LibWeb: Add <canvas> element and start fleshing out CRC2D

This patch adds HTMLCanvasElement along with a LayoutCanvas object. The DOM and layout parts are very similar to <img> elements. The <canvas> element holds a Gfx::Bitmap which is sized according to the "width" and "height" attributes on the element. Calling .getContext("2d") on a <canvas> element gives you a context object that draws into the underlying Gfx::Bitmap of the <canvas>. The context weakly points to the <canvas> which allows it to outlive the canvas element if needed. This is really quite cool. :^)
2025-07-25 17:17:44 +00:00 · 2020-03-19 19:07:56 +01:00 · 2020-03-19 19:07:56 +01:00 · a37c29e353
commit a37c29e353
parent 73d28a0551
19 changed files with 649 additions and 1 deletions
--- a/Base/home/anon/www/canvas.html
+++ b/Base/home/anon/www/canvas.html
@ -0,0 +1,27 @@
+<!DOCTYPE html>
+<html>
+<head>
+<title>Canvas 2D test!</title>
+<style type="text/css">
+body {
+    background-color: #000;
+    color: #fff; /* another css comment */
+}
+canvas {
+    border-width: 1px;
+    border-style: solid;
+    border-color: #fff;
+}
+</style>
+<script>
+    document.addEventListener("DOMContentLoaded", function() {
+        ctx = document.getElementById("foo").getContext("2d");
+        ctx.fillStyle = 'red';
+        ctx.fillRect(10, 10, 200, 100);
+    });
+</script>
+</head>
+<body link="#44f" vlink="#c4c" background="90s-bg.png">
+    <canvas id="foo" width="300" height="200"></canvas>
+</body>
+</html>
--- a/Base/home/anon/www/welcome.html
+++ b/Base/home/anon/www/welcome.html
@ -23,6 +23,7 @@ h1 {
    <p>This is a very simple browser built on the LibWeb engine.</p>
    <p>Some small test pages:</p>
    <ul>
+        <li><a href="canvas.html">canvas 2D test</a></li>
        <li><a href="events.html">simple DOM events test</a></li>
        <li><a href="dom.html">simple DOM JS test</a></li>
        <li><a href="alert.html">alert() test</a></li>
--- a/Libraries/LibWeb/Bindings/CanvasRenderingContext2DWrapper.cpp
+++ b/Libraries/LibWeb/Bindings/CanvasRenderingContext2DWrapper.cpp
@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <AK/Function.h>
+#include <LibJS/Runtime/PrimitiveString.h>
+#include <LibJS/Runtime/Value.h>
+#include <LibWeb/Bindings/CanvasRenderingContext2DWrapper.h>
+#include <LibWeb/DOM/CanvasRenderingContext2D.h>
+
+namespace Web {
+namespace Bindings {
+
+CanvasRenderingContext2DWrapper* wrap(JS::Heap& heap, CanvasRenderingContext2D& impl)
+{
+    return static_cast<CanvasRenderingContext2DWrapper*>(wrap_impl(heap, impl));
+}
+
+CanvasRenderingContext2DWrapper::CanvasRenderingContext2DWrapper(CanvasRenderingContext2D& impl)
+    : m_impl(impl)
+{
+    put_native_property(
+        "fillStyle",
+        [this](JS::Object*) {
+            return JS::js_string(heap(), m_impl->fill_style());
+        },
+        [this](JS::Object*, JS::Value value) {
+            m_impl->set_fill_style(value.to_string());
+        });
+    put_native_function("fillRect", [this](JS::Object*, const Vector<JS::Value>& arguments) {
+        if (arguments.size() >= 4) {
+            m_impl->fill_rect(arguments[0].to_i32(), arguments[1].to_i32(), arguments[2].to_i32(), arguments[3].to_i32());
+        }
+        return JS::js_undefined();
+    });
+}
+
+CanvasRenderingContext2DWrapper::~CanvasRenderingContext2DWrapper()
+{
+}
+
+}
+}
--- a/Libraries/LibWeb/Bindings/CanvasRenderingContext2DWrapper.h
+++ b/Libraries/LibWeb/Bindings/CanvasRenderingContext2DWrapper.h
@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <LibWeb/Bindings/Wrapper.h>
+
+namespace Web {
+namespace Bindings {
+
+class CanvasRenderingContext2DWrapper : public Wrapper {
+public:
+    explicit CanvasRenderingContext2DWrapper(CanvasRenderingContext2D&);
+    virtual ~CanvasRenderingContext2DWrapper() override;
+
+    CanvasRenderingContext2D& impl() { return m_impl; }
+    const CanvasRenderingContext2D& impl() const { return m_impl; }
+
+private:
+    virtual const char* class_name() const override { return "CanvasRenderingContext2DWrapper"; }
+
+    NonnullRefPtr<CanvasRenderingContext2D> m_impl;
+};
+
+CanvasRenderingContext2DWrapper* wrap(JS::Heap&, CanvasRenderingContext2D&);
+
+}
+}
--- a/Libraries/LibWeb/Bindings/HTMLCanvasElementWrapper.cpp
+++ b/Libraries/LibWeb/Bindings/HTMLCanvasElementWrapper.cpp
@ -0,0 +1,67 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <AK/Function.h>
+#include <LibJS/Runtime/PrimitiveString.h>
+#include <LibJS/Runtime/Value.h>
+#include <LibWeb/Bindings/CanvasRenderingContext2DWrapper.h>
+#include <LibWeb/Bindings/HTMLCanvasElementWrapper.h>
+#include <LibWeb/DOM/CanvasRenderingContext2D.h>
+#include <LibWeb/DOM/HTMLCanvasElement.h>
+
+namespace Web {
+namespace Bindings {
+
+HTMLCanvasElementWrapper::HTMLCanvasElementWrapper(HTMLCanvasElement& element)
+    : NodeWrapper(element)
+{
+    put_native_function("getContext", [this](JS::Object*, const Vector<JS::Value>& arguments) -> JS::Value {
+        if (arguments.size() >= 1) {
+            dbg() << "Calling getContext on " << node().tag_name();
+            auto* context = node().get_context(arguments[0].to_string());
+            dbg() << "getContext got 2D context=" << context;
+            return wrap(heap(), *context);
+        }
+        return JS::js_undefined();
+    });
+}
+
+HTMLCanvasElementWrapper::~HTMLCanvasElementWrapper()
+{
+}
+
+HTMLCanvasElement& HTMLCanvasElementWrapper::node()
+{
+    return static_cast<HTMLCanvasElement&>(NodeWrapper::node());
+}
+
+const HTMLCanvasElement& HTMLCanvasElementWrapper::node() const
+{
+    return static_cast<const HTMLCanvasElement&>(NodeWrapper::node());
+}
+
+}
+}
--- a/Libraries/LibWeb/Bindings/HTMLCanvasElementWrapper.h
+++ b/Libraries/LibWeb/Bindings/HTMLCanvasElementWrapper.h
@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <LibWeb/Bindings/NodeWrapper.h>
+
+namespace Web {
+namespace Bindings {
+
+class HTMLCanvasElementWrapper : public NodeWrapper {
+public:
+    explicit HTMLCanvasElementWrapper(HTMLCanvasElement&);
+    virtual ~HTMLCanvasElementWrapper() override;
+
+    HTMLCanvasElement& node();
+    const HTMLCanvasElement& node() const;
+
+private:
+    virtual const char* class_name() const override { return "HTMLCanvasElementWrapper"; }
+};
+
+}
+}
--- a/Libraries/LibWeb/Bindings/NodeWrapper.cpp
+++ b/Libraries/LibWeb/Bindings/NodeWrapper.cpp
@ -26,12 +26,25 @@

