structUpdateFrameCount abstract method
Updates frameCount and resynchronizes frame-dependent memory state.
This must be used when native decoders determine the frame count after
allocation/loading (for example animated GIF decoding), because changing
frameCount affects derived memory layout such as dataLength.
This is separate from directly assigning frameCount because platform
implementations may need to refresh internal views or buffers after the
frame count changes.
Implementation
void structUpdateFrameCount(int frameCount);