LibGfx: Move all image loaders and writers to a subdirectory

Userland/Libraries/LibGfx/ImageFormats/QOILoader.h

@@ -0,0 +1,70 @@
+/*
+ * Copyright (c) 2021, Linus Groh <linusg@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/Forward.h>
+#include <LibGfx/Forward.h>
+#include <LibGfx/ImageFormats/ImageDecoder.h>
+
+namespace Gfx {
+
+// Decoder for the "Quite OK Image" format (v1.0).
+// https://qoiformat.org/qoi-specification.pdf
+
+struct [[gnu::packed]] QOIHeader {
+    char magic[4];
+    u32 width;
+    u32 height;
+    u8 channels;
+    u8 colorspace;
+};
+
+struct QOILoadingContext {
+    enum class State {
+        NotDecoded = 0,
+        HeaderDecoded,
+        ImageDecoded,
+        Error,
+    };
+    State state { State::NotDecoded };
+    OwnPtr<Stream> stream {};
+    QOIHeader header {};
+    RefPtr<Bitmap> bitmap;
+};
+
+class QOIImageDecoderPlugin final : public ImageDecoderPlugin {
+public:
+    static bool sniff(ReadonlyBytes);
+    static ErrorOr<NonnullOwnPtr<ImageDecoderPlugin>> create(ReadonlyBytes);
+
+    virtual ~QOIImageDecoderPlugin() override = default;
+
+    virtual IntSize size() override;
+    virtual void set_volatile() override;
+    [[nodiscard]] virtual bool set_nonvolatile(bool& was_purged) override;
+    virtual bool initialize() override;
+    virtual bool is_animated() override { return false; }
+    virtual size_t loop_count() override { return 0; }
+    virtual size_t frame_count() override { return 1; }
+    virtual ErrorOr<ImageFrameDescriptor> frame(size_t index) override;
+    virtual ErrorOr<Optional<ReadonlyBytes>> icc_data() override;
+
+private:
+    ErrorOr<void> decode_header_and_update_context(Stream&);
+    ErrorOr<void> decode_image_and_update_context(Stream&);
+
+    QOIImageDecoderPlugin(NonnullOwnPtr<Stream>);
+
+    OwnPtr<QOILoadingContext> m_context;
+};
+
+}
+
+template<>
+struct AK::Traits<Gfx::QOIHeader> : public GenericTraits<Gfx::QOIHeader> {
+    static constexpr bool is_trivially_serializable() { return true; }
+};