LibWeb: Move CSS::EdgeRect into its own files

Also remove the unused StyleValue::to_rect() because an EdgeRect is only
ever held by a RectStyleValue.

1 files changed, 39 insertions, 0 deletions

diff --git a/Userland/Libraries/LibWeb/CSS/EdgeRect.cpp b/Userland/Libraries/LibWeb/CSS/EdgeRect.cpp
new file mode 100644
index 0000000000..df862baca9
--- /dev/null
+++ b/Userland/Libraries/LibWeb/CSS/EdgeRect.cpp
@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2021-2023, Sam Atkins <atkinssj@serenityos.org>
+ * Copyright (c) 2021, Tobias Christiansen <tobyase@serenityos.org>
+ * Copyright (c) 2022-2023, MacDue <macdue@dueutil.tech>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "EdgeRect.h"
+
+namespace Web::CSS {
+
+// https://www.w3.org/TR/CSS2/visufx.html#value-def-shape
+Gfx::FloatRect EdgeRect::resolved(Layout::Node const& layout_node, Gfx::FloatRect border_box) const
+{
+    // In CSS 2.1, the only valid <shape> value is: rect(<top>, <right>, <bottom>, <left>) where
+    // <top> and <bottom> specify offsets from the top border edge of the box, and <right>, and
+    // <left> specify offsets from the left border edge of the box.
+
+    // The value 'auto' means that a given edge of the clipping region will be the same as the edge
+    // of the element's generated border box (i.e., 'auto' means the same as '0' for <top> and
+    // <left>, the same as the used value of the height plus the sum of vertical padding and border
+    // widths for <bottom>, and the same as the used value of the width plus the sum of the
+    // horizontal padding and border widths for <right>, such that four 'auto' values result in the
+    // clipping region being the same as the element's border box).
+    auto left = border_box.left() + (left_edge.is_auto() ? 0 : left_edge.to_px(layout_node)).value();
+    auto top = border_box.top() + (top_edge.is_auto() ? 0 : top_edge.to_px(layout_node)).value();
+    auto right = border_box.left() + (right_edge.is_auto() ? border_box.width() : right_edge.to_px(layout_node)).value();
+    auto bottom = border_box.top() + (bottom_edge.is_auto() ? border_box.height() : bottom_edge.to_px(layout_node)).value();
+    return Gfx::FloatRect {
+        left,
+        top,
+        right - left,
+        bottom - top
+    };
+}
+
+}