From 8a3dc5ea0a98fb0fd1d40ab7f33d6eb19657fe3b Mon Sep 17 00:00:00 2001
From: Andreas Kling <andreas@ladybird.org>
Date: Tue, 18 Jun 2024 21:06:15 +0200
Subject: [PATCH] LibGfx: Remove home-grown PNG codec in favor of libpng+apng

---
 Tests/LibGfx/TestImageDecoder.cpp             |    5 +-
 Userland/Libraries/LibGfx/CMakeLists.txt      |    5 +
 .../LibGfx/ImageFormats/PNGLoader.cpp         | 1648 +++--------------
 .../Libraries/LibGfx/ImageFormats/PNGLoader.h |    9 +-
 .../Libraries/LibGfx/ImageFormats/PNGShared.h |   67 -
 .../LibGfx/ImageFormats/PNGWriter.cpp         |  319 +---
 .../Libraries/LibGfx/ImageFormats/PNGWriter.h |   17 +-
 vcpkg.json                                    |    8 +
 8 files changed, 306 insertions(+), 1772 deletions(-)
 delete mode 100644 Userland/Libraries/LibGfx/ImageFormats/PNGShared.h

diff --git a/Tests/LibGfx/TestImageDecoder.cpp b/Tests/LibGfx/TestImageDecoder.cpp
index fee5aec79b1..75503cdd89c 100644
--- a/Tests/LibGfx/TestImageDecoder.cpp
+++ b/Tests/LibGfx/TestImageDecoder.cpp
@@ -363,7 +363,10 @@ TEST_CASE(test_png_malformed_frame)
 
     for (auto test_input : test_inputs) {
         auto file = TRY_OR_FAIL(Core::MappedFile::map(test_input));
-        auto plugin_decoder = TRY_OR_FAIL(Gfx::PNGImageDecoderPlugin::create(file->bytes()));
+        auto plugin_decoder_or_error = Gfx::PNGImageDecoderPlugin::create(file->bytes());
+        if (plugin_decoder_or_error.is_error())
+            continue;
+        auto plugin_decoder = plugin_decoder_or_error.release_value();
         auto frame_or_error = plugin_decoder->frame(0);
         EXPECT(frame_or_error.is_error());
     }
diff --git a/Userland/Libraries/LibGfx/CMakeLists.txt b/Userland/Libraries/LibGfx/CMakeLists.txt
index 892af1ffaa3..4e2fb21beb8 100644
--- a/Userland/Libraries/LibGfx/CMakeLists.txt
+++ b/Userland/Libraries/LibGfx/CMakeLists.txt
@@ -103,3 +103,8 @@ find_package(JPEG REQUIRED)
 target_include_directories(LibGfx PRIVATE ${JPEG_INCLUDE_DIRS})
 target_link_libraries(LibGfx PRIVATE ${JPEG_LIBRARIES})
 target_link_directories(LibGfx PRIVATE ${JPEG_LIBRARY_DIRS})
+
+find_package(PNG REQUIRED)
+target_include_directories(LibGfx PRIVATE ${PNG_INCLUDE_DIRS})
+target_link_libraries(LibGfx PRIVATE ${PNG_LIBRARIES})
+target_link_directories(LibGfx PRIVATE ${PNG_LIBRARY_DIRS})
diff --git a/Userland/Libraries/LibGfx/ImageFormats/PNGLoader.cpp b/Userland/Libraries/LibGfx/ImageFormats/PNGLoader.cpp
index a8c899d811b..6ab4734be0c 100644
--- a/Userland/Libraries/LibGfx/ImageFormats/PNGLoader.cpp
+++ b/Userland/Libraries/LibGfx/ImageFormats/PNGLoader.cpp
@@ -1,1453 +1,303 @@
 /*
- * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2018-2024, Andreas Kling <andreas@ladybird.org>
  * Copyright (c) 2022, the SerenityOS developers.
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
-#include <AK/Debug.h>
-#include <AK/Endian.h>
-#include <AK/MemoryStream.h>
 #include <AK/Vector.h>
-#include <LibCompress/Zlib.h>
 #include <LibGfx/ImageFormats/PNGLoader.h>
 #include <LibGfx/ImageFormats/TIFFLoader.h>
 #include <LibGfx/ImageFormats/TIFFMetadata.h>
 #include <LibGfx/Painter.h>
+#include <png.h>
 
 namespace Gfx {
 
-struct PNG_IHDR {
-    NetworkOrdered<u32> width;
-    NetworkOrdered<u32> height;
-    u8 bit_depth { 0 };
-    PNG::ColorType color_type { 0 };
-    u8 compression_method { 0 };
-    u8 filter_method { 0 };
-    u8 interlace_method { 0 };
-};
-
-static_assert(AssertSize<PNG_IHDR, 13>());
-
-struct acTL_Chunk {
-    NetworkOrdered<u32> num_frames;
-    NetworkOrdered<u32> num_plays;
-};
-static_assert(AssertSize<acTL_Chunk, 8>());
-
-struct fcTL_Chunk {
-    enum class DisposeOp : u8 {
-        APNG_DISPOSE_OP_NONE = 0,
-        APNG_DISPOSE_OP_BACKGROUND,
-        APNG_DISPOSE_OP_PREVIOUS
-    };
-    enum class BlendOp : u8 {
-        APNG_BLEND_OP_SOURCE = 0,
-        APNG_BLEND_OP_OVER
-    };
-    NetworkOrdered<u32> sequence_number;
-    NetworkOrdered<u32> width;
-    NetworkOrdered<u32> height;
-    NetworkOrdered<u32> x_offset;
-    NetworkOrdered<u32> y_offset;
-    NetworkOrdered<u16> delay_num;
-    NetworkOrdered<u16> delay_den;
-    DisposeOp dispose_op { DisposeOp::APNG_DISPOSE_OP_NONE };
-    BlendOp blend_op { BlendOp::APNG_BLEND_OP_SOURCE };
-};
-static_assert(AssertSize<fcTL_Chunk, 26>());
-
-struct ChromaticitiesAndWhitepoint {
-    NetworkOrdered<u32> white_point_x;
-    NetworkOrdered<u32> white_point_y;
-    NetworkOrdered<u32> red_x;
-    NetworkOrdered<u32> red_y;
-    NetworkOrdered<u32> green_x;
-    NetworkOrdered<u32> green_y;
-    NetworkOrdered<u32> blue_x;
-    NetworkOrdered<u32> blue_y;
-};
-static_assert(AssertSize<ChromaticitiesAndWhitepoint, 32>());
-
-struct CodingIndependentCodePoints {
-    u8 color_primaries;
-    u8 transfer_function;
-    u8 matrix_coefficients;
-    u8 video_full_range_flag;
-};
-static_assert(AssertSize<CodingIndependentCodePoints, 4>());
-
-struct EmbeddedICCProfile {
-    StringView profile_name;
-    ReadonlyBytes compressed_data;
-};
-
-struct Scanline {
-    PNG::FilterType filter;
-    ReadonlyBytes data {};
-};
-
-struct [[gnu::packed]] PaletteEntry {
-    u8 r;
-    u8 g;
-    u8 b;
-    // u8 a;
-};
-
-template<typename T>
-struct [[gnu::packed]] Tuple {
-    T gray;
-    T a;
-};
-
-template<typename T>
-struct [[gnu::packed]] Triplet {
-    T r;
-    T g;
-    T b;
-
-    bool operator==(Triplet const& other) const = default;
-};
-
-template<typename T>
-struct [[gnu::packed]] Quartet {
-    T r;
-    T g;
-    T b;
-    T a;
-};
-
-enum PngInterlaceMethod {
-    Null = 0,
-    Adam7 = 1
-};
-
-enum RenderingIntent {
-    Perceptual = 0,
-    RelativeColorimetric = 1,
-    Saturation = 2,
-    AbsoluteColorimetric = 3,
-};
-
 struct AnimationFrame {
-    fcTL_Chunk const& fcTL;
     RefPtr<Bitmap> bitmap;
-    ByteBuffer compressed_data;
+    int x_offset { 0 };
+    int y_offset { 0 };
+    int width { 0 };
+    int height { 0 };
+    int delay_den { 0 };
+    int delay_num { 0 };
+    u8 blend_op { 0 };
+    u8 dispose_op { 0 };
 
-    AnimationFrame(fcTL_Chunk const& fcTL)
-        : fcTL(fcTL)
+    AnimationFrame(RefPtr<Bitmap> bitmap, int x_offset, int y_offset, int width, int height, int delay_den, int delay_num, u8 blend_op, u8 dispose_op)
+        : bitmap(move(bitmap))
+        , x_offset(x_offset)
+        , y_offset(y_offset)
+        , width(width)
+        , height(height)
+        , delay_den(delay_den)
+        , delay_num(delay_num)
+        , blend_op(blend_op)
+        , dispose_op(dispose_op)
     {
     }
 
-    u32 duration_ms() const
+    [[nodiscard]] int duration_ms() const
     {
-        u32 num = fcTL.delay_num;
-        if (num == 0)
+        if (delay_num == 0)
             return 1;
-        u32 denom = fcTL.delay_den != 0 ? static_cast<u32>(fcTL.delay_den) : 100u;
-        return (num * 1000) / denom;
+        u32 const denominator = delay_den != 0 ? static_cast<u32>(delay_den) : 100u;
+        auto unsigned_duration_ms = (delay_num * 1000) / denominator;
+        if (unsigned_duration_ms > INT_MAX)
+            return INT_MAX;
+        return static_cast<int>(unsigned_duration_ms);
     }
 
-    IntRect rect() const
-    {
-        return { fcTL.x_offset, fcTL.y_offset, fcTL.width, fcTL.height };
-    }
+    [[nodiscard]] IntRect rect() const { return { x_offset, y_offset, width, height }; }
 };
 
 struct PNGLoadingContext {
-    enum State {
-        NotDecoded = 0,
-        Error,
-        IHDRDecoded,
-        ImageDataChunkDecoded,
-        ChunksDecoded,
-        BitmapDecoded,
-    };
-    State state { State::NotDecoded };
-    u8 const* data { nullptr };
-    u8 const* data_current_ptr { nullptr };
-    size_t data_size { 0 };
-    i32 width { -1 };
-    i32 height { -1 };
-    u8 bit_depth { 0 };
-    PNG::ColorType color_type { 0 };
-    u8 compression_method { 0 };
-    u8 filter_method { 0 };
-    u8 interlace_method { 0 };
-    u8 channels { 0 };
-    u32 animation_next_expected_seq { 0 };
-    u32 animation_next_frame_to_render { 0 };
-    u32 animation_frame_count { 0 };
-    u32 animation_loop_count { 0 };
-    Optional<u32> last_completed_animation_frame_index;
-    bool is_first_idat_part_of_animation { false };
-    bool has_seen_iend { false };
-    bool has_seen_idat_chunk { false };
-    bool has_seen_actl_chunk_before_idat { false };
-    bool has_alpha() const { return to_underlying(color_type) & 4 || palette_transparency_data.size() > 0; }
-    Vector<Scanline> scanlines;
-    ByteBuffer unfiltered_data;
-    RefPtr<Gfx::Bitmap> bitmap;
-    ByteBuffer compressed_data;
-    Vector<PaletteEntry> palette_data;
-    ByteBuffer palette_transparency_data;
-    Vector<AnimationFrame> animation_frames;
-
-    Optional<ChromaticitiesAndWhitepoint> chromaticities_and_whitepoint;
-    Optional<CodingIndependentCodePoints> coding_independent_code_points;
-    Optional<u32> gamma;
-    Optional<EmbeddedICCProfile> embedded_icc_profile;
-    Optional<ByteBuffer> decompressed_icc_profile;
-    Optional<RenderingIntent> sRGB_rendering_intent;
-
+    ReadonlyBytes data;
+    IntSize size;
+    u32 frame_count { 0 };
+    u32 loop_count { 0 };
+    Vector<ImageFrameDescriptor> frame_descriptors;
+    Optional<ByteBuffer> icc_profile;
     OwnPtr<ExifMetadata> exif_metadata;
 
