From 3e786dbadb4df265eb958dba8be06f7e48ad0664 Mon Sep 17 00:00:00 2001
From: Nikita Tsukanov <keks9n@gmail.com>
Date: Sat, 27 Jul 2019 11:04:04 +0300
Subject: [PATCH] PixelVector and stuff

---
 src/Avalonia.Visuals/Media/PixelPoint.cs  |  55 ++++++
 src/Avalonia.Visuals/Media/PixelRect.cs   |  11 ++
 src/Avalonia.Visuals/Media/PixelVector.cs | 205 ++++++++++++++++++++++
 3 files changed, 271 insertions(+)
 create mode 100644 src/Avalonia.Visuals/Media/PixelVector.cs

diff --git a/src/Avalonia.Visuals/Media/PixelPoint.cs b/src/Avalonia.Visuals/Media/PixelPoint.cs
index 995781ee9f..1fc102045e 100644
--- a/src/Avalonia.Visuals/Media/PixelPoint.cs
+++ b/src/Avalonia.Visuals/Media/PixelPoint.cs
@@ -59,6 +59,59 @@ namespace Avalonia
         {
             return !(left == right);
         }
+        
+        /// <summary>
+        /// Converts the <see cref="Point"/> to a <see cref="Vector"/>.
+        /// </summary>
+        /// <param name="p">The point.</param>
+        public static implicit operator PixelVector(PixelPoint p)
+        {
+            return new PixelVector(p.X, p.Y);
+        }
+        
+        /// <summary>
+        /// Adds two points.
+        /// </summary>
+        /// <param name="a">The first point.</param>
+        /// <param name="b">The second point.</param>
+        /// <returns>A point that is the result of the addition.</returns>
+        public static PixelPoint operator +(PixelPoint a, PixelPoint b)
+        {
+            return new PixelPoint(a.X + b.X, a.Y + b.Y);
+        }
+
+        /// <summary>
+        /// Adds a vector to a point.
+        /// </summary>
+        /// <param name="a">The point.</param>
+        /// <param name="b">The vector.</param>
+        /// <returns>A point that is the result of the addition.</returns>
+        public static PixelPoint operator +(PixelPoint a, PixelVector b)
+        {
+            return new PixelPoint(a.X + b.X, a.Y + b.Y);
+        }
+
+        /// <summary>
+        /// Subtracts two points.
+        /// </summary>
+        /// <param name="a">The first point.</param>
+        /// <param name="b">The second point.</param>
+        /// <returns>A point that is the result of the subtraction.</returns>
+        public static PixelPoint operator -(PixelPoint a, PixelPoint b)
+        {
+            return new PixelPoint(a.X - b.X, a.Y - b.Y);
+        }
+
+        /// <summary>
+        /// Subtracts a vector from a point.
+        /// </summary>
+        /// <param name="a">The point.</param>
+        /// <param name="b">The vector.</param>
+        /// <returns>A point that is the result of the subtraction.</returns>
+        public static PixelPoint operator -(PixelPoint a, PixelVector b)
+        {
+            return new PixelPoint(a.X - b.X, a.Y - b.Y);
+        }
 
         /// <summary>
         /// Parses a <see cref="PixelPoint"/> string.
@@ -106,6 +159,8 @@ namespace Avalonia
                 return hash;
             }
         }
+        
+        
 
         /// <summary>
         /// Returns a new <see cref="PixelPoint"/> with the same Y co-ordinate and the specified X co-ordinate.
diff --git a/src/Avalonia.Visuals/Media/PixelRect.cs b/src/Avalonia.Visuals/Media/PixelRect.cs
index 9c8e5ad1c4..75987681ff 100644
--- a/src/Avalonia.Visuals/Media/PixelRect.cs
+++ b/src/Avalonia.Visuals/Media/PixelRect.cs
@@ -261,6 +261,17 @@ namespace Avalonia
         {
             return (rect.X < Right) && (X < rect.Right) && (rect.Y < Bottom) && (Y < rect.Bottom);
         }
+        
+        /// <summary>
+        /// Translates the rectangle by an offset.
+        /// </summary>
+        /// <param name="offset">The offset.</param>
+        /// <returns>The translated rectangle.</returns>
+        public PixelRect Translate(PixelVector offset)
+        {
+            return new PixelRect(Position + offset, Size);
+        }
+
 
