LibGfx: Add simple VectorGraphic abstract base class

This is currently very bare-bones with just the size and a few methods
to rasterize/draw the graphic.

Userland/Libraries/LibGfx/VectorGraphic.h

@@ -0,0 +1,30 @@
+/*
+ * Copyright (c) 2023, MacDue <macdue@dueutil.tech>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/RefCounted.h>
+#include <LibGfx/Bitmap.h>
+#include <LibGfx/Forward.h>
+#include <LibGfx/Size.h>
+
+namespace Gfx {
+
+class VectorGraphic : public RefCounted<VectorGraphic> {
+public:
+    virtual IntSize intrinsic_size() const = 0;
+    virtual void draw_transformed(Painter&, AffineTransform) const = 0;
+
+    IntSize size() const { return intrinsic_size(); }
+    IntRect rect() const { return { {}, size() }; }
+
+    ErrorOr<NonnullRefPtr<Gfx::Bitmap>> bitmap(IntSize size, AffineTransform = {}) const;
+    void draw_into(Painter&, IntRect const& dest, AffineTransform = {}) const;
+
+    virtual ~VectorGraphic() = default;
+};
+
+};