-    Checked<int> compute_row_size_for_width(int width)
-    {
-        Checked<int> row_size = width;
-        row_size *= channels;
-        row_size *= bit_depth;
-        row_size += 7;
-        row_size /= 8;
-        if (row_size.has_overflow()) {
-            dbgln("PNG too large, integer overflow while computing row size");
-            state = State::Error;
-        }
-        return row_size;
-    }
+    Vector<AnimationFrame> animation_frames;
+    Vector<u8*> row_pointers;
+    Vector<u8> image_data;
+    RefPtr<Gfx::Bitmap> decoded_frame_bitmap;
 
-    PNGLoadingContext create_subimage_context(int width, int height)
-    {
-        PNGLoadingContext subimage_context;
-        subimage_context.state = State::ChunksDecoded;
-        subimage_context.width = width;
-        subimage_context.height = height;
-        subimage_context.channels = channels;
-        subimage_context.color_type = color_type;
-        subimage_context.palette_data = palette_data;
-        subimage_context.palette_transparency_data = palette_transparency_data;
-        subimage_context.bit_depth = bit_depth;
-        subimage_context.filter_method = filter_method;
-        return subimage_context;
-    }
+    ErrorOr<size_t> read_frames(png_structp, png_infop);
 };
 
-class Streamer {
-public:
-    Streamer(u8 const* data, size_t size)
-        : m_data_ptr(data)
-        , m_size_remaining(size)
-    {
-    }
-
-    template<typename T>
-    bool read(T& value)
-    {
-        if (m_size_remaining < sizeof(T))
-            return false;
-        value = *((NetworkOrdered<T> const*)m_data_ptr);
-        m_data_ptr += sizeof(T);
-        m_size_remaining -= sizeof(T);
-        return true;
-    }
-
-    bool read_bytes(u8* buffer, size_t count)
-    {
-        if (m_size_remaining < count)
-            return false;
-        memcpy(buffer, m_data_ptr, count);
-        m_data_ptr += count;
-        m_size_remaining -= count;
-        return true;
-    }
-
-    bool wrap_bytes(ReadonlyBytes& buffer, size_t count)
-    {
-        if (m_size_remaining < count)
-            return false;
-        buffer = ReadonlyBytes { m_data_ptr, count };
-        m_data_ptr += count;
-        m_size_remaining -= count;
-        return true;
-    }
-
-    u8 const* current_data_ptr() const { return m_data_ptr; }
-    bool at_end() const { return !m_size_remaining; }
-
-private:
-    u8 const* m_data_ptr { nullptr };
-    size_t m_size_remaining { 0 };
-};
-
-static ErrorOr<void> process_chunk(Streamer&, PNGLoadingContext& context);
-
-union [[gnu::packed]] Pixel {
-    ARGB32 rgba { 0 };
-    u8 v[4];
-    struct {
-        u8 r;
-        u8 g;
-        u8 b;
-        u8 a;
-    };
-};
-static_assert(AssertSize<Pixel, 4>());
-
-void PNGImageDecoderPlugin::unfilter_scanline(PNG::FilterType filter, Bytes scanline_data, ReadonlyBytes previous_scanlines_data, u8 bytes_per_complete_pixel)
+ErrorOr<NonnullOwnPtr<ImageDecoderPlugin>> PNGImageDecoderPlugin::create(ReadonlyBytes bytes)
 {
-    // https://www.w3.org/TR/png-3/#9Filter-types
-    // "Filters are applied to bytes, not to pixels, regardless of the bit depth or colour type of the image."
-    switch (filter) {
-    case PNG::FilterType::None:
-        break;
-    case PNG::FilterType::Sub:
-        // This loop starts at bytes_per_complete_pixel because all bytes before that are
-        // guaranteed to have no valid byte at index (i - bytes_per_complete pixel).
-        // All such invalid byte indexes should be treated as 0, and adding 0 to the current
-        // byte would do nothing, so the first bytes_per_complete_pixel bytes can instead
-        // just be skipped.
-        for (size_t i = bytes_per_complete_pixel; i < scanline_data.size(); ++i) {
-            u8 left = scanline_data[i - bytes_per_complete_pixel];
-            scanline_data[i] += left;
-        }
-        break;
-    case PNG::FilterType::Up:
-        for (size_t i = 0; i < scanline_data.size(); ++i) {
-            u8 above = previous_scanlines_data[i];
-            scanline_data[i] += above;
-        }
-        break;
-    case PNG::FilterType::Average:
-        for (size_t i = 0; i < scanline_data.size(); ++i) {
-            u32 left = (i < bytes_per_complete_pixel) ? 0 : scanline_data[i - bytes_per_complete_pixel];
-            u32 above = previous_scanlines_data[i];
-            u8 average = (left + above) / 2;
-            scanline_data[i] += average;
-        }
-        break;
-    case PNG::FilterType::Paeth:
-        for (size_t i = 0; i < scanline_data.size(); ++i) {
-            u8 left = (i < bytes_per_complete_pixel) ? 0 : scanline_data[i - bytes_per_complete_pixel];
-            u8 above = previous_scanlines_data[i];
-            u8 upper_left = (i < bytes_per_complete_pixel) ? 0 : previous_scanlines_data[i - bytes_per_complete_pixel];
-            scanline_data[i] += PNG::paeth_predictor(left, above, upper_left);
-        }
-        break;
-    }
+    auto decoder = adopt_own(*new PNGImageDecoderPlugin(bytes));
+    if (!TRY(decoder->initialize()))
+        return Error::from_string_literal("PNG load error");
+
+    return decoder;
 }
 
