1 files changed, 80 insertions, 0 deletions
diff --git a/gfx/2d/Helpers.h b/gfx/2d/Helpers.h
new file mode 100644
index 0000000000..349e99973a
--- /dev/null
+++ b/gfx/2d/Helpers.h
@@ -0,0 +1,80 @@
+/* -*- 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_2D_HELPERS_H_
+#define MOZILLA_GFX_2D_HELPERS_H_
+
+#include "2D.h"
+
+namespace mozilla {
+namespace gfx {
+
+class AutoRestoreTransform final {
+ public:
+  AutoRestoreTransform() = default;
+
+  explicit AutoRestoreTransform(DrawTarget* aTarget)
+      : mDrawTarget(aTarget), mOldTransform(aTarget->GetTransform()) {}
+
+  void Init(DrawTarget* aTarget) {
+    MOZ_ASSERT(!mDrawTarget || aTarget == mDrawTarget);
+    if (!mDrawTarget) {
+      mDrawTarget = aTarget;
+      mOldTransform = aTarget->GetTransform();
+    }
+  }
+
+  ~AutoRestoreTransform() {
+    if (mDrawTarget) {
+      mDrawTarget->SetTransform(mOldTransform);
+    }
+  }
+
+ private:
+  RefPtr<DrawTarget> mDrawTarget;
+  Matrix mOldTransform;
+};
+
+class AutoPopClips final {
+ public:
+  explicit AutoPopClips(DrawTarget* aTarget)
+      : mDrawTarget(aTarget), mPushCount(0) {
+    MOZ_ASSERT(mDrawTarget);
+  }
+
+  ~AutoPopClips() { PopAll(); }
+
+  void PushClip(const Path* aPath) {
+    mDrawTarget->PushClip(aPath);
+    ++mPushCount;
+  }
+
+  void PushClipRect(const Rect& aRect) {
+    mDrawTarget->PushClipRect(aRect);
+    ++mPushCount;
+  }
+
+  void PopClip() {
+    MOZ_ASSERT(mPushCount > 0);
+    mDrawTarget->PopClip();
+    --mPushCount;
+  }
+
+  void PopAll() {
+    while (mPushCount-- > 0) {
+      mDrawTarget->PopClip();
+    }
+  }
+
+ private:
+  RefPtr<DrawTarget> mDrawTarget;
+  int32_t mPushCount;
+};
+
+}  // namespace gfx
+}  // namespace mozilla
+
+#endif  // MOZILLA_GFX_2D_HELPERS_H_