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+/* -*- 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 nsTransform2D_h___
+#define nsTransform2D_h___
+
+#include "nsCoord.h"
+
+class nsTransform2D {
+ private:
+ /**
+ * This represents the following matrix (note that the order of row/column
+ * indices is opposite to usual notation)
+ *
+ * / m00 0 m20 \
+ * M = | 0 m11 m21 |
+ * \ 0 0 1 /
+ *
+ * Transformation of a coordinate (x, y) is obtained by setting
+ * v = (x, y, 1)^T and evaluating M . v
+ **/
+
+ float m00, m11, m20, m21;
+
+ public:
+ nsTransform2D(void) {
+ m20 = m21 = 0.0f;
+ m00 = m11 = 1.0f;
+ }
+
+ ~nsTransform2D(void) = default;
+
+ /**
+ * set this transform to a translation
+ *
+ * @param tx, x translation
+ * @param ty, y translation
+ **/
+
+ void SetToTranslate(float tx, float ty) {
+ m00 = m11 = 1.0f;
+ m20 = tx;
+ m21 = ty;
+ }
+
+ /**
+ * get the translation portion of this transform
+ *
+ * @param pt, Point to return translation values in
+ **/
+
+ void GetTranslationCoord(nscoord* ptX, nscoord* ptY) const {
+ *ptX = NSToCoordRound(m20);
+ *ptY = NSToCoordRound(m21);
+ }
+
+ /**
+ * apply matrix to vector
+ *
+ * @param pt Point to transform
+ **/
+
+ void TransformCoord(nscoord* ptX, nscoord* ptY) const;
+
+ /**
+ * apply matrix to rect
+ *
+ * @param rect Rect to transform
+ **/
+
+ void TransformCoord(nscoord* aX, nscoord* aY, nscoord* aWidth,
+ nscoord* aHeight) const;
+
+ /**
+ * add a scale to a Transform via x, y pair
+ *
+ * @param ptX x value to add as x scale
+ * @param ptY y value to add as y scale
+ **/
+
+ void AddScale(float ptX, float ptY) {
+ m00 *= ptX;
+ m11 *= ptY;
+ }
+
+ /**
+ * Set the scale (overriding any previous calls to AddScale, but leaving
+ * any existing translation).
+ *
+ * @param ptX x value to add as x scale
+ * @param ptY y value to add as y scale
+ **/
+
+ void SetScale(float ptX, float ptY) {
+ m00 = ptX;
+ m11 = ptY;
+ }
+};
+
+#endif