406cc7c0c7
Add S-expression based video effects pipeline with modular effect definitions, constructs, and recipe files. Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
22 lines
825 B
Common Lisp
22 lines
825 B
Common Lisp
;; Layer effect - composite frame-b over frame-a at position
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;; Multi-input effect: uses frame-a (background) and frame-b (overlay)
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;; Params: x, y (position), opacity (0-1), mode (blend mode)
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(define-effect layer
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((x 0) (y 0) (opacity 1.0) (mode "alpha"))
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(let [bg (copy frame-a)
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fg frame-b
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;; Resize fg if needed to fit
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fg-w (width fg)
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fg-h (height fg)]
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(if (= opacity 1.0)
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;; Simple paste
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(paste bg fg x y)
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;; Blend with opacity
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(let [blended (if (= mode "alpha")
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(blend-images (crop bg x y fg-w fg-h) fg opacity)
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(blend-images (crop bg x y fg-w fg-h)
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(blend-mode (crop bg x y fg-w fg-h) fg mode)
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opacity))]
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(paste bg blended x y)))))
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