1 files changed, 111 insertions, 0 deletions
diff --git a/gfx/layers/apz/src/APZPublicUtils.cpp b/gfx/layers/apz/src/APZPublicUtils.cpp
new file mode 100644
index 0000000000..6902e0738c
--- /dev/null
+++ b/gfx/layers/apz/src/APZPublicUtils.cpp
@@ -0,0 +1,111 @@
+/* -*- 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/. */
+
+#include "mozilla/layers/APZPublicUtils.h"
+
+#include "AsyncPanZoomController.h"
+#include "mozilla/HelperMacros.h"
+#include "mozilla/StaticPrefs_general.h"
+
+namespace mozilla {
+namespace layers {
+
+namespace apz {
+
+/*static*/ void InitializeGlobalState() {
+  MOZ_ASSERT(NS_IsMainThread());
+  AsyncPanZoomController::InitializeGlobalState();
+}
+
+/*static*/ const ScreenMargin CalculatePendingDisplayPort(
+    const FrameMetrics& aFrameMetrics, const ParentLayerPoint& aVelocity) {
+  return AsyncPanZoomController::CalculatePendingDisplayPort(
+      aFrameMetrics, aVelocity, AsyncPanZoomController::ZoomInProgress::No);
+}
+
+/*static*/ gfx::IntSize GetDisplayportAlignmentMultiplier(
+    const ScreenSize& aBaseSize) {
+  return AsyncPanZoomController::GetDisplayportAlignmentMultiplier(aBaseSize);
+}
+
+ScrollAnimationBezierPhysicsSettings ComputeBezierAnimationSettingsForOrigin(
+    ScrollOrigin aOrigin) {
+  int32_t minMS = 0;
+  int32_t maxMS = 0;
+  bool isOriginSmoothnessEnabled = false;
+
+#define READ_DURATIONS(prefbase)                                              \
+  isOriginSmoothnessEnabled = StaticPrefs::general_smoothScroll() &&          \
+                              StaticPrefs::general_smoothScroll_##prefbase(); \
+  if (isOriginSmoothnessEnabled) {                                            \
+    minMS = StaticPrefs::general_smoothScroll_##prefbase##_durationMinMS();   \
+    maxMS = StaticPrefs::general_smoothScroll_##prefbase##_durationMaxMS();   \
+  }
+
+  switch (aOrigin) {
+    case ScrollOrigin::Pixels:
+      READ_DURATIONS(pixels)
+      break;
+    case ScrollOrigin::Lines:
+      READ_DURATIONS(lines)
+      break;
+    case ScrollOrigin::Pages:
+      READ_DURATIONS(pages)
+      break;
+    case ScrollOrigin::MouseWheel:
+      READ_DURATIONS(mouseWheel)
+      break;
+    case ScrollOrigin::Scrollbars:
+      READ_DURATIONS(scrollbars)
+      break;
+    default:
+      READ_DURATIONS(other)
+      break;
+  }
+
+#undef READ_DURATIONS
+
+  if (isOriginSmoothnessEnabled) {
+    static const int32_t kSmoothScrollMaxAllowedAnimationDurationMS = 10000;
+    maxMS = clamped(maxMS, 0, kSmoothScrollMaxAllowedAnimationDurationMS);
+    minMS = clamped(minMS, 0, maxMS);
+  }
+
+  // Keep the animation duration longer than the average event intervals
+  // (to "connect" consecutive scroll animations before the scroll comes to a
+  // stop).
+  double intervalRatio =
+      ((double)StaticPrefs::general_smoothScroll_durationToIntervalRatio()) /
+      100.0;
+
+  // Duration should be at least as long as the intervals -> ratio is at least 1
+  intervalRatio = std::max(1.0, intervalRatio);
+
+  return ScrollAnimationBezierPhysicsSettings{minMS, maxMS, intervalRatio};
+}
+
+ScrollMode GetScrollModeForOrigin(ScrollOrigin origin) {
+  if (!StaticPrefs::general_smoothScroll()) return ScrollMode::Instant;
+  switch (origin) {
+    case ScrollOrigin::Lines:
+      return StaticPrefs::general_smoothScroll_lines() ? ScrollMode::Smooth
+                                                       : ScrollMode::Instant;
+    case ScrollOrigin::Pages:
+      return StaticPrefs::general_smoothScroll_pages() ? ScrollMode::Smooth
+                                                       : ScrollMode::Instant;
+    case ScrollOrigin::Other:
+      return StaticPrefs::general_smoothScroll_other() ? ScrollMode::Smooth
+                                                       : ScrollMode::Instant;
+    default:
+      MOZ_ASSERT(false, "Unknown keyboard scroll origin");
+      return StaticPrefs::general_smoothScroll() ? ScrollMode::Smooth
+                                                 : ScrollMode::Instant;
+  }
+}
+
+}  // namespace apz
+}  // namespace layers
+}  // namespace mozilla