/* -*- 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_PAINTING_MATRIXSTACK_H

#define MOZILLA_PAINTING_MATRIXSTACK_H

#include "nsTArray.h"

#include "mozilla/gfx/MatrixFwd.h"

namespace mozilla {

/**

 * MatrixStack stores a stack of matrices and keeps track of the accumulated

 * transform matrix.

 */

template<typename T>

class MatrixStack

{

public:

  MatrixStack() = default;

  ~MatrixStack() { MOZ_ASSERT(mMatrices.IsEmpty()); }

  /**

   * Returns the current accumulated transform matrix.

   */

  const T& CurrentMatrix() const { return mCurrentMatrix; }

  /**

   * Returns true if any matrices are currently pushed to the stack.

   */

  bool HasTransform() const { return mMatrices.Length() > 0; }

  /**

   * Pushes the given |aMatrix| to the stack.

   */

  void Push(const T& aMatrix)

  {

    mMatrices.AppendElement(mCurrentMatrix);

    mCurrentMatrix = aMatrix * mCurrentMatrix;

  }

  /**

   * Pops the most recently added matrix from the stack.

   */

  void Pop()

  {

    MOZ_ASSERT(mMatrices.Length() > 0);

    mCurrentMatrix = mMatrices.PopLastElement();

  }

private:

  T mCurrentMatrix;

  AutoTArray<T, 2> mMatrices;

};

typedef MatrixStack<gfx::Matrix4x4Flagged> MatrixStack4x4;

} // namespace mozilla

#endif /* MOZILLA_PAINTING_MATRIXSTACK_H */