-template<typename T>
-ALWAYS_INLINE static void unpack_grayscale_without_alpha(PNGLoadingContext& context)
+PNGImageDecoderPlugin::PNGImageDecoderPlugin(ReadonlyBytes data)
+    : m_context(adopt_own(*new PNGLoadingContext))
 {
-    for (int y = 0; y < context.height; ++y) {
-        auto* gray_values = reinterpret_cast<T const*>(context.scanlines[y].data.data());
-        for (int i = 0; i < context.width; ++i) {
-            auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
-            pixel.r = gray_values[i];
-            pixel.g = gray_values[i];
-            pixel.b = gray_values[i];
-            pixel.a = 0xff;
-        }
-    }
-}
-
-template<typename T>
-ALWAYS_INLINE static void unpack_grayscale_with_alpha(PNGLoadingContext& context)
-{
-    for (int y = 0; y < context.height; ++y) {
-        auto* tuples = reinterpret_cast<Tuple<T> const*>(context.scanlines[y].data.data());
-        for (int i = 0; i < context.width; ++i) {
-            auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
-            pixel.r = tuples[i].gray;
-            pixel.g = tuples[i].gray;
-            pixel.b = tuples[i].gray;
-            pixel.a = tuples[i].a;
-        }
-    }
-}
-
-template<typename T>
-ALWAYS_INLINE static void unpack_triplets_without_alpha(PNGLoadingContext& context)
-{
-    for (int y = 0; y < context.height; ++y) {
-        auto* triplets = reinterpret_cast<Triplet<T> const*>(context.scanlines[y].data.data());
-        for (int i = 0; i < context.width; ++i) {
-            auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
-            pixel.r = triplets[i].r;
-            pixel.g = triplets[i].g;
-            pixel.b = triplets[i].b;
-            pixel.a = 0xff;
-        }
-    }
-}
-
-template<typename T>
-ALWAYS_INLINE static void unpack_triplets_with_transparency_value(PNGLoadingContext& context, Triplet<T> transparency_value)
-{
-    for (int y = 0; y < context.height; ++y) {
-        auto* triplets = reinterpret_cast<Triplet<T> const*>(context.scanlines[y].data.data());
-        for (int i = 0; i < context.width; ++i) {
-            auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
-            pixel.r = triplets[i].r;
-            pixel.g = triplets[i].g;
-            pixel.b = triplets[i].b;
-            if (triplets[i] == transparency_value)
-                pixel.a = 0x00;
-            else
-                pixel.a = 0xff;
-        }
-    }
-}
-
-NEVER_INLINE FLATTEN static ErrorOr<void> unfilter(PNGLoadingContext& context)
-{
-    // First unfilter the scanlines:
-
-    // FIXME: Instead of creating a separate buffer for the scanlines that need to be
-    //        mutated, the mutation could be done in place (if the data was non-const).
-    size_t bytes_per_scanline = context.scanlines[0].data.size();
-    size_t bytes_needed_for_all_unfiltered_scanlines = 0;
-    for (int y = 0; y < context.height; ++y) {
-        if (context.scanlines[y].filter != PNG::FilterType::None) {
-            bytes_needed_for_all_unfiltered_scanlines += bytes_per_scanline;
-        }
-    }
-    context.unfiltered_data = TRY(ByteBuffer::create_uninitialized(bytes_needed_for_all_unfiltered_scanlines));
-
-    // From section 6.3 of http://www.libpng.org/pub/png/spec/1.2/PNG-Filters.html
-    // "bpp is defined as the number of bytes per complete pixel, rounding up to one.
-    // For example, for color type 2 with a bit depth of 16, bpp is equal to 6
-    // (three samples, two bytes per sample); for color type 0 with a bit depth of 2,
-    // bpp is equal to 1 (rounding up); for color type 4 with a bit depth of 16, bpp
-    // is equal to 4 (two-byte grayscale sample, plus two-byte alpha sample)."
-    u8 bytes_per_complete_pixel = ceil_div(context.bit_depth, (u8)8) * context.channels;
-
-    u8 dummy_scanline_bytes[bytes_per_scanline];
-    memset(dummy_scanline_bytes, 0, sizeof(dummy_scanline_bytes));
-    auto previous_scanlines_data = ReadonlyBytes { dummy_scanline_bytes, sizeof(dummy_scanline_bytes) };
-
-    for (int y = 0, data_start = 0; y < context.height; ++y) {
-        if (context.scanlines[y].filter != PNG::FilterType::None) {
-            auto scanline_data_slice = context.unfiltered_data.bytes().slice(data_start, bytes_per_scanline);
-
-            // Copy the current values over and set the scanline's data to the to-be-mutated slice
-            context.scanlines[y].data.copy_to(scanline_data_slice);
-            context.scanlines[y].data = scanline_data_slice;
-
-            PNGImageDecoderPlugin::unfilter_scanline(context.scanlines[y].filter, scanline_data_slice, previous_scanlines_data, bytes_per_complete_pixel);
-
-            data_start += bytes_per_scanline;
-        }
-        previous_scanlines_data = context.scanlines[y].data;
-    }
-
-    // Now unpack the scanlines to RGBA:
-    switch (context.color_type) {
-    case PNG::ColorType::Greyscale:
-        if (context.bit_depth == 8) {
-            unpack_grayscale_without_alpha<u8>(context);
-        } else if (context.bit_depth == 16) {
-            unpack_grayscale_without_alpha<u16>(context);
-        } else if (context.bit_depth == 1 || context.bit_depth == 2 || context.bit_depth == 4) {
-            auto bit_depth_squared = context.bit_depth * context.bit_depth;
-            auto pixels_per_byte = 8 / context.bit_depth;
-            auto mask = (1 << context.bit_depth) - 1;
-            for (int y = 0; y < context.height; ++y) {
-                auto* gray_values = context.scanlines[y].data.data();
-                for (int x = 0; x < context.width; ++x) {
-                    auto bit_offset = (8 - context.bit_depth) - (context.bit_depth * (x % pixels_per_byte));
-                    auto value = (gray_values[x / pixels_per_byte] >> bit_offset) & mask;
-                    auto& pixel = (Pixel&)context.bitmap->scanline(y)[x];
-                    pixel.r = value * (0xff / bit_depth_squared);
-                    pixel.g = value * (0xff / bit_depth_squared);
-                    pixel.b = value * (0xff / bit_depth_squared);
-                    pixel.a = 0xff;
-                }
-            }
-        } else {
-            VERIFY_NOT_REACHED();
-        }
-        break;
-    case PNG::ColorType::GreyscaleWithAlpha:
-        if (context.bit_depth == 8) {
-            unpack_grayscale_with_alpha<u8>(context);
-        } else if (context.bit_depth == 16) {
-            unpack_grayscale_with_alpha<u16>(context);
-        } else {
-            VERIFY_NOT_REACHED();
-        }
-        break;
-    case PNG::ColorType::Truecolor:
-        if (context.palette_transparency_data.size() == 6) {
-            if (context.bit_depth == 8) {
-                unpack_triplets_with_transparency_value<u8>(context, Triplet<u8> { context.palette_transparency_data[0], context.palette_transparency_data[2], context.palette_transparency_data[4] });
-            } else if (context.bit_depth == 16) {
-                u16 tr = context.palette_transparency_data[0] | context.palette_transparency_data[1] << 8;
-                u16 tg = context.palette_transparency_data[2] | context.palette_transparency_data[3] << 8;
-                u16 tb = context.palette_transparency_data[4] | context.palette_transparency_data[5] << 8;
-                unpack_triplets_with_transparency_value<u16>(context, Triplet<u16> { tr, tg, tb });
-            } else {
-                VERIFY_NOT_REACHED();
-            }
-        } else {
-            if (context.bit_depth == 8)
-                unpack_triplets_without_alpha<u8>(context);
-            else if (context.bit_depth == 16)
-                unpack_triplets_without_alpha<u16>(context);
-            else
-                VERIFY_NOT_REACHED();
-        }
-        break;
-    case PNG::ColorType::TruecolorWithAlpha:
-        if (context.bit_depth == 8) {
-            for (int y = 0; y < context.height; ++y) {
-                memcpy(context.bitmap->scanline(y), context.scanlines[y].data.data(), context.scanlines[y].data.size());
-            }
-        } else if (context.bit_depth == 16) {
-            for (int y = 0; y < context.height; ++y) {
-                auto* quartets = reinterpret_cast<Quartet<u16> const*>(context.scanlines[y].data.data());
-                for (int i = 0; i < context.width; ++i) {
-                    auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
-                    pixel.r = quartets[i].r & 0xFF;
-                    pixel.g = quartets[i].g & 0xFF;
-                    pixel.b = quartets[i].b & 0xFF;
-                    pixel.a = quartets[i].a & 0xFF;
-                }
-            }
-        } else {
-            VERIFY_NOT_REACHED();
-        }
-        break;
-    case PNG::ColorType::IndexedColor:
-        if (context.bit_depth == 8) {
-            for (int y = 0; y < context.height; ++y) {
-                auto* palette_index = context.scanlines[y].data.data();
-                for (int i = 0; i < context.width; ++i) {
-                    auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
-                    if (palette_index[i] >= context.palette_data.size())
-                        return Error::from_string_literal("PNGImageDecoderPlugin: Palette index out of range");
-                    auto& color = context.palette_data.at((int)palette_index[i]);
-                    auto transparency = context.palette_transparency_data.size() >= palette_index[i] + 1u
-                        ? context.palette_transparency_data[palette_index[i]]
-                        : 0xff;
-                    pixel.r = color.r;
-                    pixel.g = color.g;
-                    pixel.b = color.b;
-                    pixel.a = transparency;
-                }
-            }
-        } else if (context.bit_depth == 1 || context.bit_depth == 2 || context.bit_depth == 4) {
-            auto pixels_per_byte = 8 / context.bit_depth;
-            auto mask = (1 << context.bit_depth) - 1;
-            for (int y = 0; y < context.height; ++y) {
-                auto* palette_indices = context.scanlines[y].data.data();
-                for (int i = 0; i < context.width; ++i) {
-                    auto bit_offset = (8 - context.bit_depth) - (context.bit_depth * (i % pixels_per_byte));
-                    auto palette_index = (palette_indices[i / pixels_per_byte] >> bit_offset) & mask;
-                    auto& pixel = (Pixel&)context.bitmap->scanline(y)[i];
-                    if ((size_t)palette_index >= context.palette_data.size())
-                        return Error::from_string_literal("PNGImageDecoderPlugin: Palette index out of range");
-                    auto& color = context.palette_data.at(palette_index);
-                    auto transparency = context.palette_transparency_data.size() >= palette_index + 1u
-                        ? context.palette_transparency_data[palette_index]
-                        : 0xff;
-                    pixel.r = color.r;
-                    pixel.g = color.g;
-                    pixel.b = color.b;
-                    pixel.a = transparency;
-                }
-            }
-        } else {
-            VERIFY_NOT_REACHED();
-        }
-        break;
-    default:
-        VERIFY_NOT_REACHED();
-        break;
-    }
-
-    // Swap r and b values:
-    for (int y = 0; y < context.height; ++y) {
-        auto* pixels = (Pixel*)context.bitmap->scanline(y);
-        for (int i = 0; i < context.bitmap->width(); ++i) {
-            auto& x = pixels[i];
-            swap(x.r, x.b);
-        }
-    }
-
-    return {};
-}
-
-static bool decode_png_header(PNGLoadingContext& context)
-{
-    if (!context.data || context.data_size < sizeof(PNG::header)) {
-        dbgln_if(PNG_DEBUG, "Missing PNG header");
-        context.state = PNGLoadingContext::State::Error;
-        return false;
-    }
-
-    if (memcmp(context.data, PNG::header.span().data(), sizeof(PNG::header)) != 0) {
-        dbgln_if(PNG_DEBUG, "Invalid PNG header");
-        context.state = PNGLoadingContext::State::Error;
-        return false;
-    }
-
-    context.data_current_ptr = context.data + sizeof(PNG::header);
-    return true;
-}
-
-static ErrorOr<void> decode_png_ihdr(PNGLoadingContext& context)
-{
-    size_t data_remaining = context.data_size - (context.data_current_ptr - context.data);
-
-    Streamer streamer(context.data_current_ptr, data_remaining);
-
-    // https://www.w3.org/TR/png/#11IHDR
-    // The IHDR chunk shall be the first chunk in the PNG datastream.
-    TRY(process_chunk(streamer, context));
-
-    context.data_current_ptr = streamer.current_data_ptr();
-
-    VERIFY(context.state == PNGLoadingContext::State::IHDRDecoded);
-    return {};
-}
-
-static bool decode_png_image_data_chunk(PNGLoadingContext& context)
-{
-    VERIFY(context.state >= PNGLoadingContext::IHDRDecoded);
-
-    if (context.state >= PNGLoadingContext::ImageDataChunkDecoded)
-        return true;
-
-    size_t data_remaining = context.data_size - (context.data_current_ptr - context.data);
-
-    Streamer streamer(context.data_current_ptr, data_remaining);
-    while (!streamer.at_end() && !context.has_seen_iend) {
-        if (auto result = process_chunk(streamer, context); result.is_error()) {
-            context.state = PNGLoadingContext::State::Error;
-            return false;
-        }
-
-        context.data_current_ptr = streamer.current_data_ptr();
-
-        if (context.state >= PNGLoadingContext::State::ImageDataChunkDecoded)
-            return true;
-    }
-
-    return false;
-}
-
-static bool decode_png_animation_data_chunks(PNGLoadingContext& context, u32 requested_animation_frame_index)
-{
-    if (context.state >= PNGLoadingContext::ImageDataChunkDecoded) {
-        if (context.last_completed_animation_frame_index.has_value()) {
-            if (requested_animation_frame_index <= context.last_completed_animation_frame_index.value())
-                return true;
-        }
-    } else if (!decode_png_image_data_chunk(context)) {
-        return false;
-    }
-
-    size_t data_remaining = context.data_size - (context.data_current_ptr - context.data);
-
-    Streamer streamer(context.data_current_ptr, data_remaining);
-    while (!streamer.at_end() && !context.has_seen_iend) {
-        if (auto result = process_chunk(streamer, context); result.is_error()) {
-            context.state = PNGLoadingContext::State::Error;
-            return false;
-        }
-
-        context.data_current_ptr = streamer.current_data_ptr();
-
-        if (context.last_completed_animation_frame_index.has_value()) {
-            if (requested_animation_frame_index <= context.last_completed_animation_frame_index.value())
-                break;
-        }
-    }
-
-    if (!context.last_completed_animation_frame_index.has_value())
-        return false;
-    return requested_animation_frame_index <= context.last_completed_animation_frame_index.value();
-}
-
-static bool decode_png_chunks(PNGLoadingContext& context)
-{
-    VERIFY(context.state >= PNGLoadingContext::IHDRDecoded);
-
-    if (context.state >= PNGLoadingContext::State::ChunksDecoded)
-        return true;
-
-    size_t data_remaining = context.data_size - (context.data_current_ptr - context.data);
-
-    context.compressed_data.ensure_capacity(context.data_size);
-
-    Streamer streamer(context.data_current_ptr, data_remaining);
-    while (!streamer.at_end() && !context.has_seen_iend) {
-        if (auto result = process_chunk(streamer, context); result.is_error()) {
-            // Ignore failed chunk and just consider chunk decoding being done.
-            // decode_png_bitmap() will check whether we got all required ones anyway.
-            break;
-        }
-
-        context.data_current_ptr = streamer.current_data_ptr();
-    }
-
-    context.state = PNGLoadingContext::State::ChunksDecoded;
-    return true;
-}
-
-static ErrorOr<void> decode_png_bitmap_simple(PNGLoadingContext& context, ByteBuffer& decompression_buffer)
-{
-    Streamer streamer(decompression_buffer.data(), decompression_buffer.size());
-
-    for (int y = 0; y < context.height; ++y) {
-        u8 filter_byte;
-        if (!streamer.read(filter_byte)) {
-            context.state = PNGLoadingContext::State::Error;
-            return Error::from_string_literal("PNGImageDecoderPlugin: Decoding failed");
-        }
-
-        if (filter_byte > 4) {
-            context.state = PNGLoadingContext::State::Error;
-            return Error::from_string_literal("PNGImageDecoderPlugin: Invalid PNG filter");
-        }
-
-        context.scanlines.append({ MUST(PNG::filter_type(filter_byte)) });
-        auto& scanline_buffer = context.scanlines.last().data;
-        auto row_size = context.compute_row_size_for_width(context.width);
-        if (row_size.has_overflow())
-            return Error::from_string_literal("PNGImageDecoderPlugin: Row size overflow");
-
-        if (!streamer.wrap_bytes(scanline_buffer, row_size.value())) {
-            context.state = PNGLoadingContext::State::Error;
-            return Error::from_string_literal("PNGImageDecoderPlugin: Decoding failed");
-        }
-    }
-
-    context.bitmap = TRY(Bitmap::create(context.has_alpha() ? BitmapFormat::BGRA8888 : BitmapFormat::BGRx8888, { context.width, context.height }));
-    return unfilter(context);
-}
-
-static int adam7_height(PNGLoadingContext& context, int pass)
-{
-    switch (pass) {
-    case 1:
-        return (context.height + 7) / 8;
-    case 2:
-        return (context.height + 7) / 8;
-    case 3:
-        return (context.height + 3) / 8;
-    case 4:
-        return (context.height + 3) / 4;
-    case 5:
-        return (context.height + 1) / 4;
-    case 6:
-        return (context.height + 1) / 2;
-    case 7:
-        return context.height / 2;
-    default:
-        VERIFY_NOT_REACHED();
-    }
-}
-
-static int adam7_width(PNGLoadingContext& context, int pass)
-{
-    switch (pass) {
-    case 1:
-        return (context.width + 7) / 8;
-    case 2:
-        return (context.width + 3) / 8;
-    case 3:
-        return (context.width + 3) / 4;
-    case 4:
-        return (context.width + 1) / 4;
-    case 5:
-        return (context.width + 1) / 2;
-    case 6:
-        return context.width / 2;
-    case 7:
-        return context.width;
-    default:
-        VERIFY_NOT_REACHED();
-    }
-}
-
-// Index 0 unused (non-interlaced case)
-static int adam7_starty[8] = { 0, 0, 0, 4, 0, 2, 0, 1 };
-static int adam7_startx[8] = { 0, 0, 4, 0, 2, 0, 1, 0 };
-static int adam7_stepy[8] = { 1, 8, 8, 8, 4, 4, 2, 2 };
-static int adam7_stepx[8] = { 1, 8, 8, 4, 4, 2, 2, 1 };
-
-static ErrorOr<void> decode_adam7_pass(PNGLoadingContext& context, Streamer& streamer, int pass)
-{
-    auto subimage_context = context.create_subimage_context(adam7_width(context, pass), adam7_height(context, pass));
-
-    // For small images, some passes might be empty
-    if (!subimage_context.width || !subimage_context.height)
-        return {};
-
-    for (int y = 0; y < subimage_context.height; ++y) {
-        u8 filter_byte;
-        if (!streamer.read(filter_byte)) {
-            context.state = PNGLoadingContext::State::Error;
-            return Error::from_string_literal("PNGImageDecoderPlugin: Decoding failed");
-        }
-
-        if (filter_byte > 4) {
-            context.state = PNGLoadingContext::State::Error;
-            return Error::from_string_literal("PNGImageDecoderPlugin: Invalid PNG filter");
-        }
-
-        subimage_context.scanlines.append({ MUST(PNG::filter_type(filter_byte)) });
-        auto& scanline_buffer = subimage_context.scanlines.last().data;
-
-        auto row_size = context.compute_row_size_for_width(subimage_context.width);
-        if (row_size.has_overflow())
-            return Error::from_string_literal("PNGImageDecoderPlugin: Row size overflow");
-        if (!streamer.wrap_bytes(scanline_buffer, row_size.value())) {
-            context.state = PNGLoadingContext::State::Error;
-            return Error::from_string_literal("PNGImageDecoderPlugin: Decoding failed");
-        }
-    }
-
-    subimage_context.bitmap = TRY(Bitmap::create(context.bitmap->format(), { subimage_context.width, subimage_context.height }));
-    TRY(unfilter(subimage_context));
-
-    // Copy the subimage data into the main image according to the pass pattern
-    for (int y = 0, dy = adam7_starty[pass]; y < subimage_context.height && dy < context.height; ++y, dy += adam7_stepy[pass]) {
-        for (int x = 0, dx = adam7_startx[pass]; x < subimage_context.width && dx < context.width; ++x, dx += adam7_stepx[pass]) {
-            context.bitmap->set_pixel(dx, dy, subimage_context.bitmap->get_pixel(x, y));
-        }
-    }
