5865cf5864
When converting a `Gfx::Bitmap` to a Skia bitmap, we cannot assume the color data is unpremultiplied. For example, everything canvas-related uses premultiplied color data: https://html.spec.whatwg.org/multipage/canvas.html#premultiplied-alpha-and-the-2d-rendering-context We were probably assuming unpremultiplied since that is what the PNG decoder gives us. Since we now make `Gfx::Bitmap` identify what alpha type is being used, we can instruct Skia a bit better :^) Update our `EdgeFlagPathRasterizer` to use premultiplied alpha instead of unpremultiplied so we can apply alpha correctly for path masks. This fixes the dark borders sometimes visible when SVGs are blended with a colored background. This also exposed an issue with our `CanvasRenderingContext2D`, which is supposed to hold a bitmap with premultiplied alpha internally but expose a bitmap with unpremultiplied alpha in `CanvasImageData`. Expand our C2D test to include the alpha channel as well. Finally, this also exposed an off-by-one issue in `EdgeFlagPathRasterizer` which caused the last scanlines for edges to render incorrectly. We had some reference images which included these corruptions (they were almost unnoticeable), so update them as well.
128 lines
4.9 KiB
C++
128 lines
4.9 KiB
C++
/*
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* Copyright (c) 2020-2022, Andreas Kling <kling@serenityos.org>
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* Copyright (c) 2024, Kenneth Myhra <kennethmyhra@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <LibGfx/Bitmap.h>
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#include <LibJS/Runtime/TypedArray.h>
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#include <LibWeb/Bindings/ImageDataPrototype.h>
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#include <LibWeb/Bindings/Intrinsics.h>
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#include <LibWeb/HTML/ImageData.h>
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#include <LibWeb/WebIDL/Buffers.h>
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#include <LibWeb/WebIDL/DOMException.h>
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#include <LibWeb/WebIDL/ExceptionOr.h>
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namespace Web::HTML {
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JS_DEFINE_ALLOCATOR(ImageData);
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// https://html.spec.whatwg.org/multipage/canvas.html#dom-imagedata
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WebIDL::ExceptionOr<JS::NonnullGCPtr<ImageData>> ImageData::create(JS::Realm& realm, u32 sw, u32 sh, Optional<ImageDataSettings> const&)
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{
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auto& vm = realm.vm();
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// 1. If one or both of sw and sh are zero, then throw an "IndexSizeError" DOMException.
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if (sw == 0 || sh == 0)
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return WebIDL::IndexSizeError::create(realm, "The source width and height must be greater than zero."_fly_string);
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// 2. Initialize this given sw, sh, and settings set to settings.
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// 3. Initialize the image data of this to transparent black.
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auto data = TRY(JS::Uint8ClampedArray::create(realm, sw * sh * 4));
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auto bitmap = TRY_OR_THROW_OOM(vm, Gfx::Bitmap::create_wrapper(Gfx::BitmapFormat::RGBA8888, Gfx::AlphaType::Unpremultiplied, Gfx::IntSize(sw, sh), sw * sizeof(u32), data->data().data()));
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return realm.heap().allocate<ImageData>(realm, realm, bitmap, data);
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}
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WebIDL::ExceptionOr<JS::NonnullGCPtr<ImageData>> ImageData::construct_impl(JS::Realm& realm, u32 sw, u32 sh, Optional<ImageDataSettings> const& settings)
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{
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return ImageData::create(realm, sw, sh, settings);
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}
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// https://html.spec.whatwg.org/multipage/canvas.html#dom-imagedata-with-data
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WebIDL::ExceptionOr<JS::NonnullGCPtr<ImageData>> ImageData::create(JS::Realm& realm, JS::Handle<WebIDL::BufferSource> const& data, u32 sw, Optional<u32> sh, Optional<ImageDataSettings> const&)
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{
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auto& vm = realm.vm();
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if (!is<JS::Uint8ClampedArray>(*data->raw_object()))
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return vm.throw_completion<JS::TypeError>(JS::ErrorType::NotAnObjectOfType, "Uint8ClampedArray");
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auto& uint8_clamped_array_data = static_cast<JS::Uint8ClampedArray&>(*data->raw_object());
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// 1. Let length be the number of bytes in data.
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auto length = uint8_clamped_array_data.byte_length().length();
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// 2. If length is not a nonzero integral multiple of four, then throw an "InvalidStateError" DOMException.
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if (length == 0 || length % 4 != 0)
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return WebIDL::InvalidStateError::create(realm, "Source data must have a non-sero length that is a multiple of four."_fly_string);
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// 3. Let length be length divided by four.
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length = length / 4;
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// 4. If length is not an integral multiple of sw, then throw an "IndexSizeError" DOMException.
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// NOTE: At this step, the length is guaranteed to be greater than zero (otherwise the second step above would have aborted the steps),
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// so if sw is zero, this step will throw the exception and return.
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if (sw == 0 || length % sw != 0)
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return WebIDL::IndexSizeError::create(realm, "Source width must be a multiple of source data's length."_fly_string);
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// 5. Let height be length divided by sw.
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auto height = length / sw;
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// 6. If sh was given and its value is not equal to height, then throw an "IndexSizeError" DOMException.
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if (sh.has_value() && sh.value() != height)
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return WebIDL::IndexSizeError::create(realm, "Source height must be equal to the calculated height of the data."_fly_string);
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// 7. Initialize this given sw, sh, settings set to settings, and source set to data.
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auto bitmap = TRY_OR_THROW_OOM(vm, Gfx::Bitmap::create_wrapper(Gfx::BitmapFormat::RGBA8888, Gfx::AlphaType::Premultiplied, Gfx::IntSize(sw, height), sw * sizeof(u32), uint8_clamped_array_data.data().data()));
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return realm.heap().allocate<ImageData>(realm, realm, bitmap, uint8_clamped_array_data);
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}
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WebIDL::ExceptionOr<JS::NonnullGCPtr<ImageData>> ImageData::construct_impl(JS::Realm& realm, JS::Handle<WebIDL::BufferSource> const& data, u32 sw, Optional<u32> sh, Optional<ImageDataSettings> const& settings)
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{
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return ImageData::create(realm, data, sw, move(sh), settings);
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}
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ImageData::ImageData(JS::Realm& realm, NonnullRefPtr<Gfx::Bitmap> bitmap, JS::NonnullGCPtr<JS::Uint8ClampedArray> data)
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: PlatformObject(realm)
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, m_bitmap(move(bitmap))
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, m_data(move(data))
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{
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}
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ImageData::~ImageData() = default;
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void ImageData::initialize(JS::Realm& realm)
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{
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Base::initialize(realm);
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WEB_SET_PROTOTYPE_FOR_INTERFACE(ImageData);
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}
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void ImageData::visit_edges(Cell::Visitor& visitor)
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{
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Base::visit_edges(visitor);
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visitor.visit(m_data);
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}
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unsigned ImageData::width() const
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{
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return m_bitmap->width();
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}
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unsigned ImageData::height() const
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{
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return m_bitmap->height();
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}
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JS::Uint8ClampedArray* ImageData::data()
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{
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return m_data;
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}
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const JS::Uint8ClampedArray* ImageData::data() const
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{
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return m_data;
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}
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}
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