1 files changed, 113 insertions, 0 deletions
diff --git a/gfx/2d/BaseSize.h b/gfx/2d/BaseSize.h
new file mode 100644
index 0000000000..536a194594
--- /dev/null
+++ b/gfx/2d/BaseSize.h
@@ -0,0 +1,113 @@
+/* -*- 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/. */
+
+#ifndef MOZILLA_GFX_BASESIZE_H_
+#define MOZILLA_GFX_BASESIZE_H_
+
+#include <algorithm>
+#include <ostream>
+
+#include "mozilla/Attributes.h"
+
+namespace mozilla::gfx {
+
+/**
+ * Do not use this class directly. Subclass it, pass that subclass as the
+ * Sub parameter, and only use that subclass. This allows methods to safely
+ * cast 'this' to 'Sub*'.
+ */
+template <class T, class Sub>
+struct BaseSize {
+  union {
+    struct {
+      T width, height;
+    };
+    T components[2];
+  };
+
+  // Constructors
+  constexpr BaseSize() : width(0), height(0) {}
+  constexpr BaseSize(T aWidth, T aHeight) : width(aWidth), height(aHeight) {}
+
+  void SizeTo(T aWidth, T aHeight) {
+    width = aWidth;
+    height = aHeight;
+  }
+
+  bool IsEmpty() const { return width <= 0 || height <= 0; }
+
+  bool IsSquare() const { return width == height; }
+
+  MOZ_ALWAYS_INLINE T Width() const { return width; }
+  MOZ_ALWAYS_INLINE T Height() const { return height; }
+
+  // Note that '=' isn't defined so we'll get the
+  // compiler generated default assignment operator
+
+  bool operator==(const Sub& aSize) const {
+    return width == aSize.width && height == aSize.height;
+  }
+  bool operator!=(const Sub& aSize) const {
+    return width != aSize.width || height != aSize.height;
+  }
+  bool operator<=(const Sub& aSize) const {
+    return width <= aSize.width && height <= aSize.height;
+  }
+  bool operator<(const Sub& aSize) const {
+    return *this <= aSize && *this != aSize;
+  }
+
+  Sub operator+(const Sub& aSize) const {
+    return Sub(width + aSize.width, height + aSize.height);
+  }
+  Sub operator-(const Sub& aSize) const {
+    return Sub(width - aSize.width, height - aSize.height);
+  }
+  Sub& operator+=(const Sub& aSize) {
+    width += aSize.width;
+    height += aSize.height;
+    return *static_cast<Sub*>(this);
+  }
+  Sub& operator-=(const Sub& aSize) {
+    width -= aSize.width;
+    height -= aSize.height;
+    return *static_cast<Sub*>(this);
+  }
+
+  Sub operator*(T aScale) const { return Sub(width * aScale, height * aScale); }
+  Sub operator/(T aScale) const { return Sub(width / aScale, height / aScale); }
+  friend Sub operator*(T aScale, const Sub& aSize) {
+    return Sub(aScale * aSize.width, aScale * aSize.height);
+  }
+  void Scale(T aXScale, T aYScale) {
+    width *= aXScale;
+    height *= aYScale;
+  }
+
+  Sub operator*(const Sub& aSize) const {
+    return Sub(width * aSize.width, height * aSize.height);
+  }
+  Sub operator/(const Sub& aSize) const {
+    return Sub(width / aSize.width, height / aSize.height);
+  }
+
+  friend Sub Min(const Sub& aA, const Sub& aB) {
+    return Sub(std::min(aA.width, aB.width), std::min(aA.height, aB.height));
+  }
+
+  friend Sub Max(const Sub& aA, const Sub& aB) {
+    return Sub(std::max(aA.width, aB.width), std::max(aA.height, aB.height));
+  }
+
+  friend std::ostream& operator<<(std::ostream& aStream,
+                                  const BaseSize<T, Sub>& aSize) {
+    return aStream << '(' << aSize.width << " x " << aSize.height << ')';
+  }
+};
+
+}  // namespace mozilla::gfx
+
+#endif /* MOZILLA_GFX_BASESIZE_H_ */