-    return {};
-}
-
-static ErrorOr<void> decode_png_adam7(PNGLoadingContext& context, ByteBuffer& decompression_buffer)
-{
-    Streamer streamer(decompression_buffer.data(), decompression_buffer.size());
-    context.bitmap = TRY(Bitmap::create(context.has_alpha() ? BitmapFormat::BGRA8888 : BitmapFormat::BGRx8888, { context.width, context.height }));
-    for (int pass = 1; pass <= 7; ++pass)
-        TRY(decode_adam7_pass(context, streamer, pass));
-    return {};
-}
-
-static ErrorOr<void> decode_png_bitmap(PNGLoadingContext& context)
-{
-    if (context.state < PNGLoadingContext::State::ChunksDecoded) {
-        if (!decode_png_chunks(context))
-            return Error::from_string_literal("PNGImageDecoderPlugin: Decoding failed");
-    }
-
-    if (context.state >= PNGLoadingContext::State::BitmapDecoded)
-        return {};
-
-    if (context.color_type == PNG::ColorType::IndexedColor && context.palette_data.is_empty())
-        return Error::from_string_literal("PNGImageDecoderPlugin: Didn't see a PLTE chunk for a palletized image, or it was empty.");
-
-    auto compressed_data_stream = make<FixedMemoryStream>(context.compressed_data.span());
-    auto decompressor_or_error = Compress::ZlibDecompressor::create(move(compressed_data_stream));
-    if (decompressor_or_error.is_error()) {
-        context.state = PNGLoadingContext::State::Error;
-        return decompressor_or_error.release_error();
-    }
-    auto decompressor = decompressor_or_error.release_value();
-    auto result_or_error = decompressor->read_until_eof();
-    if (result_or_error.is_error()) {
-        context.state = PNGLoadingContext::State::Error;
-        return result_or_error.release_error();
-    }
-    auto decompression_buffer = result_or_error.release_value();
-    context.compressed_data.clear();
-
-    context.scanlines.ensure_capacity(context.height);
-    switch (context.interlace_method) {
-    case PngInterlaceMethod::Null:
-        TRY(decode_png_bitmap_simple(context, decompression_buffer));
-        break;
-    case PngInterlaceMethod::Adam7:
-        TRY(decode_png_adam7(context, decompression_buffer));
-        break;
-    default:
-        context.state = PNGLoadingContext::State::Error;
-        return Error::from_string_literal("PNGImageDecoderPlugin: Invalid interlace method");
-    }
-
-    context.state = PNGLoadingContext::State::BitmapDecoded;
-    return {};
-}
-
-static ErrorOr<RefPtr<Bitmap>> decode_png_animation_frame_bitmap(PNGLoadingContext& context, AnimationFrame& animation_frame)
-{
-    if (context.color_type == PNG::ColorType::IndexedColor && context.palette_data.is_empty())
-        return Error::from_string_literal("PNGImageDecoderPlugin: Didn't see a PLTE chunk for a palletized image, or it was empty.");
-
-    VERIFY(!animation_frame.bitmap);
-
-    auto frame_rect = animation_frame.rect();
-    auto frame_context = context.create_subimage_context(frame_rect.width(), frame_rect.height());
-
-    auto compressed_data_stream = make<FixedMemoryStream>(animation_frame.compressed_data.span());
-    auto decompressor = TRY(Compress::ZlibDecompressor::create(move(compressed_data_stream)));
-    auto decompression_buffer = TRY(decompressor->read_until_eof());
-    frame_context.compressed_data.clear();
-
-    frame_context.scanlines.ensure_capacity(frame_context.height);
-    switch (context.interlace_method) {
-    case PngInterlaceMethod::Null:
-        TRY(decode_png_bitmap_simple(frame_context, decompression_buffer));
-        break;
-    case PngInterlaceMethod::Adam7:
-        TRY(decode_png_adam7(frame_context, decompression_buffer));
-        break;
-    default:
-        return Error::from_string_literal("PNGImageDecoderPlugin: Invalid interlace method");
-    }
-
-    context.state = PNGLoadingContext::State::BitmapDecoded;
-    return move(frame_context.bitmap);
-}
-
-static bool is_valid_compression_method(u8 compression_method)
-{
-    return compression_method == 0;
-}
-
-static bool is_valid_filter_method(u8 filter_method)
-{
-    return filter_method == 0;
-}
-
-static ErrorOr<void> process_IHDR(ReadonlyBytes data, PNGLoadingContext& context)
-{
-    if (data.size() < (int)sizeof(PNG_IHDR))
-        return Error::from_string_literal("IHDR chunk has an abnormal size");
-
-    auto const& ihdr = *(const PNG_IHDR*)data.data();
-
-    if (ihdr.width == 0 || ihdr.width > NumericLimits<i32>::max()) {
-        dbgln("PNG has invalid width {}", ihdr.width);
-        return Error::from_string_literal("Invalid width");
-    }
-
-    if (ihdr.height == 0 || ihdr.height > NumericLimits<i32>::max()) {
-        dbgln("PNG has invalid height {}", ihdr.height);
-        return Error::from_string_literal("Invalid height");
-    }
-
-    if (!is_valid_compression_method(ihdr.compression_method)) {
-        dbgln("PNG has invalid compression method {}", ihdr.compression_method);
-        return Error::from_string_literal("Unsupported compression method");
-    }
-
-    if (!is_valid_filter_method(ihdr.filter_method)) {
-        dbgln("PNG has invalid filter method {}", ihdr.filter_method);
-        return Error::from_string_literal("Unsupported filter method");
-    }
-
-    context.width = ihdr.width;
-    context.height = ihdr.height;
-    context.bit_depth = ihdr.bit_depth;
-    context.color_type = ihdr.color_type;
-    context.compression_method = ihdr.compression_method;
-    context.filter_method = ihdr.filter_method;
-    context.interlace_method = ihdr.interlace_method;
-
-    dbgln_if(PNG_DEBUG, "PNG: {}x{} ({} bpp)", context.width, context.height, context.bit_depth);
-    dbgln_if(PNG_DEBUG, "     Color type: {}", to_underlying(context.color_type));
-    dbgln_if(PNG_DEBUG, "Compress Method: {}", context.compression_method);
-    dbgln_if(PNG_DEBUG, "  Filter Method: {}", context.filter_method);
-    dbgln_if(PNG_DEBUG, " Interlace type: {}", context.interlace_method);
-
-    if (context.interlace_method != PngInterlaceMethod::Null && context.interlace_method != PngInterlaceMethod::Adam7) {
-        dbgln_if(PNG_DEBUG, "PNGLoader::process_IHDR: unknown interlace method: {}", context.interlace_method);
-        return Error::from_string_literal("Unsupported interlacing method");
-    }
-
-    switch (context.color_type) {
-    case PNG::ColorType::Greyscale:
-        if (context.bit_depth != 1 && context.bit_depth != 2 && context.bit_depth != 4 && context.bit_depth != 8 && context.bit_depth != 16)
-            return Error::from_string_literal("Unsupported bit depth for a greyscale image");
-        context.channels = 1;
-        break;
-    case PNG::ColorType::GreyscaleWithAlpha:
-        if (context.bit_depth != 8 && context.bit_depth != 16)
-            return Error::from_string_literal("Unsupported bit depth for a greyscale image with alpha");
-        context.channels = 2;
-        break;
-    case PNG::ColorType::Truecolor:
-        if (context.bit_depth != 8 && context.bit_depth != 16)
-            return Error::from_string_literal("Unsupported bit depth for a true color image");
-        context.channels = 3;
-        break;
-    case PNG::ColorType::IndexedColor:
-        if (context.bit_depth != 1 && context.bit_depth != 2 && context.bit_depth != 4 && context.bit_depth != 8)
-            return Error::from_string_literal("Unsupported bit depth for a indexed color image");
-        context.channels = 1;
-        break;
-    case PNG::ColorType::TruecolorWithAlpha:
-        if (context.bit_depth != 8 && context.bit_depth != 16)
-            return Error::from_string_literal("Unsupported bit depth for a true color image with alpha");
-        context.channels = 4;
-        break;
-    default:
-        return Error::from_string_literal("Unsupported color type");
-    }
-
-    context.state = PNGLoadingContext::IHDRDecoded;
-
-    return {};
-}
-
-static ErrorOr<void> process_IDAT(ReadonlyBytes data, PNGLoadingContext& context)
-{
-    context.compressed_data.append(data);
-    if (context.state < PNGLoadingContext::State::ImageDataChunkDecoded)
-        context.state = PNGLoadingContext::State::ImageDataChunkDecoded;
-    return {};
-}
-
-static ErrorOr<void> process_PLTE(ReadonlyBytes data, PNGLoadingContext& context)
-{
-    TRY(context.palette_data.try_append((PaletteEntry const*)data.data(), data.size() / 3));
-    return {};
-}
-
-static ErrorOr<void> process_tRNS(ReadonlyBytes data, PNGLoadingContext& context)
-{
-    switch (context.color_type) {
-    case PNG::ColorType::Greyscale:
-    case PNG::ColorType::Truecolor:
-    case PNG::ColorType::IndexedColor:
-        TRY(context.palette_transparency_data.try_append(data));
-        break;
-    default:
-        break;
-    }
-    return {};
-}
-
-static ErrorOr<void> process_cHRM(ReadonlyBytes data, PNGLoadingContext& context)
-{
-    // https://www.w3.org/TR/png/#11cHRM
-    if (data.size() != 32)
-        return Error::from_string_literal("cHRM chunk has an abnormal size");
-    context.chromaticities_and_whitepoint = *bit_cast<ChromaticitiesAndWhitepoint* const>(data.data());
-    return {};
-}
-
-static ErrorOr<void> process_cICP(ReadonlyBytes data, PNGLoadingContext& context)
-{
-    // https://www.w3.org/TR/png/#cICP-chunk
-    if (data.size() != 4)
-        return Error::from_string_literal("cICP chunk has an abnormal size");
-    context.coding_independent_code_points = *bit_cast<CodingIndependentCodePoints* const>(data.data());
-    return {};
-}
-
-static ErrorOr<void> process_iCCP(ReadonlyBytes data, PNGLoadingContext& context)
-{
-    // https://www.w3.org/TR/png/#11iCCP
-    size_t profile_name_length_max = min(80u, data.size());
-    size_t profile_name_length = strnlen((char const*)data.data(), profile_name_length_max);
-    if (profile_name_length == 0 || profile_name_length == profile_name_length_max)
-        return Error::from_string_literal("iCCP chunk does not contain a profile name");
-
-    if (data.size() < profile_name_length + 2)
-        return Error::from_string_literal("iCCP chunk is too small");
-
-    u8 compression_method = data[profile_name_length + 1];
-    if (compression_method != 0)
-        return Error::from_string_literal("Unsupported compression method in the iCCP chunk");
-
-    context.embedded_icc_profile = EmbeddedICCProfile { { data.data(), profile_name_length }, data.slice(profile_name_length + 2) };
-
-    return {};
-}
-
-static ErrorOr<void> process_gAMA(ReadonlyBytes data, PNGLoadingContext& context)
-{
-    // https://www.w3.org/TR/png/#11gAMA
-    if (data.size() != 4)
-        return Error::from_string_literal("gAMA chunk has an abnormal size");
-
-    u32 gamma = *bit_cast<NetworkOrdered<u32> const*>(data.data());
-    if (gamma & 0x8000'0000)
-        return Error::from_string_literal("Gamma value is too high");
-    context.gamma = gamma;
-
-    return {};
-}
-
-static ErrorOr<void> process_sRGB(ReadonlyBytes data, PNGLoadingContext& context)
-{
-    // https://www.w3.org/TR/png/#srgb-standard-colour-space
-    if (data.size() != 1) {
-        // Invalid per spec, but (rarely) happens in the wild. Log and ignore.
-        warnln("warning: PNG sRGB chunk has an abnormal size; ignoring");
-        return {};
-    }
-
-    u8 rendering_intent = data[0];
-    if (rendering_intent > 3)
-        return Error::from_string_literal("Unsupported rendering intent");
-
-    context.sRGB_rendering_intent = (RenderingIntent)rendering_intent;
-
-    return {};
-}
-
-static ErrorOr<void> process_acTL(ReadonlyBytes data, PNGLoadingContext& context)
-{
-    // https://www.w3.org/TR/png/#acTL-chunk
-    if (context.has_seen_idat_chunk)
-        return {}; // Ignore if we encounter it after the first idat
-    if (data.size() != sizeof(acTL_Chunk))
-        return Error::from_string_literal("acTL chunk has an abnormal size");
-
-    auto const& acTL = *bit_cast<acTL_Chunk* const>(data.data());
-    context.animation_frame_count = acTL.num_frames;
-    context.animation_loop_count = acTL.num_plays;
-    context.has_seen_actl_chunk_before_idat = true;
-    TRY(context.animation_frames.try_ensure_capacity(context.animation_frame_count));
-    return {};
-}
-
-static ErrorOr<void> process_fcTL(ReadonlyBytes data, PNGLoadingContext& context)
-{
-    // https://www.w3.org/TR/png/#fcTL-chunk
-    if (!context.has_seen_actl_chunk_before_idat)
-        return {}; // Ignore if it's not a valid animated png
-
-    if (data.size() != sizeof(fcTL_Chunk))
-        return Error::from_string_literal("fcTL chunk has an abnormal size");
-
-    auto const& fcTL = *bit_cast<fcTL_Chunk* const>(data.data());
-    if (fcTL.sequence_number != context.animation_next_expected_seq)
-        return Error::from_string_literal("Unexpected sequence number");
-
-    context.animation_next_expected_seq++;
-
-    if (fcTL.width == 0 || fcTL.height == 0)
-        return Error::from_string_literal("width and height must be greater than zero in fcTL chunk");
-
-    Checked<int> left { static_cast<int>(fcTL.x_offset) };
-    Checked<int> top { static_cast<int>(fcTL.y_offset) };
-    Checked<int> width { static_cast<int>(fcTL.width) };
-    Checked<int> height { static_cast<int>(fcTL.height) };
-    auto right = left + width;
-    auto bottom = top + height;
-    if (left < 0 || width <= 0 || right.has_overflow() || right > context.width)
-        return Error::from_string_literal("Invalid x_offset value in fcTL chunk");
-    if (top < 0 || height <= 0 || bottom.has_overflow() || bottom > context.height)
-        return Error::from_string_literal("Invalid y_offset value in fcTL chunk");
-
-    bool is_first_animation_frame = context.animation_frames.is_empty();
-    if (!is_first_animation_frame)
-        context.last_completed_animation_frame_index = context.animation_frames.size() - 1;
-
-    context.animation_frames.append({ fcTL });
-
-    if (!context.has_seen_idat_chunk && is_first_animation_frame)
-        context.is_first_idat_part_of_animation = true;
-    return {};
-}
-
-static ErrorOr<void> process_fdAT(ReadonlyBytes data, PNGLoadingContext& context)
-{
-    // https://www.w3.org/TR/png/#fdAT-chunk
-
-    if (data.size() <= 4)
-        return Error::from_string_literal("fdAT chunk has an abnormal size");
-
-    u32 sequence_number = *bit_cast<NetworkOrdered<u32> const*>(data.data());
-    if (sequence_number != context.animation_next_expected_seq)
-        return Error::from_string_literal("Unexpected sequence number");
-    context.animation_next_expected_seq++;
-
-    if (context.animation_frames.is_empty())
-        return Error::from_string_literal("No frame available");
-    auto& current_animation_frame = context.animation_frames[context.animation_frames.size() - 1];
-    auto compressed_data = data.slice(4);
-    current_animation_frame.compressed_data.append(compressed_data.data(), compressed_data.size());
-    return {};
-}
-
-static ErrorOr<void> process_eXIf(ReadonlyBytes bytes, PNGLoadingContext& context)
-{
-    context.exif_metadata = TRY(TIFFImageDecoderPlugin::read_exif_metadata(bytes));
-    return {};
-}
-
-static void process_IEND(ReadonlyBytes, PNGLoadingContext& context)
-{
-    // https://www.w3.org/TR/png/#11IEND
-    if (context.has_seen_actl_chunk_before_idat)
-        context.last_completed_animation_frame_index = context.animation_frames.size();
-
-    context.has_seen_iend = true;
-}
-
-static ErrorOr<void> process_chunk(Streamer& streamer, PNGLoadingContext& context)
-{
-    u32 chunk_size;
-    if (!streamer.read(chunk_size)) {
-        dbgln_if(PNG_DEBUG, "Bail at chunk_size");
-        return Error::from_string_literal("Error while reading from Streamer");
-    }
-
-    Array<u8, 4> chunk_type_buffer;
-    StringView const chunk_type { chunk_type_buffer.span() };
-    if (!streamer.read_bytes(chunk_type_buffer.data(), chunk_type_buffer.size())) {
-        dbgln_if(PNG_DEBUG, "Bail at chunk_type");
-        return Error::from_string_literal("Error while reading from Streamer");
-    }
-    ReadonlyBytes chunk_data;
-    if (!streamer.wrap_bytes(chunk_data, chunk_size)) {
-        dbgln_if(PNG_DEBUG, "Bail at chunk_data");
-        return Error::from_string_literal("Error while reading from Streamer");
-    }
-    u32 chunk_crc;
-    if (!streamer.read(chunk_crc)) {
-        dbgln_if(PNG_DEBUG, "Bail at chunk_crc");
-        return Error::from_string_literal("Error while reading from Streamer");
-    }
-    dbgln_if(PNG_DEBUG, "Chunk type: '{}', size: {}, crc: {:x}", chunk_type, chunk_size, chunk_crc);
-
-    if (chunk_type == "IHDR"sv) {
-        if (context.state >= PNGLoadingContext::IHDRDecoded)
-            return Error::from_string_literal("Multiple IHDR chunks");
-
-        return process_IHDR(chunk_data, context);
-    }
-
-    if (context.state < PNGLoadingContext::IHDRDecoded)
-        return Error::from_string_literal("IHDR is not the first chunk of the file");
-
-    if (chunk_type == "IDAT"sv)
-        return process_IDAT(chunk_data, context);
-    if (chunk_type == "PLTE"sv)
-        return process_PLTE(chunk_data, context);
-    if (chunk_type == "cHRM"sv)
-        return process_cHRM(chunk_data, context);
-    if (chunk_type == "cICP"sv)
-        return process_cICP(chunk_data, context);
-    if (chunk_type == "iCCP"sv)
-        return process_iCCP(chunk_data, context);
-    if (chunk_type == "gAMA"sv)
-        return process_gAMA(chunk_data, context);
-    if (chunk_type == "sRGB"sv)
-        return process_sRGB(chunk_data, context);
-    if (chunk_type == "tRNS"sv)
-        return process_tRNS(chunk_data, context);
-    if (chunk_type == "acTL"sv)
-        return process_acTL(chunk_data, context);
-    if (chunk_type == "fcTL"sv)
-        return process_fcTL(chunk_data, context);
-    if (chunk_type == "fdAT"sv)
-        return process_fdAT(chunk_data, context);
-    if (chunk_type == "eXIf"sv)
-        return process_eXIf(chunk_data, context);
-    if (chunk_type == "IEND"sv)
-        process_IEND(chunk_data, context);
-    return {};
-}
-
-PNGImageDecoderPlugin::PNGImageDecoderPlugin(u8 const* data, size_t size)
-{
-    m_context = make<PNGLoadingContext>();
-    m_context->data = m_context->data_current_ptr = data;
-    m_context->data_size = size;
-}
-
-PNGImageDecoderPlugin::~PNGImageDecoderPlugin() = default;
-
-bool PNGImageDecoderPlugin::ensure_image_data_chunk_was_decoded()
-{
-    if (m_context->state == PNGLoadingContext::State::Error)
-        return false;
-
-    if (m_context->state < PNGLoadingContext::State::ImageDataChunkDecoded) {
-        if (!decode_png_image_data_chunk(*m_context))
-            return false;
-    }
-    return true;
-}
-
-bool PNGImageDecoderPlugin::ensure_animation_frame_was_decoded(u32 animation_frame_index)
-{
-    if (m_context->state == PNGLoadingContext::State::Error)
-        return false;
-
-    if (m_context->state < PNGLoadingContext::State::ImageDataChunkDecoded) {
-        if (!decode_png_image_data_chunk(*m_context))
-            return false;
-    }
-
-    if (m_context->last_completed_animation_frame_index.has_value()) {
-        if (m_context->last_completed_animation_frame_index.value() >= animation_frame_index)
-            return true;
-    }
-
-    return decode_png_animation_data_chunks(*m_context, animation_frame_index);
-}
-
-IntSize PNGImageDecoderPlugin::size()
-{
-    return { m_context->width, m_context->height };
-}
-
-bool PNGImageDecoderPlugin::sniff(ReadonlyBytes data)
-{
-    PNGLoadingContext context;
-    context.data = context.data_current_ptr = data.data();
-    context.data_size = data.size();
-    return decode_png_header(context);
-}
-
-ErrorOr<NonnullOwnPtr<ImageDecoderPlugin>> PNGImageDecoderPlugin::create(ReadonlyBytes data)
-{
-    auto plugin = TRY(adopt_nonnull_own_or_enomem(new (nothrow) PNGImageDecoderPlugin(data.data(), data.size())));
-    if (!decode_png_header(*plugin->m_context))
-        return Error::from_string_literal("Invalid header for a PNG file");
-    TRY(decode_png_ihdr(*plugin->m_context));
-    return plugin;
-}
-
-bool PNGImageDecoderPlugin::is_animated()
-{
-    if (!ensure_image_data_chunk_was_decoded())
-        return false;
-    return m_context->has_seen_actl_chunk_before_idat;
-}
-
-size_t PNGImageDecoderPlugin::loop_count()
-{
-    if (!ensure_image_data_chunk_was_decoded())
-        return 0;
-    return m_context->animation_loop_count;
-}
-
-size_t PNGImageDecoderPlugin::frame_count()
-{
-    if (!ensure_image_data_chunk_was_decoded())
-        return 0;
-
-    if (!m_context->has_seen_actl_chunk_before_idat)
-        return 1;
-
-    auto total_frames = m_context->animation_frame_count;
-    if (!m_context->is_first_idat_part_of_animation)
-        total_frames++;
-    return total_frames;
+    m_context->data = data;
 }
 