 #include <LibJS/Runtime/PrimitiveString.h>
 #include <LibJS/Runtime/Value.h>
+#include <LibWeb/Bindings/DocumentWrapper.h>
+#include <LibWeb/Bindings/HTMLCanvasElementWrapper.h>
 #include <LibWeb/Bindings/NodeWrapper.h>
+#include <LibWeb/DOM/Document.h>
+#include <LibWeb/DOM/HTMLCanvasElement.h>
 #include <LibWeb/DOM/Node.h>

 namespace Web {
 namespace Bindings {

+NodeWrapper* wrap(JS::Heap& heap, Node& node)
+{
+    if (is<Document>(node))
+        return static_cast<NodeWrapper*>(wrap_impl(heap, to<Document>(node)));
+    if (is<HTMLCanvasElement>(node))
+        return static_cast<NodeWrapper*>(wrap_impl(heap, to<HTMLCanvasElement>(node)));
+    return static_cast<NodeWrapper*>(wrap_impl(heap, node));
+}
+
 NodeWrapper::NodeWrapper(Node& node)
    : EventTargetWrapper(node)
 {
--- a/Libraries/LibWeb/Bindings/NodeWrapper.h
+++ b/Libraries/LibWeb/Bindings/NodeWrapper.h
@ -43,5 +43,7 @@ private:
    virtual const char* class_name() const override { return "NodeWrapper"; }
 };

