summaryrefslogtreecommitdiffstats
path: root/layout/painting/MatrixStack.h
diff options
context:
space:
mode:
Diffstat (limited to 'layout/painting/MatrixStack.h')
-rw-r--r--layout/painting/MatrixStack.h61
1 files changed, 61 insertions, 0 deletions
diff --git a/layout/painting/MatrixStack.h b/layout/painting/MatrixStack.h
new file mode 100644
index 0000000000..320d08317b
--- /dev/null
+++ b/layout/painting/MatrixStack.h
@@ -0,0 +1,61 @@
+/* -*- 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 */