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. :^)

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()
+{
+}
+
+}
+}

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&);
+
+}
+}

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());
+}
+
+}
+}

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"; }
+};
+
+}
+}

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)
 {

Libraries/LibWeb/Bindings/NodeWrapper.h

@@ -43,5 +43,7 @@ private:
     virtual const char* class_name() const override { return "NodeWrapper"; }
 };
 
+NodeWrapper* wrap(JS::Heap&, Node&);
+
 }
 }

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));