+NodeWrapper* wrap(JS::Heap&, Node&);
+
 }
 }
--- a/Libraries/LibWeb/Bindings/Wrappable.h
+++ b/Libraries/LibWeb/Bindings/Wrappable.h
@ -46,7 +46,7 @@ private:
 };

 template<class NativeObject>
-inline Wrapper* wrap(JS::Heap& heap, NativeObject& native_object)
+inline Wrapper* wrap_impl(JS::Heap& heap, NativeObject& native_object)
 {
    if (!native_object.wrapper())
        native_object.set_wrapper(*heap.allocate<typename NativeObject::WrapperType>(native_object));
--- a/Libraries/LibWeb/DOM/CanvasRenderingContext2D.cpp
+++ b/Libraries/LibWeb/DOM/CanvasRenderingContext2D.cpp
@ -0,0 +1,44 @@
+#include <AK/OwnPtr.h>
+#include <LibGfx/Painter.h>
+#include <LibWeb/DOM/CanvasRenderingContext2D.h>
+#include <LibWeb/DOM/HTMLCanvasElement.h>
+
+namespace Web {
+
+CanvasRenderingContext2D::CanvasRenderingContext2D(HTMLCanvasElement& element)
+    : m_element(element.make_weak_ptr())
+{
+}
+
+CanvasRenderingContext2D::~CanvasRenderingContext2D()
+{
+}
+
+void CanvasRenderingContext2D::set_fill_style(String style)
+{
+    m_fill_style = Gfx::Color::from_string(style).value_or(Color::Black);
+}
+
+String CanvasRenderingContext2D::fill_style() const
+{
+    return m_fill_style.to_string();
+}
+
+void CanvasRenderingContext2D::fill_rect(int x, int y, int width, int height)
+{
+    auto painter = this->painter();
+    if (!painter)
+        return;
+
+    painter->fill_rect({ x, y, width, height }, m_fill_style);
+}
+
+OwnPtr<Gfx::Painter> CanvasRenderingContext2D::painter()
+{
+    if (!m_element)
+        return nullptr;
+
+    return make<Gfx::Painter>(m_element->ensure_bitmap());
+}
+
+}
--- a/Libraries/LibWeb/DOM/CanvasRenderingContext2D.h
+++ b/Libraries/LibWeb/DOM/CanvasRenderingContext2D.h
@ -0,0 +1,38 @@
+#pragma once
+
+#include <AK/RefCounted.h>
+#include <LibGfx/Color.h>
+#include <LibGfx/Forward.h>
+#include <LibWeb/Bindings/Wrappable.h>
+
+namespace Web {
+
+class CanvasRenderingContext2D
+    : public RefCounted<CanvasRenderingContext2D>
+    , public Bindings::Wrappable {
+
+    AK_MAKE_NONCOPYABLE(CanvasRenderingContext2D);
+    AK_MAKE_NONMOVABLE(CanvasRenderingContext2D);
+
+public:
+    using WrapperType = Bindings::CanvasRenderingContext2DWrapper;
+
+    static NonnullRefPtr<CanvasRenderingContext2D> create(HTMLCanvasElement& element) { return adopt(*new CanvasRenderingContext2D(element)); }
+    ~CanvasRenderingContext2D();
+
+    void set_fill_style(String);
+    String fill_style() const;
+
+    void fill_rect(int x, int y, int width, int height);
+
+private:
+    explicit CanvasRenderingContext2D(HTMLCanvasElement&);
+
+    OwnPtr<Gfx::Painter> painter();
+
+    WeakPtr<HTMLCanvasElement> m_element;
+
+    Gfx::Color m_fill_style;
+};
+
+}
--- a/Libraries/LibWeb/DOM/ElementFactory.cpp
+++ b/Libraries/LibWeb/DOM/ElementFactory.cpp
@ -29,6 +29,7 @@
 #include <LibWeb/DOM/HTMLBRElement.h>
 #include <LibWeb/DOM/HTMLBlinkElement.h>
 #include <LibWeb/DOM/HTMLBodyElement.h>
+#include <LibWeb/DOM/HTMLCanvasElement.h>
 #include <LibWeb/DOM/HTMLFontElement.h>
 #include <LibWeb/DOM/HTMLFormElement.h>
 #include <LibWeb/DOM/HTMLHRElement.h>
@ -85,6 +86,8 @@ NonnullRefPtr<Element> create_element(Document& document, const String& tag_name
    }
    if (lowercase_tag_name == "script")
        return adopt(*new HTMLScriptElement(document, lowercase_tag_name));
+    if (lowercase_tag_name == "canvas")
+        return adopt(*new HTMLCanvasElement(document, lowercase_tag_name));
    return adopt(*new Element(document, lowercase_tag_name));
 }

