layer_stack — GFX2D composite op

• 数据种类:table → rgba

• 调用:import gfx2d; gfx2d.layer_stack(layers)(或 opsgfx2d.get("layer_stack"))

用法

按 z 序合成一列 `rgba` 图层,自下而上。

> 以下的详细说明为原文 —— 摘要与标题已翻译。

Each layer is a dict:

`{"image": rgba, "mode": str = "normal", "opacity": float = 1.0}`

and the W3C rule for a blend mode against a *partially transparent* backdrop

is used — the blend function is weighted by the backdrop's own alpha,

`Cs' = (1 - a_b) Cs + a_b B(Cb, Cs)` — so a layer over empty space keeps

its own colour whatever the mode. The result is straight-alpha `rgba`.

All layers must share one shape; see :func:alpha_composite on why.

Raises ValueError: empty list, more than :data:MAX_LAYERS, a non-dict

entry, an unknown key, mismatched shapes.

参考(示例数据・文献)

• 示例数据目录(下载 URL / 许可证) —— 2-D 用 skimage.data(BSD/公有领域)加合成图,3-D 给出真实数据源(Stanford/PDS 等)的下载 URL。

• 算子来历与参考文献 —— 该算子族所依据的研究/方法出处。

• 算法的正典(作者・年份)与用途见上面的族使用指南。

可运行的示例(实际调用该算子并已验证的样例)

• gfx2d_scene — py -3.11 examples/gfx2d_scene.py

类型可衔接的下一个算子(可接受 rgba 作为输入)

premultiply · alpha_composite · sprite_blit · sprite_transform · sprite_sheet_slice · nine_slice

同类别(composite)

premultiply · unpremultiply · alpha_composite · alpha_composite_premul · blend_mode

*Provenance: gfx2d.py — GFX2D 算子登记表。本条目由 tools/opdocs.py md 自动生成(请勿手工编辑)。*

© 2026 Kazufumi Furuse — Fullseye operator documentation. Licensed under Apache-2.0.