1 files changed, 97 insertions, 0 deletions
diff --git a/gfx/2d/Helpers.h b/gfx/2d/Helpers.h
new file mode 100644
index 000000000..11c7eec5d
--- /dev/null
+++ b/gfx/2d/Helpers.h
@@ -0,0 +1,97 @@
+/* -*- Mode: C++; tab-width: 20; 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_2D_HELPERS_H_
+#define MOZILLA_GFX_2D_HELPERS_H_
+
+#include "2D.h"
+
+namespace mozilla {
+namespace gfx {
+
+class AutoRestoreTransform
+{
+ public:
+  AutoRestoreTransform()
+  {
+  }
+
+  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
+{
+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_