--- a/Libraries/LibWeb/DOM/HTMLCanvasElement.cpp
+++ b/Libraries/LibWeb/DOM/HTMLCanvasElement.cpp
@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <LibGfx/Bitmap.h>
+#include <LibWeb/CSS/StyleResolver.h>
+#include <LibWeb/DOM/CanvasRenderingContext2D.h>
+#include <LibWeb/DOM/Document.h>
+#include <LibWeb/DOM/HTMLCanvasElement.h>
+#include <LibWeb/Layout/LayoutCanvas.h>
+
+namespace Web {
+
+HTMLCanvasElement::HTMLCanvasElement(Document& document, const String& tag_name)
+    : HTMLElement(document, tag_name)
+{
+}
+
+HTMLCanvasElement::~HTMLCanvasElement()
+{
+}
+
+int HTMLCanvasElement::preferred_width() const
+{
+    bool ok = false;
+    int width = attribute("width").to_int(ok);
+    if (ok)
+        return width;
+
+    return 300;
+}
+
+int HTMLCanvasElement::preferred_height() const
+{
+    bool ok = false;
+    int height = attribute("height").to_int(ok);
+    if (ok)
+        return height;
+
+    return 300;
+}
+
+RefPtr<LayoutNode> HTMLCanvasElement::create_layout_node(const StyleProperties* parent_style) const
+{
+    auto style = document().style_resolver().resolve_style(*this, parent_style);
+    auto display = style->string_or_fallback(CSS::PropertyID::Display, "inline");
+    if (display == "none")
+        return nullptr;
+    return adopt(*new LayoutCanvas(*this, move(style)));
+}
+
+CanvasRenderingContext2D* HTMLCanvasElement::get_context(String type)
+{
+    ASSERT(type.to_lowercase() == "2d");
+    dbg() << "get_context with m_context=" << m_context.ptr();
+    if (!m_context)
+        m_context = CanvasRenderingContext2D::create(*this);
+    dbg() << "get_context returning m_context=" << m_context.ptr();
+    return m_context;
+}
+
+Gfx::Bitmap& HTMLCanvasElement::ensure_bitmap()
+{
+    if (!m_bitmap || m_bitmap->size() != Gfx::Size(preferred_width(), preferred_height())) {
+        m_bitmap = Gfx::Bitmap::create(Gfx::BitmapFormat::RGBA32, { preferred_width(), preferred_height() });
+    }
+    return *m_bitmap;
+}
+
+}
--- a/Libraries/LibWeb/DOM/HTMLCanvasElement.h
+++ b/Libraries/LibWeb/DOM/HTMLCanvasElement.h
@ -0,0 +1,66 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <AK/ByteBuffer.h>
+#include <LibGfx/Forward.h>
+#include <LibWeb/DOM/HTMLElement.h>
+
+namespace Web {
+
+class LayoutDocument;
+
+class HTMLCanvasElement : public HTMLElement {
+public:
+    using WrapperType = Bindings::HTMLCanvasElementWrapper;
+
+    HTMLCanvasElement(Document&, const String& tag_name);
+    virtual ~HTMLCanvasElement() override;
+
+    int preferred_width() const;
+    int preferred_height() const;
+
+    const Gfx::Bitmap* bitmap() const { return m_bitmap; }
+    Gfx::Bitmap& ensure_bitmap();
+
+    CanvasRenderingContext2D* get_context(String type);
+
+private:
+    virtual RefPtr<LayoutNode> create_layout_node(const StyleProperties* parent_style) const override;
+
+    RefPtr<Gfx::Bitmap> m_bitmap;
+    RefPtr<CanvasRenderingContext2D> m_context;
+};
+
+template<>
+inline bool is<HTMLCanvasElement>(const Node& node)
+{
+    return is<Element>(node) && to<Element>(node).tag_name().to_lowercase() == "canvas";
+}
+
+
+}
--- a/Libraries/LibWeb/Forward.h
+++ b/Libraries/LibWeb/Forward.h
@ -28,19 +28,24 @@

 namespace Web {

+class CanvasRenderingContext2D;
 class Document;
 class Element;
 class EventListener;
 class EventTarget;
 class Frame;
+class HTMLElement;
+class HTMLCanvasElement;
 class HtmlView;
 class Node;