 size_t PNGImageDecoderPlugin::first_animated_frame_index()
 {
-    if (!ensure_image_data_chunk_was_decoded())
-        return 0;
-    if (!m_context->has_seen_actl_chunk_before_idat)
-        return 0;
-    return m_context->is_first_idat_part_of_animation ? 0 : 1;
+    return 0;
 }
 
-static ErrorOr<RefPtr<Bitmap>> render_animation_frame(AnimationFrame const& prev_animation_frame, AnimationFrame& animation_frame, Bitmap const& decoded_frame_bitmap)
+IntSize PNGImageDecoderPlugin::size()
+{
+    return m_context->size;
+}
+
+bool PNGImageDecoderPlugin::is_animated()
+{
+    return m_context->frame_count > 1;
+}
+
+size_t PNGImageDecoderPlugin::loop_count()
+{
+    return m_context->loop_count;
+}
+
+size_t PNGImageDecoderPlugin::frame_count()
+{
+    return m_context->frame_count;
+}
+
+ErrorOr<ImageFrameDescriptor> PNGImageDecoderPlugin::frame(size_t index, Optional<IntSize>)
+{
+    if (index >= m_context->frame_descriptors.size())
+        return Error::from_errno(EINVAL);
+
+    return m_context->frame_descriptors[index];
+}
+
+ErrorOr<Optional<ReadonlyBytes>> PNGImageDecoderPlugin::icc_data()
+{
+    if (m_context->icc_profile.has_value())
+        return Optional<ReadonlyBytes>(*m_context->icc_profile);
+    return OptionalNone {};
+}
+
+ErrorOr<bool> PNGImageDecoderPlugin::initialize()
+{
+    png_structp png_ptr = png_create_read_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
+    if (!png_ptr)
+        return false;
+
+    png_infop info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr) {
+        png_destroy_read_struct(&png_ptr, nullptr, nullptr);
+        return false;
+    }
+
+    if (setjmp(png_jmpbuf(png_ptr))) {
+        png_destroy_read_struct(&png_ptr, &info_ptr, nullptr);
+        return false;
+    }
+
+    png_set_read_fn(png_ptr, &m_context->data, [](png_structp png_ptr, png_bytep data, png_size_t length) {
+        auto* read_data = reinterpret_cast<ReadonlyBytes*>(png_get_io_ptr(png_ptr));
+        if (read_data->size() < length) {
+            png_error(png_ptr, "Read error");
+            return;
+        }
+        memcpy(data, read_data->data(), length);
+        *read_data = read_data->slice(length);
+    });
+
+    png_read_info(png_ptr, info_ptr);
+
+    u32 width = 0;
+    u32 height = 0;
+    int bit_depth = 0;
+    int color_type = 0;
+    png_get_IHDR(png_ptr, info_ptr, &width, &height, &bit_depth, &color_type, nullptr, nullptr, nullptr);
+    m_context->size = { static_cast<int>(width), static_cast<int>(height) };
+
+    if (color_type == PNG_COLOR_TYPE_PALETTE)
+        png_set_palette_to_rgb(png_ptr);
+
+    if (color_type == PNG_COLOR_TYPE_GRAY && bit_depth < 8)
+        png_set_expand_gray_1_2_4_to_8(png_ptr);
+
+    if (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS))
+        png_set_tRNS_to_alpha(png_ptr);
+
+    if (bit_depth == 16)
+        png_set_strip_16(png_ptr);
+
+    if (color_type == PNG_COLOR_TYPE_GRAY || color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+        png_set_gray_to_rgb(png_ptr);
+
+    png_set_filler(png_ptr, 0xFF, PNG_FILLER_AFTER);
+    png_set_bgr(png_ptr);
+
+    char* profile_name = nullptr;
+    int compression_type = 0;
+    u8* profile_data = nullptr;
+    u32 profile_len = 0;
+    if (png_get_iCCP(png_ptr, info_ptr, &profile_name, &compression_type, &profile_data, &profile_len)) {
+        m_context->icc_profile = TRY(ByteBuffer::copy(profile_data, profile_len));
+    }
+
+    png_read_update_info(png_ptr, info_ptr);
+    m_context->frame_count = TRY(m_context->read_frames(png_ptr, info_ptr));
+
+    u8* exif_data = nullptr;
+    u32 exif_length = 0;
+    int const num_exif_chunks = png_get_eXIf_1(png_ptr, info_ptr, &exif_length, &exif_data);
+    if (num_exif_chunks > 0) {
+        m_context->exif_metadata = TRY(TIFFImageDecoderPlugin::read_exif_metadata({ exif_data, exif_length }));
+    }
+
+    png_destroy_read_struct(&png_ptr, &info_ptr, nullptr);
+    return true;
+}
+
+static ErrorOr<NonnullRefPtr<Bitmap>> render_animation_frame(AnimationFrame const& prev_animation_frame, AnimationFrame const& animation_frame, Bitmap const& decoded_frame_bitmap)
 {
     auto rendered_bitmap = TRY(prev_animation_frame.bitmap->clone());
     Painter painter(rendered_bitmap);
 
