ladybird/Libraries/LibWeb/HTML/ImageData.cpp

/*
 * Copyright (c) 2020-2022, Andreas Kling <andreas@ladybird.org>
 * Copyright (c) 2024-2025, Kenneth Myhra <kennethmyhra@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <LibGfx/Bitmap.h>
#include <LibJS/Runtime/TypedArray.h>
#include <LibWeb/Bindings/ImageDataPrototype.h>
#include <LibWeb/Bindings/Intrinsics.h>
#include <LibWeb/HTML/ImageData.h>
#include <LibWeb/HTML/StructuredSerialize.h>
#include <LibWeb/WebIDL/Buffers.h>
#include <LibWeb/WebIDL/DOMException.h>
#include <LibWeb/WebIDL/ExceptionOr.h>

namespace Web::HTML {

GC_DEFINE_ALLOCATOR(ImageData);

[[nodiscard]] static auto create_bitmap_backed_by_uint8_clamped_array(u32 const width, u32 const height, JS::Uint8ClampedArray& data)
{
    return Gfx::Bitmap::create_wrapper(Gfx::BitmapFormat::RGBA8888, Gfx::AlphaType::Unpremultiplied, Gfx::IntSize(width, height), width * sizeof(u32), data.data().data());
}

GC::Ref<ImageData> ImageData::create(JS::Realm& realm)
{
    return realm.create<ImageData>(realm);
}

// https://html.spec.whatwg.org/multipage/canvas.html#dom-imagedata
WebIDL::ExceptionOr<GC::Ref<ImageData>> ImageData::create(JS::Realm& realm, u32 sw, u32 sh, Optional<ImageDataSettings> const& settings)
{
    // 1. If one or both of sw and sh are zero, then throw an "IndexSizeError" DOMException.
    if (sw == 0 || sh == 0)
        return WebIDL::IndexSizeError::create(realm, "The source width and height must be greater than zero."_utf16);

    // 2. Initialize this given sw, sh, and settings set to settings.
    // 3. Initialize the image data of this to transparent black.
    return initialize(realm, sh, sw, settings);
}

WebIDL::ExceptionOr<GC::Ref<ImageData>> ImageData::construct_impl(JS::Realm& realm, u32 sw, u32 sh, Optional<ImageDataSettings> const& settings)
{
    return ImageData::create(realm, sw, sh, settings);
}

// https://html.spec.whatwg.org/multipage/canvas.html#dom-imagedata-with-data
WebIDL::ExceptionOr<GC::Ref<ImageData>> ImageData::create(JS::Realm& realm, GC::Root<WebIDL::BufferSource> const& data, u32 sw, Optional<u32> sh, Optional<ImageDataSettings> const& settings)
{
    auto& vm = realm.vm();

    if (!is<JS::Uint8ClampedArray>(*data->raw_object()))
        return vm.throw_completion<JS::TypeError>(JS::ErrorType::NotAnObjectOfType, "Uint8ClampedArray");

    auto& uint8_clamped_array_data = static_cast<JS::Uint8ClampedArray&>(*data->raw_object());

    // 1. Let length be the number of bytes in data.
    auto length = uint8_clamped_array_data.byte_length().length();

    // 2. If length is not a nonzero integral multiple of four, then throw an "InvalidStateError" DOMException.
    if (length == 0 || length % 4 != 0)
        return WebIDL::InvalidStateError::create(realm, "Source data must have a non-sero length that is a multiple of four."_utf16);

    // 3. Let length be length divided by four.
    length = length / 4;

    // 4. If length is not an integral multiple of sw, then throw an "IndexSizeError" DOMException.
    // NOTE: At this step, the length is guaranteed to be greater than zero (otherwise the second step above would have aborted the steps),
    //       so if sw is zero, this step will throw the exception and return.
    if (sw == 0 || length % sw != 0)
        return WebIDL::IndexSizeError::create(realm, "Source width must be a multiple of source data's length."_utf16);

    // 5. Let height be length divided by sw.
    auto height = length / sw;

    // 6. If sh was given and its value is not equal to height, then throw an "IndexSizeError" DOMException.
    if (sh.has_value() && sh.value() != height)
        return WebIDL::IndexSizeError::create(realm, "Source height must be equal to the calculated height of the data."_utf16);

    // 7. Initialize this given sw, sh, settings set to settings, and source set to data.
    // FIXME: This seems to be a spec issue, sh is an optional but height always have a value.
    return initialize(realm, height, sw, settings, uint8_clamped_array_data);
}

WebIDL::ExceptionOr<GC::Ref<ImageData>> ImageData::construct_impl(JS::Realm& realm, GC::Root<WebIDL::BufferSource> const& data, u32 sw, Optional<u32> sh, Optional<ImageDataSettings> const& settings)
{
    return ImageData::create(realm, data, sw, move(sh), settings);
}

// https://html.spec.whatwg.org/multipage/canvas.html#initialize-an-imagedata-object
WebIDL::ExceptionOr<GC::Ref<ImageData>> ImageData::initialize(JS::Realm& realm, u32 rows, u32 pixels_per_row, Optional<ImageDataSettings> const& settings, GC::Ptr<JS::Uint8ClampedArray> source, Optional<Bindings::PredefinedColorSpace> default_color_space)
{
    auto data = TRY([&]() -> WebIDL::ExceptionOr<GC::Ref<JS::Uint8ClampedArray>> {
        // 1. If source was given, then initialize the data attribute of imageData to source.
        if (source) {
            return GC::Ref<JS::Uint8ClampedArray> { *source };
        }

