ladybird/Libraries/LibWeb/HTML/HTMLCanvasElement.h

/*
 * Copyright (c) 2020, Andreas Kling <andreas@ladybird.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#pragma once

#include <AK/ByteBuffer.h>
#include <LibGfx/Forward.h>
#include <LibGfx/PaintingSurface.h>
#include <LibWeb/HTML/HTMLElement.h>
#include <LibWeb/WebIDL/Types.h>

namespace Web::HTML {

class HTMLCanvasElement final : public HTMLElement {
    WEB_PLATFORM_OBJECT(HTMLCanvasElement, HTMLElement);
    GC_DECLARE_ALLOCATOR(HTMLCanvasElement);

public:
    using RenderingContext = Variant<GC::Root<CanvasRenderingContext2D>, GC::Root<WebGL::WebGLRenderingContext>, GC::Root<WebGL::WebGL2RenderingContext>, Empty>;

    virtual ~HTMLCanvasElement() override;

    Gfx::IntSize bitmap_size_for_canvas(size_t minimum_width = 0, size_t minimum_height = 0) const;

    JS::ThrowCompletionOr<RenderingContext> get_context(String const& type, JS::Value options);
    enum class HasOrCreatedContext {
        No,
        Yes,
    };
    HasOrCreatedContext create_2d_context();

    WebIDL::UnsignedLong width() const;
    WebIDL::UnsignedLong height() const;

    WebIDL::ExceptionOr<void> set_width(WebIDL::UnsignedLong);
    WebIDL::ExceptionOr<void> set_height(WebIDL::UnsignedLong);

    String to_data_url(StringView type, JS::Value quality);
    WebIDL::ExceptionOr<void> to_blob(GC::Ref<WebIDL::CallbackType> callback, StringView type, JS::Value quality);

    void present();

    RefPtr<Gfx::PaintingSurface> surface() const;
    void allocate_painting_surface_if_needed();

private:
    HTMLCanvasElement(DOM::Document&, DOM::QualifiedName);

    virtual void initialize(JS::Realm&) override;
    virtual void visit_edges(Cell::Visitor&) override;

    virtual void apply_presentational_hints(CSS::StyleProperties&) const override;

    virtual GC::Ptr<Layout::Node> create_layout_node(CSS::StyleProperties) override;
    virtual void adjust_computed_style(CSS::StyleProperties&) override;

    template<typename ContextType>
    JS::ThrowCompletionOr<HasOrCreatedContext> create_webgl_context(JS::Value options);
    void reset_context_to_default_state();
    void notify_context_about_canvas_size_change();

    Variant<GC::Ref<HTML::CanvasRenderingContext2D>, GC::Ref<WebGL::WebGLRenderingContext>, GC::Ref<WebGL::WebGL2RenderingContext>, Empty> m_context;
};

}