Module pipe 

Compositing pipeline — replaces SplashPipe and its pipeRun* family.

The C++ design uses a struct with a function-pointer field (pipe->run) selected at pipeInit time. Here each paint operation calls a span-level function that is monomorphized over P: Pixel at compile time, eliminating per-pixel vtable overhead.

Three pipeline variants

Variant	When selected	C++ equivalent
simple	a_input == 255, no soft mask, BlendMode::Normal	pipeRunSimple*
aa	shape byte present, no soft mask, BlendMode::Normal, no group correction	pipeRunAA*
general	everything else — soft mask, blend mode, non-isolated/knockout groups	pipeRun

Modules

aa

AA pipe: shape byte present, BlendMode::Normal, no soft mask, isolated group.

blend

PDF blend modes (PDF spec §11.3.5).

general

General pipe: soft mask, non-normal blend modes, non-isolated/knockout groups.

simple

Simple pipe: a_input == 255, BlendMode::Normal, no soft mask, no shape.

Structs

PipeState

Immutable parameters for one paint operation, built once per fill/stroke/glyph call.

Enums

PipeSrc

Source colour for a single paint operation.

Traits

Pattern

A source of per-pixel colour for use with the compositing pipeline.

Functions

render_span

Select and run the appropriate pipeline variant for a horizontal span.