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LibWeb: Implement HTMLCanvasElement.toBlob()

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Karol Kosek 2023-08-03 01:29:31 +02:00 • committed by Andreas Kling
parent 3239f0fb7b
commit b731705fec
4 changed files with 52 additions and 1 deletions
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45
Userland/Libraries/LibWeb/HTML/HTMLCanvasElement.cpp
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@ -8,11 +8,15 @@
#include <AK/Checked.h>
#include <LibGfx/Bitmap.h>
#include <LibGfx/ImageFormats/PNGWriter.h>
#include <LibWeb/Bindings/ExceptionOrUtils.h>
#include <LibWeb/CSS/StyleComputer.h>
#include <LibWeb/DOM/Document.h>
#include <LibWeb/HTML/CanvasRenderingContext2D.h>
#include <LibWeb/HTML/HTMLCanvasElement.h>
#include <LibWeb/HTML/Scripting/ExceptionReporter.h>
#include <LibWeb/Layout/CanvasBox.h>
#include <LibWeb/Platform/EventLoopPlugin.h>
#include <LibWeb/WebIDL/AbstractOperations.h>
namespace Web::HTML {
@ -219,6 +223,47 @@ DeprecatedString HTMLCanvasElement::to_data_url(DeprecatedString const& type, Op
return AK::URL::create_with_data(file.value().mime_type, base64_encoded_or_error.release_value(), true).to_deprecated_string();
}
// https://html.spec.whatwg.org/multipage/canvas.html#dom-canvas-toblob
WebIDL::ExceptionOr<void> HTMLCanvasElement::to_blob(JS::NonnullGCPtr<WebIDL::CallbackType> callback, DeprecatedString const& type, Optional<double> quality)
{
// FIXME: 1. If this canvas element's bitmap's origin-clean flag is set to false, then throw a "SecurityError" DOMException.
// 2. Let result be null.
RefPtr<Gfx::Bitmap> bitmap_result;
// 3. If this canvas element's bitmap has pixels (i.e., neither its horizontal dimension nor its vertical dimension is zero),
// then set result to a copy of this canvas element's bitmap.
if (m_bitmap)
bitmap_result = TRY_OR_THROW_OOM(vm(), m_bitmap->clone());
// 4. Run these steps in parallel:
Platform::EventLoopPlugin::the().deferred_invoke([this, callback, bitmap_result, type, quality] {
// 1. If result is non-null, then set result to a serialization of result as a file with type and quality if given.
Optional<SerializeBitmapResult> file_result;
if (bitmap_result) {
if (auto result = serialize_bitmap(*bitmap_result, type, move(quality)); !result.is_error())
file_result = result.release_value();
}
// 2. Queue an element task on the canvas blob serialization task source given the canvas element to run these steps:
queue_an_element_task(Task::Source::CanvasBlobSerializationTask, [this, callback, file_result = move(file_result)] {
auto maybe_error = Bindings::throw_dom_exception_if_needed(vm(), [&]() -> WebIDL::ExceptionOr<void> {
// 1. If result is non-null, then set result to a new Blob object, created in the relevant realm of this canvas element, representing result. [FILEAPI]
JS::GCPtr<FileAPI::Blob> blob_result;
if (file_result.has_value())
blob_result = TRY(FileAPI::Blob::create(realm(), file_result->buffer, TRY_OR_THROW_OOM(vm(), String::from_utf8(file_result->mime_type))));
// 2. Invoke callback with « result ».
TRY(WebIDL::invoke_callback(*callback, {}, move(blob_result)));
return {};
});
if (maybe_error.is_throw_completion())
report_exception(maybe_error.throw_completion(), realm());
});
});
return {};
}
void HTMLCanvasElement::present()
{
m_context.visit(