1 files changed, 45 insertions, 0 deletions
diff --git a/layout/style/StyleComplexColor.h b/layout/style/StyleComplexColor.h
new file mode 100644
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+++ b/layout/style/StyleComplexColor.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/. */
+
+/* represent a color combines a numeric color and currentcolor */
+
+#ifndef mozilla_StyleComplexColor_h_
+#define mozilla_StyleComplexColor_h_
+
+#include "nsColor.h"
+
+namespace mozilla {
+
+/**
+ * This struct represents a combined color from a numeric color and
+ * the current foreground color (currentcolor keyword).
+ * Conceptually, the formula is "color * (1 - p) + currentcolor * p"
+ * where p is mForegroundRatio. See mozilla::LinearBlendColors for
+ * the actual algorithm.
+ */
+struct StyleComplexColor
+{
+  nscolor mColor;
+  uint8_t mForegroundRatio;
+
+  static StyleComplexColor FromColor(nscolor aColor) { return {aColor, 0}; }
+  static StyleComplexColor CurrentColor() { return {NS_RGBA(0, 0, 0, 0), 255}; }
+
+  bool IsNumericColor() const { return mForegroundRatio == 0; }
+  bool IsCurrentColor() const { return mForegroundRatio == 255; }
+
+  bool operator==(const StyleComplexColor& aOther) const {
+    return mForegroundRatio == aOther.mForegroundRatio &&
+           (IsCurrentColor() || mColor == aOther.mColor);
+  }
+  bool operator!=(const StyleComplexColor& aOther) const {
+    return !(*this == aOther);
+  }
+};
+
+}
+
+#endif // mozilla_StyleComplexColor_h_