        Checked<u32> size = rows;
        size *= pixels_per_row;
        size *= sizeof(u32);
        if (size.has_overflow())
            return WebIDL::IndexSizeError::create(realm, "The specified image size could not created"_utf16);

        // 2. Otherwise (source was not given), initialize the data attribute of imageData to a new Uint8ClampedArray object.
        //    The Uint8ClampedArray object must use a new Canvas Pixel ArrayBuffer for its storage, and must have a zero start
        //    offset and a length equal to the length of its storage, in bytes. The Canvas Pixel ArrayBuffer must have the
        //    correct size to store rows × pixelsPerRow pixels.
        // 3. If the Canvas Pixel ArrayBuffer cannot be allocated, then rethrow the RangeError thrown by JavaScript, and return.
        return TRY(JS::Uint8ClampedArray::create(realm, sizeof(u32) * rows * pixels_per_row));
    }());

    // AD-HOC: Create the bitmap backed by the Uint8ClampedArray.
    auto bitmap = TRY_OR_THROW_OOM(realm.vm(), create_bitmap_backed_by_uint8_clamped_array(pixels_per_row, rows, *data));

    // 4. Initialize the width attribute of imageData to pixelsPerRow.
    // 5. Initialize the height attribute of imageData to rows.

    // 6. If settings was given and settings["colorSpace"] exists, then initialize the colorSpace attribute of imageData to settings["colorSpace"].
    Bindings::PredefinedColorSpace color_space {};
    if (settings.has_value())
        color_space = settings->color_space;
    // 7. Otherwise, if defaultColorSpace was given, then initialize the colorSpace attribute of imageData to defaultColorSpace.
    else if (default_color_space.has_value())
        color_space = *default_color_space;
    // 8. Otherwise, initialize the colorSpace attribute of imageData to "srgb".
    else
        color_space = Bindings::PredefinedColorSpace::Srgb;

    return realm.create<ImageData>(realm, move(bitmap), data, color_space);
}

ImageData::ImageData(JS::Realm& realm)
    : PlatformObject(realm)
{
}

ImageData::ImageData(JS::Realm& realm, NonnullRefPtr<Gfx::Bitmap> bitmap, GC::Ref<JS::Uint8ClampedArray> data, Bindings::PredefinedColorSpace color_space)
    : PlatformObject(realm)
    , m_bitmap(move(bitmap))
    , m_color_space(color_space)
    , m_data(move(data))
{
}

ImageData::~ImageData() = default;

void ImageData::initialize(JS::Realm& realm)
{
    WEB_SET_PROTOTYPE_FOR_INTERFACE(ImageData);
    Base::initialize(realm);
}

void ImageData::visit_edges(Cell::Visitor& visitor)
{
    Base::visit_edges(visitor);
    visitor.visit(m_data);
}

WebIDL::UnsignedLong ImageData::width() const
{
    return m_bitmap->width();
}

WebIDL::UnsignedLong ImageData::height() const
{
    return m_bitmap->height();
}

JS::Uint8ClampedArray* ImageData::data()
{
    return m_data;
}

JS::Uint8ClampedArray const* ImageData::data() const
{
    return m_data;
}

// https://html.spec.whatwg.org/multipage/canvas.html#pixel-manipulation:serialization-steps
WebIDL::ExceptionOr<void> ImageData::serialization_steps(HTML::TransferDataEncoder& serialized, bool for_storage, HTML::SerializationMemory& memory)
{
    auto& vm = this->vm();

    // 1. Set serialized.[[Data]] to the sub-serialization of the value of value's data attribute.
    auto serialized_data = TRY(structured_serialize_internal(vm, m_data, for_storage, memory));
    serialized.append(move(serialized_data));

    // 2. Set serialized.[[Width]] to the value of value's width attribute.
    serialized.encode(m_bitmap->width());

    // 3. Set serialized.[[Height]] to the value of value's height attribute.
    serialized.encode(m_bitmap->height());

    // 4. Set serialized.[[ColorSpace]] to the value of value's colorSpace attribute.
    serialized.encode(m_color_space);

    // FIXME:: 5. Set serialized.[[PixelFormat]] to the value of value's pixelFormat attribute.

    return {};
}

// https://html.spec.whatwg.org/multipage/canvas.html#pixel-manipulation:deserialization-steps
WebIDL::ExceptionOr<void> ImageData::deserialization_steps(HTML::TransferDataDecoder& serialized, HTML::DeserializationMemory& memory)
{
    auto& vm = this->vm();
    auto& realm = this->realm();

    // 1. Initialize value's data attribute to the sub-deserialization of serialized.[[Data]].
    auto deserialized = TRY(structured_deserialize_internal(vm, serialized, realm, memory));
    m_data = as<JS::Uint8ClampedArray>(deserialized.as_object());

    // 2. Initialize value's width attribute to serialized.[[Width]].
    auto width = serialized.decode<int>();

    // 3. Initialize value's height attribute to serialized.[[Height]].
    auto height = serialized.decode<int>();

    // 4. Initialize value's colorSpace attribute to serialized.[[ColorSpace]].
    m_color_space = serialized.decode<Bindings::PredefinedColorSpace>();

    // FIXME: 5. Initialize value's pixelFormat attribute to serialized.[[PixelFormat]].

    // AD-HOC: Create the bitmap backed by the Uint8ClampedArray.
    m_bitmap = TRY_OR_THROW_OOM(vm, create_bitmap_backed_by_uint8_clamped_array(width, height, *m_data));

    return {};
}

}