Module drop_shadow 

DropShadowFilter — alpha extract → blur → composite under source.

Four logical passes implemented inside a single Filter::render_pass invocation (we manage our own scratch render targets — scratch_a and scratch_b):

1. Extract the source alpha, offset by offset and tinted with color, into the first scratch.
2. Horizontal Gaussian blur on the first scratch into the second.
3. Vertical Gaussian blur back into the first scratch (now the blurred shadow).
4. Composite source over the blurred shadow into output.

Structs

CompositeCache 🔒

DropShadowFilter

Drop-shadow post-process.

ExtractCache 🔒

ExtractUniforms 🔒

Functions

composite_pipeline 🔒

extract_pipeline 🔒

run_composite 🔒

run_extract 🔒