Artifact 5330713149cebca8d2a1b35e85459ba395c613120278fa4e69e80ed9ea558304:

• File etc/transformer/statistics/cumulation.tcl — part of check-in [ae6d6a67c9] at 2025-11-04 20:18:25 on branch trunk — fix: deep-seated conceptual problem with the sharing of regions in the runtime structure ware: fixed the 2 bad test results exposed by the work (morphology) note: issue was seen before, not fully understood, tracked it down on this occurence note: solved via on-demand creation of additional pixel storage in the problem nodes of the graph note: detailed explanation of issue and solution is found in the `region.h` comments chore: updated all the fetch call sites to match changed signatures chore: regenerated docs for accumulated changes. (user: aku size: 2921)

## -*- mode: tcl ; fill-column: 90 -*-
# # ## ### ##### ######## ############# #####################
## Transformers -- Cumulations along the various axes
##                 (rows, columns, bands), and the entire image.
##                 Tiled does not make sense.
##
## Note: Cumulation of the entire image is also known as `Sum Area Table`.
##
##       Due to the wrap around from one row to the next the SAT is __not separable__ into
##       a combination of row and column csums. It might be possible to use a veccache for
##       some perf boost.

# # ## ### ##### ######## ############# #####################

operator okind {
    op::row::cumulative    column
    op::column::cumulative row
} {
    op -> _ kind _

    example {
	aktive op sdf 2image smooth [aktive op sdf ring [aktive image sdf triangle width 32 height 32 a {10 10} b {50 80} c {80 30}] thickness 4]
	@1 | -matrix
    }

    section transform statistics

    note Returns image with the input ${kind}s transformed into cumulative sums.

    note This means that each pixel in a ${kind} is the sum of the values in the \
	${okind} before it, having the same ${kind}.

    note The result has the same geometry as the input. Only the contents change.

    # !xref-mark cumulation
    cached $kind cumulation AKTIVE_CSUM_FILL
}

# # ## ### ##### ######## ############# #####################

operator op::band::cumulative {
    section transform statistics

    input

    note Returns image with the input bands transformed into cumulative sums.

    note This means that each pixel in a band is the sum of the values in the \
	bands before it, having the same row and column.

    note The result has the same geometry as the input. Only the contents change.

    state -setup {
	aktive_geometry_copy (domain, aktive_image_get_geometry (srcs->v[0]));
    }

    blit prefixsum {
	{DH {y 0 1 up} {y 0 1 up}}
	{DW {x 0 1 up} {x 0 1 up}}
    } {raw sum-bands {
	// dstvalue = row/col start - 1-strided full band vector
	// srcvalue = row/col start - 1-strided full band vector

	aktive_cumulative_sum (dstvalue, DD, srcvalue, 1);

	// Applies only when src can be assumed to contain only positive or negative values
	// If a mix is present the result can return to the initial value
	// ASSERT (dstvalue[DD-1] > dstvalue[0], "bad cumulation is flat");
    }}

    pixels {
	// No caching is required for the bands.
	// The request is passed unchanged.
	// We can and do use a regular blitter.

	aktive_rectangle_def_as (subrequest, request);
	TRACE_RECTANGLE_M("band csum", &subrequest);
	aktive_block* src = aktive_region_fetch_area (0, &subrequest);

	#define AH (dst->height)
	#define AW (dst->width)
	#define AX (dst->x)
	#define AY (dst->y)
	@@prefixsum@@
	#undef AH
	#undef AW
	#undef AX
	#undef AY

	TRACE_DO (__aktive_block_dump ("band csum out", block));
    }
}

##
# # ## ### ##### ######## ############# #####################
::return