector rasters that would exhaust the cache.
This limit is a royal 36MB/element (3000x3000x4) as cap (if the SVG is square). This avoids performance regressions when repeatedly scaling large vector images, but also allows for large SVG backgrounds to be cached.
It allows for the bad practice of slapping a large SVG on a site as html background, considering they are likely, even when using large sizes for "responsive" layout, not going to exceed 3000 px in the largest dimension (and if they do, the web designer needs to be slapped with a big trout).