-    static constexpr Color transparent_black = { 0, 0, 0, 0 };
-
     auto frame_rect = animation_frame.rect();
-    switch (prev_animation_frame.fcTL.dispose_op) {
-    case fcTL_Chunk::DisposeOp::APNG_DISPOSE_OP_NONE:
+    switch (prev_animation_frame.dispose_op) {
+    case PNG_DISPOSE_OP_BACKGROUND:
+        painter.clear_rect(rendered_bitmap->rect(), Color::NamedColor::Transparent);
         break;
-    case fcTL_Chunk::DisposeOp::APNG_DISPOSE_OP_BACKGROUND:
-        painter.clear_rect(rendered_bitmap->rect(), transparent_black);
+    case PNG_DISPOSE_OP_PREVIOUS:
+        painter.blit(frame_rect.location(), decoded_frame_bitmap, frame_rect, 1.0f, false);
         break;
-    case fcTL_Chunk::DisposeOp::APNG_DISPOSE_OP_PREVIOUS: {
-        painter.blit(frame_rect.location(), *prev_animation_frame.bitmap, frame_rect, 1.0f, false);
+    default:
         break;
     }
-    }
-    switch (animation_frame.fcTL.blend_op) {
-    case fcTL_Chunk::BlendOp::APNG_BLEND_OP_SOURCE:
+    switch (animation_frame.blend_op) {
+    case PNG_BLEND_OP_SOURCE:
         painter.blit(frame_rect.location(), decoded_frame_bitmap, decoded_frame_bitmap.rect(), 1.0f, false);
         break;
-    case fcTL_Chunk::BlendOp::APNG_BLEND_OP_OVER:
+    case PNG_BLEND_OP_OVER:
         painter.blit(frame_rect.location(), decoded_frame_bitmap, decoded_frame_bitmap.rect(), 1.0f, true);
         break;
+    default:
+        break;
     }
     return rendered_bitmap;
 }
 
-ErrorOr<ImageFrameDescriptor> PNGImageDecoderPlugin::frame(size_t index, Optional<IntSize>)
+ErrorOr<size_t> PNGLoadingContext::read_frames(png_structp png_ptr, png_infop info_ptr)
 {
-    if (m_context->state == PNGLoadingContext::State::Error)
-        return Error::from_string_literal("PNGImageDecoderPlugin: Decoding failed");
+    if (png_get_acTL(png_ptr, info_ptr, &frame_count, &loop_count)) {
+        // acTL chunk present: This is an APNG.
 
-    if (!ensure_image_data_chunk_was_decoded())
-        return Error::from_string_literal("PNGImageDecoderPlugin: Decoding image data chunk");
+        png_set_acTL(png_ptr, info_ptr, frame_count, loop_count);
 
-    auto set_descriptor_duration = [](ImageFrameDescriptor& descriptor, AnimationFrame const& animation_frame) {
-        descriptor.duration = static_cast<int>(animation_frame.duration_ms());
-        if (descriptor.duration < 0)
-            descriptor.duration = NumericLimits<int>::min();
-    };
-    auto load_default_image = [&]() -> ErrorOr<void> {
-        if (m_context->state < PNGLoadingContext::State::BitmapDecoded) {
-            // NOTE: This forces the chunk decoding to happen.
-            TRY(decode_png_bitmap(*m_context));
+        for (size_t frame_index = 0; frame_index < frame_count; ++frame_index) {
+            png_read_frame_head(png_ptr, info_ptr);
+            u32 width = 0;
+            u32 height = 0;
+            u32 x = 0;
+            u32 y = 0;
+            u16 delay_num = 0;
+            u16 delay_den = 0;
+            u8 dispose_op = 0;
+            u8 blend_op = 0;
+
+            if (!png_get_valid(png_ptr, info_ptr, PNG_INFO_fcTL)) {
+                return Error::from_string_literal("Missing fcTL chunk in APNG frame");
+            }
+
+            png_get_next_frame_fcTL(png_ptr, info_ptr, &width, &height, &x, &y, &delay_num, &delay_den, &dispose_op, &blend_op);
+
+            decoded_frame_bitmap = TRY(Bitmap::create(BitmapFormat::BGRA8888, IntSize { static_cast<int>(width), static_cast<int>(height) }));
+
+            row_pointers.resize(height);
+            for (u32 i = 0; i < height; ++i) {
+                row_pointers[i] = decoded_frame_bitmap->scanline_u8(i);
+            }
+
+            png_read_image(png_ptr, row_pointers.data());
+
+            auto animation_frame = AnimationFrame(nullptr, x, y, width, height, delay_den, delay_num, blend_op, dispose_op);
+
+            if (frame_index == 0) {
+                animation_frame.bitmap = decoded_frame_bitmap;
+                frame_descriptors.append({ decoded_frame_bitmap, animation_frame.duration_ms() });
+            } else {
+                animation_frame.bitmap = TRY(render_animation_frame(animation_frames.last(), animation_frame, *decoded_frame_bitmap));
+                frame_descriptors.append({ animation_frame.bitmap, animation_frame.duration_ms() });
+            }
+            animation_frames.append(move(animation_frame));
         }
+    } else {
+        // This is a single-frame PNG.
 
