1 files changed, 39 insertions, 0 deletions
diff --git a/layout/generic/ColumnUtils.h b/layout/generic/ColumnUtils.h
new file mode 100644
index 0000000000..15fa0efca5
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+++ b/layout/generic/ColumnUtils.h
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+/* -*- 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/. */
+
+/* A namespace class for static muti-column utilities. */
+
+#ifndef mozilla_ColumnUtils_h
+#define mozilla_ColumnUtils_h
+
+#include "nsCoord.h"
+#include "nsStyleConsts.h"
+
+class nsContainerFrame;
+
+namespace mozilla {
+
+// ColumnUtils is a namespace class containing utility functions used by
+// multi-column containers like ColumnSetWrapperFrame and nsColumnSetFrame.
+//
+class ColumnUtils final {
+ public:
+  // Compute used value of 'column-gap' for aFrame.
+  static nscoord GetColumnGap(const nsContainerFrame* aFrame,
+                              nscoord aPercentageBasis);
+
+  // Clamp used column width to a minimum of 1px.
+  static nscoord ClampUsedColumnWidth(const Length& aColumnWidth);
+
+  // Compute the intrinsic inline-size of a column container, given a non-zero
+  // column-count, column gap, and column box's inline-size.
+  static nscoord IntrinsicISize(uint32_t aColCount, nscoord aColGap,
+                                nscoord aColISize);
+};
+
+}  // namespace mozilla
+
+#endif  // mozilla_ColumnUtils_h