ladybird/Userland/Libraries/LibGfx/PNGLoader.h
Liav A 57e19a7e56 LibGfx: Re-structure the whole initialization pattern for image decoders
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.
2023-01-20 15:13:31 +00:00

37 lines
950 B
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <LibGfx/ImageDecoder.h>
namespace Gfx {
struct PNGLoadingContext;
class PNGImageDecoderPlugin final : public ImageDecoderPlugin {
public:
static ErrorOr<bool> sniff(ReadonlyBytes);
static ErrorOr<NonnullOwnPtr<ImageDecoderPlugin>> create(ReadonlyBytes);
virtual ~PNGImageDecoderPlugin() override;
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;
virtual size_t loop_count() override;
virtual size_t frame_count() override;
virtual ErrorOr<ImageFrameDescriptor> frame(size_t index) override;
private:
PNGImageDecoderPlugin(u8 const*, size_t);
OwnPtr<PNGLoadingContext> m_context;
};
}