-        VERIFY(m_context->bitmap);
-        return {};
-    };
+        frame_count = 1;
+        loop_count = 0;
 
-    if (index == 0) {
-        TRY(load_default_image());
+        decoded_frame_bitmap = TRY(Bitmap::create(BitmapFormat::BGRA8888, size));
+        row_pointers.resize(size.height());
+        for (int i = 0; i < size.height(); ++i)
+            row_pointers[i] = decoded_frame_bitmap->scanline_u8(i);
 
-        ImageFrameDescriptor descriptor { m_context->bitmap };
-        if (m_context->has_seen_actl_chunk_before_idat && m_context->is_first_idat_part_of_animation)
-            set_descriptor_duration(descriptor, m_context->animation_frames[0]);
-        return descriptor;
+        png_read_image(png_ptr, row_pointers.data());
+        frame_descriptors.append({ move(decoded_frame_bitmap), 0 });
     }
+    return this->frame_count;
+}
 
-    if (!m_context->has_seen_actl_chunk_before_idat)
-        return Error::from_string_literal("PNGImageDecoderPlugin: Invalid frame index");
+PNGImageDecoderPlugin::~PNGImageDecoderPlugin() = default;
 
-    if (!ensure_animation_frame_was_decoded(index))
-        return Error::from_string_literal("PNGImageDecoderPlugin: Decoding image data chunk");
-
-    if (index >= m_context->animation_frames.size())
-        return Error::from_string_literal("PNGImageDecoderPlugin: Invalid animation frame index");
-
-    // We need to assemble each frame up until the one requested,
-    // so decode all bitmaps that haven't been decoded yet.
-    for (size_t i = m_context->animation_next_frame_to_render; i <= index; i++) {
-        if (i == 0) {
-            // If the default image hasn't been loaded, load it now
-            TRY(load_default_image()); // May modify animation_frames!
-
-            auto& animation_frame = m_context->animation_frames[i];
-            animation_frame.bitmap = m_context->bitmap;
-        } else {
-            auto& animation_frame = m_context->animation_frames[i];
-            VERIFY(!animation_frame.bitmap);
-
-            auto decoded_bitmap = TRY(decode_png_animation_frame_bitmap(*m_context, animation_frame));
-
-            auto prev_animation_frame = m_context->animation_frames[i - 1];
-            animation_frame.bitmap = TRY(render_animation_frame(prev_animation_frame, animation_frame, *decoded_bitmap));
-        }
-        m_context->animation_next_frame_to_render = i + 1;
-    }
-
-    auto const& animation_frame = m_context->animation_frames[index];
-    VERIFY(animation_frame.bitmap);
-
-    ImageFrameDescriptor descriptor { animation_frame.bitmap };
-    set_descriptor_duration(descriptor, animation_frame);
-    return descriptor;
+bool PNGImageDecoderPlugin::sniff(ReadonlyBytes data)
+{
+    Array<u8, 8> png_signature { 0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a };
+    if (data.size() < png_signature.size())
+        return false;
+    return data.slice(0, png_signature.size()) == ReadonlyBytes(png_signature.data(), png_signature.size());
 }
 
 Optional<Metadata const&> PNGImageDecoderPlugin::metadata()
@@ -1457,40 +307,4 @@ Optional<Metadata const&> PNGImageDecoderPlugin::metadata()
     return OptionalNone {};
 }
 
-ErrorOr<Optional<ReadonlyBytes>> PNGImageDecoderPlugin::icc_data()
-{
-    if (!decode_png_chunks(*m_context))
-        return Error::from_string_literal("PNGImageDecoderPlugin: Decoding chunks failed");
-
-    if (m_context->embedded_icc_profile.has_value()) {
-        if (!m_context->decompressed_icc_profile.has_value()) {
-            auto compressed_data_stream = make<FixedMemoryStream>(m_context->embedded_icc_profile->compressed_data);
-            auto decompressor_or_error = Compress::ZlibDecompressor::create(move(compressed_data_stream));
-            if (decompressor_or_error.is_error()) {
-                m_context->embedded_icc_profile.clear();
-                return decompressor_or_error.release_error();
-            }
-            auto decompressor = decompressor_or_error.release_value();
-            auto result_or_error = decompressor->read_until_eof();
-            if (result_or_error.is_error()) {
-                m_context->embedded_icc_profile.clear();
-                return result_or_error.release_error();
-            }
-            m_context->decompressed_icc_profile = result_or_error.release_value();
-        }
-
-        return m_context->decompressed_icc_profile.value();
-    }
-
-    // FIXME: Eventually, look at coding_independent_code_points, chromaticities_and_whitepoint, gamma, sRGB_rendering_intent too.
-    // The order is:
-    // 1. Use coding_independent_code_points if it exists, ignore the rest.
-    // 2. Use embedded_icc_profile if it exists, ignore the rest.
-    // 3. Use sRGB_rendering_intent if it exists, ignore the rest.
-    // 4. Use gamma to adjust gamma and chromaticities_and_whitepoint to adjust color.
-    // (Order between 2 and 3 isn't fully clear, but "It is recommended that the sRGB and iCCP chunks do not appear simultaneously in a PNG datastream."
-
-    return OptionalNone {};
-}
-
 }
diff --git a/Userland/Libraries/LibGfx/ImageFormats/PNGLoader.h b/Userland/Libraries/LibGfx/ImageFormats/PNGLoader.h
index b3f0c0d1aae..00caf4dd917 100644
--- a/Userland/Libraries/LibGfx/ImageFormats/PNGLoader.h
+++ b/Userland/Libraries/LibGfx/ImageFormats/PNGLoader.h
@@ -7,7 +7,6 @@
 #pragma once
 
 #include <LibGfx/ImageFormats/ImageDecoder.h>
-#include <LibGfx/ImageFormats/PNGShared.h>
 
 namespace Gfx {
 
@@ -30,12 +29,10 @@ public:
     virtual Optional<Metadata const&> metadata() override;
     virtual ErrorOr<Optional<ReadonlyBytes>> icc_data() override;
 
-    static void unfilter_scanline(PNG::FilterType filter, Bytes scanline_data, ReadonlyBytes previous_scanlines_data, u8 bytes_per_complete_pixel);
-
 private:
-    PNGImageDecoderPlugin(u8 const*, size_t);
-    bool ensure_image_data_chunk_was_decoded();
-    bool ensure_animation_frame_was_decoded(u32);
+    explicit PNGImageDecoderPlugin(ReadonlyBytes);
+
+    ErrorOr<bool> initialize();
 
     OwnPtr<PNGLoadingContext> m_context;
 };
diff --git a/Userland/Libraries/LibGfx/ImageFormats/PNGShared.h b/Userland/Libraries/LibGfx/ImageFormats/PNGShared.h
deleted file mode 100644
index b8cac67c186..00000000000
--- a/Userland/Libraries/LibGfx/ImageFormats/PNGShared.h
+++ /dev/null
@@ -1,67 +0,0 @@
-/*
- * Copyright (c) 2022, the SerenityOS developers.
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
-
-#pragma once
-
-#include <AK/Array.h>
-#include <AK/Error.h>
-#include <AK/SIMD.h>
-
-namespace Gfx::PNG {
-
-// https://www.w3.org/TR/PNG/#5PNG-file-signature
-static constexpr Array<u8, 8> header = { 0x89, 'P', 'N', 'G', 13, 10, 26, 10 };
-
-// https://www.w3.org/TR/PNG/#6Colour-values
-enum class ColorType : u8 {
-    Greyscale = 0,
-    Truecolor = 2, // RGB
-    IndexedColor = 3,
-    GreyscaleWithAlpha = 4,
-    TruecolorWithAlpha = 6,
-};
-
-// https://www.w3.org/TR/PNG/#9Filter-types
-enum class FilterType : u8 {
-    None,
-    Sub,
-    Up,
-    Average,
-    Paeth,
-};
-
-inline ErrorOr<FilterType> filter_type(u8 byte)
-{
-    if (byte <= 4)
-        return static_cast<FilterType>(byte);
-    return Error::from_string_literal("PNGImageDecoderPlugin: Invalid PNG filter");
-}
-
-// https://www.w3.org/TR/PNG/#9Filter-type-4-Paeth
-ALWAYS_INLINE u8 paeth_predictor(u8 a, u8 b, u8 c)
-{
-    int p = a + b - c;
-    int pa = AK::abs(p - a);
-    int pb = AK::abs(p - b);
-    int pc = AK::abs(p - c);
-    if (pa <= pb && pa <= pc)
-        return a;
-    if (pb <= pc)
-        return b;
-    return c;
-}
-
-ALWAYS_INLINE AK::SIMD::u8x4 paeth_predictor(AK::SIMD::u8x4 a, AK::SIMD::u8x4 b, AK::SIMD::u8x4 c)
-{
-    return AK::SIMD::u8x4 {
-        paeth_predictor(a[0], b[0], c[0]),
-        paeth_predictor(a[1], b[1], c[1]),
-        paeth_predictor(a[2], b[2], c[2]),
-        paeth_predictor(a[3], b[3], c[3]),
-    };
-}
-
-};
diff --git a/Userland/Libraries/LibGfx/ImageFormats/PNGWriter.cpp b/Userland/Libraries/LibGfx/ImageFormats/PNGWriter.cpp
index 7128e547080..f768709bef4 100644
--- a/Userland/Libraries/LibGfx/ImageFormats/PNGWriter.cpp
+++ b/Userland/Libraries/LibGfx/ImageFormats/PNGWriter.cpp
@@ -1,284 +1,69 @@
 /*
- * Copyright (c) 2021, Pierre Hoffmeister
- * Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
- * Copyright (c) 2021, Aziz Berkay Yesilyurt <abyesilyurt@gmail.com>
+ * Copyright (c) 2024, Andreas Kling <kling@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
-#include <AK/Concepts.h>
-#include <AK/FixedArray.h>
-#include <AK/SIMDExtras.h>
-#include <AK/String.h>
-#include <LibCompress/Zlib.h>
-#include <LibCrypto/Checksum/CRC32.h>
+#include <AK/NonnullOwnPtr.h>
+#include <AK/Vector.h>
 #include <LibGfx/Bitmap.h>
 #include <LibGfx/ImageFormats/PNGWriter.h>
-
-#pragma GCC diagnostic ignored "-Wpsabi"
+#include <png.h>
 
 namespace Gfx {
 
-class PNGChunk {
-    using data_length_type = u32;
-
-public:
-    explicit PNGChunk(String);
-    auto const& data() const { return m_data; }
-    String const& type() const { return m_type; }
-    ErrorOr<void> reserve(size_t bytes) { return m_data.try_ensure_capacity(bytes); }
-
-    template<typename T>
-    ErrorOr<void> add_as_big_endian(T);
-
-    ErrorOr<void> add_u8(u8);
-
-    ErrorOr<void> compress_and_add(ReadonlyBytes);
-    ErrorOr<void> add(ReadonlyBytes);
-
-    ErrorOr<void> store_type();
-    void store_data_length();
-    u32 crc();
-
-private:
-    ByteBuffer m_data;
-    String m_type;
+struct WriterContext {
+    Vector<u8*> row_pointers;
+    ByteBuffer png_data;
 };
 
