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+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
+ * 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 "mozilla/Attributes.h"
+
+namespace mozilla {
+namespace 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;
+ }
+
+ // 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);
+ }
+};
+
+} // namespace gfx
+} // namespace mozilla
+
+#endif /* MOZILLA_GFX_BASESIZE_H_ */