57e19a7e56
When trying to figure out the correct implementation, we now have a very
strong distinction on plugins that are well suited for sniffing, and
plugins that need a MIME type to be chosen.
Instead of having multiple calls to non-static virtual sniff methods for
each Image decoding plugin, we have 2 static methods for each
implementation:
1. The sniff method, which in contrast to the old method, gets a
ReadonlyBytes parameter and ensures we can figure out the result
with zero heap allocations for most implementations.
2. The create method, which just creates a new instance so we don't
expose the constructor to everyone anymore.
In addition to that, we have a new virtual method called initialize,
which has a per-implementation initialization pattern to actually ensure
each implementation can construct a decoder object, and then have a
correct context being applied to it for the actual decoding.
66 lines
1.7 KiB
C++
66 lines
1.7 KiB
C++
/*
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* Copyright (c) 2021, Linus Groh <linusg@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/Forward.h>
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#include <LibGfx/Forward.h>
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#include <LibGfx/ImageDecoder.h>
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namespace Gfx {
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// Decoder for the "Quite OK Image" format (v1.0).
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// https://qoiformat.org/qoi-specification.pdf
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struct [[gnu::packed]] QOIHeader {
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char magic[4];
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u32 width;
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u32 height;
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u8 channels;
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u8 colorspace;
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};
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struct QOILoadingContext {
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enum class State {
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NotDecoded = 0,
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HeaderDecoded,
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ImageDecoded,
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Error,
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};
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State state { State::NotDecoded };
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u8 const* data { nullptr };
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size_t data_size { 0 };
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QOIHeader header {};
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RefPtr<Bitmap> bitmap;
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Optional<Error> error;
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};
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class QOIImageDecoderPlugin final : public ImageDecoderPlugin {
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public:
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static ErrorOr<bool> sniff(ReadonlyBytes);
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static ErrorOr<NonnullOwnPtr<ImageDecoderPlugin>> create(ReadonlyBytes);
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virtual ~QOIImageDecoderPlugin() override = default;
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virtual IntSize size() override;
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virtual void set_volatile() override;
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[[nodiscard]] virtual bool set_nonvolatile(bool& was_purged) override;
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virtual bool initialize() override;
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virtual bool is_animated() override { return false; }
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virtual size_t loop_count() override { return 0; }
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virtual size_t frame_count() override { return 1; }
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virtual ErrorOr<ImageFrameDescriptor> frame(size_t index) override;
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private:
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ErrorOr<void> decode_header_and_update_context(InputMemoryStream&);
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ErrorOr<void> decode_image_and_update_context(InputMemoryStream&);
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QOIImageDecoderPlugin(u8 const*, size_t);
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OwnPtr<QOILoadingContext> m_context;
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};
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}
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