-PNGChunk::PNGChunk(String type)
-    : m_type(move(type))
-{
-    VERIFY(m_type.bytes().size() == 4);
-
-    // NOTE: These are MUST() because they should always be able to fit in m_data's inline capacity.
-    MUST(add_as_big_endian<data_length_type>(0));
-    MUST(store_type());
-}
-
-ErrorOr<void> PNGChunk::store_type()
-{
-    TRY(add(type().bytes()));
-    return {};
-}
-
-void PNGChunk::store_data_length()
-{
-    auto data_length = BigEndian<u32>(m_data.size() - sizeof(data_length_type) - m_type.bytes().size());
-    __builtin_memcpy(m_data.offset_pointer(0), &data_length, sizeof(u32));
-}
-
-u32 PNGChunk::crc()
-{
-    u32 crc = Crypto::Checksum::CRC32({ m_data.offset_pointer(sizeof(data_length_type)), m_data.size() - sizeof(data_length_type) }).digest();
-    return crc;
-}
-
-ErrorOr<void> PNGChunk::compress_and_add(ReadonlyBytes uncompressed_bytes)
-{
-    return add(TRY(Compress::ZlibCompressor::compress_all(uncompressed_bytes, Compress::ZlibCompressionLevel::Best)));
-}
-
-ErrorOr<void> PNGChunk::add(ReadonlyBytes bytes)
-{
-    TRY(m_data.try_append(bytes));
-    return {};
-}
-
-template<typename T>
-ErrorOr<void> PNGChunk::add_as_big_endian(T data)
-{
-    auto data_out = AK::convert_between_host_and_big_endian(data);
-    TRY(m_data.try_append(&data_out, sizeof(T)));
-    return {};
-}
-
-ErrorOr<void> PNGChunk::add_u8(u8 data)
-{
-    TRY(m_data.try_append(data));
-    return {};
-}
-
-ErrorOr<void> PNGWriter::add_chunk(PNGChunk& png_chunk)
-{
-    png_chunk.store_data_length();
-    u32 crc = png_chunk.crc();
-    TRY(png_chunk.add_as_big_endian(crc));
-    TRY(m_data.try_append(png_chunk.data().data(), png_chunk.data().size()));
-    return {};
-}
-
-ErrorOr<void> PNGWriter::add_png_header()
-{
-    TRY(m_data.try_append(PNG::header.data(), PNG::header.size()));
-    return {};
-}
-
-ErrorOr<void> PNGWriter::add_IHDR_chunk(u32 width, u32 height, u8 bit_depth, PNG::ColorType color_type, u8 compression_method, u8 filter_method, u8 interlace_method)
-{
-    PNGChunk png_chunk { "IHDR"_string };
-    TRY(png_chunk.add_as_big_endian(width));
-    TRY(png_chunk.add_as_big_endian(height));
-    TRY(png_chunk.add_u8(bit_depth));
-    TRY(png_chunk.add_u8(to_underlying(color_type)));
-    TRY(png_chunk.add_u8(compression_method));
-    TRY(png_chunk.add_u8(filter_method));
-    TRY(png_chunk.add_u8(interlace_method));
-    TRY(add_chunk(png_chunk));
-    return {};
-}
-
-ErrorOr<void> PNGWriter::add_iCCP_chunk(ReadonlyBytes icc_data)
-{
-    // https://www.w3.org/TR/png/#11iCCP
-    PNGChunk chunk { "iCCP"_string };
-
-    TRY(chunk.add("embedded profile"sv.bytes()));
-    TRY(chunk.add_u8(0)); // \0-terminate profile name
-
-    TRY(chunk.add_u8(0)); // compression method deflate
-    TRY(chunk.compress_and_add(icc_data));
-
-    TRY(add_chunk(chunk));
-    return {};
-}
-
-ErrorOr<void> PNGWriter::add_IEND_chunk()
-{
-    PNGChunk png_chunk { "IEND"_string };
-    TRY(add_chunk(png_chunk));
-    return {};
-}
-
-union [[gnu::packed]] Pixel {
-    ARGB32 rgba { 0 };
-    struct {
-        u8 red;
-        u8 green;
-        u8 blue;
-        u8 alpha;
-    };
-    AK::SIMD::u8x4 simd;
-
-    ALWAYS_INLINE static AK::SIMD::u8x4 gfx_to_png(Pixel pixel)
-    {
-        swap(pixel.red, pixel.blue);
-        return pixel.simd;
-    }
-};
-static_assert(AssertSize<Pixel, 4>());
-
-ErrorOr<void> PNGWriter::add_IDAT_chunk(Gfx::Bitmap const& bitmap)
-{
-    PNGChunk png_chunk { "IDAT"_string };
-    TRY(png_chunk.reserve(bitmap.size_in_bytes()));
-
-    ByteBuffer uncompressed_block_data;
-    TRY(uncompressed_block_data.try_ensure_capacity(bitmap.size_in_bytes() + bitmap.height()));
-
-    auto dummy_scanline = TRY(FixedArray<Pixel>::create(bitmap.width()));
-    auto const* scanline_minus_1 = dummy_scanline.data();
-
-    for (int y = 0; y < bitmap.height(); ++y) {
-        auto* scanline = reinterpret_cast<Pixel const*>(bitmap.scanline(y));
-
-        struct Filter {
-            PNG::FilterType type;
-            ByteBuffer buffer {};
-            int sum = 0;
-
-            ErrorOr<void> append(u8 byte)
-            {
-                TRY(buffer.try_append(byte));
-                sum += static_cast<i8>(byte);
-                return {};
-            }
-
-            ErrorOr<void> append(AK::SIMD::u8x4 simd)
-            {
-                TRY(append(simd[0]));
-                TRY(append(simd[1]));
-                TRY(append(simd[2]));
-                TRY(append(simd[3]));
-                return {};
-            }
-        };
-
-        Filter none_filter { .type = PNG::FilterType::None };
-        TRY(none_filter.buffer.try_ensure_capacity(sizeof(Pixel) * bitmap.width()));
-
-        Filter sub_filter { .type = PNG::FilterType::Sub };
-        TRY(sub_filter.buffer.try_ensure_capacity(sizeof(Pixel) * bitmap.width()));
-
-        Filter up_filter { .type = PNG::FilterType::Up };
-        TRY(up_filter.buffer.try_ensure_capacity(sizeof(Pixel) * bitmap.width()));
-
-        Filter average_filter { .type = PNG::FilterType::Average };
-        TRY(average_filter.buffer.try_ensure_capacity(sizeof(ARGB32) * bitmap.width()));
-
-        Filter paeth_filter { .type = PNG::FilterType::Paeth };
-        TRY(paeth_filter.buffer.try_ensure_capacity(sizeof(ARGB32) * bitmap.width()));
-
-        auto pixel_x_minus_1 = Pixel::gfx_to_png(dummy_scanline[0]);
-        auto pixel_xy_minus_1 = Pixel::gfx_to_png(dummy_scanline[0]);
-
-        for (int x = 0; x < bitmap.width(); ++x) {
-            auto pixel = Pixel::gfx_to_png(scanline[x]);
-            auto pixel_y_minus_1 = Pixel::gfx_to_png(scanline_minus_1[x]);
-
-            TRY(none_filter.append(pixel));
-
-            TRY(sub_filter.append(pixel - pixel_x_minus_1));
-
-            TRY(up_filter.append(pixel - pixel_y_minus_1));
-
-            // The sum Orig(a) + Orig(b) shall be performed without overflow (using at least nine-bit arithmetic).
-            auto sum = AK::SIMD::to_u16x4(pixel_x_minus_1) + AK::SIMD::to_u16x4(pixel_y_minus_1);
-            auto average = AK::SIMD::to_u8x4(sum / 2);
-            TRY(average_filter.append(pixel - average));
-
-            TRY(paeth_filter.append(pixel - PNG::paeth_predictor(pixel_x_minus_1, pixel_y_minus_1, pixel_xy_minus_1)));
-
-            pixel_x_minus_1 = pixel;
-            pixel_xy_minus_1 = pixel_y_minus_1;
-        }
-
-        scanline_minus_1 = scanline;
-
-        // 12.8 Filter selection: https://www.w3.org/TR/PNG/#12Filter-selection
-        // For best compression of truecolour and greyscale images, the recommended approach
-        // is adaptive filtering in which a filter is chosen for each scanline.
-        // The following simple heuristic has performed well in early tests:
-        // compute the output scanline using all five filters, and select the filter that gives the smallest sum of absolute values of outputs.
-        // (Consider the output bytes as signed differences for this test.)
-        Filter& best_filter = none_filter;
-        if (abs(best_filter.sum) > abs(sub_filter.sum))
-            best_filter = sub_filter;
-        if (abs(best_filter.sum) > abs(up_filter.sum))
-            best_filter = up_filter;
-        if (abs(best_filter.sum) > abs(average_filter.sum))
-            best_filter = average_filter;
-        if (abs(best_filter.sum) > abs(paeth_filter.sum))
-            best_filter = paeth_filter;
-
-        TRY(uncompressed_block_data.try_append(to_underlying(best_filter.type)));
-        TRY(uncompressed_block_data.try_append(best_filter.buffer));
-    }
-
-    TRY(png_chunk.compress_and_add(uncompressed_block_data));
-    TRY(add_chunk(png_chunk));
-    return {};
-}
-
 ErrorOr<ByteBuffer> PNGWriter::encode(Gfx::Bitmap const& bitmap, Options options)
 {
-    PNGWriter writer;
-    TRY(writer.add_png_header());
-    TRY(writer.add_IHDR_chunk(bitmap.width(), bitmap.height(), 8, PNG::ColorType::TruecolorWithAlpha, 0, 0, 0));
-    if (options.icc_data.has_value())
-        TRY(writer.add_iCCP_chunk(options.icc_data.value()));
-    TRY(writer.add_IDAT_chunk(bitmap));
-    TRY(writer.add_IEND_chunk());
-    return ByteBuffer::copy(writer.m_data);
+    auto context = make<WriterContext>();
+    int width = bitmap.width();
+    int height = bitmap.height();
+
+    png_structp png_ptr = png_create_write_struct(PNG_LIBPNG_VER_STRING, nullptr, nullptr, nullptr);
+    if (!png_ptr) {
+        return Error::from_string_literal("Failed to create PNG write struct");
+    }
+
+    png_infop info_ptr = png_create_info_struct(png_ptr);
+    if (!info_ptr) {
+        png_destroy_write_struct(&png_ptr, nullptr);
+        return Error::from_string_literal("Failed to create PNG info struct");
+    }
+
+    if (setjmp(png_jmpbuf(png_ptr))) {
+        png_destroy_write_struct(&png_ptr, &info_ptr);
+        return Error::from_string_literal("Error during PNG encoding");
+    }
+
+    if (options.icc_data.has_value()) {
+        png_set_iCCP(png_ptr, info_ptr, "embedded profile", 0, options.icc_data->data(), options.icc_data->size());
+    }
+
+    if (bitmap.format() == BitmapFormat::BGRA8888 || bitmap.format() == BitmapFormat::BGRx8888) {
+        png_set_bgr(png_ptr);
+    }
+
+    png_set_write_fn(png_ptr, &context->png_data, [](png_structp png_ptr, u8* data, size_t length) {
+        auto* buffer = reinterpret_cast<ByteBuffer*>(png_get_io_ptr(png_ptr));
+        buffer->append(data, length); }, nullptr);
+
+    png_set_IHDR(png_ptr, info_ptr, width, height, 8, PNG_COLOR_TYPE_RGBA, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
+
+    context->row_pointers.resize(height);
+    for (int y = 0; y < height; ++y) {
+        context->row_pointers[y] = const_cast<u8*>(bitmap.scanline_u8(y));
+    }
+
+    png_set_rows(png_ptr, info_ptr, context->row_pointers.data());
+    png_write_png(png_ptr, info_ptr, PNG_TRANSFORM_IDENTITY, nullptr);
+
+    png_destroy_write_struct(&png_ptr, &info_ptr);
+
+    return context->png_data;
 }
 
 }
diff --git a/Userland/Libraries/LibGfx/ImageFormats/PNGWriter.h b/Userland/Libraries/LibGfx/ImageFormats/PNGWriter.h
index 0891261ed29..054425fbe63 100644
--- a/Userland/Libraries/LibGfx/ImageFormats/PNGWriter.h
+++ b/Userland/Libraries/LibGfx/ImageFormats/PNGWriter.h
@@ -1,21 +1,18 @@
 /*
- * Copyright (c) 2021, Pierre Hoffmeister
- * Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2024, Andreas Kling <andreas@ladybird.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #pragma once
 
+#include <AK/Forward.h>
 #include <AK/Optional.h>
-#include <AK/Vector.h>
+#include <AK/Span.h>
 #include <LibGfx/Forward.h>
-#include <LibGfx/ImageFormats/PNGShared.h>
 
 namespace Gfx {
 
-class PNGChunk;
-
 // This is not a nested struct to work around https://llvm.org/PR36684
 struct PNGWriterOptions {
     // Data for the iCCP chunk.
@@ -31,14 +28,6 @@ public:
 
 private:
     PNGWriter() = default;
-
-    Vector<u8> m_data;
-    ErrorOr<void> add_chunk(PNGChunk&);
-    ErrorOr<void> add_png_header();
-    ErrorOr<void> add_IHDR_chunk(u32 width, u32 height, u8 bit_depth, PNG::ColorType color_type, u8 compression_method, u8 filter_method, u8 interlace_method);
-    ErrorOr<void> add_iCCP_chunk(ReadonlyBytes icc_data);
-    ErrorOr<void> add_IDAT_chunk(Gfx::Bitmap const&);
-    ErrorOr<void> add_IEND_chunk();
 };
 
 }
diff --git a/vcpkg.json b/vcpkg.json
index 5d580b09110..e0f99ebe465 100644
--- a/vcpkg.json
+++ b/vcpkg.json
@@ -7,6 +7,10 @@
     },
     "icu",
     "libjpeg-turbo",
+    {
+      "name": "libpng",
+      "features": [ "apng" ]
+    },
     "skia",
     "sqlite3",
     "woff2"
@@ -24,6 +28,10 @@
       "name": "libjpeg-turbo",
       "version": "3.0.2"
     },
+    {
+      "name": "libpng",
+      "version": "1.6.43#1"
+    },
     {
       "name": "skia",
       "version": "124#0"