1 files changed, 32 insertions, 0 deletions
diff --git a/layout/generic/AspectRatio.cpp b/layout/generic/AspectRatio.cpp
new file mode 100644
index 0000000000..2fe51fed5e
--- /dev/null
+++ b/layout/generic/AspectRatio.cpp
@@ -0,0 +1,32 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "AspectRatio.h"
+
+#include "mozilla/WritingModes.h"
+
+namespace mozilla {
+
+nscoord AspectRatio::ComputeRatioDependentSize(
+    LogicalAxis aRatioDependentAxis, const WritingMode& aWM,
+    nscoord aRatioDeterminingSize,
+    const LogicalSize& aContentBoxSizeToBoxSizingAdjust) const {
+  MOZ_ASSERT(*this,
+             "Infinite or zero ratio may have undefined behavior when "
+             "computing the size");
+  const LogicalSize& boxSizingAdjust = mUseBoxSizing == UseBoxSizing::No
+                                           ? LogicalSize(aWM)
+                                           : aContentBoxSizeToBoxSizingAdjust;
+  return aRatioDependentAxis == LogicalAxis::eLogicalAxisInline
+             ? ConvertToWritingMode(aWM).ApplyTo(aRatioDeterminingSize +
+                                                 boxSizingAdjust.BSize(aWM)) -
+                   boxSizingAdjust.ISize(aWM)
+             : ConvertToWritingMode(aWM).Inverted().ApplyTo(
+                   aRatioDeterminingSize + boxSizingAdjust.ISize(aWM)) -
+                   boxSizingAdjust.BSize(aWM);
+}
+
+}  // namespace mozilla