1 files changed, 95 insertions, 0 deletions
diff --git a/gfx/src/nsPoint.h b/gfx/src/nsPoint.h
new file mode 100644
index 0000000000..86688d2142
--- /dev/null
+++ b/gfx/src/nsPoint.h
@@ -0,0 +1,95 @@
+/* -*- 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 NSPOINT_H
+#define NSPOINT_H
+
+#include <cstdint>
+#include "nsCoord.h"
+#include "mozilla/gfx/BasePoint.h"
+#include "mozilla/gfx/Point.h"
+
+// nsIntPoint represents a point in one of the types of pixels.
+// Uses of nsIntPoint should eventually be converted to CSSIntPoint,
+// LayoutDeviceIntPoint, etc. (see layout/base/Units.h).
+typedef mozilla::gfx::IntPoint nsIntPoint;
+
+// nsPoint represents a point in app units.
+
+struct nsPoint : public mozilla::gfx::BasePoint<nscoord, nsPoint> {
+  typedef mozilla::gfx::BasePoint<nscoord, nsPoint> Super;
+
+  nsPoint() = default;
+  nsPoint(const nsPoint& aPoint) = default;
+  nsPoint(nscoord aX, nscoord aY) : Super(aX, aY) {}
+
+  inline nsIntPoint ScaleToNearestPixels(float aXScale, float aYScale,
+                                         nscoord aAppUnitsPerPixel) const;
+  inline nsIntPoint ToNearestPixels(nscoord aAppUnitsPerPixel) const;
+
+  /**
+   * Return this point scaled to a different appunits per pixel (APP) ratio.
+   * @param aFromAPP the APP to scale from
+   * @param aToAPP the APP to scale to
+   */
+  [[nodiscard]] inline nsPoint ScaleToOtherAppUnits(int32_t aFromAPP,
+                                                    int32_t aToAPP) const;
+
+  [[nodiscard]] inline nsPoint RemoveResolution(const float resolution) const;
+  [[nodiscard]] inline nsPoint ApplyResolution(const float resolution) const;
+};
+
+inline nsPoint ToAppUnits(const nsIntPoint& aPoint, nscoord aAppUnitsPerPixel);
+
+inline nsIntPoint nsPoint::ScaleToNearestPixels(
+    float aXScale, float aYScale, nscoord aAppUnitsPerPixel) const {
+  return nsIntPoint(
+      NSToIntRoundUp(NSAppUnitsToDoublePixels(x, aAppUnitsPerPixel) * aXScale),
+      NSToIntRoundUp(NSAppUnitsToDoublePixels(y, aAppUnitsPerPixel) * aYScale));
+}
+
+inline nsIntPoint nsPoint::ToNearestPixels(nscoord aAppUnitsPerPixel) const {
+  return ScaleToNearestPixels(1.0f, 1.0f, aAppUnitsPerPixel);
+}
+
+inline nsPoint nsPoint::ScaleToOtherAppUnits(int32_t aFromAPP,
+                                             int32_t aToAPP) const {
+  if (aFromAPP != aToAPP) {
+    nsPoint point;
+    point.x = NSToCoordRound(NSCoordScale(x, aFromAPP, aToAPP));
+    point.y = NSToCoordRound(NSCoordScale(y, aFromAPP, aToAPP));
+    return point;
+  }
+  return *this;
+}
+
+inline nsPoint nsPoint::RemoveResolution(const float resolution) const {
+  if (resolution != 1.0f) {
+    nsPoint point;
+    point.x = NSToCoordRound(NSCoordToFloat(x) / resolution);
+    point.y = NSToCoordRound(NSCoordToFloat(y) / resolution);
+    return point;
+  }
+  return *this;
+}
+
+inline nsPoint nsPoint::ApplyResolution(const float resolution) const {
+  if (resolution != 1.0f) {
+    nsPoint point;
+    point.x = NSToCoordRound(NSCoordToFloat(x) * resolution);
+    point.y = NSToCoordRound(NSCoordToFloat(y) * resolution);
+    return point;
+  }
+  return *this;
+}
+
+// app units are integer multiples of pixels, so no rounding needed
+inline nsPoint ToAppUnits(const nsIntPoint& aPoint, nscoord aAppUnitsPerPixel) {
+  return nsPoint(NSIntPixelsToAppUnits(aPoint.x, aAppUnitsPerPixel),
+                 NSIntPixelsToAppUnits(aPoint.y, aAppUnitsPerPixel));
+}
+
+#endif /* NSPOINT_H */