LibWeb/HTML: Implement ImageData initialization closer to spec

Author: https://github.com/LucasChollet
Commit: https://github.com/LadybirdBrowser/ladybird/commit/715bf0de2c7
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/3709
Reviewed-by: https://github.com/AtkinsSJ ✅

Libraries/LibWeb/HTML/ImageData.cpp

@@ -19,28 +19,15 @@ namespace Web::HTML {
 GC_DEFINE_ALLOCATOR(ImageData);
 
 // 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&)
+WebIDL::ExceptionOr<GC::Ref<ImageData>> ImageData::create(JS::Realm& realm, u32 sw, u32 sh, Optional<ImageDataSettings> const& settings)
 {
-    auto& vm = realm.vm();
-
     // 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."_string);
 
     // 2. Initialize this given sw, sh, and settings set to settings.
     // 3. Initialize the image data of this to transparent black.
-    //
-    // If the Canvas Pixel ArrayBuffer cannot be allocated, then rethrow the RangeError thrown by JavaScript, and return.
-    Checked<u32> size = sw;
-    size *= sh;
-    size *= sizeof(u32);
-    if (size.has_overflow())
-        return WebIDL::IndexSizeError::create(realm, "The specified image size could not created"_string);
-
-    auto data = TRY(JS::Uint8ClampedArray::create(realm, size.value()));
-    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()));
-
-    return realm.create<ImageData>(realm, bitmap, data);
+    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)
@@ -49,7 +36,7 @@ WebIDL::ExceptionOr<GC::Ref<ImageData>> ImageData::construct_impl(JS::Realm& rea
 }
 
 // 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&)
+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();
 
@@ -82,9 +69,8 @@ WebIDL::ExceptionOr<GC::Ref<ImageData>> ImageData::create(JS::Realm& realm, GC::
         return WebIDL::IndexSizeError::create(realm, "Source height must be equal to the calculated height of the data."_string);
 
     // 7. Initialize this given sw, sh, settings set to settings, and source set to data.
-    auto bitmap = TRY_OR_THROW_OOM(vm, Gfx::Bitmap::create_wrapper(Gfx::BitmapFormat::RGBA8888, Gfx::AlphaType::Unpremultiplied, Gfx::IntSize(sw, height), sw * sizeof(u32), uint8_clamped_array_data.data().data()));
-
-    return realm.create<ImageData>(realm, bitmap, uint8_clamped_array_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)
@@ -92,9 +78,53 @@ WebIDL::ExceptionOr<GC::Ref<ImageData>> ImageData::construct_impl(JS::Realm& rea
     return ImageData::create(realm, data, sw, move(sh), settings);
 }
 
-ImageData::ImageData(JS::Realm& realm, NonnullRefPtr<Gfx::Bitmap> bitmap, GC::Ref<JS::Uint8ClampedArray> data)
+// 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"_string);
+
+        // 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(), Gfx::Bitmap::create_wrapper(Gfx::BitmapFormat::RGBA8888, Gfx::AlphaType::Unpremultiplied, Gfx::IntSize(pixels_per_row, rows), pixels_per_row * sizeof(u32), data->data().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, 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))
 {
 }

Libraries/LibWeb/HTML/ImageData.h

@@ -39,13 +39,18 @@ public:
     JS::Uint8ClampedArray* data();
     const JS::Uint8ClampedArray* data() const;
 
+    Bindings::PredefinedColorSpace color_space() const { return m_color_space; }
+
 private:
-    ImageData(JS::Realm&, NonnullRefPtr<Gfx::Bitmap>, GC::Ref<JS::Uint8ClampedArray>);
+    [[nodiscard]] static WebIDL::ExceptionOr<GC::Ref<ImageData>> initialize(JS::Realm&, u32 rows, u32 pixels_per_row, Optional<ImageDataSettings> const&, GC::Ptr<JS::Uint8ClampedArray> = {}, Optional<Bindings::PredefinedColorSpace> = {});
+
+    ImageData(JS::Realm&, NonnullRefPtr<Gfx::Bitmap>, GC::Ref<JS::Uint8ClampedArray>, Bindings::PredefinedColorSpace);
 
     virtual void initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
 
     NonnullRefPtr<Gfx::Bitmap> m_bitmap;
+    Bindings::PredefinedColorSpace m_color_space;
     GC::Ref<JS::Uint8ClampedArray> m_data;
 };
 

Libraries/LibWeb/HTML/ImageData.idl

@@ -13,5 +13,5 @@ interface ImageData {
     readonly attribute unsigned long width;
     readonly attribute unsigned long height;
     readonly attribute Uint8ClampedArray data;
-    [FIXME] readonly attribute PredefinedColorSpace colorSpace;
+    readonly attribute PredefinedColorSpace colorSpace;
 };