MARKUS

// Copyright (c) Wiesław Šoltés. All rights reserved.

// Licensed under the MIT license. See LICENSE file in the project root for full license information.

using System.Windows;

using System.Windows.Media;

using static System.Math;

namespace ZoomAndPan

{

    /// <summary>

    /// WPF Matrix helper methods.

    /// </summary>

    public static class MatrixHelper

    {

        /// <summary>

        /// Creates a translation matrix using the specified offsets.

        /// </summary>

        /// <param name="offsetX">X-coordinate offset.</param>

        /// <param name="offsetY">Y-coordinate offset.</param>

        /// <returns>The created translation matrix.</returns>

        public static Matrix Translate(double offsetX, double offsetY)

        {

            return new Matrix(1.0, 0.0, 0.0, 1.0, offsetX, offsetY);

        }

        /// <summary>

        /// Prepends a translation around the center of provided matrix.

        /// </summary>

        /// <param name="matrix">The matrix to prepend translation.</param>

        /// <param name="offsetX">X-coordinate offset.</param>

        /// <param name="offsetY">Y-coordinate offset.</param>

        /// <returns>The created translation matrix.</returns>

        public static Matrix TranslatePrepend(Matrix matrix, double offsetX, double offsetY)

        {

            return Translate(offsetX, offsetY) * matrix;

        }

        /// <summary>

        /// Creates a matrix that scales along the x-axis and y-axis.

        /// </summary>

        /// <param name="scaleX">Scaling factor that is applied along the x-axis.</param>

        /// <param name="scaleY">Scaling factor that is applied along the y-axis.</param>

        /// <returns>The created scaling matrix.</returns>

        public static Matrix Scale(double scaleX, double scaleY)

        {

            return new Matrix(scaleX, 0, 0, scaleY, 0.0, 0.0);

        }

        /// <summary>

        /// Creates a matrix that is scaling from a specified center.

        /// </summary>

        /// <param name="scaleX">Scaling factor that is applied along the x-axis.</param>

        /// <param name="scaleY">Scaling factor that is applied along the y-axis.</param>

        /// <param name="centerX">The center X-coordinate of the scaling.</param>

        /// <param name="centerY">The center Y-coordinate of the scaling.</param>

        /// <returns>The created scaling matrix.</returns>

        public static Matrix ScaleAt(double scaleX, double scaleY, double centerX, double centerY)

        {

            return new Matrix(scaleX, 0, 0, scaleY, centerX - (scaleX * centerX), centerY - (scaleY * centerY));

        }

        /// <summary>

        /// Prepends a scale around the center of provided matrix.

        /// </summary>

        /// <param name="matrix">The matrix to prepend scale.</param>

        /// <param name="scaleX">Scaling factor that is applied along the x-axis.</param>

        /// <param name="scaleY">Scaling factor that is applied along the y-axis.</param>

        /// <param name="centerX">The center X-coordinate of the scaling.</param>

        /// <param name="centerY">The center Y-coordinate of the scaling.</param>

        /// <returns>The created scaling matrix.</returns>

        public static Matrix ScaleAtPrepend(Matrix matrix, double scaleX, double scaleY, double centerX, double centerY)

        {

            return ScaleAt(scaleX, scaleY, centerX, centerY) * matrix;

        }

        /// <summary>

        /// Creates a skew matrix.

        /// </summary>

        /// <param name="angleX">Angle of skew along the X-axis in radians.</param>

        /// <param name="angleY">Angle of skew along the Y-axis in radians.</param>

        /// <returns>When the method completes, contains the created skew matrix.</returns>

        public static Matrix Skew(float angleX, float angleY)

        {

            return new Matrix(1.0, Tan(angleX), Tan(angleY), 1.0, 0.0, 0.0);

        }

        /// <summary>

        /// Creates a matrix that rotates.

        /// </summary>

        /// <param name="radians">Angle of rotation in radians. Angles are measured clockwise when looking along the rotation axis.</param>

        /// <returns>The created rotation matrix.</returns>

        public static Matrix Rotation(double radians)

        {

            double cos = Cos(radians);

            double sin = Sin(radians);

            return new Matrix(cos, sin, -sin, cos, 0, 0);

        }

        /// <summary>

        /// Creates a matrix that rotates about a specified center.

        /// </summary>

        /// <param name="angle">Angle of rotation in radians.</param>

        /// <param name="centerX">The center X-coordinate of the rotation.</param>

        /// <param name="centerY">The center Y-coordinate of the rotation.</param>

        /// <returns>The created rotation matrix.</returns>

        public static Matrix Rotation(double angle, double centerX, double centerY)

        {

            return Translate(-centerX, -centerY) * Rotation(angle) * Translate(centerX, centerY);

        }

        /// <summary>

        /// Creates a matrix that rotates about a specified center.

        /// </summary>

        /// <param name="angle">Angle of rotation in radians.</param>

        /// <param name="center">The center of the rotation.</param>

        /// <returns>The created rotation matrix.</returns>

        public static Matrix Rotation(double angle, Vector center)

        {

            return Translate(-center.X, -center.Y) * Rotation(angle) * Translate(center.X, center.Y);

        }

        /// <summary>

        /// Transforms a point by this matrix.

        /// </summary>

        /// <param name="matrix">The matrix to use as a transformation matrix.</param>

        /// <param name="point">>The original point to apply the transformation.</param>

        /// <returns>The result of the transformation for the input point.</returns>

        public static Point TransformPoint(Matrix matrix, Point point)

        {

            return new Point(

                (point.X * matrix.M11) + (point.Y * matrix.M21) + matrix.OffsetX,

                (point.X * matrix.M12) + (point.Y * matrix.M22) + matrix.OffsetY);

        }

    }

}