Add files via upload

include/export.hpp

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+#pragma once
+
+#include "sppm.hpp"
+
+#include <string>
+
+namespace sppm {
+
+// Exports a looping GIF89a animation. The GIF uses the document palette and
+// composites layers A through D for each frame. GIF has no audio channel.
+bool exportGif(const Document& document, const std::string& path,
+               std::string& error);
+
+// Exports the selected cover frame as a lossless RGBA PNG.
+bool exportPngCover(const Document& document, const std::string& path,
+                    std::string& error);
+
+// Exports a Motion-JPEG MP4 animation. Frames are composited over white at
+// native Switchnote resolution; audio tracks are not muxed.
+bool exportMp4(const Document& document, const std::string& path,
+               std::string& error);
+
+} // namespace sppm