 namespace Bindings {

+class CanvasRenderingContext2DWrapper;
 class DocumentWrapper;
 class EventListenerWrapper;
 class EventTargetWrapper;
+class HTMLCanvasElementWrapper;
 class NodeWrapper;
 class Wrappable;
 class Wrapper;
--- a/Libraries/LibWeb/Layout/LayoutCanvas.cpp
+++ b/Libraries/LibWeb/Layout/LayoutCanvas.cpp
@ -0,0 +1,64 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <LibGUI/Painter.h>
+#include <LibGfx/Font.h>
+#include <LibGfx/StylePainter.h>
+#include <LibWeb/Layout/LayoutCanvas.h>
+
+namespace Web {
+
+LayoutCanvas::LayoutCanvas(const HTMLCanvasElement& element, NonnullRefPtr<StyleProperties> style)
+    : LayoutReplaced(element, move(style))
+{
+}
+
+LayoutCanvas::~LayoutCanvas()
+{
+}
+
+void LayoutCanvas::layout()
+{
+    rect().set_width(node().preferred_width());
+    rect().set_height(node().preferred_height());
+    LayoutReplaced::layout();
+}
+
+void LayoutCanvas::render(RenderingContext& context)
+{
+    if (!is_visible())
+        return;
+
+    // FIXME: This should be done at a different level. Also rect() does not include padding etc!
+    if (!context.viewport_rect().intersects(enclosing_int_rect(rect())))
+        return;
+
+    if (node().bitmap())
+        context.painter().draw_scaled_bitmap(enclosing_int_rect(rect()), *node().bitmap(), node().bitmap()->rect());
+    LayoutReplaced::render(context);
+}
+
+}
--- a/Libraries/LibWeb/Layout/LayoutCanvas.h
+++ b/Libraries/LibWeb/Layout/LayoutCanvas.h
@ -0,0 +1,57 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include <LibWeb/DOM/HTMLCanvasElement.h>
+#include <LibWeb/Layout/LayoutReplaced.h>
+
+namespace Web {
+
+class HTMLCanvasElement;
+
+class LayoutCanvas : public LayoutReplaced {
+public:
+    LayoutCanvas(const HTMLCanvasElement&, NonnullRefPtr<StyleProperties>);
+    virtual ~LayoutCanvas() override;
+
+    virtual void layout() override;
+    virtual void render(RenderingContext&) override;
+
+    const HTMLCanvasElement& node() const { return static_cast<const HTMLCanvasElement&>(LayoutReplaced::node()); }
+
+private:
+    virtual const char* class_name() const override { return "LayoutCanvas"; }
+    virtual bool is_canvas() const override { return true; }
+};
+
+template<>
+inline bool is<LayoutCanvas>(const LayoutNode& node)
+{
+    return node.is_canvas();
+}
+
+}
--- a/Libraries/LibWeb/Layout/LayoutNode.h
+++ b/Libraries/LibWeb/Layout/LayoutNode.h
@ -87,6 +87,7 @@ public:
    virtual bool is_replaced() const { return false; }
    virtual bool is_widget() const { return false; }
    virtual bool is_image() const { return false; }
+    virtual bool is_canvas() const { return false; }
    virtual bool is_box() const { return false; }
    virtual bool is_table() const { return false; }
    virtual bool is_table_row() const { return false; }
--- a/Libraries/LibWeb/Makefile
+++ b/Libraries/LibWeb/Makefile
@ -1,7 +1,9 @@
 LIBWEB_OBJS = \
+    Bindings/CanvasRenderingContext2DWrapper.o \
    Bindings/DocumentWrapper.o \
    Bindings/EventListenerWrapper.o \
    Bindings/EventTargetWrapper.o \
+    Bindings/HTMLCanvasElementWrapper.o \
    Bindings/NodeWrapper.o \
    Bindings/Wrappable.o \
    CSS/DefaultStyleSheetSource.o \
@ -14,6 +16,7 @@ LIBWEB_OBJS = \
    CSS/StyleRule.o \
    CSS/StyleSheet.o \
    CSS/StyleValue.o \
+    DOM/CanvasRenderingContext2D.o \
    DOM/CharacterData.o \
    DOM/Comment.o \
    DOM/Document.o \
@ -26,6 +29,7 @@ LIBWEB_OBJS = \
    DOM/HTMLBRElement.o \
    DOM/HTMLBlinkElement.o \
    DOM/HTMLBodyElement.o \
+    DOM/HTMLCanvasElement.o \
    DOM/HTMLElement.o \
    DOM/HTMLFontElement.o \
    DOM/HTMLFormElement.o \
@ -52,6 +56,7 @@ LIBWEB_OBJS = \
    Layout/LayoutBlock.o \
    Layout/LayoutBox.o \
    Layout/LayoutBreak.o \
+    Layout/LayoutCanvas.o \
    Layout/LayoutDocument.o \
    Layout/LayoutImage.o \
    Layout/LayoutInline.o \