         /// <summary>
         /// Gets the union of two rectangles.
diff --git a/src/Avalonia.Visuals/Media/PixelVector.cs b/src/Avalonia.Visuals/Media/PixelVector.cs
new file mode 100644
index 0000000000..b959b462c2
--- /dev/null
+++ b/src/Avalonia.Visuals/Media/PixelVector.cs
@@ -0,0 +1,205 @@
+// Copyright (c) The Avalonia Project. All rights reserved.
+// Licensed under the MIT license. See licence.md file in the project root for full license information.
+
+using System;
+using System.Globalization;
+using Avalonia.Animation.Animators;
+using JetBrains.Annotations;
+
+namespace Avalonia
+{
+    /// <summary>
+    /// Defines a vector.
+    /// </summary>
+    public readonly struct PixelVector
+    {
+        /// <summary>
+        /// The X vector.
+        /// </summary>
+        private readonly int _x;
+
+        /// <summary>
+        /// The Y vector.
+        /// </summary>
+        private readonly int _y;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="PixelVector"/> structure.
+        /// </summary>
+        /// <param name="x">The X vector.</param>
+        /// <param name="y">The Y vector.</param>
+        public PixelVector(int x, int y)
+        {
+            _x = x;
+            _y = y;
+        }
+
+        /// <summary>
+        /// Gets the X vector.
+        /// </summary>
+        public int X => _x;
+
+        /// <summary>
+        /// Gets the Y vector.
+        /// </summary>
+        public int Y => _y;
+
+        /// <summary>
+        /// Converts the <see cref="PixelVector"/> to a <see cref="PixelPoint"/>.
+        /// </summary>
+        /// <param name="a">The vector.</param>
+        public static explicit operator PixelPoint(PixelVector a)
+        {
+            return new PixelPoint(a._x, a._y);
+        }
+
+        /// <summary>
+        /// Calculates the dot product of two vectors
+        /// </summary>
+        /// <param name="a">First vector</param>
+        /// <param name="b">Second vector</param>
+        /// <returns>The dot product</returns>
+        public static int operator *(PixelVector a, PixelVector b)
+        {
+            return a.X * b.X + a.Y * b.Y;
+        }
+
+        /// <summary>
+        /// Scales a vector.
+        /// </summary>
+        /// <param name="vector">The vector</param>
+        /// <param name="scale">The scaling factor.</param>
+        /// <returns>The scaled vector.</returns>
+        public static PixelVector operator *(PixelVector vector, int scale)
+        {
+            return new PixelVector(vector._x * scale, vector._y * scale);
+        }
+
+        /// <summary>
+        /// Scales a vector.
+        /// </summary>
+        /// <param name="vector">The vector</param>
+        /// <param name="scale">The divisor.</param>
+        /// <returns>The scaled vector.</returns>
+        public static PixelVector operator /(PixelVector vector, int scale)
+        {
+            return new PixelVector(vector._x / scale, vector._y / scale);
+        }
+
+        /// <summary>
+        /// Length of the vector
+        /// </summary>
+        public double Length => Math.Sqrt(X * X + Y * Y);
+
+        /// <summary>
+        /// Negates a vector.
+        /// </summary>
+        /// <param name="a">The vector.</param>
+        /// <returns>The negated vector.</returns>
+        public static PixelVector operator -(PixelVector a)
+        {
+            return new PixelVector(-a._x, -a._y);
+        }
+
+        /// <summary>
+        /// Adds two vectors.
+        /// </summary>
+        /// <param name="a">The first vector.</param>
+        /// <param name="b">The second vector.</param>
+        /// <returns>A vector that is the result of the addition.</returns>
+        public static PixelVector operator +(PixelVector a, PixelVector b)
+        {
+            return new PixelVector(a._x + b._x, a._y + b._y);
+        }
+
+        /// <summary>
+        /// Subtracts two vectors.
+        /// </summary>
+        /// <param name="a">The first vector.</param>
+        /// <param name="b">The second vector.</param>
+        /// <returns>A vector that is the result of the subtraction.</returns>
+        public static PixelVector operator -(PixelVector a, PixelVector b)
+        {
+            return new PixelVector(a._x - b._x, a._y - b._y);
+        }
+
+        /// <summary>
+        /// Check if two vectors are equal (bitwise).
+        /// </summary>
+        /// <param name="other"></param>
+        /// <returns></returns>
+        public bool Equals(PixelVector other)
+        {
+            // ReSharper disable CompareOfFloatsByEqualityOperator
+            return _x == other._x && _y == other._y;
+            // ReSharper restore CompareOfFloatsByEqualityOperator
+        }
+
+        /// <summary>
+        /// Check if two vectors are nearly equal (numerically).
+        /// </summary>
+        /// <param name="other">The other vector.</param>
+        /// <returns>True if vectors are nearly equal.</returns>
+        [Pure]
+        public bool NearlyEquals(PixelVector other)
+        {
+            const float tolerance = float.Epsilon;
+
+            return Math.Abs(_x - other._x) < tolerance && Math.Abs(_y - other._y) < tolerance;
+        }
+
+        public override bool Equals(object obj)
+        {
+            if (ReferenceEquals(null, obj)) return false;
+
+            return obj is PixelVector vector && Equals(vector);
+        }
+
+        public override int GetHashCode()
+        {
+            unchecked
+            {
+                return (_x.GetHashCode() * 397) ^ _y.GetHashCode();
+            }
+        }
+
+        public static bool operator ==(PixelVector left, PixelVector right)
+        {
+            return left.Equals(right);
+        }
+
+        public static bool operator !=(PixelVector left, PixelVector right)
+        {
+            return !left.Equals(right);
+        }
+
+        /// <summary>
+        /// Returns the string representation of the point.
+        /// </summary>
+        /// <returns>The string representation of the point.</returns>
+        public override string ToString()
+        {
+            return string.Format(CultureInfo.InvariantCulture, "{0}, {1}", _x, _y);
+        }
+
+        /// <summary>
+        /// Returns a new vector with the specified X coordinate.
+        /// </summary>
+        /// <param name="x">The X coordinate.</param>
+        /// <returns>The new vector.</returns>
+        public PixelVector WithX(int x)
+        {
+            return new PixelVector(x, _y);
+        }
+
+        /// <summary>
+        /// Returns a new vector with the specified Y coordinate.
+        /// </summary>
+        /// <param name="y">The Y coordinate.</param>
+        /// <returns>The new vector.</returns>
+        public PixelVector WithY(int y)
+        {
+            return new PixelVector(_x, y);
+        }
+    }
+}