SiandClaude Opus 5.5
9fb4428a3b
A blurred copy of the overlay's own alpha is drawn in a colour beneath it: moved by an offset for a shadow, centred for a glow, with a size, a spread and an opacity. The mask is integer-only so a seed still reproduces it, and reaches past the canvas so an image lying off it still casts onto it. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
48 lines
1.9 KiB
C++
48 lines
1.9 KiB
C++
#pragma once
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#include <cstdint>
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#include <mutex>
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#include <string>
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#include <vector>
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#include "core/effect.hpp"
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namespace effector {
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// Lays one picture from disk over its input: a logo, a texture, a frame. The
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// overlay is fitted to the canvas in the chosen way, placed from the top left
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// or from the centre, nudged by an offset and mixed in by its opacity, with a
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// soft shadow or glow cut from its own outline beneath it if asked. Like the
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// blur it needs no source images of its own, so it can lead a chain; given
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// sources it fills the canvas from a randomly chosen one first.
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class OverlayEffect : public Effect {
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public:
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std::string name() const override { return "overlay"; }
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std::string title() const override { return "Image overlay"; }
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std::string description() const override {
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return "Lays a single image from disk over its input, fitted to the canvas, centred or "
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"not, nudged by an offset and mixed in by its opacity, optionally with a shadow or "
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"a glow around it.";
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}
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const std::vector<ParamSpec>& params() const override;
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bool needsSources() const override { return false; }
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Image render(const std::vector<Image>& sources, int width, int height, Rng& rng,
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const ParamValues& values) const override;
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private:
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// The same file is re-read on every param change otherwise, and a render is
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// a keystroke away in the interface. Renders can overlap, so it is guarded.
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// Returns the decoded file and its alpha, reading it only when the path
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// differs from the one already held.
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void loadOverlay(const std::string& path, Image& image,
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std::vector<std::uint8_t>& alpha) const;
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mutable std::mutex cacheMutex_;
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mutable std::string cachedPath_;
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mutable Image cached_;
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mutable std::vector<std::uint8_t> cachedAlpha_;
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};
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} // namespace effector
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